1 FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See section 10, Rule 13] CONTROL DEVICE FOR ROTATING ELECTRICAL MACHINE MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED 2 DESCRIPTION Field [0001] The present invention relates to a control device 5 for a rotating electrical machine, in particular, to a control device to control a rotating electrical machine, obtaining rotor position information without using a position sensor to detect the rotational position of a rotor. 10 Background [0002] Driving rotating electrical machines requires position information on rotors. To this end, a typical control device for a rotating electrical machine uses a 15 position sensor for acquiring a rotor position. Unfortunately, problems such as an increase in the size of the system, an increase in cost, and a decrease in environmental resistance arise because of the use of the position sensor. It is thus required that position 20 sensorless control for driving rotating electrical machines without using position sensors be applied to control devices for rotating electrical machines. [0003] Position sensorless control is roughly classified into two types of methods: one involves estimating the 25 rotor position using the saliency of the rotor, and the other involves estimating the rotor position using the interlinkage magnetic flux calculated from the induced voltage generated in the rotating electrical machine. The former is hereinafter referred to as the “saliency method”, 30 and the latter is hereinafter referred to as the “induced voltage and interlinkage magnetic flux method”. The saliency of the rotor is the magnetic anisotropy of the inductance of the rotor, i.e. the characteristic that the 3 inductance changes depending on the rotor position. In other words, the saliency method is a method that utilizes the angle dependence of inductance. [0004] The saliency method includes exciting information 5 on saliency by superimposing a position estimation voltage or a position estimation current on a rotating electrical machine, and estimating a rotor position on the basis of the excited information. In general, the saliency method is used in the low-speed region where the induced voltage 10 necessary for position estimation is not sufficiently obtained, and the induced voltage and interlinkage magnetic flux method is used in the high-speed region where the induced voltage is sufficiently obtained. For the conventional position sensorless control, one of the two 15 position sensorless control methods is switched to the other in correspondence to a torque speed region for position sensorless control suitable for the torque speed region. [0005] Against the above-mentioned technical background, 20 in recent years, there has been an increasing demand for higher output densities of rotating electrical machines, and rotating electrical machines emerge which are magnetically designed to actively utilize the magnetic saturation region. Such a magnetically designed rotating 25 electrical machine will be hereinafter referred to as a “high output density rotating electrical machine”. The emergence of high output density rotating electrical machines results in an expansion of the torque speed region. The torque speed region resulting from the emergence of 30 high output density rotating electrical machines will be hereinafter referred to as the “expanded torque speed region”. [0006] When the saliency method and the induced voltage 4 and interlinkage magnetic flux method are applied to a high output density rotating electrical machine, it is difficult to drive the machine over the entire range of the expanded torque speed region. In particular, in the low-speed 5 region and the low-speed high-torque region where the degree of magnetic saturation is large, correction processing on an estimated position based on the degree of magnetic saturation does not ensure sufficient position estimation accuracy, or causes the phenomenon of increased 10 position estimation error and unstable operation of the rotating electrical machine. [0007] To address this problem, Patent Literature 1 below discloses a method of estimating the rotor position using the anisotropy of magnetic saturation. This method 15 is called the “magnetic saturation method”. The magnetic saturation method includes superimposing a position estimation voltage on each of the d- and q-axes of the rotating coordinate system, and performing position estimation on the basis of the value obtained by 20 multiplying the d-axis amplitude and the q-axis amplitude of the position estimation current generated due to the superimposition of the position estimation voltage. [0008] Patent Literature 1 includes a saliency-based position estimator and a magnetic-saturation-based position 25 estimator. In Patent Literature 1, a position estimation error correlation amount Δθ1 is calculated using the saliency method, and a position estimation error correlation amount Δθ2 is calculated using the magnetic saturation method. Then, the rotor position in the low30 speed low-torque region is estimated using the position estimation error correlation amount Δθ1, and the rotor position in the low-speed high-torque region is estimated using the position estimation error correlation amount Δθ2. 5 Then, a weighted average of the contributions of the position estimation error correlation amount Δθ1 and the position estimation error correlation amount Δθ2 is calculated in accordance with the degree of magnetic 5 saturation, and the rotational position is estimated on the basis of the weighted average contribution. Citation List Patent Literature 10 [0009] Patent Literature 1: Japanese Patent No. 5145850 Summary Technical Problem [0010] However, Patent Literature 1 does not include a 15 position estimator for high-speed region driving, and hence, position sensorless control in the high-speed region is difficult to achieve with the technique of Patent Literature 1. [0011] It is conceivable that the magnetic saturation 20 method which is the technique of Patent Literature 1 may be combined with the saliency method and the induced voltage and interlinkage magnetic flux method described above. However, in the prior art including Patent Literature 1, sufficient consideration has not been given as to how to 25 switch between the three estimation methods of the saliency method, the induced voltage and interlinkage magnetic flux method, and the magnetic saturation method to output an estimated value, or how to combine the estimation methods to output a combined value. It is thus difficult for the 30 prior art including Patent Literature 1 to implement position sensorless control that covers the expanded torque speed region in respect of the control of high output density rotating electrical machines. 6 [0012] The present invention has been made in view of the above, and an object thereof is to obtain a control device for a rotating electrical machine capable of implementing position sensorless control that covers the 5 expanded torque speed region. Solution to Problem [0013] In order to solve the above-mentioned problems and achieve the object, the present invention a control 10 device for a rotating electrical machine, the control device being to drive and control a multi-phase rotating electrical machine, the control device comprising: a current detecting means to detect rotating electrical machine currents flowing through a rotating electrical 15 machine; a position estimating means to estimate a rotor position on a basis of the rotating electrical machine currents, the rotor position being a rotational position of a rotor of the rotating electrical machine; and a controller to calculate rotating electrical machine drive 20 voltage commands and a position estimation voltage command for each phase on the basis of the rotating electrical machine currents and an estimated rotor position that is an estimated value of the rotor position, the rotating electrical machine drive voltage commands being for driving 25 the rotating electrical machine, the position estimation voltage command for each phase being for estimating the rotor position. The position estimating means calculates a first estimated rotor position, a second estimated rotor position, and a third estimated rotor position. The 30 position estimating means outputs: the estimated rotor position obtained by selecting one of the first estimated rotor position, the second estimated rotor position, and the third estimated rotor position; or the estimated rotor 7 position obtained by combining at least two of the first estimated rotor position, the second estimated rotor position, and the third estimated rotor position. The first estimated rotor position is based on AC components of 5 position estimation current amplitudes that are amplitudes of position estimation currents generated by application of position estimation voltages based on the position estimation voltage commands, the second estimated rotor position is based on a DC component of the position 10 estimation current amplitudes, and the third estimated rotor position is based on the rotating electrical machine currents and an interlinkage magnetic flux calculated from an induced voltage generated due to saliency of the rotor. 15 Advantageous Effects of Invention [0014] The control device for a rotating electrical machine according to the present invention can achieve the effect of implementing position sensorless control that covers the expanded torque speed region. 20 Brief Description of Drawings [0015] FIG. 1 is a diagram illustrating an exemplary configuration of a control device for a rotating electrical machine according to a first embodiment. 25 FIG. 2 is a diagram illustrating position estimation voltage commands that are output from the position estimation voltage calculation unit illustrated in FIG. 1. FIG. 3 is a diagram illustrating a detailed exemplary configuration of the position estimator illustrated in FIG. 30 1. FIG. 4 is a first diagram for explaining the operation of the second estimated position calculator illustrated in FIG. 3. 8 FIG. 5 is a second diagram for explaining the operation of the second estimated position calculator illustrated in FIG. 3. FIG. 6 is a diagram illustrating a detailed exemplary 5 configuration of the third estimated position calculator illustrated in FIG. 3. FIG. 7 is a diagram illustrating an exemplary configuration of a control device for a rotating electrical machine according to a second embodiment. 10 FIG. 8 is a diagram illustrating a detailed exemplary configuration of the position estimator illustrated in FIG. 7. FIG. 9 is a diagram illustrating a detailed exemplary configuration of the first estimated position/speed 15 calculator illustrated in FIG. 8. FIG. 10 is a diagram illustrating a detailed exemplary configuration of the second estimated position/speed calculator illustrated in FIG. 8. FIG. 11 is a diagram illustrating a detailed exemplary 20 configuration of the third estimated position/speed calculator illustrated in FIG. 8. FIG. 12 is a diagram illustrating a detailed exemplary configuration of the estimated position switch illustrated in FIG. 8. 25 FIG. 13 is a diagram for explaining drive regions in the estimated position switch illustrated in FIGS. 8 and 12. FIG. 14 is a diagram illustrating an exemplary configuration of a control device for a rotating electrical machine according to a third embodiment. 30 FIG. 15 is a diagram illustrating a detailed exemplary configuration of the position estimator illustrated in FIG. 14. FIG. 16 is a diagram illustrating a detailed exemplary 9 configuration of the estimated position switch illustrated in FIG. 15. FIG. 17 is a diagram for explaining drive regions in the estimated position switch illustrated in FIGS. 15 and 5 16. FIG. 18 is a diagram illustrating an exemplary configuration of a control device for a rotating electrical machine according to a fourth embodiment. FIG. 19 is a diagram illustrating a detailed exemplary 10 configuration of the position estimator illustrated in FIG. 18. FIG. 20 is a diagram illustrating a detailed exemplary configuration of the estimated position switch illustrated in FIG. 19. 15 FIG. 21 is a diagram for explaining drive regions in the estimated position switch illustrated in FIGS. 19 and 20. FIG. 22 is a diagram illustrating an exemplary configuration of a control device for a rotating electrical 20 machine according to a fifth embodiment. FIG. 23 is a diagram illustrating a detailed exemplary configuration of the position estimator illustrated in FIG. 22. FIG. 24 is a diagram illustrating a detailed exemplary 25 configuration of the estimated position switch illustrated in FIG. 23. FIG. 25 is a diagram illustrating a first exemplary hardware configuration of the control device for a rotating electrical machine according to any of the first to fifth 30 embodiments. FIG. 26 is a diagram illustrating a second exemplary hardware configuration of the control device for a rotating electrical machine according to any of the first to fifth 10 embodiments. Description of Embodiments [0016] Hereinafter, control devices for rotating 5 electrical machines according to embodiments of the present invention will be described in detail based on the drawings. The present invention is not limited to the following embodiments. Hereinafter, a “control device for a rotating electrical machine” may be simply referred to as a “control 10 device”. [0017] First Embodiment A control device for a rotating electrical machine according to the first embodiment is a control device that drives and controls a multi-phase rotating electrical 15 machine. The multi-phase rotating electrical machine is a rotating electrical machine to which an AC voltage of three phases or four or more phases is applicable. [0018] FIG. 1 is a diagram illustrating an exemplary configuration of the control device 100 for a rotating 20 electrical machine according to the first embodiment. As illustrated in FIG. 1, the control device 100 according to the first embodiment includes a voltage applicator 3 which is a voltage applying means, a current detector 2 which is a current detecting means, a position estimator 4 which is 25 a position estimating means, and a controller 5 which is a control means. [0019] The voltage applicator 3 supplies AC power to the rotating electrical machine 1 on the basis of rotating electrical machine voltage commands vu*, vv*, and vw* for 30 driving the rotating electrical machine 1. [0020] An example of the rotating electrical machine 1 is a three-phase synchronous reluctance motor that generates torque using the saliency of a rotor 1a. The 11 synchronous reluctance motor is a motor in which the magnetic resistance of the rotor 1a changes depending on the rotor position. [0021] The current detector 2 detects rotating 5 electrical machine currents iu, iv, and iw which are currents flowing through the rotating electrical machine 1. The rotating electrical machine currents iu, iv, and iw are each an AC current supplied from the voltage applicator 3 to the corresponding phase of the rotating electrical 10 machine 1. The current detector 2 outputs the detected rotating electrical machine currents iu, iv, and iw to the position estimator 4 and the controller 5. [0022] The position estimator 4 calculates an estimated rotor position θ^ on the basis of the rotating electrical 15 machine currents iu, iv, and iw. The controller 5 calculates the rotating electrical machine voltage commands vu*, vv*, and vw* on the basis of the rotating electrical machine currents iu, iv, and iw and the estimated rotor position θ^ such that an output torque of the rotating 20 electrical machine 1 has a value indicated by a torque command value τ*. The estimated rotor position θ^ is an estimated value of a rotor position. The rotor position is a rotational position of the rotor 1a of the rotating electrical machine 1. The estimated rotor position θ^ is 25 represented by an electrical angle. [0023] The controller 5 is divided into a drive voltage command calculation unit 5a which is a first calculation unit and a position estimation voltage calculation unit 5b which is a second calculation unit. The drive voltage 30 command calculation unit 5a includes a current command calculator 6, a current controller 7, a rotating coordinate inverse converter 8, a two-to-three phase converter 9, a drive current extractor 11, a three-to-two phase converter 12 12, a rotating coordinate converter 13, and an adder 14. Note that the division into the drive voltage command calculation unit 5a and the position estimation voltage calculation unit 5b illustrated in FIG. 1 is an example, 5 and the components of the controller 5 may be divided in any way. [0024] The position estimation voltage calculation unit 5b calculates position estimation voltage commands vuf*, vvf*, and vwf* for estimating the rotor position. Each of the 10 position estimation voltage commands vuh*, vvh*, and vwh* is provided for a corresponding one of the phases. The drive voltage command calculation unit 5a calculates rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* for driving the rotating electrical machine 1 on the basis 15 of the rotating electrical machine currents iu, iv, and iw and the estimated rotor position θ^. Note that the adder 14 adds the position estimation voltage commands vuh*, vvh*, and vwh* to the rotating electrical machine drive voltage commands vuf*, vvf*, and vwf*. The adder 14 outputs the 20 rotating electrical machine voltage commands vu*, vv*, and vw to the voltage applicator 3. [0025] In the drive voltage command calculation unit 5a, the current command calculator 6 receives the torque command value τ*, which is a command value for output 25 torque of the rotating electrical machine 1. [0026] The current command calculator 6 calculates rotating electrical machine drive current commands idf* and iqf* in a rotating two-phase coordinate system, using the torque command value τ*. The rotating electrical machine 30 drive current commands idf* and iqf* are current commands in the rotating two-phase coordinate system necessary for the rotating electrical machine 1 to generate the output corresponding to the torque command value τ*. The current 13 command calculator 6 according to the first embodiment calculates current commands that minimize the effective current value relative to torque, in other words, minimize the copper loss relative to torque. 5 [0027] Of the rotating electrical machine drive current commands idf* and iqf* in the rotating two-phase coordinate system, the rotating electrical machine drive current command idf* is a d-axis drive current command value indicating an armature current component in the d-axis 10 direction that minimizes a magnetic resistance of the rotor 1a. The rotating electrical machine drive current command iqf* is a q-axis drive current command value indicating an armature current component in the q-axis direction orthogonal to the d-axis direction. Not only the torque 15 command value τ*, but also motor constants of the rotating electrical machine 1 are used for the calculation of the rotating electrical machine drive current commands idf* and iqf* in the rotating two-phase coordinate system. Examples of motor constants can include a mutual inductance of the 20 rotating electrical machine 1 and the number of poles of the rotating electrical machine 1. Note that, instead of motor constants, a predetermined expression or table indicating the relationship between current commands and torque can be used. 25 [0028] The drive current extractor 11 extracts rotating electrical machine drive currents iuf, ivf, and iwf in a three-phase coordinate system from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system detected by the current detector 2. The 30 rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system are rotating electrical machine drive currents in the three-phase coordinate system generated from the rotating electrical 14 machine drive voltage commands vuf*, vvf*, and vwf* in the three-phase coordinate system for driving the rotating electrical machine 1. The rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* are drive voltage 5 commands output from the two-to-three phase converter 9 and input to the adder 14. The adder 14 receives the rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* and the position estimation voltage commands vuh*, vvh*, and vwh*. The position estimation voltage commands vuh*, vvh*, 10 and vwh* are voltage commands for estimating the rotor position of the rotating electrical machine 1. [0029] The adder 14 adds the rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* in the three-phase coordinate system and the position estimation voltage 15 commands vuh*, vvh*, and vwh* in the three-phase coordinate system to generate the rotating electrical machine voltage commands vu*, vv*, and vw*, and outputs the generated rotating electrical machine voltage commands vu*, vv*, and vw* to the voltage applicator 3. The position estimation 20 voltage commands vuh*, vvh*, and vwh* are calculated by the position estimation voltage calculation unit 5b. [0030] FIG. 2 is a diagram illustrating position estimation voltage commands that are output from the position estimation voltage calculation unit 5b illustrated 25 in FIG. 1. FIG. 2 illustrates, by way of example, the position estimation voltage commands vuh*, vvh*, and vwh* in the three-phase coordinate system that provide square wave voltages of the u-, v-, and w-phases shown in that order from the upper stage side. These wave voltages are 120° 30 out of phase with one another. Note that FIG. 2 depicts the position estimation voltage commands vuh*, vvh*, and vwh* in the three-phase coordinate system that are square wave voltages, but the present invention is not limited to this. 15 Sine wave voltages may be used instead of square wave voltages. [0031] Returning back to FIG. 1, the drive current extractor 11 according to the first embodiment uses a notch 5 filter, for example, and removes position estimation current amplitudes Iuh, Ivh, and Iwh in the three-phase coordinate system from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system, thereby extracting the rotating electrical machine drive 10 currents iuf, ivf, and iwf in the three-phase coordinate system. Note that the position estimation current amplitudes Iuh, Ivh, and Iwh in the three-phase coordinate system are generated by the application of the position estimation voltage commands vuh*, vvh*, and vwh*. Note that 15 the method of extracting the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system can use a low-pass filter or a high-pass filter instead of 20 the notch filter. [0032] The three-to-two phase converter 12 converts the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system extracted by the drive current extractor 11 into rotating electrical machine drive 25 currents iαf and iβf in a stationary two-phase coordinate system. The rotating coordinate converter 13 performs coordinate conversion, using the estimated rotor position θ^ estimated by the position estimator 4, and converts the rotating electrical machine drive currents iαf and iβf in 30 the stationary two-phase coordinate system into rotating electrical machine drive currents idf and iqf in the rotating two-phase coordinate system. [0033] The current controller 7 performs current control 16 such that the rotating electrical machine drive currents idf and iqf in the rotating two-phase coordinate system obtained through conversion in the rotating coordinate converter 13 agree with the rotating electrical machine 5 drive current commands idf* and iqf* calculated by the current command calculator 6, and calculates rotating electrical machine drive voltage commands vdf* and vqf* in the rotating two-phase coordinate system. Current control in the current controller 7 can be exemplified by 10 proportional integral (PI) control. [0034] The rotating coordinate inverse converter 8 converts, using the estimated rotor position θ^, the rotating electrical machine drive voltage commands vdf* and vqf* in the rotating two-phase coordinate system calculated 15 by the current controller 7 into rotating electrical machine drive voltage commands vαf* and vβf* in the stationary two-phase coordinate system. The two-to-three phase converter 9 converts the rotating electrical machine drive voltage commands vαf* and vβf* in the stationary two20 phase coordinate system into the rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* in the three-phase coordinate system described above. [0035] Next, the position estimator 4 will be described in detail. FIG. 3 is a diagram illustrating a detailed 25 exemplary configuration of the position estimator 4 illustrated in FIG. 1. As illustrated in FIG. 3, the position estimator 4 includes a signal processor 41, a position estimation current amplitude calculator 403, a signal processor 42, an estimated position calculator 406, 30 an estimated position calculator 407, an estimated position calculator 408, and an estimated position switch 409. Note that the estimated position calculator 406 is defined as a first estimated position calculator, the estimated position 17 calculator 407 is defined as a second estimated position calculator, and an estimated position calculator 408 is defined as a third estimated position calculator. [0036] The signal processor 41 includes a position 5 estimation current extractor 401 and a drive current extractor 402. The position estimation current extractor 401 extracts position estimation currents iuh, ivh, and iwh from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system. The drive current 10 extractor 402 extracts the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system. [0037] The position estimation current amplitude 15 calculator 403 calculates the position estimation current amplitudes Iuh, Ivh, and Iwh in the three-phase coordinate system on the basis of the position estimation currents iuh, ivh, and iwh in the three-phase coordinate system. [0038] The signal processor 42 includes an AC component 20 extractor 404 and a DC component extractor 405. The AC component extractor 404 extracts three-phase AC components Iuhac, Ivhac, and Iwhac of the position estimation current amplitudes from the position estimation current amplitudes Iuh, Ivh, and Iwh. The DC component extractor 405 extracts a 25 DC component Ihdc of the position estimation current amplitudes from the position estimation current amplitudes Iuh, Ivh, and Iwh. [0039] The estimated position calculator 406 estimates a first estimated rotor position θ^1 on the basis of the 30 three-phase AC components Iuhac, Ivhac, and Iwhac of the position estimation current amplitudes. The method of rotor position estimation used in the estimated position calculator 406 is the saliency method. That is, the first 18 estimated rotor position θ^1 is an estimated rotor position that is calculated on the basis of the AC components of the position estimation current amplitudes, i.e. the amplitudes of the position estimation currents generated by the 5 application of the position estimation voltages. The first estimated rotor position θ^1 is one of the candidate values of the estimated rotor position θ^ that is ultimately output from the position estimator 4. [0040] The estimated position calculator 407 calculates 10 a second estimated rotor position θ^2 on the basis of the DC component Ihdc of the position estimation current amplitudes. The method of rotor position estimation used in the estimated position calculator 407 is the magnetic saturation method. The second estimated rotor position θ^2 15 is one of the candidate values of the estimated rotor position θ^ that is ultimately output from the position estimator 4. [0041] The estimated position calculator 408 calculates a third estimated rotor position θ^3 on the basis of: the 20 rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system; and the interlinkage magnetic flux calculated from the induced voltage generated due to the saliency of the rotor 1a. The method of rotor position estimation used in the estimated position 25 calculator 408 is the induced voltage and interlinkage magnetic flux method. The third estimated rotor position θ^3 is one of the candidate values of the estimated rotor position θ^ that is ultimately output from the position estimator 4. 30 [0042] The estimated position switch 409 outputs, as the estimated rotor position θ^, position information obtained by selecting one of the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third 19 estimated rotor position θ^3, or position information obtained by combining at least two estimated rotor positions. [0043] Next, the function of the position estimator 4 5 will be described in more detail with reference to FIGS. 4 to 6 in addition to FIG. 3. FIG. 4 is a first diagram for explaining the operation of the estimated position calculator 407 illustrated in FIG. 3. FIG. 5 is a second diagram for explaining the operation of the estimated 10 position calculator 407 illustrated in FIG. 3. FIG. 6 is a diagram illustrating a detailed exemplary configuration of the estimated position calculator 408 illustrated in FIG. 3. [0044] The drive current extractor 402 uses a notch filter, for example, and removes the position estimation 15 current amplitudes Iuh, Ivh, and Iwh in the three-phase coordinate system, generated by the application of the position estimation voltage commands vuh*, vvh*, and vwh*, from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system, thereby extracting 20 the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system. The position estimation current extractor 401 calculates the position estimation current amplitudes Iuh, Ivh, and Iwh in the threephase coordinate system by subtracting the rotating 25 electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system calculated by the drive current extractor 402 from the rotating electrical machine currents iu, iv, and iw in the three-phase coordinate system. Note that the method of extracting or calculating the 30 rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system and the position estimation current amplitudes Iuh, Ivh, and Iwh in the threephase coordinate system is not limited to this, and may use 20 a band-pass filter, a band-stop filter, a low-pass filter, or a high-pass filter. [0045] As described above, the position estimation current amplitude calculator 403 calculates the position 5 estimation current amplitudes Iuh, Ivh, and Iwh in the threephase coordinate system on the basis of the position estimation current amplitudes Iuh, Ivh, and Iwh in the threephase coordinate system. Note that the position estimation current amplitudes Iuh, Ivh, and Iwh in the three-phase 10 coordinate system can be expressed by Formula (1) below using the DC component Ihdc of the position estimation current amplitudes and the AC component Ihac of the position estimation current amplitudes described above. [0046] [Formula 1] ∙∙∙(1) 15 [0047] Note that the method of calculation by the position estimation current amplitude calculator 403 is well-known, and a detailed description thereof is omitted here. For details of the method of calculation, refer to 20 paragraphs [0034] to [0055] of the specification of Japanese Patent No. 5324646, for example. The description thereof is incorporated in the present specification and forms a part of the present specification. [0048] This method calculates the magnetic pole position, 25 using the relative relationship between the AC components of the position estimation current amplitudes Iuh, Ivh, and 21 Iwh in the three-phase coordinate system, and eliminates the need to calculate the absolute values of the position estimation current amplitudes Iuh, Ivh, and Iwh. Formula (2) below can be thus used to calculate the position estimation 5 current amplitudes Iuh, Ivh, and Iwh in the three-phase coordinate system. [0049] [Formula 2] ∙∙∙(2) [0050] In Formula (2), “t” is time and “Th” is one AC 10 period. Formula (2) omits the coefficient of “√(2/Th)”, which is otherwise added before the integral signs when absolute values are calculated through autocorrelation. That is, calculations by the position estimation current amplitude calculator 403 do not require multiplication and 15 square root operations. The position estimation current amplitude calculator 403 according to the first embodiment therefore makes it possible to speed up the calculation processing and shorten the calculation time. [0051] As described above, the DC component extractor 20 405 extracts the DC component Ihdc of the position estimation current amplitudes from the position estimation current amplitudes Iuh, Ivh, and Iwh. Specifically, the DC component extractor 405 extracts the DC component Ihdc of the position estimation current amplitudes by, as indicated 25 by Formula (3) below, calculating the average of the 22 position estimation current amplitudes Iuh, Ivh, and Iwh in the three-phase coordinate system calculated by the position estimation current amplitude calculator 403. [0052] [Formula 3] ∙∙∙(3) 5 [0053] In addition, as described above, the AC component extractor 404 extracts the three-phase AC components Iuhac, Ivhac, and Iwhac of the position estimation current amplitudes from the position estimation current amplitudes 10 Iuh, Ivh, and Iwh. Specifically, the AC component extractor 404 calculates the three-phase AC components Iuhac, Ivhac, and Iwhac of the position estimation current amplitudes by subtracting, from each of the input position estimation current amplitudes Iuh, Ivh, and Iwh, the DC component Ihdc of 15 the position estimation current amplitudes extracted by the DC component extractor 405. Using Formulas (1) and (3), the three-phase AC components Iuhac, Ivhac, and Iwhac of the position estimation current amplitudes can be expressed by Formula (4) below. Note that the method of calculating the 20 DC component Ihdc of the position estimation current amplitudes and the three-phase AC components Iuhac, Ivhac, and Iwhac of the position estimation current amplitudes is not limited to this, and may use a low-pass filter or a high-pass filter. 25 [0054] [Formula 4] ∙∙∙(4) 23 [0055] The estimated position calculator 406 calculates the first estimated rotor position θ^1 by utilizing the fact that the three-phase AC components Iuhac, Ivhac, and Iwhac 5 of the position estimation current amplitudes are functions of the rotor position θ, that is, functions of sin(2θ) or cos(2θ). Specifically, the first estimated rotor position θ^1 can be calculated through the calculation of the arc cosine of one of the three-phase AC components Iuhac, Ivhac, 10 and Iwhac of the position estimation current amplitudes represented by Formula (4). Alternatively, the first estimated rotor position θ^1 can be calculated through a three-phase-to-two-phase conversion on and an arc tangent calculation on the three-phase AC components Iuhac, Ivhac, 15 and Iwhac of the position estimation current amplitudes expressed in the three-phase coordinate system. Still alternatively, the first estimated rotor position θ^1 can be calculated through a process of: separating each of the three-phase AC components Iuhac, Ivhac, and Iwhac of the 20 position estimation current amplitudes into six sections of the 60°electrical angles with a zero-crossing point located at a center of the corresponding three-phase AC components; and linearly approximating one of the three-phase AC components Iuhac, Ivhac, and Iwhac that has the zero-crossing 25 point in each section. [0056] The estimated position calculator 407 calculates the second estimated rotor position θ^2 on the basis of the DC component Ihdc of the position estimation current amplitudes. FIG. 4 illustrates the behavior of the DC 30 component Ihdc of the position estimation current amplitudes in maximum torque per ampere (MTPA) control in relation to 24 a current phase φ and a magnitude |idqf| of the drive current vector. Note that the MTPA control is control for minimizing the magnitude |idqf| of a drive current vector among drive current vectors generating the same torque. 5 The magnitude |idqf| of the drive current vector corresponds to the square root of the sum of squares of the d-axis component and the q-axis component into which the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system are subjected to rotating 10 coordinate conversion. In FIG. 4, the magnitude |idqf| of the drive current vector is given between 20% and 100% of the rated current with 20%-current increments. In addition, in FIG. 4, the current phase φ is defined as a lead phase with respect to the d-axis. 15 [0057] In the first embodiment, the MTPA control for the rotating electrical machine 1 is based on the assumption that the control range of the current phase φ is 45° to 55°. In FIG. 4, in the range where the magnitude |idqf| of the drive current vector is 60% or more of the rated current 20 and the current phase φ is 45° to 55°, the DC component Ihdc of the position estimation current amplitudes decreases monotonically with respect to the current phase φ. The estimated position calculator 407 according to the first embodiment calculates the second estimated rotor position 25 θ^2 by utilizing this characteristic. [0058] Note that the characteristic required for rotor position estimation is the uniqueness between the DC component Ihdc of the position estimation current amplitudes and the drive current vector, and the relationship between 30 the DC component Ihdc of the position estimation current amplitudes and the current phase φ is not limited to monotonous reduction. [0059] FIG. 5 depicts an extraction from the plots of 25 the magnitude |idqf| of the drive current vector illustrated in FIG. 4, specifically, the DC component Ihdc of the position estimation current amplitudes in the case where the magnitude |idqf| of the drive current vector is 5 100% current, that is, the rated current. In FIG. 5, the current phase command value is denoted by φ*, and the DC component Ihdc of the position estimation current amplitudes for the case of driving with the current phase command value φ* is denoted by Ihdc(φ*). In addition, a position 10 estimation error in a rotor position is denoted by Δθ2, and the DC component Ihdc of the position estimation current amplitudes for the case of driving with the actual current phase φ shifted from the current phase command value φ* by the position estimation error Δθ2 is defined as Ihdc(φ). 15 With these definitions, the position estimation error Δθ2 is proportional to the difference between Ihdc(φ*) and Ihdc(φ). In this specification, the difference between Ihdc(φ*) and Ihdc(φ) is referred to as the “Ihdc error”. [0060] In a case where the estimated position calculator 20 407 is configured by a phase locked loop (PLL), the estimated position calculator 407 calculates the second estimated rotor position θ^2 by operating the PLL such that the Ihdc error becomes zero. Note that the PLL, which may be configured to make the Ihdc error zero, is, for example, 25 a proportional integrator or a proportional integral integrator. The proportional integral integrator includes a proportional integrator and another integrator on the stage following the proportional integrator. Note that the estimated position calculator 407 stores in advance the 30 relationship between the current phase φ and the DC component Ihdc of the position estimation current amplitudes in association with the range of torque or rotating electrical machine current to be used. 26 [0061] As illustrated in FIG. 6, the estimated position calculator 408 includes a position estimation error calculator 4080 and a PLL 4081. As described above, the estimated position calculator 408 is a calculator that 5 estimates the third estimated rotor position θ^3 on the basis of the interlinkage magnetic flux calculated from the induced voltage generated due to the saliency of the rotor 1a. [0062] The position estimation error calculator 4080 10 calculates a position estimation error “−(θ^3−θ)” in a rotor position on the basis of the rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* in the three-phase coordinate system and the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase 15 coordinate system. The PLL 4081 calculates the third estimated rotor position θ^3 from the position estimation error “−(θ^3−θ)” in the rotor position. [0063] The position estimation error calculator 4080 includes three-to-two phase converters 40800 and 40801, a 20 rotating coordinate converter 40802, an interlinkage magnetic flux inductance AC component calculator 40803, an interlinkage magnetic flux inductance AC component estimator 40804, and a rotor position estimation error calculator 40805. 25 [0064] The three-to-two phase converter 40800 converts the rotating electrical machine drive voltage commands vuf*, vvf*, and vwf* in the three-phase coordinate system into the rotating electrical machine drive voltage commands vαf* and vβf* in the stationary two-phase coordinate system. 30 [0065] The three-to-two phase converter 40801 converts the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system into the rotating electrical machine drive currents iαf and iβf in the 27 stationary two-phase coordinate system. [0066] The rotating coordinate converter 40802 performs coordinate conversion using the estimated rotor position θ^3 to convert the rotating electrical machine drive 5 currents iαf and iβf in the stationary two-phase coordinate system into the rotating electrical machine drive currents idf and iqf in the rotating two-phase coordinate system. [0067] The PLL 4081 calculates the third estimated rotor position θ^3 by performing PLL operation such that the 10 position estimation error “−(θ^3−θ)” in the rotor position becomes zero. The PLL 4081, which may be configured to make the position estimation error “−(θ^3−θ)” zero, can use, for example, a proportional integrator or a proportional integral differentiator. 15 [0068] Next, the operation of the interlinkage magnetic flux inductance AC component calculator 40803 will be described. First, the model of the rotating electrical machine 1 is expressed by Formulas (5) to (8) below in the stationary two-phase coordinate system. 20 [0069] [Formula 5] ∙∙∙(5) [0070] [Formula 6] ∙∙∙(6) [0071] [Formula 7] ∙∙∙(7) 25 28 [0072] [Formula 8] ∙∙∙(8) [0073] In Formula (5), vdq is a vector made up of a daxis rotating electrical machine voltage vd and a q-axis 5 rotating electrical machine voltage vq, idq is a vector made up of a d-axis rotating electrical machine current id and a q-axis rotating electrical machine current iq, Rs is a winding resistance of the rotating electrical machine 1, ωs is the rotation angular speed of the coordinates 10 representing the model, and ψdq of Formula (5) is the interlinkage magnetic flux. J of Formula (6) is a transformation matrix. The interlinkage magnetic flux ψdq of Formula (5) can be expressed by Formula (7). Ldq of Formula (7) can be expressed by a matrix as in Formula (8) 15 with Lsdc, Lmac, and an electrical angle θ of the rotor position. In Formula (8), Lsdc is an inductance DC component that does not change depending on the rotor position, and Lmac is an inductance AC component that changes depending on the rotor position. Note that 20 inductance change is usually represented by a sine function or cosine function of 2θ with respect to the electrical angle θ of the rotor position. [0074] From Formula (7) and Formula (8), the interlinkage magnetic flux ψdq is expressed by Formula (9) 25 below. [0075] [Formula 9] ∙∙∙(9) 29 [0076] The first term of Formula (9) is a term including the inductance DC component Lsdc that does not change depending on the rotor position. The second term of 5 Formula (9) is a term including the inductance AC component Lmac that changes depending on the rotor position, and this term is the “interlinkage magnetic flux inductance AC component”. That is, the interlinkage magnetic flux inductance AC component is an interlinkage magnetic flux 10 generated by the inductance AC component and the rotating electrical machine current. [0077] The interlinkage magnetic flux inductance AC component calculator 40803 performs the following calculations in order to calculate the interlinkage 15 magnetic flux inductance AC component. First, the interlinkage magnetic flux inductance AC component calculator 40803 calculates the interlinkage magnetic flux ψdq of the rotating electrical machine using Formula (10) below. 20 [0078] [Formula 10] ∙∙∙(10) [0079] In Formula (10), vαβ* is a vector made up of an α- axis rotating electrical machine voltage command vα* and a β-axis rotating electrical machine voltage command vβ*. 25 [0080] In addition, the integral in Formula (10) is expressed by Formula (11) below in the s-domain in the Laplace transform. [0081] [Formula 11] 30 ∙∙∙(11) [0082] When the interlinkage magnetic flux ψαβ of the rotating electrical machine 1 is calculated by integration, the initial value is usually unknown. For this reason, a 5 high-pass filter having a sufficiently low cutoff frequency with respect to a fundamental frequency component of the interlinkage magnetic flux ψαβ of the rotating electrical machine 1 is used. Here, the transfer function of the high-pass filter is expressed by Formula (12) below, where 10 ωhpf represents the cutoff frequency. [0083] [Formula 12] ∙∙∙(12) [0084] When the high-pass filter of Formula (12) applies to the interlinkage magnetic flux ψαβ expressed by Formula 15 (11), thus, the resulting interlinkage magnetic flux ψ^hpfαβ is calculated using Formula (13) below. [0085] [Formula 13] ∙∙∙(13) [0086] In addition, Formula (13) is modified into 20 Formula (14) below. [0087] [Formula 14] ∙∙∙(14) 31 [0088] Further, the interlinkage magnetic flux inductance AC component calculator 40803 uses the third estimated rotor position θ^3 to perform coordinate 5 conversion of the interlinkage magnetic flux ψ^hpfαβ in the stationary two-phase coordinate system into an interlinkage magnetic flux ψ^hpfdq in the rotating two-phase coordinate system. An interlinkage magnetic flux inductance AC component ψ^acdq,calc in the rotating coordinate system is 10 calculated using Formula (15) below according to Formula (9). [0089] [Formula 15] ∙∙∙(15) [0090] The interlinkage magnetic flux inductance AC 15 component ψ^acdq,calc calculated with Formula (15) is hereinafter referred to as the “interlinkage magnetic flux inductance AC component calculated value”. [0091] As represented by Formula (16) below, the interlinkage magnetic flux inductance AC component 20 estimator 40804 uses the estimated rotor position θ^3 and the rotating electrical machine current idq to estimate the interlinkage magnetic flux inductance AC component which is the second term of Formula (9). [0092] [Formula 16] ∙∙∙(16) 25 [0093] Assuming that the estimated value θ^3 and a true value θ of the rotor position are approximately equal in 32 Formula (16), Formula (16) is simplified as represented by Formula (17) below. [0094] [Formula 17] ∙∙∙(17) 5 [0095] ψ^acdq of Formula (17) is an estimated value of the interlinkage magnetic flux inductance AC component calculated by the interlinkage magnetic flux inductance AC component estimator 40804. This estimated value is hereinafter referred to as the “interlinkage magnetic flux 10 inductance AC component estimated value”. [0096] The position estimation error calculator 4080 uses the interlinkage magnetic flux inductance AC component calculated value ψ^acdq,calc and the interlinkage magnetic flux inductance AC component estimated value ψ^acdq to 15 calculate the position estimation error “−(θ^3−θ)” in the rotor position. An outer product of the interlinkage magnetic flux inductance AC component calculated value ψ^acdq,calc and the interlinkage magnetic flux inductance AC component estimated value ψ^acdq is expressed by Formula 20 (18) below using Formula (15), that is, the calculated value of the second term of Formula (9), and Formula (16). [0097] [Formula 18] ∙∙∙(18) [0098] Then, assuming that the estimated value and the 25 true value of the rotor position are approximately equal, that is, θ^3≒θ, the estimation error in the rotor position can be calculated using Formula (19) below. 33 [0099] [Formula 19] ∙∙∙(19) [0100] The above is the calculation processing by the estimated position calculator 408. Note that the rotating 5 electrical machine voltage commands and the rotating electrical machine currents, which are used for position estimation, are rotating electrical machine drive voltage commands and rotating electrical machine drive currents, respectively. 10 [0101] Returning back to FIG. 3, the estimated position switch 409 selects one of or switches between the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third estimated rotor position θ^3 and outputs the resulting estimated rotor position. 15 Alternatively, the estimated position switch 409 selects information on at least two of the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third estimated rotor position θ^3, takes a weighted average thereof at a preset ratio, and outputs the weighted 20 average as the estimated rotor position θ^. In this way, the estimated position switch 409 selects or switches and outputs the estimation information on the rotor position. [0102] As described above, according to the first embodiment, the position estimator 4 selects and outputs 25 one of the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third estimated rotor position θ^3. Alternatively, the position estimator 4 outputs the estimated rotor position θ^ obtained by combining at least two of the first estimated rotor 34 position θ^1, the second estimated rotor position θ^2, and the third estimated rotor position θ^3. This enables position sensorless control that uses a desired estimated rotor position, and also enables position sensorless 5 control in the torque speed region of the operating range. [0103] Second Embodiment In the first embodiment, position information obtained by selecting one of the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third 10 estimated rotor position θ^3, or position information obtained by combining at least two estimated rotor positions is output as the estimated rotor position θ^. As discussed above, the first estimated rotor position θ^1 is position information estimated using the saliency method, 15 the second estimated rotor position θ^2 is position information estimated using the magnetic saturation method, and the third estimated rotor position θ^3 is position information estimated using the induced voltage and interlinkage magnetic flux method. 20 [0104] The methods of rotor position estimation have their own features. As described above, a feature of the saliency method is that estimation accuracy is high in the low-speed region and the drive region that provides a small degree of magnetic saturation. A feature of the magnetic 25 saturation method is that the estimation accuracy is high in the low-speed region and the drive region that provides a large degree of magnetic saturation. A feature of the induced voltage and interlinkage magnetic flux method is that the estimation accuracy is high in the high-speed 30 region. In the first embodiment, no particular discussion is made as to the relationship between estimated position information and drive regions. In contrast, the second embodiment describes how to estimate the rotation speed of 35 the rotor 1a as well as the rotor position, and to switch the estimated rotor position information on the basis of the estimated speed information and magnetic saturation information. Note that magnetic saturation information is 5 defined as information that correlates with the degree of magnetic saturation of the rotating electrical machine 1. [0105] FIG. 7 is a diagram illustrating an exemplary configuration of a control device 100A for a rotating electrical machine according to the second embodiment. The 10 control device 100A according to the second embodiment is different from the control device 100 according to the first embodiment illustrated in FIG. 1 in that the position estimator 4 is replaced with a position estimator 4A. The other configuration is the same as or equivalent to the 15 configuration of the first embodiment. The same or equivalent components are denoted by the same reference signs, and redundant descriptions are omitted. [0106] FIG. 8 is a diagram illustrating a detailed exemplary configuration of the position estimator 4A 20 illustrated in FIG. 7. The position estimator 4A according to the second embodiment illustrated in FIG. 8 is different from the position estimator 4 according to the first embodiment illustrated in FIG. 3 in that the estimated position calculators 406, 407, and 408 and the estimated 25 position switch 409 are replaced with estimated position/speed calculators 406A, 407A, and 408A and an estimated position switch 409A, respectively. When the estimated position/speed calculators 406A, 407A, and 408A are distinguished from one another without reference signs, 30 they are referred to as the “first estimated position/speed calculator”, the “second estimated position/speed calculator”, and the “third estimated position/speed calculator”. 36 [0107] The estimated position/speed calculator 406A calculates the first estimated rotor position θ^1 and a first estimated speed ω^1 on the basis of the three-phase AC components Iuhac, Ivhac, and Iwhac of the position 5 estimation current amplitudes. The estimated position/speed calculator 406A uses the saliency method as in the first embodiment. That is, the first estimated speed ω^1 is an estimated speed calculated on the basis of the saliency of the rotor 1a detected from the position 10 estimation current. [0108] The estimated position/speed calculator 407A calculates the second estimated rotor position θ^2 and a second estimated speed ω^2 on the basis of the DC component Ihdc of the position estimation current amplitudes. The 15 estimated position/speed calculator 407A uses the magnetic saturation method as in the first embodiment. That is, the second estimated speed ω^2 is an estimated speed calculated on the basis of the DC component Ihdc of the position estimation current amplitudes. 20 [0109] The estimated position/speed calculator 408A calculates the third estimated rotor position θ^3 and a third estimated speed ω^3 on the basis of: the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system; and the interlinkage 25 magnetic flux calculated from the induced voltage generated due to the saliency of the rotor. The estimated position/speed calculator 408A uses the induced voltage and interlinkage magnetic flux method as in the first embodiment. That is, the third estimated speed ω^3 is an 30 estimated speed calculated on the basis of: the rotating electrical machine drive currents iuf, ivf, and iwf in the three-phase coordinate system; and the interlinkage magnetic flux calculated from the induced voltage generated 37 due to the saliency of the rotor 1a. [0110] The estimated position switch 409A receives τ*, τf*, τ^m, τ^1, if*, iff*, and if. τ* is the torque command value described above, and if is the drive current. τf* is 5 a value of the torque command value τ* filtered in consideration of the delay of the control system. τ^m is an estimated torque calculated from the drive current if and rotating electrical machine parameters on the basis of the mathematical model of the rotating electrical machine. τ^1 10 is an estimated torque obtained using a lookup table with the drive current if as an argument. if* is a rotating electrical machine drive current command. iff* is a value of the rotating electrical machine drive current command if* filtered in consideration of the delay of the control 15 system. In the drive current if, the frequency of the drive current if is used. The estimated position switch 409A uses at least one of these items of input information as magnetic saturation information. [0111] FIG. 9 is a diagram illustrating a detailed 20 exemplary configuration of the estimated position/speed calculator 406A illustrated in FIG. 8. As illustrated in FIG. 9, the estimated position/speed calculator 406A includes the estimated position calculator 406 and an estimated speed calculator 4060. The estimated position 25 calculator 406 illustrated in FIG. 9 is a component equivalent to the estimated position calculator 406 illustrated in FIG. 3. The estimated speed calculator 4060 calculates the first estimated speed ω^1 by pseudodifferentiating the first estimated rotor position θ^1 30 calculated by the estimated position calculator 406. The estimated position/speed calculator 406A outputs the first estimated rotor position θ^1 and the first estimated speed ω^1 calculated. Note that pseudo-differentiation is to 38 apply a differential operation and a filterring process to an input value. The pseudo-differentiating processor can be implemented by a differentiator and a low-pass filter. [0112] FIG. 10 is a diagram illustrating a detailed 5 exemplary configuration of the estimated position/speed calculator 407A illustrated in FIG. 8. The estimated position/speed calculator 407A is configured as a type-2 calculator including a lookup table (LUT) 4070, an LUT 4071, a subtractor 4072, a divider 4073, a proportional 10 integrator 4074, and an integrator 4075, as illustrated in FIG. 10. [0113] The LUT 4070 stores the torque command value τ* and Ihdc*, i.e. the DC component Ihdc of the position estimation current amplitudes that is obtained in the case 15 of driving with the torque command value τ*. The estimated position/speed calculator 407A refers to the table value Ihdc* stored in the LUT 4070. [0114] The subtractor 4072 calculates a difference ΔIh between the DC component Ihdc and the table value Ihdc* of 20 the position estimation current amplitudes. [0115] The LUT 4071 stores a coefficient KIhθ2 for deriving the position estimation error Δθ2 from the torque command value τ*. The estimated position/speed calculator 407A refers to the coefficient KIhθ2 stored in the LUT 4071. 25 [0116] The divider 4073 obtains the position estimation error Δθ2 by dividing the difference ΔIh by KIhθ2. The proportional integrator 4074 calculates the second estimated speed ω^2 on the basis of the position estimation error Δθ2. The integrator 4075 calculates the second 30 estimated rotor position θ^2 on the basis of the second estimated speed ω^2. [0117] Note that FIG. 10 depicts a configuration in which the second estimated speed ω^2 is calculated first, 39 and the second estimated rotor position θ^2 is calculated on the basis of the second estimated speed ω^2, but the present invention is not limited to this. To the contrary, the second estimated rotor position θ^2 may be calculated 5 first, and the second estimated speed ω^2 may be calculated by pseudo-differentiating the second estimated rotor position θ^2. [0118] In addition, FIG. 10 depicts an example in which the argument of the LUT 4070 and the LUT 4071 is the torque 10 command value τ*, but the present invention is not limited to this. Instead of the torque command value τ*, the rotating electrical machine drive current command if* may be used as the argument of the LUT 4070 and the LUT 4071. [0119] FIG. 11 is a diagram illustrating a detailed 15 exemplary configuration of the estimated position/speed calculator 408A illustrated in FIG. 8. As illustrated in FIG. 11, the estimated position/speed calculator 408A includes the position estimation error calculator 4080 and a PLL 4081A. 20 [0120] The position estimation error calculator 4080 illustrated in FIG. 11 is a component equivalent to the position estimation error calculator 4080 illustrated in FIG. 6. The PLL 4081A has the calculator configured such that the position estimation error “−(θ^3−θ)” becomes zero. 25 Specifically, the PLL 4081A is configured as a type-2 calculator including a proportional integrator 4081Aa and an integrator 4081Ab, similarly to the estimated position/speed calculator 407A illustrated in FIG. 10. [0121] In the PLL 4081A, the proportional integrator 30 4081Aa calculates the third estimated speed ω^3 on the basis of the position estimation error “−(θ^3−θ)”. The integrator 4081Ab calculates the third estimated rotor position θ^3 on the basis of the third estimated speed ω^3. 40 [0122] Note that the PLL 4081A of FIG. 11 is configured to calculate the third estimated speed ω^3 first, and calculate the third estimated rotor position θ^3 on the basis of the third estimated speed ω^3, but the present 5 invention is not limited to this. To the contrary, the PLL 4081A may be configured to calculate the third estimated rotor position θ^3 first, and calculate the third estimated speed ω^3 by pseudo-differentiating the third estimated rotor position θ^3. 10 [0123] FIG. 12 is a diagram illustrating a detailed exemplary configuration of the estimated position switch 409A illustrated in FIG. 8. As illustrated in FIG. 12, the estimated position switch 409A includes an estimated speed selector 411A and an estimated position selector 410A. The 15 estimated speed selector 411A selects one of the first estimated speed ω^1, the second estimated speed ω^2, and the third estimated speed ω^3, and outputs the selected estimated speed ω^ as speed information to the estimated position selector 410A. The estimated position selector 20 410A selects or switches and outputs the estimation information on the rotor position, on the basis of the speed information output from the estimated speed selector 411A and the magnetic saturation information described above. 25 [0124] In the estimated position selector 410A, speed information that is used for selecting or switching the estimated rotor position θ^ is one of the first estimated speed ω^1, the second estimated speed ω^2, and the third estimated speed ω^3. That is, the estimated speed selector 30 411A selects one of the first estimated speed ω^1, the second estimated speed ω^2, and the third estimated speed ω^3, and outputs the estimated speed to the estimated position selector 410A. 41 [0125] FIG. 13 is a diagram for explaining drive regions in the estimated position switch 409A illustrated in FIGS. 8 and 12. In FIG. 13, the horizontal axis is the rotation speed of the rotating electrical machine, and the vertical 5 axis is the torque of the rotating electrical machine. The rotation speed is an example of speed information. The torque is information that correlates with the abovementioned magnetic saturation information. [0126] In FIG. 13, (1) is a drive region for driving 10 with the saliency method, (2) is a drive region for driving with the magnetic saturation method, and (3) is a drive region for driving with the induced voltage and interlinkage magnetic flux method. The broken lines in FIG. 13 mean boundaries between the methods of rotor position 15 estimation described above, and serve as thresholds for boundary determination. The boundaries are defined using magnetic saturation information and speed information. That is, magnetic saturation information and speed information are used for region determination, and the 20 method of rotor position estimation allocated to the determined region is selected. [0127] Specifically, when the rotation speed is smaller than the threshold and the torque is smaller than the threshold, the estimated position switch 409A selects and 25 outputs the first estimated rotor position θ^1. When the rotation speed is smaller than the threshold and the torque is larger than the threshold, the estimated position switch 409A selects and outputs the second estimated rotor position θ^2. When the rotation speed is larger than the 30 threshold, the estimated position switch 409A selects and outputs the third estimated rotor position θ^3. [0128] Although the boundaries for switching are represented by straight lines in FIG. 13, the boundaries do 42 not have to be straight lines and may be curved lines. [0129] As described above, according to the second embodiment, an appropriate method of rotor position estimation can be switched on the basis of the magnetic 5 saturation information and rotation speed of the rotor. This enables desired position sensorless control in the torque speed region of the operating range. [0130] Third Embodiment In the second embodiment, the estimated position 10 switch 409A selects or switches the estimation information on the rotor position on the basis of the magnetic saturation information and rotation speed of the rotor 1a. The estimation information on the rotor position may change discontinuously before and after the estimation information 15 is selected or switched, and the problem of shock occurring at the time of the switching can arise. Therefore, the third embodiment describes how to reduce the shock reduction at the time of the switching. [0131] FIG. 14 is a diagram illustrating an exemplary 20 configuration of a control device 100B for a rotating electrical machine according to the third embodiment. The control device 100B according to the third embodiment illustrated in FIG. 14 is different from the control device 100A according to the second embodiment illustrated in FIG. 25 7 in that the position estimator 4A is replaced with a position estimator 4B. The other configuration is the same as or equivalent to the configuration of the second embodiment. The same or equivalent components are denoted by the same reference signs, and redundant descriptions are 30 omitted. [0132] FIG. 15 is a diagram illustrating a detailed exemplary configuration of the position estimator 4B illustrated in FIG. 14. The position estimator 4B 43 according to the third embodiment illustrated in FIG. 15 is different from the position estimator 4A according to the second embodiment illustrated in FIG. 8 in that the estimated position switch 409A is replaced with an 5 estimated position switch 409B. The other configuration is the same as or equivalent to the configuration in FIG. 8. The same or equivalent components are denoted by the same reference signs, and redundant descriptions are omitted. [0133] FIG. 16 is a diagram illustrating a detailed 10 exemplary configuration of the estimated position switch 409B illustrated in FIG. 15. The estimated position switch 409B according to the third embodiment illustrated in FIG. 16 is different from the estimated position switch 409A according to the second embodiment illustrated in FIG. 12 15 in that the estimated position selector 410A is replaced with an estimated position combiner 410B. [0134] In the estimated position switch 409B, the estimated position combiner 410B outputs, as the estimated rotor position θ^, position information obtained by 20 combining at least two of the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third estimated rotor position θ^3 on the basis of magnetic saturation information and speed information. [0135] In the estimated position switch 409B, magnetic 25 saturation information that is used for estimated rotor position combining is similar to magnetic saturation information that is used in the second embodiment. In addition, speed information that is used for estimated rotor position switching is similar to speed information 30 that is used in the second embodiment. [0136] The estimated position combiner 410B combines the first estimated rotor position θ^1, the second estimated rotor position θ^2, and the third estimated rotor position 44 θ^3 through weighted averaging on the basis of magnetic saturation information and speed information. FIG. 17 is a diagram for explaining drive regions in the estimated position switch 409B illustrated in FIGS. 15 and 16. In 5 FIG. 17, the horizontal axis is the rotation speed of the rotating electrical machine, and the vertical axis is the torque of the rotating electrical machine. The torque is an example of information that correlates with magnetic saturation information, as in the second embodiment. 10 [0137] In FIG. 17, (1) is a drive region for driving with the saliency method alone, (2) is a drive region for driving with the magnetic saturation method alone, and (3) is a drive region for driving with the induced voltage and interlinkage magnetic flux method alone. In addition, the 15 regions represented by a plurality of numbers such as “(1)(2)” are drive regions that use the estimation methods corresponding to these numbers. [0138] For example, the region “(1)(2)” is a drive region for driving with the saliency method and the 20 magnetic saturation method. In this drive region, the estimated rotor position θ^ to be output is generated by combining the first estimated rotor position θ^1 estimated using the saliency method and the second estimated rotor position θ^2 estimated using the magnetic saturation method. 25 Note that the boundaries between drive regions are represented by broken lines as in FIG. 13. In FIG. 17, the boundaries between drive regions are represented by straight lines as in FIG. 13, but the boundaries do not have to be straight lines and may be curved lines. 30 [0139] In FIG. 17, Wspd is a weight based on speed information, and Wms is a weight based on magnetic saturation information. The values of the weight Wspd and the weight Wms vary in the range of zero to one, depending 45 on speed information and magnetic saturation information, respectively. Specifically, the estimated position combiner 410B generates the estimated rotor position θ^ through combining in the drive regions defined in FIG. 17 5 by using Formulas (20) and (21) below. [0140] [Formula 20] ∙∙∙(20) [0141] [Formula 21] ∙∙∙(21) 10 [0142] In Formula (21), θ^4 is a “Wms-weighted average value of the saliency method and the magnetic saturation method”. This weighted average value θ^4 is hereinafter referred to as the “fourth estimated rotor position”. [0143] In Formula (20), θ^5 is a “Wspd-weighted average 15 value of the fourth estimated rotor position θ^4 and the third estimated rotor position θ^3 which is a calculated value obtained with the induced voltage and interlinkage magnetic flux method alone”. This combined value obtained through weighted averaging is hereinafter referred to as 20 the “fifth estimated rotor position”. [0144] For example, in the case of Wspd=1, Formula (20) is transformed into θ^5=θ^3, and the third estimated rotor position θ^3 is output as the estimated rotor position θ^ from the estimated position combiner 410B. In the case of 25 Wspd=0, Formula (20) is transformed into θ^5=θ^4, and the value θ^4 weighted in correspondence to the value of the weight Wms, that is, the fourth estimated rotor position θ^4 which is a weighted average value of the saliency method 46 and the magnetic saturation method, is provided according to Formula (21) and output as the estimated rotor position θ^ from the estimated position combiner 410B. In the case of 0