FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
MULTIGROUP-MULTIPHASE ROTARY ELECTRICAL MACHINE CONTROL DEVICE AND
MULTIGROUP-MULTIPHASE ROTARY ELECTRICAL MACHINE DRIVE DEVICE
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI
2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION
AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
Description
Title of Invention: MULTIGROUP-MULTIPHASE ROTARY ELECTRICAL
MACHINE CONTROL DEVICE AND MULTIGROUP-MULTIPHASE ROTARY ELECTRICAL
MACHINE DRIVE DEVICE
5
Technical Field
[0001] The present invention relates to a multigroup,
multiphase rotary electric machine control device and a multigroup,
multiphase rotary electric machine drive device, which are to be
10 used in, for example, an electric power steering apparatus or an
elevator hoisting machine.
Background Art
[0002] There has been disclosed a control device configured
15 to control a multigroup, multiphase rotary electric machine through
use of a plurality of three-phase inverters (see, for example,
Patent Literature 1). Further, there has been disclosed a control
device configured to correct a current value of each phase in order
to reduce torque ripple that occurs in a rotary electric machine
20 including windings having axial eccentricity (see, for example,
Patent Literature 2).
Citation List
Patent Literature
25 [0003] [PTL 1] JP 2013-504293 A (p.4 and p.5, FIG. 12)
3
[PTL 2] JP 2009-296706 A (p.6 and p.7, FIG. 1)
Summary of Invention
Technical Problem
[0004] In general, along with a manufacturing 5 error of the
rotary electric machine, eccentricity or circularity deviation of
a stator or a rotor occurs. Because of this eccentricity or
circularity deviation, a gap between the stator and the rotor
changes during one rotation period. Therefore, there have been
10 problems in that a magnetic flux density varies during the one
rotation period, and thus vibration and noise are caused.
[0005] In the related-art method of controlling the rotary
electric machine, the magnetic flux density variation caused during
the one rotation period cannot be corrected, and occurrence of the
15 vibration and the noise cannot be suppressed.
[0006] The present invention has been made to solve the
above-mentioned problems, and has an object to correct magnetic
flux density variation caused during one rotation period even when
eccentricity or circularity deviation of a stator or a rotor occurs
20 along with a manufacturing error of a rotary electric machine. As
a result, occurrence of vibration and noise of the rotary electric
machine can be suppressed.
Solution to Problem
25 [0007] A multigroup, multiphase rotary electric machine
4
control device according to the present invention is a multigroup,
multiphase rotary electric machine control device, which is
configured to control a multigroup, multiphase rotary electric
machine including different groups of windings arranged at
positions in mechanical spatial phase differing 5 by 180/N (N is an
integer of 2 or more) degrees, the multigroup, multiphase rotary
electric machine control device including:
a control target calculation unit configured to calculate an
initial current command value of each phase based on a torque command
10 value;
a correction coefficient calculation unit configured to
calculate a per-group correction coefficient corresponding to each
group from a spatial mode M (M is 0 or a positive integer) of an
electromagnetic force caused by magnetic flux density variation
15 with respect to a rotational periodicity at the time of rotation
of the multigroup, multiphase rotary electric machine; and
a current command value correction unit configured to
calculate a current command value of the each phase, which is
corrected based on the initial current command value and the
20 per-group correction coefficient.
Advantageous Effects of Invention
[0008] According to the present invention, the multigroup,
multiphase rotary electric machine control device includes:
25 the correction coefficient calculation unit configured to
5
calculate the per-group correction coefficient corresponding to
each group from the spatial mode M (M is 0 or a positive integer)
of the electromagnetic force caused by the magnetic flux density
variation with respect to the rotational periodicity at the time
of rotation of the multigroup, multiphase rotary 5 electric machine;
and
the current command value correction unit configured to
calculate the current command value of the each phase, which is
corrected based on the initial current command value and the
10 per-group correction coefficient.
Therefore, even when eccentricity or circularity deviation
of the stator or the rotor occurs along with the manufacturing error
of the rotary electric machine, the magnetic flux density variation
caused during one rotation period can be corrected.
15
Brief Description of Drawings
[0009] FIG. 1 is a schematic sectional view for illustrating
a rotary electric machine in a first embodiment of the present
invention.
20 FIG. 2 is a schematic view for illustrating connection between
the rotary electric machine and an inverter in the first embodiment
of the present invention.
FIG. 3 is a schematic diagram for illustrating a rotary
electric machine control device according to the first embodiment
25 of the present invention.
6
FIG. 4 is a flow chart for illustrating a flow of processing
to be performed by the rotary electric machine control device
according to the first embodiment of the present invention.
FIG. 5 is a configuration diagram for illustrating a hardware
configuration of the rotary electric machine 5 control device
according to the first embodiment of the present invention.
FIG. 6 is a schematic sectional view for illustrating a rotary
electric machine in a second embodiment of the present invention.
FIG. 7 is a schematic sectional view for illustrating a rotary
10 electric machine in a third embodiment of the present invention.
FIG. 8 is a schematic sectional view for illustrating a rotary
electric machine in a fourth embodiment of the present invention.
FIG. 9 is a schematic sectional view for illustrating a rotary
electric machine in a fifth embodiment of the present invention.
15
Description of Embodiments
[0010] First Embodiment
FIG. 1 is a schematic sectional view for illustrating the
structure of a multigroup, multiphase rotary electric machine in
20 a first embodiment for embodying the present invention. In this
embodiment, description is given of a three-group three-phase
distributed-winding permanent-magnet synchronous rotary electric
machine illustrated in FIG. 1 as an example. In FIG. 1, a rotational
axis direction of the rotary electric machine is represented by
25 a "z axis", and directions perpendicular to the z axis are
7
represented by an "x axis" and a "y axis".
[0011] As illustrated in FIG. 1, a rotary electric machine 2
of this embodiment includes a rotor 201 and a stator 202. The rotor
201 includes a rotor core 203, permanent magnets 204, and a shaft
205. The rotor core 203 is formed by laminating 5 magnetic steel
sheets. The rotor core 203 has six V-shaped paired magnet slots
206 arranged at equal intervals in a circumferential direction.
The permanent magnets 204 are inserted into the magnet slots 206,
and one V shape forms one pole. The permanent magnets 204 are
10 arranged so that N poles and S poles are arranged alternately in
the circumferential direction. The shaft 205 is provided on a
radially inner side of the rotor core 203, and is press-fitted into
the rotor core 203.
[0012] The stator 202 includes thirty-six stator teeth 208
15 protruding in a radially inner direction from an annular stator
yoke 207, and a stator coil 210 inserted in stator slots 209 formed
between adjacent stator teeth 208 and arranged with a distributed
winding in which a coil is arranged for every six slots in the
circumferential direction.
20 [0013] The stator coil 210 includes, in association with the
three groups and the three phases, a U1 coil, a V1 coil, and a W1
coil, which correspond to the three phases of the first group, a
U2 coil, a V2 coil, and a W2 coil, which correspond to the three
phases of the second group, and a U3 coil, a V3 coil, and a W3 coil,
25 which correspond to the three phases of the third group.
8
[0014] In FIG. 1, the plus and minus signs of the stator coil
represent whether the direction of the current is upward or downward
in a direction perpendicular to the drawing sheet. The three-phase
coils of the first group are received in twelve stator slots 209
adjacent to each other in the circumferential 5 direction of the
thirty-six stator slots 209. Further, the three-phase coils of the
second group are received in twelve stator slots 209 adjacent to
the twelve stator slots 209 receiving the three-phase coils of the
first group, and the three-phase coils of the third group are
10 received in the remaining twelve stator slots 209 adjacent to each
other. As described above, the three-layer three-phase coils are
arranged so that the three groups are located at positions shifted
by 120 degrees with respect to a mechanical angle of 360 degrees
corresponding to one mechanical rotation.
15 [0015] FIG. 2 is a schematic view for illustrating connection
between the rotary electric machine 2 and an inverter 3 of this
embodiment. As illustrated in FIG. 2, the three-phase coils of the
three groups are connected to different three-phase inverters 301,
302, and 303, respectively. The three-phase coils of the three
20 groups are individually controlled by the three-phase inverters
301, 302, and 303, respectively.
[0016] Next, description is given of correction for
eccentricity or circularity deviation of the stator 202 or the rotor
201.
25 [0017] It is assumed that, as illustrated in FIG. 1, the stator
9
202 and the rotor 201 of the rotary electric machine 2 are mutually
eccentric, specifically, the stator 202 and the rotor 201 are
brought close to each other in the +x direction, and the stator
202 and the rotor 201 are separated away from each other in the
5 -x direction.
[0018] When current control of the related art is performed
under this state, currents are controlled to be equally supplied
to the three groups. As a result, in the +x direction, a gap
dimension is smaller than a reference value, and hence a gap magnetic
10 flux density is increased. On the other hand, in the -x direction,
the gap dimension is larger than the reference value, and hence
the gap magnetic flux density is decreased. In such a case, a
harmonic wave that increases and decreases once with respect to
one period in mechanical angle is superimposed on an electromagnetic
15 force that is proportional to the square of the gap magnetic flux
density. In this case, the reference value refers to a gap dimension
obtained when it is assumed that neither of eccentricity nor
circularity deviation of the stator 202 or the rotor 201 occurs
in the rotary electric machine.
20 [0019] In the six-pole thirty-six-slot rotary electric
machine illustrated in FIG. 1, one period in mechanical angle
corresponds to three periods in electric angle, and therefore
deformation of the electromagnetic force having the fundamental
wave (electric angle spatial first order) in the electric angle
25 corresponds to the spatial third order in the mechanical angle.
10
Therefore, in the six-pole thirty-six-slot rotary electric machine,
a deformation mode corresponding to the spatial third order is
generated as the lowest-order electromagnetic force excluding the
spatial zero order, and causes resonance at the lowest frequency.
Meanwhile, when eccentricity occurs as described 5 above, a harmonic
wave of the electromagnetic force that increases and decreases once
with respect to one period in mechanical angle is superimposed,
and the above-mentioned spatial third-order electromagnetic force
is modulated into spatial second order and spatial fourth order
10 to cause resonance. The eigenvalue of the spatial second order
(mode 2) is lower in resonant frequency than the eigenvalue of the
spatial third order. Further, in general, a resonant frequency
having a lower order is larger in transfer function at the time
of resonance, and hence problems are liable to occur as vibration
15 and noise.
[0020] FIG. 3 is a schematic diagram for illustrating a rotary
electric machine control device of this embodiment. A control
device 1 of this embodiment includes a control target calculation
unit 410 (see Step S1 of FIG. 4), a correction coefficient
20 calculation unit 411 to be described later, a current command value
correction unit 412 (see Step S3 of FIG. 4), a voltage conversion
unit 413 (see Step S4 of FIG. 4), and a PWM calculation unit 414
(see Step S5 of FIG. 4). The control target calculation unit 410
is configured to compute a per-phase current initial value 102 of
25 each group based on a torque command value 101 transmitted from
11
the outside. The current command value correction unit 412 is
configured to calculate a per-phase current command value 104 of
each group corrected through use of a correction coefficient 103,
based on the per-phase current initial value 102 of each group and
the correction coefficient 103 calculated 5 by the correction
coefficient calculation unit 411. The voltage conversion unit 413
is configured to convert the per-phase current command value 104
into a per-phase voltage command value 106 of each group, based
on the per-phase current command value 104 and an actually-supplied
10 current value 105 of each phase of each group. The PWM calculation
unit 414 is configured to compute a gate signal 107 to be output
to the inverter 3, based on the per-phase voltage command value
106. The per-phase current initial value 102 of each group
corresponds to a current command value of each phase of each group
15 in a case in which neither eccentricity nor circularity deviation
of the stator 202 or the rotor 201 occurs.
[0021] The inverter 3 includes the three-phase inverters 301,
302, and 303 illustrated in FIG. 2. The inverter 3 operates as a
power conversion unit. The inverter 3 causes a current to flow
20 through a winding of each phase of each group based on the gate
signal 107 output from the PWM calculation unit 414. The shaft 205
of the rotary electric machine 2 has a function of detecting a
rotational position thereof to transmit a detection value 109 of
the rotational position to the control target calculation unit 410.
25 Further, the rotary electric machine 2 has a function of detecting
12
variation of a magnetic flux density of each group to transmit a
detection value 108 of the variation to the correction coefficient
calculation unit 411. In this embodiment, the control device 1 and
the inverter 3 form a drive device for the rotary electric machine
5 2.
[0022] The correction coefficient calculation unit 411
calculates the correction coefficient based on a ratio between an
average value and the magnetic flux density of each group so that
the magnetic flux densities of the three groups are averaged (see
10 Step S2 of FIG. 4). In other words, the correction coefficient
calculation unit 411 calculates a per-group correction coefficient
corresponding to each group from a spatial mode M (M is 0 or a positive
integer) of an electromagnetic force caused by magnetic flux density
variation with respect to a rotational periodicity at the time of
15 rotation of the rotary electric machine. The spatial mode M
represents a state in which the magnetic flux density varies M times
in a sine-wave shape with respect to one mechanical rotation of
the rotary electric machine. Further, the magnetic flux density
is detected by, for example, a Hall sensor.
20 [0023] The current command value correction unit 412
multiplies the command value of each group by the correction
coefficient 103 to calculate the corrected per-phase current
command value of each group (see Step S3 of FIG. 4).
[0024] FIG. 4 is a flow chart for illustrating a flow of
25 processing to be performed by the rotary electric machine control
13
device of this embodiment.
[0025] As illustrated in FIG. 4, in the control device 1, in
Step S1, the control target calculation unit 410 receives the torque
command value 101 and the detection value 109 of the rotational
position of the rotary electric machine 2 to compute 5 the per-phase
current initial value 102 of each group based on the torque command
value 101 and the detection value 109 of the rotational position.
[0026] In Step S2, in parallel to the processing of Step S1,
the correction coefficient calculation unit 411 uses the detection
10 value 108 of the magnetic flux density, which is detected by the
Hall sensor, to obtain an average value of the detection values
108 of the magnetic flux densities of the three groups so that the
magnetic flux densities of the three groups are averaged, to thereby
calculate the correction coefficient 103 from the ratio between
15 the average value and the detection value 108 of the magnetic flux
density of each group.
[0027] In Step S3, the current command value correction unit
412 receives the per-phase current initial value 102 of each group
and the correction coefficient 103 of each group to multiply the
20 per-phase current initial value 102 of each group by the correction
coefficient 103 of each group, to thereby calculate the current
command value 104 of each group.
[0028] In Step S4, the voltage conversion unit 413 receives
the current command value 104 of each group and the detected current
25 value 105 of each group to calculate the per-phase voltage command
14
value 106 of each group based on the current command value 104 of
each group and the current value 105 of each group. As the
calculation method, for example, the voltage conversion unit 413
performs PI control until the difference between the current command
value 104 of each group and the current value 5 105 of each group
becomes 0 to calculate the per-phase voltage command value 106 of
each group.
[0029] In Step S5, the PWM calculation unit 414 computes the
gate signal 107 to be output to the inverter 3 based on the per-phase
10 voltage command value 106 of each group to control the operation
of the inverter 3.
[0030] FIG. 5 is a configuration diagram for illustrating a
hardware configuration of the control device 1. As described above,
the control device 1 and the inverter 3 form the drive device. The
15 drive device uses the rotary electric machine 2 to drive a load
(not shown) connected to the rotary electric machine 2. As
illustrated in FIG. 5, the control device 1 includes, as a hardware
configuration, a processor 501 and a storage device 502. Functions
of the control target calculation unit 410, the correction
20 coefficient calculation unit 411, the current command value
correction unit 412, the voltage conversion unit 413, and the PWM
calculation unit 414 illustrated in FIG. 3 are implemented by the
processor 501 reading out and executing a program stored in the
storage device 502.
25 [0031] The storage device 502 includes, although not shown,
15
a volatile storage device, for example, a random access memory,
and a non-volatile auxiliary storage device, for example, a flash
memory. In place of the non-volatile auxiliary storage device, a
hard disk or other auxiliary storage device may be included.
[0032] A program is input to the processor 5 501 from the
auxiliary storage device of the storage device 502 via the volatile
storage device. The processor 501 executes the program input from
the storage device 502. Further, the processor 501 outputs
computed results or other data to the volatile storage device of
10 the storage device 502, or outputs the data to the auxiliary storage
device via the volatile storage device to store the data.
[0033] The control target calculation unit 410, the correction
coefficient calculation unit 411, the current command value
correction unit 412, the voltage conversion unit 413, and the PWM
15 calculation unit 414 may be implemented by a system LSI or other
processing circuit.
[0034] In the control device 1 configured as described above,
a state in which a gap dimension has variation due to eccentricity
or circularity deviation of the stator 202 or the rotor 201 is
20 detected or estimated so as to suppress generation of a low-order
mode in the electromagnetic force along with the variation. In the
example illustrated in FIG. 1, correction is performed so that the
per-phase current command value of a group present on a side (+x
direction) on which the gap dimension is decreased due to
25 eccentricity is decreased, and so that the per-phase current command
16
value of a group present on a side (-x direction) on which the gap
dimension is increased is increased.
[0035] In the rotary electric machine controlled by the
control device 1 configured as described above, a low-order waveform
is not generated in the magnetic flux density distribution 5 of the
gap. Therefore, an electromagnetic force that causes low-order
deformation is not generated, and it is possible to prevent
occurrence of resonance at a low frequency or occurrence of
resonance having large response.
10 [0036] In this embodiment, the three-phase windings of the
three groups are arranged at every 120 degrees in mechanical angle,
and hence the variation in gap magnetic flux density can be detected
by three (eccentricity) vectors shifted by 120 degrees. Therefore,
an exciting force that deforms once with respect to one period in
15 mechanical angle and an exciting force that deforms twice with
respect to one period in mechanical angle can be suppressed. The
exciting force that deforms once is generated by eccentricity, and
the exciting force that deforms twice is generated by elliptical
deformation. Therefore, the control device 1 of this embodiment
20 can correct each of the eccentricity and the elliptical deformation.
Further, even when the eccentricity and the elliptical deformation
simultaneously occur, the eccentricity and the elliptical
deformation can be detected as superimposition, and hence both of
them can be simultaneously corrected.
25 [0037] Next, a method of detecting the magnetic flux density
17
variation for correction is described. As one detection method,
there is known a method of using a magneto-electric device
configured to detect magnetism to output electricity. Examples of
the magneto-electric device include a Hall sensor, a tunnel
magnetoresistive effect (TMR) element, a giant 5 magnetoresistive
(GMR) element, and a search coil.
[0038] For example, Hall sensors are arranged at equal
intervals of every 120 degrees in mechanical angle at center
positions of the three groups and on leading end portions (gap
10 surfaces) of the stator teeth 208 of the rotary electric machine
2. With this arrangement, the variation in gap magnetic flux
density can be detected, and hence the correction value is
calculated so as to reduce the variation based on the detected
magnetic flux densities. Specifically, a correction value for
15 decreasing the current command value is calculated for a group
positioned at a place corresponding to a sensor having a high
magnetic flux density, and a correction value for increasing the
current command value is calculated for a group positioned at a
place corresponding to a sensor having a low magnetic flux density.
20 Similar effects can be achieved even when other magneto-electric
devices are used. It is described that the sensors are arranged
for every 120 degrees, but three or more sensors may be used to
detect the variation with a smaller detection pitch.
[0039] Further, in place of the search coil, the stator coil
25 may be used for detection. In this case, the variation in gap
18
magnetic flux density can be detected without adding members
dedicated to detection.
[0040] In the above-mentioned correction method, detection of
the magnetic flux density variation may be continuously executed
during operation to correct the correction coefficient 5 as required,
or detection of the magnetic flux density variation may be executed
at the initial stage to calculate the correction coefficient and
then estimate the magnetic flux variation during operation through
use of the calculated value. Eccentricity and deviation from
10 circularity do not greatly change over time, and hence when the
correction coefficient calculated at the initial stage is used,
a calculation load of the control device can be reduced. Meanwhile,
when eccentricity caused by whirling greatly changes over time,
it is preferred to continuously detect the magnetic flux density
15 variation to correct the correction coefficient as required.
[0041] As another detection method, there is known a method
of detecting actual energization current variation of each group
with respect to the current command value to calculate the
correction coefficient. Otherwise, there is known a method of
20 detecting energization variation of each group of a no-load induced
voltage to calculate the correction coefficient.
[0042] The method of correcting the magnetic flux density
variation described in this embodiment is particularly effective
when the stator 202 or the rotor 201 is formed of a combination
25 of cores divided in the circumferential direction, and also when
19
the stator 202 or the rotor 201 is annularly formed by bending a
linearly punched-out core. Further, the method is particularly
effective also when a component in contact with the stator 202 or
the rotor 201, for example, a frame is formed by bending planar
components into an annular shape and then 5 assembling those
components with respect to the stator 202 or the rotor 201 by a
method such as shrink-fitting or press-fitting. The reason
therefor is because circularity deviation is liable to occur in
the stator and the rotor 201 formed by those methods.
10 [0043] In this embodiment, the eccentricity is detected from
three or more detection points, and hence an eccentricity amount
and an eccentricity direction can be calculated, that is, an
eccentricity vector can be calculated. The detection value 109 of
the rotational position can be corrected through use of this
15 eccentricity vector. The correction is performed through use of
a correspondence table of a correction value with respect to an
eccentricity vector, which is prepared in advance. This correction
may be applied only in initial correction, or may be continuously
applied.
20 [0044] In this manner, the detection error of the rotational
position due to eccentricity can be reduced, and thus vibration
and noise caused by an exciting force or torque pulsation due to
deviation from an ideal value of the current command value (current
command value in a case in which no eccentricity or circularity
25 deviation occurs) can be reduced.
20
[0045] In the control device of this embodiment, an exciting
force that deforms three times at equal intervals and equal
amplitudes with respect to one period in mechanical angle (triangle
deformation) cannot be corrected because the correction values in
the three groups become equal to each other. 5 However, when
eccentricity is superimposed thereto, correction is possible.
[0046] Further, in the control device of this embodiment, an
exciting force that deforms four times with respect to one period
in mechanical angle cannot be corrected accurately because the
10 degree of freedom for correction is insufficient.
[0047] Second Embodiment
FIG. 6 is a schematic sectional view for illustrating the
structure of a multigroup, multiphase rotary electric machine in
a second embodiment for embodying the present invention. In this
15 embodiment, description is given of a four-group three-phase
concentrated-winding permanent-magnet synchronous rotary electric
machine illustrated in FIG. 6 as an example.
[0048] As illustrated in FIG. 6, the rotary electric machine
2 of this embodiment is a four-group three-phase
20 concentrated-winding rotary electric machine having eight poles
and twelve slots. Phase coils of each group are arranged so as to
be wound around the stator teeth 208, and a U-phase coil, a V-phase
coil, and a W-phase coil are arranged in order. One period in
electric angle corresponds to 90 degrees in mechanical angle, and
25 windings of the first group, the second group, the third group,
21
and the fourth group are arranged in order for every one pole pair
and three slots.
[0049] In this embodiment, the rotary electric machine 2 is
connected to a control device similar to the control device
according to the first embodiment illustrated in 5 FIG. 3. However,
the inverter 3 includes four three-phase inverters respectively
corresponding to the four groups. Currents flowing through the
per-phase windings of the four groups are corrected by different
correction coefficients.
10 [0050] The control device configured as described above can
address and correct not only the eccentricity or the circularity
deviation of the stator or the rotor 201, but also triangle
deformation. As a result, occurrence of vibration and noise of the
rotary electric machine can be suppressed.
15 [0051] Third Embodiment
FIG. 7 is a schematic sectional view for illustrating the
structure of a multigroup, multiphase rotary electric machine in
a third embodiment for embodying the present invention. In this
embodiment, description is given of a two-group three-phase
20 distributed-winding permanent-magnet synchronous rotary electric
machine illustrated in FIG. 7 as an example.
[0052] As illustrated in FIG. 7, the rotary electric machine
2 of this embodiment is a two-group three-phase distributed-winding
rotary electric machine having eight poles and forty-eight slots.
25 The winding of the first group is wound in the circumferential
22
direction for four poles and twenty-four slots, and then the winding
of the second group is wound for other four poles and twenty-four
slots.
[0053] In this embodiment, the rotary electric machine 2 is
connected to a control device similar to 5 the control device
according to the first embodiment illustrated in FIG. 3. However,
the inverter 3 includes two three-phase inverters respectively
corresponding to the two groups. Currents flowing through the
per-phase windings of the two groups are corrected by different
10 correction coefficients.
[0054] In the control device configured as described above,
windings of different groups are always arranged at positions
mechanically opposing each other at 180 degrees. Therefore, when
eccentricity occurs, the direction in which the stator and the rotor
15 201 approach each other and the direction in which the stator and
the rotor 201 separate away from each other can be detected, and
thus the eccentricity can be corrected. As a result, occurrence
of vibration and noise of the rotary electric machine can be
suppressed.
20 [0055] However, in the rotary electric machine of this
embodiment, when the core has elliptical deformation, the stator
and the rotor 201 approach and separate away from each other in
the same way at positions opposing each other at 180 degrees, and
hence correction cannot be performed.
25 [0056] Fourth Embodiment
23
FIG. 8 is a schematic sectional view for illustrating the
structure of a multigroup, multiphase rotary electric machine in
a fourth embodiment for embodying the present invention. In this
embodiment, description is given of a two-group three-phase
distributed-winding permanent-magnet synchronous 5 rotary electric
machine illustrated in FIG. 8 as an example.
[0057] As illustrated in FIG. 8, the rotary electric machine
2 of this embodiment is a two-group three-phase distributed-winding
rotary electric machine having eight poles and forty-eight slots.
10 The winding of the first group is wound in the circumferential
direction for two poles and twelve slots. Then, the winding of the
second group is wound for other two poles and twelve slots, and
then the winding of the first group and the winding of the second
group are wound. In this manner, the windings of the first group
15 and the windings of the second group are alternately arranged two
times for every 90 degrees in mechanical angle.
[0058] In this embodiment, the rotary electric machine 2 is
connected to a control device similar to the control device
according to the first embodiment illustrated in FIG. 3. However,
20 the inverter 3 includes two three-phase inverters respectively
corresponding to the two groups. Currents flowing through the
per-phase windings of the two groups are corrected by different
correction coefficients.
[0059] In the control device configured as described above,
25 windings of different groups are always arranged at positions
24
mechanically opposing each other at 90 degrees. Therefore, when
elliptical deformation occurs, the approaching direction and the
separating direction (short-axis direction and long-axis
direction) can be detected, and thus the elliptical deformation
can be corrected. As a result, occurrence of vibration 5 and noise
of the rotary electric machine can be suppressed.
[0060] However, in the rotary electric machine of this
embodiment, windings of the same group are arranged at positions
opposing each other at 180 degrees. Therefore, eccentricity cannot
10 be corrected because the eccentricity is averaged in the windings
of the same group and the first group and the second group hardly
have a difference with respect to the eccentricity.
[0061] Fifth Embodiment
FIG. 9 is a schematic sectional view for illustrating the
15 structure of a multigroup, multiphase rotary electric machine in
a fifth embodiment for embodying the present invention. In this
embodiment, description is given of a two-group three-phase
concentrated-winding permanent-magnet synchronous rotary electric
machine illustrated in FIG. 9 as an example.
20 [0062] As illustrated in FIG. 9, the rotary electric machine
2 of this embodiment is a dual three-phase concentrated-winding
rotary electric machine having ten poles and twelve slots. The
windings of the first group and the windings of the second group
are alternately arranged for every tooth in the circumferential
25 direction with respect to the stator teeth 208.
25
[0063] In this embodiment, the rotary electric machine 2 is
connected to a control device similar to the control device
according to the first embodiment illustrated in FIG. 3. However,
the inverter 3 includes two three-phase inverters respectively
corresponding to the two groups. Currents flowing 5 through the
per-phase windings of the two groups are corrected by different
correction coefficients.
[0064] In the control device configured as described above,
windings of different groups are arranged at positions mechanically
10 opposing each other at 180 degrees, and hence occurrence of a
low-order electromagnetic force, which is caused by eccentricity,
can be suppressed. As a result, occurrence of vibration and noise
of the rotary electric machine can be suppressed.
15 Reference Signs List
[0065] 1 control device, 2 rotary electric machine, 3 inverter,
201 rotor, 202 stator, 203 rotor core, 204 permanent magnets, 205
shaft, 206 magnet slot, 207 stator yoke, 208 stator teeth, 209 stator
slot, 210 stator coil, 410 control target calculation unit, 411
20 correction coefficient calculation unit, 412 current command value
correction unit, 413 voltage conversion unit, 414 PWM calculation
unit.
26
We Claim :
[Claim 1] A multigroup, multiphase rotary electric machine control
device, which is configured to control a multigroup, multiphase
rotary electric machine including different groups of windings
arranged at positions in mechanical spatial phase 5 differing by 180/N
(N is an integer of 2 or more) degrees, the multigroup, multiphase
rotary electric machine control device comprising:
a control target calculation unit configured to calculate an
initial current command value of each phase based on a torque command
10 value;
a correction coefficient calculation unit configured to
calculate a per-group correction coefficient corresponding to each
group from a spatial mode M (M is 0 or a positive integer) of an
electromagnetic force caused by magnetic flux density variation
15 with respect to a rotational periodicity at the time of rotation
of the multigroup, multiphase rotary electric machine; and
a current command value correction unit configured to
calculate a current command value of the each phase, which is
corrected based on the initial current command value and the
20 per-group correction coefficient.
[Claim 2] The multigroup, multiphase rotary electric machine
control device according to claim 1, wherein the correction
coefficient calculation unit is configured to calculate the
25 per-group correction coefficient through use of a detection value
27
of magnetic flux variation of the each group of the multigroup,
multiphase rotary electric machine.
[Claim 3] The multigroup, multiphase rotary electric machine
control device according to claim 2, wherein the 5 detection value
of the magnetic flux variation of the each group of the multigroup,
multiphase rotary electric machine is detected at a plurality of
locations of a gap between a rotor and a stator of the multigroup,
multiphase rotary electric machine.
10
[Claim 4] The multigroup, multiphase rotary electric machine
control device according to claim 2, wherein the detection value
of the magnetic flux variation of the each group of the multigroup,
multiphase rotary electric machine is calculated from eccentricity
15 vectors detected at three or more locations of a gap between a rotor
and a stator of the multigroup, multiphase rotary electric machine.
[Claim 5] The multigroup, multiphase rotary electric machine
control device according to claim 2, wherein the detection value
20 of the magnetic flux variation of the each group of the multigroup,
multiphase rotary electric machine is calculated from variation
in no-load induced voltage through use of a stator coil of the
multigroup, multiphase rotary electric machine.
25 [Claim 6] The multigroup, multiphase rotary electric machine
28
control device according to claim 1, wherein the correction
coefficient calculation unit is configured to calculate the
per-group correction coefficient through use of an estimated value
of magnetic flux variation of the each group of the multigroup,
multiphase rotary 5 electric machine.
[Claim 7] The multigroup, multiphase rotary electric machine
control device according to any one of claims 1 to 6, wherein the
correction coefficient calculation unit is configured to calculate
10 an eccentricity vector from the magnetic flux variation of the each
group of the multigroup, multiphase rotary electric machine to
correct output of a rotational angle detector.
[Claim 8] The multigroup, multiphase rotary electric machine
15 control device according to any one of claims 1 to 7, wherein the
magnetic flux density variation with respect to the rotational
periodicity at the time of rotation of the multigroup, multiphase
rotary electric machine is caused by an eccentricity error of the
multigroup, multiphase rotary electric machine.
20
[Claim 9] The multigroup, multiphase rotary electric machine
control device according to any one of claims 1 to 7, wherein the
magnetic flux density variation with respect to the rotational
periodicity at the time of rotation of the multigroup, multiphase
25 rotary electric machine is caused by an elliptical deformation of
the multigroup, multiphase
[Claim 10] A multigroup, multiphase
device, comprising:
the multigroup, 5 multiphase
device of any one of claims 1 to
an inverter configured to receive a current command
correction value from the
machine control device
10 of the multigroup, multiphase
current command correction value