JPWO2018025416A1 - Electric motor drive device, electric motor system, and refrigeration cycle device - Google Patents

Abstract

  An electric motor drive device (2) used in an electric motor (3) provided with a first three-phase winding part (11) and a second three-phase winding part (12), wherein the first three-phase winding part A first inverter (4) connected to (11) and a second inverter (5) connected to the second three-phase winding (12), the first inverter (4) Is the electric signal output to the first three-phase winding section (11) and the amplitude of the first electric signal that is output to the second three-phase winding section (12) by the second inverter (5). It is different from the amplitude of the second electric signal which is a signal.

Description

  The present invention relates to an electric motor driving device for driving an electric motor, an electric motor system including the electric motor driving device, and a refrigeration cycle apparatus including the electric motor system.

  In recent years, electric motors having a plurality of winding portions each having a coil for each phase have been proposed. Hereinafter, an electric motor having a plurality of winding portions as described above is also referred to as an electric motor in which winding portions are multiplexed.

  An example of an electric motor in which winding portions are multiplexed is disclosed in Patent Document 1. Patent Document 1 describes an electric motor system that includes a plurality of three-phase coils, that is, a plurality of winding portions, and drives the plurality of three-phase coils by different inverters.

Japanese Patent No. 5350034

  According to the above conventional technique, each inverter applies driving voltages having different phases to each three-phase coil, but the driving voltage, that is, the amplitude of the electric signal output from the inverter is the same between the inverters. That is, in the conventional technique, each inverter applies the same drive voltage with a phase shift. On the other hand, the current capacity of the inverter may be different for each inverter. In such a case, if the amplitude of the output electric signal is the same between the inverters, the upper limit is determined according to the inverter having a small current capacity, which is inefficient. For this reason, it is desired that a plurality of inverters can output electrical signals having different amplitudes.

  The present invention has been made in view of the above, and is an electric motor drive device for driving an electric motor having a plurality of winding portions, wherein a plurality of inverters respectively driving the plurality of winding portions have different amplitudes of electricity. An object of the present invention is to obtain an electric motor drive device that outputs a signal.

  In order to solve the above-described problems and achieve the object, the present invention is an electric motor drive device used for an electric motor including a first winding portion and a second winding portion, and includes the first winding portion. And a second inverter connected to the second winding portion. The amplitude of the first electric signal, which is an electric signal output from the first inverter to the first winding portion, and the second electric signal, which is an electric signal output from the second inverter to the second winding portion. It is different from the amplitude.

  The electric motor drive device according to the present invention has an effect of obtaining an electric motor drive device in which a plurality of inverters respectively driving a plurality of winding sections output electric signals having different amplitudes.

The figure which shows the structural example of the electric motor system concerning Embodiment 1. FIG. The figure which shows the signal input into a control part, and the signal output from a control part The figure which shows the structural example of the control part of Embodiment 1. FIG. The figure which shows an example of the electric current output from the 1st inverter and 2nd inverter of Embodiment 1 FIG. 3 is a diagram illustrating a configuration example of a control circuit according to the first embodiment. The figure which shows the structural example of the air conditioner concerning Embodiment 2. FIG.

  Hereinafter, an electric motor drive device, an electric motor system, and a refrigeration cycle device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of an electric motor system according to a first embodiment of the present invention. As shown in FIG. 1, the electric motor system 1 according to the first embodiment includes an electric motor 3 having a first three-phase winding portion 11 and a second three-phase winding portion 12, and an electric motor driving device that drives the electric motor 3. 2 is provided. The motor drive device 2 includes a DC power supply 81, a DC power supply 82, a DC power input from the DC power supply 81, a first inverter 4 connected to the first three-phase winding unit 11, and a DC power supply 82. And a second inverter 5 connected to the second three-phase winding section 12 while receiving DC power. Furthermore, the electric motor drive device 2 includes a control unit 90 that controls the operation of the electric motor drive device 2.

  As shown in FIG. 1, among the lines to which the DC power input from the DC power supply 81 to the first inverter 4 is supplied, the wiring connected to the positive terminal of the DC power supply 81, that is, the positive-side wiring is P1. The wiring connected to the negative terminal of the DC power supply 81, that is, the negative wiring is referred to as N1. Of the wires supplied with DC power input from the DC power source 82 to the second inverter 5, the wire connected to the positive terminal of the DC power source 82, that is, the positive side wire is called P <b> 2. The wiring connected to the negative terminal of the negative electrode, that is, the negative wiring is referred to as N2. The positive side of the DC power supply 81 is also referred to as the P1 side, the negative side of the DC power supply 81 is also referred to as the N1 side, the positive side of the DC power supply 82 is also referred to as the P2 side, and the negative side of the DC power supply 82 is also referred to as the N2 side.

  The first three-phase winding part 11 that is the first winding part includes a U-phase winding part 11a, a V-phase winding part 11b, and a W-phase winding part 11c. The first three-phase winding portion 11 includes a terminal 13a provided at the end of the U-phase winding portion 11a, a terminal 13b provided at the end of the V-phase winding portion 11b, and a W-phase winding. And a terminal 13c provided at an end of the line portion 11c. The second three-phase winding portion 12 that is the second winding portion includes a U-phase winding portion 12a, a V-phase winding portion 12b, and a W-phase winding portion 12c. The second three-phase winding portion 12 includes a terminal 14a provided at the end of the U-phase winding portion 12a, a terminal 14b provided at the end of the V-phase winding portion 12b, and a W-phase winding. And a terminal 14c provided at the end of the line portion 12c.

  The first inverter 4 outputs a first electric signal, which is an electric signal, to the first three-phase winding unit 11. The first inverter 4 includes switching elements 4a and 4b that are a pair of switching elements connected in series, switching elements 4c and 4d that are a pair of switching elements connected in series, and a switching element that is a pair of switching elements connected in series. 4e, 4f. Each switching element pair of switching element 4a and switching element 4b, switching element 4c and switching element 4d, switching element 4e and switching element 4f is referred to as an arm. The midpoint of each arm of the first inverter 4 is connected to the corresponding phase winding section of the first three-phase winding section 11.

  Specifically, an arm composed of the switching element 4a and the switching element 4b is connected to the terminal 13a, and an arm composed of the switching element 4c and the switching element 4d is connected to the terminal 13b, and the switching element 4e and the switching element The arm constituted by the element 4f is connected to the terminal 13c. In addition, each switching element connected to the P1 side, that is, P1 in each arm is also referred to as an upper switching element, and each switching element connected to the N1 side, that is, N1 in each arm is also referred to as a lower switching element.

  The second inverter 5 outputs a second electric signal that is an electric signal to the second three-phase winding portion 12. The second inverter 5 includes switching elements 5a and 5b that are a pair of switching elements connected in series, switching elements 5c and 5d that are a pair of switching elements connected in series, and a switching element that is a pair of switching elements connected in series. 5e, 5f. Each switching element pair of switching element 5a and switching element 5b, switching element 5c and switching element 5d, switching element 5e and switching element 5f is called an arm. The midpoint of each arm of the second inverter 5 is connected to the corresponding winding portion of the second three-phase winding portion 12.

  Specifically, an arm composed of the switching element 5a and the switching element 5b is connected to the terminal 14a, and an arm composed of the switching element 5c and the switching element 5d is connected to the terminal 14b, and the switching element 5e and the switching element The arm constituted by the element 5f is connected to the terminal 14c. In addition, each switching element connected to the P2 side, that is, P2 in each arm is also referred to as an upper switching element, and each switching element connected to the N2 side, that is, N2 in each arm is also referred to as a lower switching element.

  As the switching elements in the first inverter 4 and the second inverter 5, any elements may be used, but wide band gap semiconductors such as GaN (gallium nitride), SiC (silicon carbide: silicon carbide), diamond, and the like. Can be used. By using a wide band gap semiconductor, the withstand voltage is high and the allowable current density is also high, so that the module can be miniaturized. Since the wide band gap semiconductor has high heat resistance, it is possible to reduce the size of the radiating fin of the radiating portion.

  In addition, the electric motor drive device 2 according to the present embodiment includes a first DC voltage detector (not shown) that detects a DC voltage of DC power input from the DC power supply 81 to the first inverter 4, and a first DC voltage detector 82. And a second DC voltage detector (not shown) that detects a DC voltage of the DC power input to the two inverters 5. The first DC voltage detection unit outputs a signal VDC1 indicating the detected DC voltage. The second DC voltage detection unit outputs a signal VDC2 indicating the detected DC voltage. Furthermore, the electric motor drive device 2 receives IU1 which is a signal indicating the U-phase current flowing through the first three-phase winding unit 11, IV1 which is a signal indicating the V-phase current, and IW1 which is a signal indicating the W-phase current, respectively. Current detection units 21, 31, 41 to be detected, IU 2 indicating a U-phase current flowing through the second three-phase winding unit 12, IV 2 indicating a V-phase current, and a signal indicating a W-phase current. Current detection units 22, 32, and 42 for detecting a certain IW2, respectively.

  Based on Vdc1, Vdc2, Iu1, Iv1, Iw1, Iu2, Iv2, and Iw2, which will be described later, the control unit 90 includes six drive signals PWM (Pulse Width Modulation) 1 input to each switching element of the first inverter 4 and The six drive signals PWM2 that are input to the switching elements of the second inverter 5 are generated. PWM1 that is the first PWM signal and PWM2 that is the second PWM signal are PWM signals. The PWM signal is a pulse signal indicating that each switching element is turned on or off.

  In addition, although the example which each detects the electric current for three phases of the 1st three-phase coil | winding part 11 and the 2nd three-phase coil | winding part 12 is shown here, two-phase part is assumed on the assumption of three-phase balance. When the other phase is estimated from the current, the current detection units of the first three-phase winding unit 11 and the second three-phase winding unit 12 may be provided for two phases. When estimating a three-phase current from a direct current flowing between the direct current power supply 81 and the first inverter 4 and a direct current flowing between the direct current power supply 82 and the second inverter 5, the current detector is connected to the direct current. It is good also as a structure provided in total two places, one place between the power supply 81 and the 1st inverter 4, and one place between the DC power supply 82 and the 2nd inverter 5. FIG. Further, even if current detection is performed by a method of providing a current detection unit between the lower switching element of the first inverter 4 and N1 and between the lower switching element of the second inverter 5 and N2, etc. good.

  Further, the positive electrode side wiring P1 of the DC power source 81 and the positive electrode side wiring P2 of the DC power source 82 may be connected, and the negative electrode side wiring N1 of the DC power source 81 and the negative electrode side wiring N2 of the DC power source 82 may be connected. May be connected. When the positive-side wiring P1 of the DC power source 81 and the positive-side wiring P2 of the DC power source 82 are connected, and the negative-side wiring N1 of the DC power source 81 and the negative-side wiring N2 of the DC power source 82 are connected, The first inverter 4 and the second inverter 5 share a DC voltage.

  In FIG. 1, in order to avoid complication of the drawing, the connection relationship between the control unit 90 and each component and the illustration of the converter described later are omitted. The connection relationship between the control unit 90 and each component will be described with reference to FIG. FIG. 2 is a diagram illustrating a signal input to the control unit 90 and a signal output from the control unit 90.

  As shown in FIG. 2, Vdc <b> 1 that is a signal obtained by level-converting VDC <b> 1 by the converter 111 is input to the control unit 90. Further, Iu1, Iv1, and Iw1, which are signals obtained by converting the levels of IU1, IV1, and IW1 by converters 121, 131, and 141, respectively, are input to the control unit 90.

  Each converter has an appropriate input voltage range in each part to which the signal output from the converter is input after the signal level-converted by the converter with respect to the signal input to the converter. Next, voltage level conversion is performed. Here, a configuration in which converters are provided for all of the signals input to and output from the control unit 90 will be described. However, converters may not be provided for signals that do not require voltage level conversion. .

  Further, Vdc2, Iu2, Iv2, and Iw2, which are signals obtained by level-converting VDC2, IU2, IV2, and IW2 by converters 112, 122, 132, and 142, are input to control unit 90.

  Based on Vdc1, Iu1, Iv1, Iw1, Vdc2, Iu2, Iv2, and Iw2, the control unit 90 includes six drive signals PWM1 that are PWM signals for driving the switching elements of the first inverter 4, and Six drive signals PWM2, which are PWM signals for driving the switching elements of the two inverters 5, are generated. The six drive signals PWM1 are level-converted by the converter 171 and input to the switching elements of the first inverter 4 as the six drive signals pwm1. The six drive signals PWM2 are level-converted by the converter 172 and input to the switching elements of the second inverter 5 as the six drive signals pwm2.

  Specifically, the PWM1 is a PWM signal Up1, Vp1, Wp1 indicating whether the upper switching elements of the U phase, the V phase, and the W phase are turned on or off, and the U phase, the V phase, and the W phase. Un1, Vn1, and Wn1, which are PWM signals indicating whether the lower switching elements of the phase are turned on or off, respectively. Up1, Vp1, Wp1, Un1, Vn1, and Wn1 are converted by the converter 171 into up1, vp1, wp1, un1, vn1, and wn1, respectively. up1, vp1, wp1, un1, vn1, wn1 are respectively input to the switching elements 4a, 4c, 4e, 4b, 4d, 4f. The six drive signals pwm1 are these up1, vp1, wp1, un1, vn1, wn1.

  Similarly, PWM2 is a PWM signal Up2, Vp2, Wp2 that indicates whether the upper switching elements of the U phase, V phase, and W phase are turned on or off, and the U phase, V phase, and W phase, respectively. Un2, Vn2, and Wn2, which are PWM signals indicating whether the lower switching elements are turned on or off, respectively. Up2, Vp2, Wp2, Un2, Vn2, and Wn2 are converted by the converter 172 into up2, vp2, wp2, un2, vn2, and wn2, respectively. Up2, vp2, wp2, un2, vn2, and wn2 are input to switching elements 5a, 5c, 5e, 5b, 5d, and 5f, respectively. The six drive signals pwm2 are these up2, vp2, wp2, un2, vn2, wn2.

  FIG. 3 is a diagram illustrating a configuration example of the control unit 90 according to the first embodiment. As shown in FIG. 3, the control unit 90 includes a coordinate conversion unit 201, a voltage command calculation unit 211, a voltage command distribution unit 221, and a PWM drive signal generation unit 231.

  The coordinate conversion unit 201 converts Iu1, Iv1, and Iw1 into an excitation current component Iγ1 and a torque current component Iδ1 in the γδ coordinate system. The γδ coordinate system is a control coordinate system and is a two-axis orthogonal coordinate system in a rotating magnetic field. The coordinate conversion unit 201 performs coordinate conversion of Iu2, Iv2, and Iw2 into an excitation current component Iγ2 and a torque current component Iδ2 in the γδ coordinate system. Iγ1 and Iδ1 are excitation current components and torque current components corresponding to the first three-phase winding portion 11, and Iγ2 and Iδ2 are excitation current components and torque current corresponding to the second three-phase winding portion 12. It is an ingredient.

  The voltage command calculation unit 211 calculates a voltage command by performing vector control using the rotation speed command ω *, Iγ1, Iδ1, Iγ2, Iδ2, and motor parameters. The voltage commands are Vrγ1 * and Vrγ2 * indicating voltages to be generated in the direction of the excitation current component, and Vrδ1 * and Vrδ2 * indicating voltages to be generated in the direction of the torque current component. Specifically, the voltage command calculation unit 211 calculates Vrγ1 * and Vrδ1 * based on the rotation speed command ω *, Iγ1 and Iδ1, and motor parameters corresponding to the first three-phase winding unit 11. Similarly, the voltage command calculation unit 211 calculates Vrγ2 * and Vrδ2 * based on the rotation speed command ω *, Iγ2 and Iδ2, and the motor parameters corresponding to the second three-phase winding unit 12. The motor parameter is information such as winding resistance, inductance, and induced voltage of the electric motor 3 and is held in advance by the voltage command calculation unit 211. The rotation speed command ω * may be instructed from the outside of the electric motor system 1 or based on at least one of a signal input from the outside of the electric motor system 1 and a signal obtained in the electric motor system 1. May be determined.

  The voltage command distribution unit 221 redistributes the voltage command calculated by the voltage command calculation unit 211 to the first inverter 4 and the second inverter 5. When redistribution is not performed, the voltage commands corresponding to the first inverter 4 are Vrγ1 * and Vrδ1 *, and the voltage commands corresponding to the second inverter 5 are Vrγ2 * and Vrδ2 *. In this case, if the characteristics of the first three-phase winding portion 11 and the second three-phase winding portion 12 are the same, the output currents of the first inverter 4 and the second inverter 5 are substantially the same.

  However, depending on the specifications of the switching element used in each inverter, there is a case where it is desired to vary the magnitude of the output current, that is, the amplitude ratio among the inverters. When the ratio of the magnitude of the output current is desired to be different between the inverters, for example, the current capacity of the switching element used in the first inverter 4 and the current capacity of the switching element used in the second inverter 5 are different. Is the case. In addition, when the load of the motor 3 periodically fluctuates in a certain period, the fluctuation of the harmonic component load having a frequency higher than the period of this periodic fluctuation is suppressed by one inverter, and the above-described The peak current can be suppressed by determining the output voltage of each inverter so as to characterize periodic fluctuations. As a result, there is a case where even a higher load side drive can be handled as compared with the case where one inverter handles both the periodic fluctuation and the harmonic component. Hereinafter, the periodic fluctuation is referred to as a fundamental wave.

  For this reason, in the present embodiment, the voltage command distribution unit 221 does not directly use the voltage command calculated by the voltage command calculation unit 211 as the voltage command of the first inverter 4 and the second inverter 5, Redistribute to one inverter 4 and second inverter 5. Specifically, the voltage command distribution unit 221 performs the following processing.

The voltage command distribution unit 221 calculates Vγ * and Vδ * by the following equation (1).
Vγ * = Vrγ1 * + Vrγ2 *
Vδ * = Vrδ1 * + Vrδ2 * (1)

  Voltage command distribution unit 221 redistributes Vγ * and Vδ * to first inverter 4 and second inverter 5, respectively, and voltage commands Vγ1 * and Vδ1 * corresponding to first inverter 4 after redistribution. And the voltage commands Vγ2 * and Vδ2 * corresponding to the second inverter 5 after redistribution are output to the PWM drive signal generation unit 231.

As an example, a case where the ratio of the magnitude of the output current is varied between inverters will be described. The magnitude of the output current of the first inverter 4 to the magnitude of the output current of the second inverter 5 is A: B (A and B are real numbers satisfying A≈B), and the output of the first inverter 4 The magnitude of the output voltage of the first inverter 4 vs. the magnitude of the output voltage of the second inverter 5 for setting the magnitude of the current to the magnitude of the output current of the second inverter 5 to A: B is a: Let b. At this time, Vγ1 *, Vδ1 *, Vγ2 * and Vδ2 * are calculated by the following equation (2).
Vγ1 * = (a / (a + b)) × Vγ *
Vγ2 * = (b / (a + b)) × Vγ *
Vδ1 * = (a / (a + b)) × Vδ *
Vδ2 * = (b / (a + b)) × Vδ * (2)

  Examples of obtaining the voltage command value ratio from the current amplitude ratio include the following examples. Assume that there is an inverter # 1 having a current capacity of x amperes and an inverter # 2 having a current capacity of y amperes. Assuming that the relationship of x> y holds, inverter # 2 wants to suppress the current value more than inverter # 1, so the voltage command ratio is (inverter # 1: inverter # 2) = (x: y) To do. By doing so, inverter # 2 can suppress the flowing current by suppressing the voltage command value.

  Further, when one inverter is made to correspond to the fundamental wave and the other inverter is made to correspond to the high frequency component, Vγ * and Vδ * are separated into a component below the reference frequency and a component having a frequency higher than the reference frequency, respectively. . Then, for Vγ *, the voltage command distribution unit 221 sets a component equal to or lower than the reference frequency as Vγ1 *, and sets a component having a frequency higher than the reference frequency of Vγ * as Vγ2 *. Further, the voltage command distribution unit 221 sets Vδ * as a component equal to or lower than the reference frequency and Vδ2 * as a component having a frequency higher than the reference frequency.

  The reference frequency can be the frequency of the fundamental wave described above. For example, the reference frequency can be a frequency corresponding to one cycle of the mechanical angle of the electric motor 3. Or it is good also as a frequency higher than the fundamental frequency. As an example, a frequency that is N (N is an integer of 2 or more) times the frequency of the fundamental wave, that is, an Nth-order harmonic component may be set as the reference frequency. In this case, one inverter outputs up to the Nth order or lower harmonic component, and the other inverter outputs a higher frequency component than the Nth harmonic.

  In addition, the component below the reference frequency and the component higher than the reference frequency are separated by extracting components below the reference frequency of Vγ * and Vδ * using a low-pass filter, and each of the components below the reference frequency from Vγ * and Vδ *. This is realized by obtaining a component having a frequency higher than the reference frequency. Alternatively, separation of a component below the reference frequency and a component having a frequency higher than the reference frequency is performed by extracting a component having a frequency higher than the reference frequency of Vγ * and Vδ * using a high-pass filter, and using the reference from Vγ * and Vδ *, respectively. It may be realized by subtracting a frequency component higher than the frequency to obtain a component equal to or lower than the reference frequency, or may be realized by a method other than these.

  In the above example, the ratio between the component below the reference frequency and the component higher than the reference frequency, that is, the frequency band below the reference frequency is the first frequency band, and the frequency band higher than the reference frequency is the second frequency. In the case of the band, the ratio of the amplitude of the signal of the first frequency band component to the amplitude of the signal of the second frequency band component in each signal is 1: 0 for one inverter and 0 for the other inverter. : 1. However, the ratio of the component below the reference frequency and the component at a frequency higher than the reference frequency is not limited to this. The ratio between the amplitude of the signal of the first frequency band component and the amplitude of the signal of the second frequency band component in the first electric signal that is the electric signal output from the first inverter 4 is the second The ratio of the amplitude of the signal of the first frequency band component and the amplitude of the signal of the second frequency band component in the second electric signal that is the electric signal output from the inverter 5 may be different. As an example, the ratio of components below the reference frequency and components higher than the reference frequency is 0.2: 0.8 for one inverter and 0.8: 0.2 for the other inverter. The ratio of the component below the reference frequency and the component having a frequency higher than the reference frequency can be arbitrarily set for each inverter.

  The PWM drive signal generation unit 231 generates and outputs PWM1, which is a PWM signal for controlling each switching element of the first inverter 4, based on Vdc1, Vγ1 *, and Vδ1 *. The PWM drive signal generation unit 231 generates and outputs PWM2, which is a PWM signal for controlling each switching element of the second inverter 5, based on Vdc2, Vγ2 *, and Vδ2 *.

  As described above, since Vγ1 * and Vδ1 * are different, PWM1 and PWM2 generated by the PWM drive signal generation unit 231 are different. At this time, the PWM drive signal generation unit 231 may change the PWM1 and the PWM2 by changing the duty of the PWM1 and the PWM2.

  In the above example, the case where the magnitudes of the output currents are different between the first inverter 4 and the second inverter 5 has been described. However, the output voltage of the first inverter 4 and the second inverter 5 is different. You may make it vary in magnitude | size. That is, the amplitude of the first electric signal that is an electric signal output from the first inverter 4 to the first three-phase winding unit 11 and the second inverter 5 output to the second three-phase winding unit 12. The amplitude of the second electrical signal that is an electrical signal only needs to be different. The amplitude of the first electrical signal is the amplitude of the current of the first electrical signal, and the amplitude of the second electrical signal is the amplitude of the current of the second electrical signal. Alternatively, the amplitude of the first electrical signal is the amplitude of the voltage of the first electrical signal, and the amplitude of the second electrical signal is the amplitude of the voltage of the second electrical signal.

  FIG. 4 is a diagram illustrating an example of currents output from the first inverter 4 and the second inverter 5 of the present embodiment. FIG. 4 shows an example in which the voltage command distribution unit 221 separates a component equal to or lower than the reference frequency and a component having a frequency higher than the reference frequency. In the example shown in FIG. 4, the reference frequency is the fundamental wave frequency, the first inverter 4 is made to correspond to a component below the fundamental wave, and the second inverter 5 is made to correspond to a component having a frequency higher than the fundamental wave. . In the example of FIG. 4, the period of the fundamental wave is a period in which one period of the mechanical angle, that is, one rotation of the electric motor 3 is one period.

  4A shows the mechanical angle, FIG. 4B shows the electrical angle, and FIG. 4C shows the current flowing through Iu1, that is, the U phase of the first three-phase winding portion 11. FIG. 4D shows the current flowing through Iu 2, that is, the U phase of the second three-phase winding portion 12. The electrical angle is mechanical angle x number of pole pairs.

  As shown in FIG. 4, Iu1 corresponding to the first inverter 4 becomes a signal that fluctuates with the period of the fundamental wave, and Iu2 corresponding to the second inverter 5 fluctuates at a high frequency that is higher than the fundamental wave. Signal.

  Next, the hardware configuration of the control unit 90 of the present embodiment will be described. The control unit 90 is realized by a processing circuit. This processing circuit may be a processing circuit that is dedicated hardware, or may be a control circuit including a processor. In the case of dedicated hardware, the processing circuit is, for example, a circuit called a microcontroller. The processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof.

  When the processing circuit for realizing the control unit 90 is realized by a control circuit including a processor, this control circuit is, for example, the control circuit 400 having the configuration shown in FIG. FIG. 5 is a diagram illustrating a configuration example of the control circuit 400 of the present embodiment. The control circuit 400 includes a processor 401 and a memory 402. The processor 401 is a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor, DSP (Digital Signal Processor)) or the like. The memory 402 is, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Memory, or a Nonvolatile Memory Programmable Memory). A semiconductor memory, a magnetic disk, and the like are applicable.

  When the processing circuit that implements the control unit 90 is the control circuit 400 including a processor, the processor 401 reads out and executes a program describing the processing of the control unit 90 stored in the memory 402. The memory 402 is also used as a temporary memory in each process executed by the processor 401.

  As described above, in the present embodiment, the voltage command distribution unit 221 redistributes the voltage command to the first inverter 4 and the second inverter 5. For this reason, an output voltage can be flexibly set for every inverter. Therefore, the first inverter 4 and the second inverter 5 can apply currents having different sizes to the first three-phase winding unit 11 and the second three-phase winding unit 12. In addition, a current including a harmonic component having a frequency higher than the reference frequency can be output to the winding portion on one side.

  Moreover, in this Embodiment, since an output voltage can be flexibly set for every inverter, the freedom degree of selection of the module used as the 1st inverter 4 and the 2nd inverter 5 increases. That is, since restrictions on the current capacity are reduced, various modules can be used. Moreover, since the harmonic component which is a frequency higher than a reference frequency can be applied to the motor 3 using one inverter, it is higher than the case where one inverter supports both the fundamental wave and the harmonic component. There is a possibility that even the load can be accommodated.

  Further, since the output voltage can be varied for each inverter, it is easy to take measures against heat of the modules constituting the inverter. That is, when the temperature of one of the two inverters is high, the ratio of the output voltages can be determined so as to reduce the output voltage of one of the two inverters. As a result, it is possible to prevent performance deterioration due to a high temperature while maintaining the torque realized by the total of the two inverters.

Embodiment 2. FIG.
FIG. 6 is a diagram illustrating a configuration example of the air conditioner 300 according to the second embodiment of the present invention. The air conditioner 300 according to the present embodiment includes the electric motor drive device 2 and the electric motor 3 described in the first embodiment. That is, the air conditioner 300 of the present embodiment is equipped with the electric motor system 1 of the first embodiment. In addition, in FIG. 6, the part of the heat pump apparatus concerning a refrigerating cycle is shown in the air conditioner 300, and illustration of another part is abbreviate | omitted. In the air conditioner 300 according to the present embodiment, the compressor 251, the four-way valve 259, the outdoor heat exchanger 252, the expansion valve 261, and the indoor heat exchanger 257 that incorporate the electric motor 3 according to the first embodiment are connected via a refrigerant pipe. It has a refrigeration cycle attached to it and constitutes a separate air conditioner.

  The compressor 251 includes a compression mechanism 250 that compresses the refrigerant and an electric motor 3 that operates the compressor. The refrigerant circulates between the outdoor heat exchanger 252 and the indoor heat exchanger 257 from the compressor 251 for cooling and heating. The refrigeration cycle to perform is comprised. In addition, the structure shown in FIG. 6 is applicable not only to an air conditioner but also to a device having a refrigeration cycle such as a refrigerator and a freezer, that is, a refrigeration cycle device.

  As described above, since the air conditioner 300 according to the present embodiment is equipped with the electric motor system 1 described in the first embodiment, the degree of freedom in selecting an inverter used in the electric motor system 1 can be increased. . In addition, heat countermeasures for the modules constituting the inverter are facilitated.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  DESCRIPTION OF SYMBOLS 1 Electric motor system, 2 Electric motor drive device, 3 Electric motor, 4 1st inverter, 4a-4f, 5a-5f Switching element, 5 2nd inverter, 11 1st 3 phase winding part, 11a, 12a U phase winding Wire portion, 11b, 12b V-phase winding portion, 11c, 12c W-phase winding portion, 12 second three-phase winding portion, 13a, 13b, 13c, 14a, 14b, 14c terminals, 81, 82 DC power supply, 90 control unit, 201 coordinate conversion unit, 211 voltage command calculation unit, 221 voltage command distribution unit, 231 PWM drive signal generation unit, 250 compression mechanism, 251 compressor, 252 outdoor heat exchanger, 257 indoor heat exchanger, 259 four-way Valve, 261 expansion valve, 300 air conditioner.

In order to solve the above-described problems and achieve the object, the present invention is an electric motor drive device used for an electric motor including a first winding portion and a second winding portion, and includes the first winding portion. And a second inverter connected to the second winding portion. The first frequency band component of the first electrical signal, which is an electrical signal output from the first inverter to the first winding section, and the second frequency band component different from the first frequency band The ratio between the amplitude of the first signal and the second frequency band in the second electric signal that is the electric signal output from the second inverter to the second winding portion This is different from the ratio of the component amplitude to the signal amplitude .

Claims (9)

An electric motor driving device used for an electric motor including a first winding portion and a second winding portion,
A first inverter connected to the first winding section;
A second inverter connected to the second winding portion;
With
The amplitude of the first electric signal, which is an electric signal output from the first inverter to the first winding portion, and the second electric signal, which is output from the second inverter to the second winding portion. The electric motor drive device is different from the amplitude of the electric signal.   The amplitude of the first electric signal is an amplitude of a current of the first electric signal, and an amplitude of the second electric signal is an amplitude of a current of the second electric signal. Electric motor drive device.   The amplitude of the first electric signal is an amplitude of a voltage of the first electric signal, and an amplitude of the second electric signal is an amplitude of a voltage of the second electric signal. Electric motor drive device. A control unit for outputting a first PWM signal to the first inverter and outputting a second PWM signal to the second inverter;
With
4. The electric motor drive device according to claim 1, wherein the first PWM signal and the second PWM signal are different. 5.   The motor driving device according to claim 4, wherein a duty of the first PWM signal is different from a duty of the second PWM signal.   When the frequency band below the reference frequency is the first frequency band and the frequency band higher than the reference frequency is the second frequency band, the amplitude of the signal of the component of the first frequency band in the first electric signal Between the amplitude of the signal of the component of the second frequency band and the amplitude of the signal of the component of the first frequency band in the second electric signal and the amplitude of the signal of the component of the second frequency band The electric motor drive device according to any one of claims 1 to 5, wherein the ratio is different from the ratio.   The electric motor drive device according to claim 6, wherein the reference frequency is a frequency corresponding to one cycle of a mechanical angle of the electric motor. An electric motor comprising a first winding portion and a second winding portion;
A first inverter connected to the first winding section;
A second inverter connected to the second winding portion;
With
The amplitude of the first electric signal, which is an electric signal output from the first inverter to the first winding portion, and the second electric signal, which is output from the second inverter to the second winding portion. The motor system is different from the amplitude of the electrical signal. An electric motor drive device according to any one of claims 1 to 7,
A compressor that is driven by the motor driving device and includes a first winding portion and a second winding portion;
A refrigeration cycle apparatus comprising:

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