Title of the invention: Iron core excitation system in electrical equipment, iron core excitation method in electrical equipment, program and modulation operation setting device for inverter power supply
Technical field
[0001]
　The present invention relates to an iron core excitation system in an electric device, an iron core excitation method in an electric device, a program, and a modulation operation setting device for an inverter power supply.
　The present application claims priority based on Japanese Patent Application No. 2018-177724 filed in Japan on September 21, 2018, the contents of which are incorporated herein by reference.
Background technology
[0002]
　For example, an inverter power supply is used as a power supply device for driving a motor of a train, a hybrid vehicle, a home electric appliance, or the like. In addition, a reactor is used as a filter circuit for an inverter power supply. The inverter power supply is configured by using a switching circuit having a plurality of switching elements. When the switching element performs a switching operation or the like, the time waveform of the exciting current output from the inverter power supply becomes a waveform in which harmonics are superimposed on the fundamental wave. Therefore, there is a risk that the temperature of the electric device (iron core) may rise and the efficiency of the electric device may decrease.
[0003]
　Therefore, Patent Document 1 discloses a reactor iron core in which the ratio of the iron loss when excited by a waveform including a harmonic component to the iron loss when excited by a sine wave alone is less than 1.15.
　Further, Patent Document 2 describes a three-phase motor with a sinusoidal current by superimposing a current having the same amplitude and opposite phase as the harmonic component of the exciting current when the three-phase motor is driven by the PWM inverter on the exciting current. It is disclosed that the iron loss can be reduced by 1.05 times as much as when the motor is driven.
Prior art literature
Patent documents
[0004]
Patent Document 1: Japanese Patent Application Laid-Open No. 9-45534
Patent Document 2 : Japanese Patent Application Laid-Open No. 4995518
Outline of the invention
Problems to be solved by the invention
[0005]
　However, in the technique described in Patent Document 1, it is allowed that the iron loss when excited by a waveform containing a harmonic component is larger than the iron loss when excited by a sine wave alone. Further, in the method described in Patent Document 2, the iron loss increases as compared with the case where the three-phase motor is driven by the sinusoidal current.
[0006]
　The present invention has been made in view of the above problems, and an object of the present invention is to reduce iron loss of an iron core excited by using an inverter power supply.
Means to solve problems
[0007]
　The iron core excitation system in the electric device of the present invention includes an electric device having an iron core, an inverter power supply that outputs an excitation signal including a magnetic flux to the electric device to excite the iron core, and a modulation operation of the inverter power supply. The modulation operation setting device is an excitation system for an iron core in an electric device having a modulation operation setting device, wherein the modulation operation setting device is a minor loop of a hysteresis loop showing a relationship between a magnetic flux density of the iron core and a magnetic field strength. It has a function as a setting means for setting the modulation operation of the inverter power supply based on the relationship between the maximum value and the minimum value of the magnetic field strength, and the relationship between the maximum value and the minimum value of the magnetic field strength is the inverter power supply. The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics is adjusted to be smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. It is characterized by having a relationship.
[0008]
　The iron core excitation system in the electric device of the present invention includes an electric device having an iron core, an inverter power source that outputs an excitation signal including a magnetic flux to the electric device to excite the iron core, and a modulation operation of the inverter power source. A modulation operation setting device for setting the above, and a magnetic field strength in the case where the modulation operation setting device excites the iron core with an excitation signal including harmonics by the inverter power supply. A minor loop of a hysteresis loop with the magnetic flux density generated in the iron core, and a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. The modulation operation of the inverter power supply is set based on the relationship of the area of ​​the closed region created by the above, and the relationship is the iron loss of the iron core when the iron core is excited by an excitation signal including a magnetic flux by the inverter power supply. However, the relationship is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by the excitation signal excluding the harmonics.
[0009]
　The iron core excitation system in the electric device of the present invention includes an electric device having an iron core, an inverter power source that outputs an excitation signal including harmonics to excite the iron core to the electric device, and a modulation operation of the inverter power source. It is an excitation system of an iron core in an electric device having a modulation operation setting device for setting the above, and the modulation operation setting device is a magnetic field strength when the iron core is excited by an excitation signal including harmonics by the inverter power supply. A minor loop of a hysteresis loop with the magnetic flux density generated in the iron core, and a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. Based on the relationship of, the modulation operation of the inverter power supply is set, and the relationship is at least one of the regions where the magnetic flux density of the hysteresis loop increases when the iron core is excited by the excitation signal excluding the harmonics. At least one of a plurality of minor loops included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply excites the iron core with an excitation signal excluding the harmonics. The area of ​​the closed region formed by the portion located on the side where the magnetic field strength is smaller than that of the hysteresis loop and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonic is the harmonic. It is made up of a portion located on the side where the magnetic field strength is larger than the hysteresis loop when the iron core is excited by the excitation signal excluding the above, and a hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. When the iron loss of the iron core is larger than the area of ​​the closed region and the iron core is excited by an excitation signal including harmonics by the inverter power supply, and the iron core is excited by an excitation signal excluding the harmonics. The relationship is adjusted so as to be smaller than the iron loss of the iron core.
[0010]
　The iron core excitation system in the electric device of the present invention includes an electric device having an iron core, an inverter power source that outputs an excitation signal including harmonics to excite the iron core to the electric device, and a modulation operation of the inverter power source. It is an excitation system of an iron core in an electric device having a modulation operation setting device for setting the above, and the modulation operation setting device is a magnetic field strength when the iron core is excited by an excitation signal including harmonics by the inverter power supply. A minor loop of a hysteresis loop with the magnetic flux density generated in the iron core, and a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. Based on the relationship of, the modulation operation of the inverter power supply is set, and the relationship is at least one of the regions where the magnetic flux density of the hysteresis loop is reduced when the iron core is excited by the excitation signal excluding the harmonics. At least one of a plurality of minor loops included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply excites the iron core with an excitation signal excluding the harmonics. The area of ​​the closed region formed by the portion located on the side where the magnetic field strength is larger than that of the hysteresis loop and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonic is the harmonic. It is made up of a portion located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the above, and a hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. When the iron loss of the iron core is larger than the area of ​​the closed region and the iron core is excited by an excitation signal including harmonics by the inverter power supply, and the iron core is excited by an excitation signal excluding the harmonics. The relationship is adjusted so as to be smaller than the iron loss of the iron core.
[0011]
　The method for exciting an iron core in an electric device of the present invention is a method for exciting an iron core in an electric device related to an inverter power source that outputs an excitation signal including a harmonic to the electric device in order to excite the iron core of the electric device. The method of exciting the iron core in the electric device is based on the relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop showing the relationship between the magnetic flux density of the iron core and the magnetic field strength of the inverter power supply. It has a setting process for setting a modulation operation, and the relationship between the maximum value and the minimum value of the magnetic field strength is that the iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply. The relationship is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by the excitation signal excluding the harmonics.
[0012]
　The method for exciting an iron core in an electric device of the present invention is a method for exciting an iron core in an electric device related to an inverter power source that outputs an excitation signal including a harmonic to the electric device in order to excite the iron core of the electric device. The method of exciting the iron core in the electric device includes a minor loop of a hysteresis loop of a magnetic field strength when the iron core is excited by an excitation signal including harmonics by the inverter power supply and a magnetic flux density generated in the iron core, and the above-mentioned. Modulation operation of the inverter power supply based on the relationship of the area of ​​the closed region formed by the hysteresis loop between the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. The relationship is that the iron loss of the iron core when the iron core is excited by the excitation signal including the harmonics by the inverter power supply excites the iron core with the excitation signal excluding the harmonics. It is characterized in that the relationship is adjusted so as to be smaller than the iron loss of the iron core.
[0013]
　The method for exciting an iron core in an electric device of the present invention is a method for exciting an iron core in an electric device related to an inverter power supply that outputs an excitation signal including harmonics to the electric device in order to excite the iron core of the electric device. The method of exciting the iron core in the electric device includes a minor loop of a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal including harmonics by the inverter power supply and the magnetic flux density generated in the iron core, and the above-mentioned There is a setting step to set the modulation operation of the inverter power supply based on the relationship between the hysteresis loop of the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. However, the relationship is such that in at least a part of the region where the magnetic flux density of the hysteresis loop increases when the iron core is excited by the excitation signal excluding the harmonics, the excitation signal including the harmonics is generated by the inverter power supply. At least one of the plurality of minor loops included in the hysteresis loop when exciting the iron core is on the side where the magnetic field strength is smaller than that of the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. The area of ​​the closed region formed by the located portion and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics is the hysteresis when the iron core is excited by the excitation signal excluding the harmonics. It is larger than the area of ​​the closed region created by the portion located on the side where the magnetic field strength is larger than the loop and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and is increased by the inverter power supply. The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics is adjusted to be smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. It is characterized by having a relationship.
[0014]
　The method for exciting an iron core in an electric device of the present invention is a method for exciting an iron core in an electric device related to an inverter power source that outputs an excitation signal including harmonics to the electric device in order to excite the iron core of the electric device. The method of exciting the iron core in the electric device includes a minor loop of a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal including harmonics by the inverter power supply and the magnetic flux density generated in the iron core, and the above-mentioned There is a setting step to set the modulation operation of the inverter power supply based on the relationship between the hysteresis loop of the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. However, the relationship is that in at least a part of the region where the magnetic flux density of the hysteresis loop is reduced when the iron core is excited by the excitation signal excluding the harmonics, the excitation signal including the harmonics by the inverter power supply. At least one of the plurality of minor loops included in the hysteresis loop when exciting the iron core is on the side where the magnetic field strength is larger than that of the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. The area of ​​the closed region formed by the located portion and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics is the hysteresis when the iron core is excited by the excitation signal excluding the harmonics. It is larger than the area of ​​the closed region created by the portion located on the side where the magnetic field strength is smaller than the loop and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and is increased by the inverter power supply. The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics is adjusted to be smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. It is characterized by having a relationship.
[0015]
　The program of the present invention is characterized in that a computer functions as each means of an excitation system for an iron core in the electric device.
[0016]
　The inverter power supply modulation operation setting device of the present invention is an inverter power supply modulation operation setting device that outputs an excitation signal including a magnetic flux to the electric device in order to excite the iron core of the electric device, and modulates the inverter power supply. The operation setting device sets the modulation operation of the inverter power supply based on the relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop showing the relationship between the magnetic flux density of the iron core and the magnetic field strength. The relationship between the maximum value and the minimum value of the magnetic field strength is that the iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is the iron core of the excitation signal excluding the harmonics. The relationship is adjusted so as to be smaller than the iron loss of the iron core when the above-mentioned iron core is excited.
[0017]
　The inverter power supply modulation operation setting device of the present invention is an inverter power supply modulation operation setting device that outputs an excitation signal including a magnetic flux to the electric device in order to excite the iron core of the electric device, and modulates the inverter power supply. The operation setting device includes a minor loop of a hysteresis loop between the magnetic field strength when the iron core is excited by an excitation signal including harmonics by the inverter power supply and the magnetic flux density generated in the iron core, and excitation excluding the harmonics. Based on the relationship between the area of ​​the closed region formed by the hysteresis loop between the magnetic field strength when exciting the iron core with a signal and the magnetic flux density generated in the iron core, the modulation operation of the inverter power supply is set, and the relationship is described. Is that the iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is larger than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. It is characterized in that the relationship is adjusted so as to be small.
[0018]
　The inverter power supply modulation operation setting device of the present invention is an inverter power supply modulation operation setting device that outputs an excitation signal including harmonics to the electric device in order to excite the iron core of the electric device, and modulates the inverter power supply. The operation setting device includes a minor loop of a hysteresis loop between the magnetic field strength and the magnetic field density generated in the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply, and excitation excluding the harmonics. The modulation operation of the inverter power supply is set based on the relationship between the magnetic field strength when the iron core is excited by a signal and the hysteresis loop between the magnetic field strength generated in the iron core, and the relationship excludes the harmonics. In at least a part of the region where the magnetic field density of the hysteresis loop increases when the iron core is excited by the exciting signal, the hysteresis loop is included in the hysteresis loop when the iron core is excited by the exciting signal including harmonics by the inverter power supply. At least one of the plurality of minor loops is a portion located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the harmonics are excluded. The area of ​​the closed region created by the hysteresis loop when the iron core is excited by the excitation signal is located on the side where the magnetic field strength is larger than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. It becomes larger than the area of ​​the closed region formed by the portion to be magnetized and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the iron core is excited by the excitation signal including the harmonics by the inverter power supply. The iron loss of the iron core is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by the excitation signal excluding the harmonics.
[0019]
　The inverter power supply modulation operation setting device of the present invention is an inverter power supply modulation operation setting device that outputs an excitation signal including harmonics to the electric device in order to excite the iron core of the electric device, and modulates the inverter power supply. The operation setting device includes a minor loop of a hysteresis loop between the magnetic field strength and the magnetic field density generated in the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply, and excitation excluding the harmonics. The modulation operation of the inverter power supply is set based on the relationship between the magnetic field strength when the iron core is excited by a signal and the hysteresis loop between the magnetic field strength generated in the iron core, and the relationship excludes the harmonics. In at least a part of the region where the magnetic field density of the hysteresis loop is reduced when the iron core is excited by the exciting signal, the hysteresis loop is included in the hysteresis loop when the iron core is excited by the exciting signal including harmonics by the inverter power supply. At least one of the plurality of minor loops is a portion located on the side where the magnetic field strength is larger than that of the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the harmonics are excluded. The area of ​​the closed region created by the hysteresis loop when the iron core is excited by the excitation signal is located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. It becomes larger than the area of ​​the closed region formed by the portion to be magnetized and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the iron core is excited by the excitation signal including the harmonics by the inverter power supply. The iron loss of the iron core is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by the excitation signal excluding the harmonics.
Effect of the invention
[0020]
　According to the present invention, it is possible to reduce the iron loss of the iron core excited by using the inverter power supply.
A brief description of the drawing
[0021]
FIG. 1 is a diagram illustrating an example of operation of a PWM inverter.
FIG. 2 is a diagram showing a first example of a hysteresis loop of an iron core when excited by a sine wave and a hysteresis loop of an iron core when excited by a harmonic wave.
FIG. 3 is a diagram showing the two hysteresis loops shown in FIG. 2 superimposed.
FIG. 4 is a diagram showing a time waveform of magnetic flux density when the hysteresis loop shown in FIG. 2 is obtained.
FIG. 5 is a diagram showing a second example of a hysteresis loop of an iron core when excited by a sine wave and a hysteresis loop of an iron core when excited by a harmonic wave.
FIG. 6 is a diagram showing the two hysteresis loops shown in FIG. 5 superimposed.
FIG. 7 is an enlarged view of regions A (and I), B, and C in FIG.
FIG. 8 is an enlarged view showing a portion of regions D, E, and F in FIG.
9 is an enlarged view showing regions G and H in FIG. 6. FIG.
FIG. 10 is a diagram showing a time waveform of magnetic flux density when the hysteresis loop shown in FIG. 5 is obtained.
11 is a diagram showing a time change of an integrated value of a minute area HdB in the hysteresis loop shown in FIGS. 2, 5 to 9. FIG.
[Fig. 12] Fig. 12 is a diagram showing an example of the relationship between the relative magnetic permeability of a soft magnetic material plate (electrical steel sheet) constituting an iron core and the magnetic field strength.
[Fig. 13] Fig. 13 is a diagram showing an example of the relationship between the carrier frequency and the modulation rate and the iron loss ratio.
[Fig. 14] Fig. 14 is a diagram showing an example of a configuration of an iron core excitation system in an electric device.
[Fig. 15] Fig. 15 is a flowchart illustrating an example of operation of an iron core excitation system in an electric device.
Mode for carrying out the invention
[0022]
　Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the
　present embodiment, a case where the inverter power source for exciting the iron core of the electric device is controlled by the PWM (Pulse Width Modulation) method will be described as an example. Such an inverter will be referred to as a PWM inverter. Therefore, first, the outline of the PWM inverter will be described.
　FIG. 1 is a diagram illustrating an example of operation of the PWM inverter. FIG. 1 shows the time waveforms of the fundamental wave, the carrier wave (carrier wave), and the output voltage. In FIG. 1, the waveforms of the fundamental wave and the carrier wave are shown in the upper row, and the waveforms of the output voltage are shown in the lower row. Further, in FIG. 1, the amplitudes of the fundamental waves 101a and 101b are defined as E 0, and the amplitudes of the carrier waves 102 (and the output voltage 103) are defined as E c . The amplitude E 0 of the fundamental waves 101a and 101b corresponds to the peak value of the voltage applied to the electric device, and the amplitude E c of the carrier wave 102 corresponds to the peak value of the output voltage of the inverter.
[0023]
　As shown in FIG. 1, the output voltage 103 of the PWM inverter is a pulse signal whose value is E c or 0 (zero) depending on the magnitude relationship between the carrier wave 102 and the fundamental waves 101a and 101b . Here, the modulation factor m of the PWM inverter is represented by E 0 ÷ E c . The operation method of the PWM inverter is not limited to the method shown in FIG. 1, and other known methods such as a multi-level method can be used.
[0024]

　Next, the knowledge obtained by the present inventor will be described.
　The iron loss W [W / kg] of the iron core is obtained from the area surrounded by the hysteresis loop of the magnetic field strength H [A / m] and the magnetic flux density B [T] generated in the iron core. Specifically, the iron loss W of the iron core is obtained by the following equation (1).
[0025]
[Number 1]

[0026]
　Here, ρ is the density [kg / m 3 ], f is the excitation frequency [Hz], and V is the volume of the iron core [m 3 ].
　The present inventor has focused on the fact that iron loss can be reduced if the area of ​​the hysteresis loop can be reduced. In order to reduce the hysteresis loop, the magnetic field strength H may be reduced without changing the magnitude of the magnetic flux density B.
　First, the present inventor excites the same iron core with an excitation signal whose time waveform is a sine wave containing no harmonics, and when the time waveform is a waveform in which harmonics are superimposed on the sine wave. The respective hysteresis loops when excited by a signal were investigated. The results are shown in FIGS. 2 and 3. In the following description, a sine wave whose time waveform does not include harmonics is referred to as a sine wave as necessary, and a waveform in which harmonics are superimposed on the sine wave is referred to as a harmonic as necessary.
[0027]
　FIG. 2 is a diagram showing an example of a hysteresis loop of the iron core when excited by a sine wave (FIG. 2 (a)) and a hysteresis loop of the iron core when excited by a harmonic wave (FIG. 2 (b)). FIG. 3 is a diagram showing the hysteresis loop of the iron core when excited by the sine wave shown in FIG. 2 (a) and the hysteresis loop of the iron core when excited by the harmonic wave shown in FIG. 2 (b). is there. FIG. 3A shows the entire hysteresis loop, and FIG. 3B shows a part of FIG. 3A in an enlarged manner. The hysteresis loop of the iron core when excited by harmonics has a minor loop that vibrates in a short cycle as shown in FIG. 3 (b). Here, the minor loop in the hysteresis loop when excited by a harmonic wave starts from the intersection with the hysteresis loop when excited by a sine wave when the magnetic field strength H changes with time in the direction of increasing, and is next. Similarly, the range up to the point where it intersects with the hysteresis loop when excited by a sine wave when the magnetic field strength H changes with time in the increasing direction is defined as one minor loop. Therefore, on the scales shown in FIGS. 2 (b) and 3 (a), the vibrating lines (plurality of minor loops) appear to be filled because they are indistinguishably close to each other. Note that FIG. 2 (and FIG. 3) show the results of setting the modulation factor m of the PWM inverter to 0.2 and setting the carrier frequency (frequency of the carrier wave) to 100 [kHz].
[0028]
　That is, in the example shown in FIG. 3B, a part of the hysteresis loop HL when the iron core is excited by the excitation signal excluding the harmonics is shown by the “sine wave”, and the excitation signal including the harmonics is shown. A part of the hysteresis loop when exciting the iron core is shown by "harmonics (reference example)".
　The hysteresis loop when the iron core is excited by an excitation signal including harmonics includes a plurality of minor loops. One of the plurality of minor loops M included in FIG. 3B has a point M1 as a start point and a point M5 as an end point.
　The point M1 is the intersection with the hysteresis loop HL when the iron core is excited by the excitation signal excluding the harmonics when the magnetic field strength H is changing in the direction of increasing (rightward in FIG. is there.
　The maximum value of the magnetic field strength H in the minor loop M corresponds to the magnetic field strength H at the point M2 on the minor loop M.
　The point M3 on the minor loop M is a hysteresis when the iron core is excited by an excitation signal excluding harmonics when the magnetic field strength H is changing in the direction of decreasing (to the left in FIG. 3B). It is the intersection with the loop HL.
　The minimum value of the magnetic field strength H in the minor loop M corresponds to the magnetic field strength H at the point M4 on the minor loop M.
　As described above, the point M5 on the minor loop M corresponds to the end point of the minor loop M. Further, the point M5 corresponds to the start point of the minor loop adjacent to the minor loop M (the minor loop located above the minor loop M in FIG. 3B).
[0029]
　A minor loop as shown in FIG. 3B is generated in the hysteresis loop of the iron core when excited by harmonics. In the region shown in FIG. 3B, the absolute value | Hmax | of the maximum value Hmax of the magnetic field strength H in the minor loop exceeds the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in the minor loop (| Hmax). |> | Hmin |).
　The "maximum value Hmax of the magnetic field strength H in the minor loop" is the maximum value of the magnetic field strength H in one minor loop.
　The "minimum value Hmin of the magnetic field strength H in the minor loop" is the minimum value of the magnetic field strength H in one minor loop.
　In the examples shown in FIGS. 2 to 3, the iron loss of the iron core when excited by a sine wave and the iron loss of the iron core when excited by a harmonic wave are 10.84 [W / kg] and 17. It was 88 [W / kg].
[0030]
　FIG. 4 is a diagram showing a time waveform of the magnetic flux density B when the hysteresis loops shown in FIGS. 2 to 3 are obtained. The time on the horizontal axis of FIG. 4 is the time when the reference time is set to 0 (that is, the value on the horizontal axis of FIG. 4 is the same as the elapsed time from time 0). This also applies to FIGS. 10 and 11 described later.
　The waveform ratio of the time waveform 401 of the magnetic flux density B when excited by a sine wave and the waveform ratio of the time waveform 402 of the magnetic flux density B when excited by a harmonic are 1.1108 and 1.1155, respectively. Both were substantially the same as the waveform rate of the sine wave (= π / 2√2≈1.1107). Therefore, it is considered that the reason why the iron loss of the iron core when excited by harmonics is larger than the iron loss of the iron core when excited by a sine wave is due to the increase in the magnetic field strength H.
[0031]
　From the above, the present inventor can reduce the area of ​​the hysteresis loop and reduce the iron loss of the iron core by adjusting the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength H in the minor loop. I came up with the idea of ​​being able to do it.
　Therefore, in the region shown in FIG. 3B, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in at least a part of the minor loops is the absolute value | Hmax of the maximum value Hmax of the magnetic field strength H in the minor loops. The modulation factor m and the carrier frequency of the PWM inverter were adjusted so as to exceed | (| Hmax | <| Hmin |). The results are shown in FIGS. 5 to 9. 5 to 9 show an example in which the modulation factor m of the PWM inverter is 0.4 and the frequency of the carrier wave is 100 [kHz].
[0032]
　FIG. 5 is a diagram showing an example of a hysteresis loop of the iron core when excited by a sine wave (FIG. 5 (a)) and a hysteresis loop of the iron core when excited by a harmonic wave (FIG. 5 (b)). FIG. 6 is a diagram showing the hysteresis loop of the iron core when excited by the sine wave shown in FIG. 5 (a) and the hysteresis loop of the iron core when excited by the harmonic wave shown in FIG. 5 (b). is there. FIG. 6 shows the entire hysteresis loop. 7 to 9 are enlarged views of a part of FIG. Specifically, FIGS. 7 (a), 7 (b), 7 (c), 8 (a), 8 (b), 8 (c), 9 (a), 9 (b). Is an enlarged view showing regions A (and I), B, C, D, E, F, G, and H shown in FIG. 6, respectively.
[0033]
　The region shown in FIG. 3 (b) corresponds to the region (region C) shown in FIG. 7 (c). Of the three minor loops included in the region C shown in FIG. 7 (c), the third minor loop MA (M1 to M2 to M3 to M4 to M5) from the top and the second minor loop MB (M5 to M5) from the top. In M6 to M7 to M8 to M9), the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H could exceed the absolute value | Hmax | of the maximum value Hmax of the magnetic field strength H.
　Here, the minor loop adjusted so as to satisfy the relationship of | Hmin |> | Hmax | is referred to as the "first minor loop" of claim 2. In FIG. 7 (c), the third minor loop MA (M1 to M2 to M3 to M4 to M5) from the top and the second minor loop MB (M5 to M6 to M7 to M8 to M9) from the top are respectively. Corresponds to the "first minor loop" of claim 2.
　Further, in the region C shown in FIG. 7C (that is, the region where the magnetic field density of the hysteresis loop HL increases when the iron core is excited by the excitation signal excluding the harmonics), the excitation signal including the harmonics is generated by the inverter power supply. The third from the top of FIG. 7 (c) among the three minor loops included in the hysteresis loop (the hysteresis loop shown in "Hysteresis (Example)" in FIG. 7 (c)) in the case of exciting the iron core in With the starting point M1 (intersection with the hysteresis loop HL) of the minor loop MA (M1 to M2 to M3 to M4 to M5) as a reference point, the minimum value of the magnetic field strength H in the minor loop MA (that is, on the minor loop MA). The absolute value [Hmin] of the difference between the value of the magnetic field strength H at the point M4 and the value of the magnetic field strength H at the reference point M1 is the maximum value of the magnetic field strength H in the minor loop MA (that is, the point on the minor loop MA). The relationship between the value of the magnetic field strength H at M2) and the absolute value [Hmax] of the difference between the value of the magnetic field strength H at the reference point M1 is satisfied.
　Here, the minor loop adjusted so as to satisfy the relationship of [Hmin]> [Hmax] is referred to as the "third minor loop" of claim 5. Further, the reference point (starting point of the third minor loop) is set as the "first reference point" of claim 5. In FIG. 7 (c), the minor loop MA (M1 to M2 to M3 to M4 to M5) corresponds to the "third minor loop" of claim 5, and the point M1 corresponds to the minor loop MA of claim 5. Corresponds to the "first reference point".
[0034]
　Taking the starting point M5 (intersection with the hysteresis loop HL) of the second minor loop MB (M5 to M6 to M7 to M8 to M9) from the top in FIG. 7 (c) as a reference point, the magnetic field strength H in the minor loop MB The absolute value [Hmin] of the difference between the minimum value (that is, the value of the magnetic field strength H at the point M8 on the minor loop MB) and the value of the magnetic field strength H at the reference point M5 is the maximum of the magnetic field strength H in the minor loop MB. The relationship that exceeds the absolute value [Hmax] of the difference between the value (that is, the value of the magnetic field strength H at the point M6 on the minor loop MB) and the value of the magnetic field strength H at the reference point M5 is satisfied. The minor loop MB (M5 to M6 to M7 to M8 to M9) corresponds to the "third minor loop" of claim 5, and the point M5 corresponds to the "first reference point" of claim 5 corresponding to the minor loop MB. Equivalent to.
　There may be only one minor loop or a plurality of minor loops corresponding to the "third minor loop" in at least a part of the region where the magnetic flux density B of the hysteresis loop increases. Further, only one "first reference point" corresponding to one "third minor loop" is determined, and when there are a plurality of "third minor loops", each of the "third minor loops" is determined. There is a corresponding "first reference point". Therefore, even if there is only one reference point corresponding to the "first reference point" in at least a part of the region where the magnetic flux density B of the hysteresis loop increases, which corresponds to the number of "third minor loops". , There may be more than one. For example, in FIG. 7C, the point M1 corresponds to the minor loop MA (third minor loop) as the “first reference point”, and the point M1 corresponds to the minor loop MB (third minor loop) as the “first reference point”. Points M5 are determined respectively.
　Further, the relationship of | Hmin |> | Hmax | and [Hmin]> [Hmax] may be satisfied at the same time in one minor loop. In this case, the "first minor loop" and the "third minor loop" can be the same minor loop. For example, in the minor loop MA and the minor loop MB of FIG. 7C, the relationships of | Hmin |> | Hmax | and [Hmin]> [Hmax] are both satisfied.
[0035]
　Further, in the example shown in FIG. 7 (c), the following relationship is also satisfied.
　In region C shown in FIG. 7 (c), a hysteresis loop in the case where the iron core is excited by an excitation signal including harmonics by an inverter power supply (hysteresis loop shown in “harmonic (Example)” in FIG. 7 (c)). In the third minor loop MA from the top in FIG. 7 (c) among the three minor loops included in the above, the hysteresis loop HL in the case of exciting the iron core with a sine wave excitation signal not including harmonics (FIG. 7 (FIG. 7 (Fig. 7)). Closed regions M3 to M4 to M5 formed by the portion located on the side where the magnetic field strength is small (left side in FIG. 7 (c)) and the hysteresis loop HL with respect to the "hysteresis loop indicated by the" sine wave "in c). The area S1 of ~ M3 is hysteresis with a portion located on the side (right side of FIG. 7 (c)) where the magnetic field strength is larger than that of the hysteresis loop HL (hysteresis loop shown by “sine wave” in FIG. 7 (c)). It is larger than the area S2 of the closed regions M1 to M2 to M3 to M1 formed by the loop HL.
　Further, also in the second minor loop MB from the top of FIG. 7 (c) among the three minor loops included in the region C shown in FIG. 7 (c), the iron core is a sinusoidal excitation signal containing no harmonics. Hysteresis loop HL (hysteresis loop shown by "sine wave" in FIG. 7 (c)) when exciting, and the portion located on the side where the magnetic field strength is small (left side in FIG. 7 (c)) and the hysteresis loop The area S3 of the closed regions M7 to M8 to M9 to M7 formed by the HL has a larger magnetic field strength than the hysteresis loop HL (the hysteresis loop indicated by the “sine wave” in FIG. 7C) (FIG. 7). It is larger than the area S4 of the closed regions M5 to M6 to M7 to M5 formed by the portion located on the right side of (c) and the hysteresis loop HL.
[0036]
　Further, in the region D shown in FIG. 8A (that is, the region where the magnetic flux density of the hysteresis loop HL when the iron core is excited by the excitation signal excluding the harmonics), the excitation signal including the harmonics is generated by the inverter power supply. Of the plurality of minor loops included in the hysteresis loop (the hysteresis loop shown by "harmonic (Example)" in FIG. 8 (a)) in the case of exciting the iron core in FIG. 8 (a), for example, 2 from the bottom of FIG. 8 (a). When the start point M1 (intersection with the hysteresis loop HL) of the third minor loop MA (M1 to M2 to M3 to M4 to M5) is used as a reference point, the minimum value of the magnetic field strength H in the minor loop MA (that is, on the minor loop MA). The absolute value [Hmin] of the difference between the value of the magnetic field strength H at the point M4 and the value of the magnetic field strength H at the reference point M1 is the maximum value of the magnetic field strength H in the minor loop MA (that is, on the minor loop MA). The relationship between the value of the magnetic field strength H at the point M2) and the value of the magnetic field strength H at the reference point M1 exceeds the absolute value [Hmax]. Here, the minor loop MA (M1 to M2 to M3 to M4 to M5) corresponds to the "third minor loop" of claim 5, and the point M1 corresponds to the "first reference" of claim 5 corresponding to the minor loop MA. Corresponds to "point".
　Taking the starting point M5 (intersection with the hysteresis loop HL) of the third minor loop MB (M5 to M6 to M7 to M8 to M9) from the bottom of FIG. 8A as a reference point, the magnetic field strength H in the minor loop MB The absolute value [Hmin] of the difference between the minimum value (that is, the value of the magnetic field strength H at the point M8 on the minor loop MB) and the value of the magnetic field strength H at the reference point M5 is the maximum of the magnetic field strength H in the minor loop MB. It satisfies the relationship exceeding the absolute value [Hmax] of the difference between the value (that is, the value of the magnetic field strength H at the point M6 on the minor loop MB) and the value of the magnetic field strength H at the reference point M5. The minor loop MB (M5 to M6 to M7 to M8 to M9) corresponds to the "third minor loop" of claim 5, and the point M5 corresponds to the "first reference point" of claim 5 corresponding to the minor loop MB. Equivalent to.
[0037]
　In the examples shown in FIGS. 7 (c) and 8 (a), a plurality of minor loops corresponding to the "first minor loop" exist in the region where the magnetic flux density B of the hysteresis loop increases, but the "first minor loop" Even when there is only one minor loop corresponding to the above in the region where the magnetic flux density B of the hysteresis loop increases, the iron loss of the iron core can be reduced.
　In the examples shown in FIGS. 7 (c) and 8 (a), a plurality of minor loops corresponding to the "third minor loop" exist in the region where the magnetic flux density B of the hysteresis loop increases, and the "first reference point". There are a plurality of points corresponding to in the region where the magnetic flux density B of the hysteresis loop increases, but there is only one minor loop corresponding to the "third minor loop" in the region where the magnetic flux density B of the hysteresis loop increases. Even in this case, the iron loss of the iron core can be reduced. In this case, there is only one point corresponding to the "first reference point" in the region where the magnetic flux density B of the hysteresis loop increases.
[0038]
　Further, in the example shown in FIG. 8A, the following relationship is also satisfied.
　In the region D shown in FIG. 8A, a hysteresis loop in the case where the iron core is excited by an excitation signal including harmonics by an inverter power supply (hysteresis loop shown in “Hysteresis (Example)” in FIG. 8A). Of the plurality of minor loops included in, for example, in the second minor loop MA from the bottom in FIG. 8A, a hysteresis loop HL in the case of exciting the iron core with a sine wave excitation signal not including harmonics (FIG. 8). Closed regions M3 to M4 to be formed by the portion located on the side where the magnetic field strength is small (left side in FIG. 8A) and the hysteresis loop HL with respect to the "hysteresis loop indicated by the" sine wave "in (a)"). The area S1 of M5 to M3 is located on the side (right side of FIG. 8A) where the magnetic field strength is larger than that of the hysteresis loop HL (hysteresis loop shown by “sine wave” in FIG. 8A). It is larger than the area S2 of the closed regions M1 to M2 to M3 to M1 formed by the hysteresis loop HL.
　Further, also in the third minor loop MB from the bottom of FIG. 8 (a) among the plurality of minor loops included in the region D shown in FIG. 8 (a), the iron core is a sinusoidal excitation signal containing no harmonics. Hysteresis loop HL (hysteresis loop shown by "sine wave" in FIG. 8 (a)), and the portion located on the side where the magnetic field strength is small (left side in FIG. 8 (a)) and the hysteresis loop. The area S3 of the closed regions M7 to M8 to M9 to M7 formed by the HL has a larger magnetic field strength than the hysteresis loop HL (the hysteresis loop indicated by the “sine wave” in FIG. 8A) (FIG. 8). It is larger than the area S4 of the closed regions M5 to M6 to M7 to M5 formed by the portion located on the right side of (a) and the hysteresis loop HL.
[0039]
　In the examples shown in FIGS. 5 to 9 in which such adjustment is performed, the iron loss of the iron core when excited by a sine wave and the iron loss of the iron core when excited by a harmonic wave are 10.84 [W, respectively. / Kg], 5.47 [W / kg]. In this way, by adjusting the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength H in the minor loop, or by being included in the hysteresis loop shown by "harmonic (Example)" in FIG. 7 (c) or the like. The absolute value [Hmin] of the difference between the minimum value of the magnetic field strength H in the minor loop and the value of the magnetic field strength at the reference point M1 and the maximum value of the magnetic field strength H in the minor loop and the value of the magnetic field strength at the reference point M1. By adjusting the relationship with the absolute value [Hmax] of the difference, or among the minor loops included in the hysteresis loop shown in "Hysteresis (Example)" in FIG. 7 (c) and the like, FIG. 7 (c). ) Etc., by adjusting the relationship between the areas S1 and S3 of the part located inside the hysteresis loop indicated by "sine wave" and the areas S2 and S4 of the part located outside, the iron core when excited by harmonics. It can be seen that the iron loss of the iron core can be made smaller than the iron loss of the iron core when excited by a sine wave.
[0040]
　FIG. 10 is a diagram showing a time waveform of the magnetic flux density B when the hysteresis loops shown in FIGS. 5 to 9 are obtained. The times A to I shown in FIG. 10 correspond to the regions A to I shown in FIG. 6 respectively (for example, the changes in the magnetic flux density B and the magnetic field strength H in the vicinity of the time A shown in FIG. 10 are the regions shown in FIG. It becomes as shown in A (as shown in FIG. 7A)).
　The waveform ratio of the time waveform 1001 of the magnetic flux density B when excited by a sine wave and the waveform ratio of the time waveform 1002 of the magnetic flux density B when excited by a harmonic are 1.1108 and 1.1154, respectively. Is almost the same. Therefore, even if the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength H in the minor loop is adjusted, the magnetic field strength H is reduced without significantly changing the effective value (that is, magnetic energy) of the magnetic flux density in the iron core. It can be seen that the iron loss of the iron core can be reduced as compared with the case where the iron core is excited by a sine wave.
[0041]
　FIG. 11 is a diagram showing the time change of the integrated value of the minute area HdB in the hysteresis loop shown in FIGS. 2 and 5 to 9. The minute area HdB is the product of the value of the magnetic field strength H and the amount of change dB of the magnetic flux density B in a unit time. However, in FIG. 11, the integrated value of HdB is shown as a relative value when the value at time I (= 0.005 [s]) when the iron core is excited by a sine wave is 1.
　Specifically, in the region where the magnetic flux density B increases in the hysteresis loop (regions A, B, C, D, E in FIG. 6) (see the arrow line 501 in FIG. 5), the minute area HdB is on the horizontal axis (magnetic field). This is the area of ​​a strip-shaped region surrounded by the hysteresis loop and the vertical axis (axis of magnetic flux density B) in the region when the hysteresis loop is cut in parallel with the axis of intensity H). The amount of change dB of the magnetic flux density B in the unit time at this time is a positive value. Further, in the region where the magnetic flux density B decreases in the hysteresis loop (regions E, F, G, H, I in FIG. 6) (see the arrow line 502 in FIG. 5), the minute area HdB is the horizontal axis (magnetic field strength H). This is the area of ​​a strip-shaped region surrounded by the hysteresis loop and the vertical axis (the axis of the magnetic flux density B) in the region when the hysteresis loop is cut in parallel with the axis). The amount of change dB of the magnetic flux density B in the unit time at this time is a negative value.
[0042]
　Similar to FIG. 10, the times A to I shown in FIG. 11 correspond to the regions A to I shown in FIG. 6, respectively. By integrating the HdB from the time A to the time I, the integrated value of the minute region HdB for one round of the hysteresis loop can be obtained. Therefore, the iron loss value can be calculated from the integrated value of the minute region HdB at time I by using the density, frequency, and volume of the iron core based on the equation (1).
[0043]
　In FIG. 11, graph 1101 (sine wave) shows the integrated value of the minute region HdB when the iron core is excited by the sine wave. Graph 1102 (harmonics (reference example)) shows the integrated value of the minute region HdB when the iron core is excited by the harmonics in which the magnetic flux density B and the magnetic field strength H change like the hysteresis loop shown in FIGS. Shown. Graph 1103 (harmonics (examples)) shows the integrated value of the minute region HdB when the iron core is excited by the harmonics in which the magnetic flux density B and the magnetic field strength H change like the hysteresis loop shown in FIGS. 5 to 9. Shown.
[0044]
　As shown in Graphs 1101 and 1102, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in a part of the minor loop of the region C is the magnetic field strength H in the minor loop when the iron core is excited by a sine wave. When the value is lower than the absolute value of the maximum value Hmax | Hmax | (| Hmax |> | Hmin |) (as shown in FIG. 3B), the change in the magnetic flux density B with respect to the change in the magnetic field strength H The integrated value of the minute region HdB increases in regions other than the region where is small. On the other hand, as shown in Graph 1103, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in a part of the minor loop of the region C is the absolute value | Hmax of the maximum value Hmax of the magnetic field strength H in the minor loop. When the value exceeds Hmax | (| Hmax | <| Hmin |) (that is, as shown in FIG. 7C), the integrated value of the minute region HdB increases in the time zone centered around time C. It can be seen that it is reduced.
[0045]
　From the above, the following can be understood.
　In at least a part (part or all) of the region where the magnetic flux density B increases in the hysteresis loop, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in the minor loop is the maximum value of the magnetic field strength H in the minor loop. When the PWM inverter was operated so as to exceed the absolute value of Hmax | Hmax | (| Hmax | <| Hmin |) (that is, as in the example shown in FIG. 7C), the iron core was excited by a sine wave. The iron loss of the iron core can be reduced as compared with the case (in the following description, operating the PWM inverter in this way is referred to as a first operation as necessary). The first operation may be performed on one or more minor loops in at least a part of the region where the magnetic flux density B increases in the hysteresis loop, and the iron loss of the iron core can be reduced.
[0046]
　On the other hand, the relationship between the increase / decrease in the magnetic flux density B and the magnetic field strength H is only reversed between the region where the magnetic flux density B increases in the hysteresis loop and the region where the magnetic flux density B decreases in the hysteresis loop. For example, in the regions F, G, and H of FIG. 6 (the region where the magnetic flux density of the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics), the iron core is excited by the excitation signal including the harmonics. The starting point of the minor loop of the hysteresis loop is when the iron core is excited by an excitation signal excluding harmonics when the magnetic field strength H of the minor loop changes with time in the direction of decreasing (for example, to the left in FIG. 9). It is the intersection with the hysteresis loop. Therefore, what has been described with reference to FIGS. 5 to 11 is also applied in the region where the magnetic flux density B is reduced in the hysteresis loop. That is, in at least a part (part or all) of the region where the magnetic flux density B is reduced in the hysteresis loop, the maximum value Hmax of the magnetic field strength H in the minor loop (corresponding to the “second minor loop” of claim 3). If the PWM inverter is operated so that the absolute value | Hmax | of the absolute value | Hmax | exceeds the absolute value | Hmin | of the minimum value Hmin of the magnetic flux strength H in the minor loop (| Hmin | <| Hmax |), the iron core is a sine wave. The iron loss of the iron core can be reduced as compared with the case of exciting the above (in the following description, operating the PWM inverter in this way is referred to as a second operation if necessary). There may be only one minor loop corresponding to the "second minor loop" or a plurality of minor loops in the region where the magnetic flux density B of the hysteresis loop is reduced.
　That is, in the examples shown in FIGS. 6 (regions F, G, H) and FIGS. 8 (c) to 9 (b), the second operation of the PWM inverter described above is not realized, but the second operation of the PWM inverter is realized. When the iron loss of the iron core is excited by the excitation signal including harmonics by the inverter power supply, and the iron core is excited by the excitation signal (sine wave excitation signal) excluding the harmonics. It can be made smaller than the iron loss of the iron core.
[0047]
　In the examples shown in FIGS. 6 (regions F, G, H) and 8 (c) to 9 (b), a plurality of elements included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by an inverter power supply. The absolute value [Hmax] of the difference between the maximum value of the magnetic field strength H in each of the minor loops and the value of the magnetic field strength H at the reference point (the starting point of the minor loop) is the minimum value of the magnetic field strength H in the minor loop M. , The relationship exceeding the absolute value [Hmin] of the difference from the value of the magnetic field strength H at the reference point (the starting point of the minor loop) is not satisfied.
　The maximum value of the magnetic field strength H in each of the plurality of minor loops (corresponding to the "fourth minor loop" of claim 6) included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply. The absolute value [Hmax] of the difference between the value of the magnetic field strength H and the value of the magnetic field strength H at the reference point (the starting point of the minor loop) (corresponding to the “second reference point” of claim 6) is the magnetic field strength in the minor loop M. The inverter can also be satisfied by satisfying the relationship that exceeds the absolute value [Hmin] of the difference between the minimum value of H and the value of the magnetic field strength H at the reference point (the starting point of the minor loop) ([Hmin] <[Hmax]). The iron loss of the iron core when the iron core is excited by the excitation signal including harmonics by the power supply should be smaller than the iron loss of the iron core when the iron core is excited by the excitation signal (sinusoidal excitation signal) excluding the harmonics. Can be done.
　There may be only one minor loop or a plurality of minor loops corresponding to the "fourth minor loop" in at least a part of the region where the magnetic flux density B of the hysteresis loop is reduced. Further, only one "second reference point" corresponding to one "fourth minor loop" is determined, and when there are a plurality of "fourth minor loops", each "fourth minor loop" is used. There is a corresponding "second reference point". Therefore, even if there is only one reference point corresponding to the "second reference point" in at least a part of the region where the magnetic flux density B of the hysteresis loop is reduced, which corresponds to the number of "fourth minor loops". , There may be more than one. Further, the relations of | Hmin | << Hmax | and [Hmin] <[Hmax] may be satisfied at the same time in one minor loop. In this case, the "second minor loop" and the "fourth minor loop" can be the same minor loop.
[0048]
　Further, in the examples shown in FIGS. 6 (regions F, G, H) and FIGS. 8 (c) to 9 (b) (examples in which the magnetic flux density of the hysteresis loop decreases), they are shown by "harmonics (examples)". Among the minor loops included in the hysteresis loop, it is located inside the hysteresis loop shown by "sine wave" in FIGS. 8 (c) to 9 (b) (on the right side of FIGS. 8 (c) to 9 (b)). The area of ​​the portion (closed region) to be formed is not larger than the area of ​​the portion (closed region) located on the outside (left side of FIGS. 8 (c) to 9 (b)).
　In an example in which the magnetic flux density of the hysteresis loop is reduced, among the minor loops included in the hysteresis loop shown in "Harmonics (Example)", FIGS. 8 (c) to 9 (b) are shown by "sine waves". The area of ​​the portion (closed region) located inside the hysteresis loop (right side of FIGS. 8 (c) to 9 (b)) is located outside (left side of FIGS. 8 (c) to 9 (b)). Even if the area is made larger than the area of ​​the part (closed region), the iron loss of the iron core when the iron core is excited by the excitation signal including harmonics by the inverter power supply, and the excitation signal excluding the harmonics (sine wave excitation signal) It can be made smaller than the iron loss of the iron core when the iron core is excited by.
[0049]
　Here, in the hysteresis loop, in the region where the change in the magnetic flux density B is small with respect to the change in the magnetic field strength H (for example, the regions A, B, D, E, F, H, I shown in FIG. 6), the PWM inverter is used. Therefore, it is difficult to execute the first operation and the second operation (it is difficult to set | Hmax | <| Hmin | or | Hmin | <| Hmax |). Therefore, in the control of the PWM inverter as described above, the region where the absolute value of the magnetic field strength H is small and the change in the magnetic flux density B is large with respect to the change in the magnetic field strength H (for example, the regions C and G shown in FIG. 6), that is, It is preferable to carry out in a region having a large magnetic permeability.
　Specifically, when the iron core is excited by an excitation signal (that is, a sine wave excitation signal) excluding harmonics among a plurality of regions included in the hysteresis loop (for example, regions A to I shown in FIG. 6). Region C (region shown in FIG. 7 (c)) and region G (shown in FIG. 9 (a) in the example shown in FIG. 6) in which the absolute value of the magnetic field strength H of the iron core is 100 [A / m] or less. In the area)), it is preferable to perform the first operation or the second operation on the PWM inverter.
　Regions where the absolute value of the magnetic field strength H is 100 [A / m] or less (in the example shown in FIG. 6, region C (region shown in FIG. 7 (c)), region G (region shown in FIG. 9 (a))) It is preferable to realize either the first operation or the second operation in all of the above, but it is sufficient that either the first operation or the second operation is realized in only a part of the above. For example, in a part of the region where the magnetic flux density increases in the hysteresis loop, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in one or more minor loops is the maximum value Hmax of the magnetic field strength H in the minor loop. If there is a region that exceeds the absolute value | Hmax |, in some other parts, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in the minor loop is the absolute value of the maximum value Hmax of the magnetic field strength H in the minor loop. It does not have to exceed | Hmax |.
[0050]
　FIG. 12 is a diagram showing an example of the relationship between the relative magnetic permeability μ r and the magnetic field strength H of the soft magnetic material plate (electrical steel sheet) constituting the iron core . Here, the relative magnetic permeability μ r on the vertical axis is a relative value with the maximum value as 1. Further, the graphs for the soft magnetic material plates (electrical steel sheets) constituting the iron core used when obtaining the results shown in FIGS. 2 to 11 are shown.
[0051]
　Here, when an iron core having a large relative magnetic permeability μ r in a region where the magnetic field strength H is 100 [A / m] or less is used, the first operation and the second operation described above become easier. This will be described below.
　A large relative permeability corresponds to a small skin depth. A small skin depth means a large eddy current density. Since the eddy current is generated in a direction that hinders the change of the magnetic flux, the magnetic field strength H tends to change so as to hinder the flow of the exciting current (in the region where the magnetic flux density B increases in the hysteresis loop, the magnetic field strength H decreases. In the region where the magnetic flux density B is reduced in the hysteresis loop, the magnetic field strength H is likely to increase). Therefore, the first operation and the second operation are easier for the iron core having a large relative magnetic permeability μ r .
[0052]
　As described above, the first operation and the second operation are realized by, for example, changing the modulation factor m and the carrier frequency of the PWM inverter.
　FIG. 13 is a diagram showing an example of the relationship between the carrier frequency and the modulation factor m and the iron loss ratio. The iron loss ratio is obtained by dividing the iron loss of the iron core when excited by a sine wave waveform (PWM inverter) on which harmonics are superimposed by the iron loss of the iron core when excited by the sine wave that does not include the harmonics. Value. In the example shown in FIG. 13, when the modulation factor m is in the range of 0.4 or more and 1.0 or less and the carrier frequency is in the range of 50 [kHz] or more (100 [kHz] or less), the first The operation of is realized, and the iron loss of the iron core can be made smaller than the iron loss of the iron core when excited by a sine wave that does not include harmonics. Further, when the modulation factor m is 2.0 and the carrier frequency is in the range of 5 [kHz] or more and 15 [kHz] or less, the first operation is realized, and a sine wave containing no harmonics is used. The iron loss of the iron core can be made smaller than the iron loss of the iron core when excited. Further, when the modulation factor m is 2.0 and the carrier frequency is in the range of 20 [kHz] or more (100 [kHz] or less), the iron loss of the iron core is excited by a sine wave containing no harmonics. It is equivalent to the iron loss of the iron core in the case. On the other hand, when the modulation factor m and the carrier frequency are other than that, the first operation is not realized, and the iron loss of the iron core is made smaller than the iron loss of the iron core when excited by a sine wave containing no harmonics. Can't.
[0053]
　Therefore, for example, the first operation and the second operation can be realized as follows.
　First, prepare the same or equivalent electric equipment and PWM inverter as actually used. Then, the hysteresis loop and the iron loss of the iron core when the excitation signal is output from the PWM inverter to the electric device to excite the iron core of the electric device are measured by changing the modulation factor m and the carrier frequency. To do. Further, the iron loss of the iron core when the iron core of the electric device is excited by outputting the signal obtained by removing the harmonics from the excitation signal output from the PWM inverter to the electric device is measured. In addition, instead of these measurements, electromagnetic field analysis (numerical analysis) may be performed.
[0054]
　Then, the modulation factor m and the carrier frequency in which the first operation is realized are searched for. At this time, for example, it can be obtained by measuring or analyzing a hysteresis loop (including a minor loop), and it can be confirmed that the first operation is realized from the hysteresis loop. Similarly for the second operation, the modulation factor m and the carrier frequency at which the second operation is realized are searched for.
　Then, from the searched modulation factor m and carrier frequency, the iron loss of the iron core when the iron core is excited by the excitation signal from the PWM inverter excites the iron core with the signal obtained by removing the harmonics from the excitation signal. Select one that is less than the iron loss of the iron core in the case.
　Then, the information in which the region of the hysteresis loop that executes the first operation and the modulation factor m and the carrier frequency selected for the first operation are associated with each other is stored as the modulation information. Similarly, information in which the region of the hysteresis loop for performing the second operation and the modulation factor m and the carrier frequency selected for the second operation are associated with each other is stored as modulation information. In the modulation information, the region of the hysteresis loop that executes the first operation (second operation) is the region (the magnetic flux density B) that is assumed to be the region in which the magnetic flux density B increases (decreases) in the hysteresis loop. It is a region determined by the magnetic field strength H).
[0055]
　At this time, when the electric device is an electric device that does not perform steady operation (that is, the excitation condition is changed), the set of the modulation factor m and the carrier frequency selected for the first operation is as large as possible. It is preferable to memorize the set of. This is so that the modulation factor m and the carrier frequency that satisfy the operation command of the electric device can be selected as much as possible. This also applies to the modulation factor m and the carrier frequency selected for the second operation.
　For example, if the electric device is a motor, the operation command of the electric device includes a target value (target range) of the operating state of the motor. The target value (target range) of the operating state of the motor includes the target value (target range) of the rotation speed of the motor and the target value (target range) of the torque.
[0056]
　After that, when the iron core of the electric device is excited by using the PWM inverter, if the magnetic flux density B and the magnetic field strength H of the iron core of the electric device are within the region of the hysteresis loop for performing the first operation, the first operation is performed. Instructs the PWM inverter to operate at the modulation factor m and the carrier frequency stored in association with the region of the hysteresis loop for carrying out the operation of. Similarly, when the magnetic flux density B and the magnetic field strength H of the iron core of the electric device are within the region of the hysteresis loop that performs the second operation, they are stored in association with the region of the hysteresis loop that performs the second operation. Instruct the PWM inverter to operate at the set modulation factor m and carrier frequency.
[0057]

　FIG. 14 is a diagram showing an example of a configuration of an excitation system for an iron core in an electric device. In the following description, the exciting system of the iron core in the electric device will be abbreviated as the exciting system, if necessary.
　In FIG. 14, the excitation system includes an electrical device 1410, a PWM inverter 1420, and a modulation operation setting device 1430.
[0058]
　The electric device 1410 is not particularly limited as long as it is an electric device having an iron core. For example, as the electrical equipment 1410, a motor, a reactor, a transformer (transformer, current transformer, transformer) and the like can be used. The electrical equipment may be single-phase or three-phase. In a three-phase motor, in the case of distributed winding, a plurality of phases of coils are wound around one tooth of the stator core. Therefore, since the magnetic flux in the stator core becomes complicated, there is a possibility that the range of the modulation factor m and the carrier frequency that can reduce the iron loss of the iron core cannot be specified. Therefore, as for the three-phase motor, it is preferable to use the centralized winding three-phase motor as the electric device 1410.
[0059]
　The PWM inverter 1420 is a power source that excites the iron core of the electric device 1410. In the present embodiment, the PWM inverter 1420, the amplitude E of the carrier wave c shall the and the carrier frequency (modulation rate m of the PWM inverter) can be continuously changed.
[0060]
　An example of the function of the modulation operation setting device 1430 will be described below. The hardware of the modulation operation setting device 1430 is realized by using, for example, an information processing device including a CPU, ROM, RAM, HDD, and various interfaces, or a PLC (Programmable Logic Controller). The modulation operation setting device 1430 functions as a setting means for setting the modulation operation of the inverter power supply.
[0061]
　The modulation information storage unit 1431 stores the modulation information. The modulation information is information in which the region of the hysteresis loop that executes the first operation or the second operation and the parameters that determine the modulation operation are associated with each other. In this embodiment, the inverter power supply is controlled by the PWM method. Therefore, the parameters that determine the modulation operation include the modulation factor m and the carrier frequency as described in the section. The method of obtaining the modulation information is as described in the section . Here, in the hysteresis loop, when the iron core is excited in a region where the absolute value of the magnetic field strength H is 100 [A / m] or less (specifically, an excitation signal excluding harmonics (that is, a sine wave excitation signal)). The first operation and the second operation shall be performed in a region where the absolute value of the magnetic field strength H of the iron core is 100 [A / m] or less).
[0062]
　The hysteresis region determination unit 1432 determines whether or not the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 is stored in the modulation information storage unit 1431.
　Here, for the magnetic flux density B of the iron core of the electric device 1410, for example, a search coil for detecting the magnetic flux of the iron core of the electric device 1410 is arranged, and the electromotive force induced in the search coil is applied to Faraday's law of electromagnetic induction. Can be derived based on. Further, the magnetic field strength H of the iron core of the electric device 1410 can be derived from, for example, the exciting current flowing through the electric device 1410 based on Ampere's law. It is also possible to install an H coil in the electric device 1410 and measure the magnetic field strength H.
[0063]
　First, the hysteresis region determination unit 1432 has the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 in the region of the hysteresis loop that executes the first operation or the region of the hysteresis loop that executes the second operation. Determine if there is a current value for.
[0064]
　As a result of this determination, the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 are within the region of the hysteresis loop for performing the first operation or the region of the hysteresis loop for performing the second operation. If not, the hysteresis region determination unit 1432 determines that the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 is not stored in the modulation information storage unit 1431, and indicates that. The information is output to the PWM signal generation unit 1433.
[0065]
　On the other hand, when the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 are in the region of the hysteresis loop for performing the first operation or the region of the hysteresis loop for performing the second operation, In the hysteresis region determination unit 1432, the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 are either a hysteresis loop region for performing the first operation or a hysteresis loop region for performing the second operation. Judge whether it is within the range of.
[0066]
　Then, the hysteresis region determination unit 1432 performs the first operation when the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 are within the region of the hysteresis loop for performing the first operation. It is determined whether or not there is modulation information including the modulation factor m and the carrier frequency satisfying the operation command of the electric device 1410 in the modulation information including the region of the hysteresis loop.
[0067]
　As a result of this determination, if there is no modulation information including the modulation factor m and the carrier frequency satisfying the operation command of the electric device 1410 in the modulation information including the region of the hysteresis loop for executing the first operation, the hysteresis region determination unit The 1432 determines that the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 is not stored in the modulation information storage unit 1431, and outputs the information indicating that to the PWM signal generation unit. Output to 1433.
[0068]
　On the other hand, if there is modulation information including the modulation factor m and the carrier frequency satisfying the operation command of the electric device 1410 in the modulation information including the region of the hysteresis loop for executing the first operation, the hysteresis region determination unit 1432 may use the modulation information. It is determined that the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 is stored in the modulation information storage unit 1431. Then, the hysteresis region determination unit 1432 selects one of the modulation information including the modulation factor m and the carrier frequency satisfying the operation command of the electric device 1410, and the PWM signal generation unit 1433 selects the information for specifying the selected modulation information. Output to.
[0069]
　The modulation information can be selected according to a preset rule such as selecting the modulation information having the smallest modulation factor m.
　Further, when the electric device 1410 is an electric device that performs steady operation (that is, the excitation condition is not changed), the hysteresis region determination unit 1432 includes the modulation information including the region of the hysteresis loop that executes the first operation. , It is possible not to determine whether or not there is modulation information including the modulation factor m and the carrier frequency that satisfy the operation command of the electric device 1410. In this case, the hysteresis region determination unit 1432 selects one of the modulation information including the region of the hysteresis loop that executes the first operation, and outputs information for identifying the selected modulation information to the PWM signal generation unit 1433. To do.
[0070]
　Further, the hysteresis region determination unit 1432 also determines that the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 are within the region of the hysteresis loop for performing the second operation, the iron core of the electric device 1410. The information for specifying the modulation information or the modulation information is stored in the modulation information storage unit 1431 as in the case where the current values ​​of the magnetic flux density B and the magnetic field strength H of the above are within the region of the hysteresis loop for performing the first operation. Information indicating that it is not stored is output to the PWM signal generation unit 1433.
[0071]
　When the PWM signal generation unit 1433 outputs information that identifies the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 from the hysteresis region determination unit 1432, the PWM signal generation unit 1433 includes the modulation information. The parameters (modulation rate m and carrier frequency) that determine the modulation operation are read from the modulation information storage unit 1431. Then, the PWM signal generation unit 1433 generates a PWM signal including information necessary for generating a fundamental wave and a carrier wave, and outputs the PWM signal to the PWM inverter 1420. On the information, for example, the amplitude E of the carrier wave c may include the carrier frequency, frequency and the like of the fundamental wave, the parameters that can be modified when generating the fundamental wave and a carrier wave in PWM inverter 1420.
[0072]
　On the other hand, the PWM signal generation unit 1433 indicates that the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 is not stored in the modulation information storage unit 1431 by the hysteresis region determination unit 1432. When the indicated information is output, the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength H in the minor loop for reducing iron loss is adjusted as parameters (modulation rate m and carrier frequency) that determine the modulation operation. ) Is adopted. Then, the PWM signal generation unit 1433 generates a PWM signal including information necessary for generating a fundamental wave and a carrier wave based on the adopted value, and outputs the PWM signal to the PWM inverter 1420.
[0073]
　As the values ​​of the parameters that determine the modulation operation at this time, for example, the parameters (modulation rate m and carrier frequency) that determine the modulation operation when performing the first operation or the second operation can be used. Even if such a parameter is set, the first operation or the second operation cannot be performed in the region where the change in the magnetic flux density B becomes dull with respect to the change in the magnetic field strength H. That is, even if such a parameter is set, it does not contribute to the reduction of iron loss (adjustment of the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength H in the minor loop for the purpose).
[0074]
　However, as described in the section, operating the PWM inverter with parameters that determine the modulation operation when performing the first operation or the second operation is continued for one cycle of the hysteresis loop. Even if this is done, the iron loss of the iron core can be reduced as compared with the case where the iron core is excited by a sine wave on which harmonics are not superimposed (see graphs 1101 and 1103 in FIG. 11). Therefore, in this way, the loss of the iron core can be reduced more reliably. However, this is not always necessary, and parameters (modulation rate m and carrier frequency) that determine the modulation operation may be set so as to return to the operation in the existing PWM inverter.
[0075]
　The PWM inverter 1420 performs a PWM modulation operation based on the PWM signal output from the PWM signal generation unit 1433 as described above, and excites the iron core in the electric device 1410.
[0076]

　Next, an example of the operation of the drive system of the present embodiment will be described with reference to the flowchart of FIG.
　First, in step S1501, when the PWM signal generation unit 1433 is instructed to start the operation of the electric device 1410, the PWM signal generation unit 1433 outputs a PWM signal including information necessary for generating a fundamental wave and a carrier wave to the PWM inverter 1420. This instructs the start of operation of the electric device 1410. The parameters (modulation rate m and carrier frequency) that determine the modulation operation output at this time are not particularly limited. For example, the parameters (modulation rate m and carrier frequency) that determine the modulation operation output at this time can be set to predetermined values ​​as the values ​​at the start of operation.
[0077]
　Next, in step S1502, the hysteresis region determination unit 1432 acquires (derives) the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410.
　Next, in step S1503, the hysteresis region determination unit 1432 stores the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 acquired in step S1502 in the modulation information storage unit 1431. Judge whether or not. As a result of this determination, if the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 is stored in the modulation information storage unit 1431, the process proceeds to step S1504.
[0078]
　When the process proceeds to step S1504, the hysteresis region determination unit 1432 outputs information for specifying the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 to the PWM signal generation unit 1433. When the electric device 1410 is an electric device that does not perform steady operation (that is, the excitation condition is changed), modulation information including a modulation factor m and a carrier frequency that satisfy the operation command of the electric device 1410 is specified, and a PWM signal generator is specified. It is output to 1433.
[0079]
　Next, in step S1504, the PWM signal generation unit 1433 sets the parameters (modulation rate m and carrier frequency) that determine the modulation operation included in the modulation information specified by the information output in step S1504 to the modulation information storage unit 1431. Read from. Then, the PWM signal generation unit 1433 generates the fundamental wave and the carrier wave based on the parameters (modulation rate m and carrier frequency) that determine the read modulation operation and the information of the fundamental wave input from the outside. Generates a PWM signal containing the information required for.
[0080]
　Next, in step S1506, the PWM signal generation unit 1433 outputs the PWM signal to the PWM inverter 1420. The PWM inverter 1420 performs a PWM modulation operation based on the PWM signal to excite the iron core in the electric device 1410.
　Next, in step S1507, the modulation operation setting device 1430 determines whether or not to terminate the operation of the electric device 1410. This determination can be realized, for example, by whether or not the operator has performed an operation for terminating the operation of the electric device 1410 on the user interface of the modulation operation setting device 1430.
[0081]
　As a result of this determination, if the operation of the electric device 1410 is not terminated, the process returns to step S1502, and the excitation of the iron core in the electric device 1410 is continued. Then, in step S1507, when it is determined that the operation of the electric device 1410 is terminated, the process according to the flowchart of FIG. 15 is terminated.
[0082]
　In step S1503 described above, if it is determined that the modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410 acquired in step S1502 is not stored in the modulation information storage unit 1431, the process is processed. Goes to step S1508. When the process proceeds to step S1508, the hysteresis region determination unit 1432 outputs to the PWM signal generation unit 1433 information indicating that there is no modulation information corresponding to the current values ​​of the magnetic flux density B and the magnetic field strength H of the iron core of the electric device 1410. To do.
[0083]
　Next, in step S1509, the PWM signal generation unit 1433 sets the parameters (modulation rate m and carrier frequency) that determine the modulation operation to the maximum value Hmax and the minimum value of the magnetic field strength H in the minor loop for reducing iron loss. A value that does not contribute to (adjustment of the relationship with Hmin). Then, the PWM signal generation unit 1433 generates a PWM signal including information necessary for generating the fundamental wave and the carrier wave. Then, the process proceeds to step S1506 described above, and the PWM signal generation unit 1433 outputs the PWM signal to the PWM inverter 1420.
[0084]
As described
　above, in the present embodiment, the modulation operation setting device 1430 excites including harmonics by adjusting the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength in the minor loop of the hysteresis loop. The modulation operation of the PWM inverter 1420 is set so that the iron loss of the iron core is smaller than the iron loss of the iron core when the iron core of the electric device is excited by the signal obtained by removing the harmonics from the signal. Specifically, in the modulation operation setting device 1430, in a part of the region where the magnetic flux density B increases (decreases) in the hysteresis loop, the absolute value | Hmin | of the minimum value Hmin of the magnetic field strength H in some minor loops is set. , The PWM inverter 1420 is operated so as to exceed (fall below) the absolute value | Hmax | of the maximum value Hmax of the magnetic field strength H in the minor loop. Therefore, it is possible to reduce the iron loss of the iron core excited by using the inverter power supply.
[0085]

<< First Modification Example >> In the
　present embodiment, a case where both the first operation and the second operation are performed has been described as an example. However, only the first or second operation may be performed. In such a case, when the electric device is an electric device that performs steady operation (that is, the excitation condition is not changed), the hysteresis region determination unit 1432 is not always necessary. That is, when only the first operation is performed, the modulation factor m and the carrier frequency with respect to the first operation can be continuously selected. Similarly, when only the second operation is performed, the modulation factor m and the carrier frequency to be selected for the second operation can be continuously selected. In addition, in order to reduce iron loss more reliably, in addition to the modulation factor m and carrier frequency, other parameters that determine the modulation operation (carrier wave amplitude, fundamental wave amplitude, etc.) are also included to obtain modulation information. May be good.
[0086]
<< Second modification >> Further
　, the iron loss of the iron core should be smaller than the iron loss of the iron core when the excitation signal output from the PWM inverter 1420 is excited by a signal obtained by removing the harmonic component (that is,). If the relationship between the maximum value Hmax and the minimum value Hmin of the magnetic field strength H in the minor loop is adjusted without changing the maximum value of the magnetic flux density B), the first value is not necessarily the first. It is not necessary to perform the operation and the second operation. In FIG. 11, even if the integrated value of the minute region HdB does not decrease, the rate of increase of the integrated value of the minute region HdB (increase amount per unit time) is the integration of the minute region HdB when the iron core is excited by a sine wave. This is because if it is smaller than the value (graph 1101), the iron loss of the iron core can be reduced.
[0087]
<< Third modification >> In the
　present embodiment, a case where only reduction of iron loss of the iron core is considered is described as an example. For example, it may be necessary to suppress the heat generation of the iron core more than other parts, for example, it is necessary to suppress the operation as the electric device 1410 from being guaranteed due to the temperature rise due to the heat generation of the iron core. In such a case, the reduction of the iron loss of the iron core takes precedence over the reduction of the loss of other parts.
[0088]
　The main loss of the electric device 1410 is copper loss in addition to iron loss. Copper loss can be reduced by increasing the coil placement space in the electrical equipment 1410 to reduce the coil current density (increasing the cross-sectional area of ​​the coil) and reducing the DC resistance of the coil. Further, the main loss of the inverter power supply is the switching loss. The switching loss can be reduced, for example, by reducing the current flowing through each switching element by synchronizing and operating a plurality of inverter power supplies in parallel.
[0089]
　However, as a breakdown of the loss of the electric device 1410, the copper loss or the switching loss may occupy a larger proportion than the iron loss. In that case, the efficiency of the electrical equipment may not be improved even if the modulation operation is determined for the purpose of reducing only the iron loss. Therefore, modulation information (modulation operation is determined so that the iron loss of the iron core is smaller than the iron loss of the iron core when the iron core of the electric device is excited by a signal obtained by removing the harmonic from the excitation signal including the harmonics. Instead of finding the parameter), it is modulated so that the loss of the entire excitation system (the sum of the loss of the electrical equipment 1410 (mainly iron loss and copper loss) and the loss of the PWM inverter 1420 (mainly the switching loss)) is small. Information (parameters that determine the modulation operation) may be obtained.
[0090]
<< Fourth Modification Example >> In the
　present embodiment, a case where a PWM inverter is used as an inverter power source has been described as an example. However, the inverter power supply is not limited to the one having a PWM inverter. The parameters that determine the modulation operation of the inverter power supply (modulation rate m and carrier frequency in this embodiment) are determined based on the modulation method of the inverter power supply. For example, when a PAM (Pulse Amplitude Modulation) inverter is used, the ratio of the DC voltage supplied to the inverter unit to the output voltage to the motor is included in the parameters that determine the modulation operation.
[0091]
<< Other Modifications >>
　The embodiment of the present invention described above can be realized by executing a program by a computer. Further, a computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a non-volatile memory card, a ROM, or the like can be used.
　In addition, the embodiments of the present invention described above are merely examples of embodiment in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. It is a thing. That is, the present invention can be implemented in various forms without departing from the technical idea or its main features.
Code description
[0092]
　1410: Electrical equipment, 1420: PWM inverter, 1430: Modulation operation setting device, 1431: Modulation information storage unit, 1432: Hysteresis region determination unit, 1433: PWM signal generation unit
The scope of the claims
[Claim 1]
　An electric device having an iron core, an inverter power supply that outputs an excitation signal including a magnetic flux to the electric device to excite the iron core, and a modulation operation setting device that sets a modulation operation of the inverter power supply. The
　modulation operation setting device is based on the relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop showing the relationship between the magnetic flux density of the iron core and the magnetic field strength. Therefore, it has a function as a setting means for setting the modulation operation of the inverter power supply,
　and the relationship between the maximum value and the minimum value of the magnetic field strength is such that the iron core is excited by an excitation signal including harmonics by the inverter power supply. The inside of the electric device is characterized in that the iron loss of the iron core in the case is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by the excitation signal excluding the harmonics. Iron core excitation system.
[Claim 2]
　The setting means
　excites the iron core with an excitation signal including the harmonics in at least a part of a region where the magnetic flux density of the hysteresis loop increases when the iron core is excited by an excitation signal excluding the harmonics. As a relationship between the maximum value and the minimum value of the magnetic field strength in the first minor loop, which is a minor loop of any one of the hysteresis loops, the absolute value of the minimum value of the magnetic field strength is the first minor loop. The excitation system for an iron core in an electric device according to claim 1, wherein the modulation operation of the inverter power supply is set so that a relationship exceeding the absolute value of the maximum value of the magnetic field strength in the above can be obtained.
[Claim 3]
　The setting means
　excites the iron core with an excitation signal containing the harmonics in at least a part of a region where the magnetic flux density of the hysteresis loop is reduced when the iron core is excited with an excitation signal excluding the harmonics. As a relationship between the maximum value and the minimum value of the magnetic field strength in the second minor loop, which is a minor loop of any one of the hysteresis loops, the absolute value of the maximum value of the magnetic field strength is the second minor loop. The excitation system for an iron core in an electric device according to claim 1 or 2, wherein the modulation operation of the inverter power supply is set so that a relationship exceeding the absolute value of the minimum value of the magnetic field strength in the above can be obtained.
[Claim 4]
　In the setting means,
　when the iron core is excited by an excitation signal excluding the harmonics among a plurality of regions included in the hysteresis loop, the absolute value of the magnetic field strength of the iron core is 100 [A / m] or less. The electric device according to any one of claims 1 to 3, wherein the modulation operation of the inverter power supply is set so that the relationship between the maximum value and the minimum value of the magnetic field strength can be obtained in the above region. The excitation system of the iron core inside.
[Claim 5]
　The setting means
　excites the iron core with an excitation signal including the harmonics in at least a part of a region where the magnetic flux density of the hysteresis loop increases when the iron core is excited by an excitation signal excluding the harmonics. As a relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop in the
　case of the above, any one of the hysteresis loops in the case of exciting the iron core with an excitation signal including the harmonics. One of the intersections of
　the third minor loop , which is the above , and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics is set as the first reference point, and the minimum magnetic field strength in the third minor loop is set. The absolute value of the difference between the value and the value of the magnetic field strength at the first reference point is the absolute value of the difference between
　the maximum value of the magnetic field strength in the third minor loop and the value of the magnetic field strength at the first reference point. The iron core excitation system in an electric device according to claim 1, wherein the modulation operation of the inverter power supply is set so that a relationship exceeding the above can be obtained.
[Claim 6]
　The setting means
　excites the iron core with an excitation signal including the harmonics in at least a part of a region where the magnetic flux density of the hysteresis loop is reduced when the iron core is excited by an excitation signal excluding the harmonics. As a relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop in the
　case of the above, any one of the hysteresis loops in the case of exciting the iron core with an excitation signal including the harmonics. The second reference point is one of the intersections of
　the fourth minor loop , which is the above , and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the maximum magnetic field strength in the fourth minor loop is set. The absolute value of the difference between the value and the value of the magnetic field strength at the second reference point is the absolute value of the difference between
　the minimum value of the magnetic field strength in the fourth minor loop and the value of the magnetic field strength at the second reference point. The excitation system for an iron core in an electric device according to claim 1 or 5, wherein the modulation operation of the inverter power supply is set so as to obtain a relationship exceeding the above.
[Claim 7]
　An electric device having an iron core, an inverter power supply that outputs an excitation signal including a magnetic flux to the electric device to excite the iron core, and a modulation operation setting device that sets a modulation operation of the inverter power supply. In the excitation system of the iron core, the
　modulation operation setting device is a hysteresis loop of the magnetic field strength and the magnetic flux density generated in the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply. Based on the relationship between the minor loop of the above and the area of ​​the closed region formed by the hysteresis loop of the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics and the magnetic flux density generated in the iron core. The modulation operation of the inverter power supply is set, and the relationship is that the iron loss of the iron core when the iron core is excited by the excitation signal including the harmonics by the inverter power supply is the iron core by the excitation signal excluding the harmonics. An exciting system for an iron core in an electric device, characterized in that the relationship is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited.
[Claim 8]
　An electric device having an iron core, an inverter power supply that outputs an excitation signal including harmonics to excite the iron core to the electric device, and a modulation operation setting device that sets a modulation operation of the inverter power supply. In the excitation system of the iron core, the
　modulation operation setting device is a hysteresis loop of the magnetic field strength and the magnetic field density generated in the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply. Based on the relationship between the minor loop of the above and the hysteresis loop of the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics and the magnetic field density generated in the iron core, the modulation operation of the inverter power supply is performed. The
　relationship is set to the
　excitation signal including the harmonics by the inverter power supply in at least a part of the region where the magnetic field density of the hysteresis loop increases when the iron core is excited by the excitation signal excluding the harmonics. At least one of the plurality of minor loops included in the hysteresis loop when exciting the iron core is on the side where the magnetic field strength is smaller than that of the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. The area of ​​the closed region formed by the portion located at and the hysteresis loop in the case of exciting the iron core with the excitation signal excluding the harmonics is the case where the iron core is excited by the excitation signal excluding the harmonics. It is larger than the area of ​​the closed region created by the portion located on the side where the magnetic field strength is larger than the hysteresis loop and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics.
　The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. An exciting system of iron cores in electrical equipment, characterized by a coordinated relationship.
[Claim 9]
　An electric device having an iron core, an inverter power supply that outputs an excitation signal including harmonics to excite the iron core to the electric device, and a modulation operation setting device that sets a modulation operation of the inverter power supply. In the excitation system of the iron core, the
　modulation operation setting device is a hysteresis loop of the magnetic field strength and the magnetic field density generated in the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply. Based on the relationship between the minor loop of the above and the hysteresis loop of the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics and the magnetic field density generated in the iron core, the modulation operation of the inverter power supply is performed. The
　relationship is set to the
　excitation signal including the harmonics by the inverter power supply in at least a part of the region where the magnetic field density of the hysteresis loop decreases when the iron core is excited by the excitation signal excluding the harmonics. At least one of the plurality of minor loops included in the hysteresis loop when exciting the iron core is on the side where the magnetic field strength is larger than that of the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. The area of ​​the closed region formed by the portion located at and the hysteresis loop in the case of exciting the iron core with the excitation signal excluding the harmonics is the case where the iron core is excited by the excitation signal excluding the harmonics. It is larger than the area of ​​the closed region created by the portion located on the side where the magnetic field strength is smaller than the hysteresis loop and the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics.
　The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. An exciting system of iron cores in electrical equipment, characterized by a coordinated relationship.
[Claim 10]
　In the modulation operation setting device,
　when the iron core is excited by an excitation signal excluding the harmonics among a plurality of regions included in the hysteresis loop, the absolute value of the magnetic field strength of the iron core is 100 [A / m]. The invention according to any one of claims 7 to 9, wherein the modulation operation of the inverter power supply is set so that the relationship between the maximum value and the minimum value of the magnetic field strength can be obtained in the following region. Excitation system for iron cores in electrical equipment.
[Claim 11]
　The inverter power supply has a PWM (Pulse Width Modulation) inverter, and the
　setting means or the modulation operation setting device sets the modulation operation of the inverter power supply by setting the modulation factor and the frequency of the carrier wave. The excitation system for an iron core in an electric device according to any one of claims 1 to 10.
[Claim 12]
　A method for exciting an iron core in an electric device relating to an inverter power supply that outputs an excitation signal including a harmonic to the electric device in order to excite the iron core of the electric device, the method for exciting the iron core in the
　electric device is the iron core. It has a setting step of setting the modulation operation of the inverter power supply based on the relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop showing the relationship between the magnetic flux density and the magnetic field strength of the
　magnetic field. The relationship between the maximum value and the minimum value of the strength is that the iron loss of the iron core when the iron core is excited by the excitation signal including the harmonics by the inverter power supply excites the iron core with the excitation signal excluding the harmonics. A method for exciting an iron core in an electric device, which is characterized in that the relationship is adjusted so as to be smaller than the iron loss of the iron core in the case of the above.
[Claim 13]
　A method for exciting an iron core in an electric device relating to an inverter power supply that outputs an excitation signal including a harmonic to the electric device in order to excite the iron core of the electric device, and a method for exciting the iron core in the
　electric device is the inverter. A minor loop of a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal including harmonics by a power source and the magnetic flux density generated in the iron core, and the iron core is excited by an excitation signal excluding the harmonics. Based on the relationship between the area of ​​the closed region formed by the hysteresis loop between the magnetic field strength and the magnetic flux density generated in the iron core in the case, the modulation operation of the inverter power supply is set, and the relationship is harmonic by the inverter power supply. The iron loss of the iron core when the iron core is excited by an excitation signal including a wave is adjusted to be smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. A method of exciting an iron core in an electrical device, which is characterized by having a relationship.
[Claim 14]
　A method for exciting an iron core in an electric device relating to an inverter power supply that outputs an excitation signal including a magnetic flux to the electric device in order to excite the iron core of the electric device, and a method for exciting the iron core in the
　electric device is the inverter. A minor loop of a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal including harmonics by a power source and the magnetic flux density generated in the iron core, and the iron core is excited by an excitation signal excluding the harmonics. It has a setting step of setting the modulation operation of the inverter power supply based on the relationship between the magnetic field strength and the magnetic flux density generated in the iron core in the case, and the relationship is
　the excitation excluding the harmonics.
　A plurality included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply in at least a part of the region where the magnetic flux density of the hysteresis loop increases when the iron core is excited by a signal. At least one of the minor loops is a portion located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the excitation signal excluding the harmonics. The area of ​​the closed region created by the hysteresis loop when exciting the iron core is located on the side where the magnetic field strength is larger than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. And, it becomes larger than the area of ​​the closed region formed by the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics.
　The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. A method of exciting an iron core in an electrical device, which is characterized in that the relationship is adjusted so as to.
[Claim 15]
　A method for exciting an iron core in an electric device relating to an inverter power supply that outputs an excitation signal including a magnetic flux to the electric device in order to excite the iron core of the
　electric device. A minor loop of a hysteresis loop of the magnetic field strength when the iron core is excited by an excitation signal including harmonics by a power source and the magnetic flux density generated in the iron core, and the iron core is excited by an excitation signal excluding the harmonics. It has a setting step of setting the modulation operation of the inverter power supply based on the relationship between the magnetic field strength and the magnetic flux density generated in the iron core in the case, and the relationship is
　the excitation excluding the harmonics.
　A plurality included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply in at least a part of the region where the magnetic flux density of the hysteresis loop is reduced when the iron core is excited by a signal. At least one of the minor loops is a portion located on the side where the magnetic field strength is larger than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the excitation signal excluding the harmonics. The area of ​​the closed region created by the hysteresis loop when exciting the iron core is located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. And, it becomes larger than the area of ​​the closed region formed by the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics.
　The iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. A method of exciting an iron core in an electrical device, which is characterized in that the relationship is adjusted so as to.
[Claim 16]
　A program characterized in that a computer functions as each means of an iron core excitation system in an electric device according to any one of claims 1 to 11.
[Claim 17]
　An inverter power supply modulation operation setting device that outputs an excitation signal including harmonics to the electric device to excite the iron core of the electric device. The
　inverter power supply modulation operation setting device is a magnetic field density and a magnetic field of the iron core. The modulation operation of the inverter power supply is set based on the relationship between the maximum value and the minimum value of the magnetic field strength in the minor loop of the hysteresis loop showing the relationship with the strength, and the relationship between the maximum value and the minimum value of the
　magnetic field strength is set. Is that the iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is larger than the iron loss of the iron core when the iron core is excited by an excitation signal excluding the harmonics. A modulation operation setting device for an inverter power supply, characterized in that the relationship is adjusted so as to be smaller.
[Claim 18]
　An inverter power supply modulation operation setting device that outputs an excitation signal including a harmonic to the electric device in order to excite the iron core of the electric device. The
　inverter power supply modulation operation setting device uses the inverter power supply to generate harmonics. A minor loop of a hysteresis loop of the magnetic field strength when the iron core is excited by the including excitation signal and the magnetic flux density generated in the iron core, and the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics. The modulation operation of the inverter power supply is set based on the relationship between the magnetic flux density generated in the iron core and the area of ​​the closed region formed by the hysteresis loop, and the relationship is the excitation signal including harmonics by the inverter power supply. The relationship is adjusted so that the iron loss of the iron core when the iron core is excited is smaller than the iron loss of the iron core when the iron core is excited by the excitation signal excluding the harmonics. A characteristic inverter power supply modulation operation setting device.
[Claim 19]
　An inverter power supply modulation operation setting device that outputs an excitation signal including harmonics to the electric device to excite the iron core of the electric device, and the inverter power supply modulation operation setting device generates
　harmonics by the inverter power supply. A minor loop of a hysteresis loop between the magnetic field strength when the iron core is excited by the including excitation signal and the magnetic flux density generated in the iron core, and the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics. The modulation operation of the inverter power supply is set based on the relationship between the magnetic flux density generated in the iron core and the hysteresis loop, and the relationship is
　the case where the iron core is excited by an excitation signal excluding the harmonics. At
　least one of a plurality of minor loops included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply in at least a part of the region where the magnetic flux density of the hysteresis loop increases . A portion located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and a hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. The area of ​​the closed region created by and is located on the side where the magnetic field strength is larger than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the excitation signal excluding the harmonics. The area of ​​the closed region created by the hysteresis loop when the iron core is excited is larger than the area of ​​the closed region, and
　the iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is the harmonic. An inverter power supply modulation operation setting device, characterized in that the relationship is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding waves.
[Claim 20]
　An inverter power supply modulation operation setting device that outputs an excitation signal including harmonics to the electric device to excite the iron core of the electric device, and the inverter power supply modulation operation setting device generates
　harmonics by the inverter power supply. A minor loop of a hysteresis loop between the magnetic field strength when the iron core is excited by the including excitation signal and the magnetic flux density generated in the iron core, and the magnetic field strength when the iron core is excited by the excitation signal excluding the harmonics. The modulation operation of the inverter power supply is set based on the relationship between the magnetic flux density generated in the iron core and the hysteresis loop, and the relationship is
　the case where the iron core is excited by an excitation signal excluding the harmonics. At
　least one of a plurality of minor loops included in the hysteresis loop when the iron core is excited by an excitation signal including harmonics by the inverter power supply in at least a part of the region where the magnetic flux density of the hysteresis loop decreases A portion located on the side where the magnetic field strength is larger than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and a hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics. The area of ​​the closed region created by and is located on the side where the magnetic field strength is smaller than the hysteresis loop when the iron core is excited by the excitation signal excluding the harmonics, and the excitation signal excluding the harmonics. The area of ​​the closed region created by the hysteresis loop when the iron core is excited is larger than the area of ​​the closed region, and
　the iron loss of the iron core when the iron core is excited by an excitation signal including harmonics by the inverter power supply is the harmonic. An inverter power supply modulation operation setting device, characterized in that the relationship is adjusted so as to be smaller than the iron loss of the iron core when the iron core is excited by an excitation signal excluding waves.