JP2021035179A - Polyphase motor driving device - Google Patents

Abstract

To provide a polyphase motor driving device that reduces potential fluctuation between a main circuit and the ground, which can occur when the polyphase motor driving device passes an electric current to a plurality of windings in a polyphase motor.SOLUTION: In the polyphase motor driving device in an embodiment, a first main circuit is connected to a first winding and supplies AC power to the first winding, on the basis of a first PWM signal that has been modulated by a single-phase pulse width modulation (hereinafter, referred to as PWM) method. A second main circuit is connected to a second winding and supplies AC power to the second winding, on the basis of a second PWM signal that has been modulated by the PWM method. The first control unit is provided in association with the first main circuit, and supplies the first PWM signal in which the phase with respect to a reference phase has been determined on the basis of a speed of the polyphase motor, to the first main circuit. The second control unit is provided in association with the second main circuit, and supplies the second PWM signal in which the phase with respect to the reference phase has been determined on the basis of the speed of the polyphase motor, to the second main circuit.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a multi-phase electric motor drive device.

The multi-phase motor drive device uses a plurality of single-phase inverters of a PWM (Pulse Width Modulation) control method to drive a multi-phase motor having a plurality of windings electrically isolated from each other. The multi-phase electric motor is driven by supplying AC power from each of the above-mentioned single-phase inverters to each of the above-mentioned windings. In such a multi-phase motor drive device, if the carrier signals used for PWM control of a plurality of single-phase inverters are synchronized, the timing at which the current flows through the multi-phase motor may be the same for each single-phase inverter. When the timing of the current flowing through the above-mentioned multi-phase motor coincides, the potential fluctuation between the main circuit and the ground may become large.

Japanese Unexamined Patent Publication No. 2013-39033

An object of the present invention is to provide a multi-phase motor drive device that reduces potential fluctuations between a main circuit and the ground that may occur when a multi-phase motor drive device passes a current through a plurality of windings of a multi-phase motor. Is.

The multi-phase electric motor drive device of the embodiment includes a first main circuit, a second main circuit, a first control unit, and a second control unit. The polyphase motor includes a plurality of windings including at least a first winding and a second winding, and the windings are electrically isolated from each other and magnetically coupled to each other. The first main circuit is connected to the first winding and supplies AC power to the first winding based on the first PWM signal modulated by a single-phase pulse width modulation (hereinafter referred to as PWM) method. The second main circuit is connected to the second winding and supplies AC power to the second winding based on the second PWM signal modulated by the PWM method. The first control unit is provided in association with the first main circuit, and supplies the first PWM signal whose phase with respect to the reference phase is determined based on the speed of the polyphase electric motor to the first main circuit. The second control unit is provided in association with the second main circuit, and supplies the second PWM signal whose phase with respect to the reference phase is determined based on the speed of the polyphase electric motor to the second main circuit.

The block diagram of the multi-phase electric motor drive device of an embodiment. The figure for demonstrating the relationship between the multi-phase electric motor of embodiment, and each single-phase inverter. The block diagram of the main part of the polyphase electric motor drive device of an embodiment. The block diagram of the current control circuit of an embodiment. The block diagram of the current control circuit of an embodiment. The figure for demonstrating the gate signal generated by the PWM control which synchronized the carrier signal of each phase of embodiment. The figure for demonstrating the potential fluctuation with respect to the main circuit of embodiment. The figure for demonstrating the potential fluctuation with respect to the main circuit of embodiment. The figure for demonstrating the potential fluctuation between NE when the modulation factor is 0. The figure for demonstrating the result of the simulation of embodiment. The figure for demonstrating the example in which the phase of the carrier of the single-phase inverter corresponding to the adjacent phase of the multi-phase electric motor of an embodiment is shifted at equal intervals. The figure for demonstrating the example in which the phase of the carrier of the single-phase inverter corresponding to the adjacent phase of the multi-phase electric motor of an embodiment is shifted at equal intervals. The figure for demonstrating the example in which the phase of the carrier of the single-phase inverter corresponding to each phase of the multi-phase electric motor of an embodiment is aligned. The figure for demonstrating the example in which the phase of the carrier of the single-phase inverter corresponding to each phase of the multi-phase electric motor of an embodiment is aligned. The flowchart of the process of adjusting the carrier phase between the single-phase inverters of an embodiment. The figure for demonstrating a predetermined function for defining a phase difference of an embodiment. The figure for demonstrating the predetermined function for defining the phase difference of the 1st modification.

Hereinafter, the multi-phase electric motor drive device of the embodiment will be described with reference to the drawings.
In the following description, the variable speed multi-phase motor drive device is simply referred to as a multi-phase motor drive device. In addition, the same reference numerals are given to configurations having the same or similar functions. Then, the duplicate description of those configurations may be omitted. It should be noted that being electrically connected may be simply "connected". The "single-phase pulse width modulation" shown in the following description is pulse width modulation that outputs single-phase alternating current, and may be simply called PWM. The "carrier wave" is a triangular wave or a sawtooth wave used for control by the carrier comparison PWM method (PWM control). "Carrier frequency" is the reciprocal of the repetition period of a triangular or sawtooth wave on a particular carrier. The "fundamental wave" refers to the component having the lowest frequency among the signal components of a specific carrier wave. The "harmonic component" is a harmonic component with respect to the frequency of the fundamental wave, and is an odd number of harmonics of one or more orders included in any of current, voltage, and electric power unless otherwise specified. It is an ingredient. In addition, in the case of "same waveform", the case where the waveforms are substantially equal is also included.

(Embodiment)
FIG. 1 is a configuration diagram of the multi-phase electric motor drive device 1 of the embodiment.
The multi-phase electric motor drive device 1 includes a DC power supply 2, a multi-phase electric motor (M) 3, and a control device 10.

The DC power supply 2 is a power source for the multi-phase electric motor drive device 1, and supplies DC power to the control device 10 described later. The DC power supply 2 outputs a desired voltage (DC voltage) between the negative electrode N and the positive electrode P.

The polyphase electric motor 3 has a plurality of windings, and the windings are electrically insulated from each other and magnetically coupled to each other. The first winding and the second winding, which will be described later, are examples of a plurality of windings.

The control device 10 includes, for example, a single-phase inverter 101, a single-phase inverter 102, a single-phase inverter 10N, a synchronization signal generation circuit 150, a speed phase control circuit 160, and a rotation angle detector 170.

The single-phase inverter 101 includes, for example, a main circuit 111 (first main circuit), a current control circuit 121 (first control unit), a capacitor 131, and a current sensor 141.

The main circuit 111 is an example of the first main circuit. For example, the main circuit 111 includes switches S1, S2, S3, and S4 of IGBTs (Insulated Gate Bipolar Transistor) and diodes D1, D2, D3, and D4 connected in antiparallel, respectively, and is formed in a full bridge type. Has been done. The pair of the switch S1 and the diode D1 and the pair of the switch S2 and the diode D2 form a positive arm connected to the positive electrode P. The pair of the switch S3 and the diode D3 and the pair of the switch S4 and the diode D4 form a negative arm connected to the negative electrode N. The form shown in the figure is an example, and the switches S1, S2, S3, and S4 may be other types of semiconductor devices such as FETs (Field-Effect Transistors) without limitation. It may be formed in a half-bridge type.

The input side of the main circuit 111 is connected in parallel to the DC power supply 2 and the capacitor 131, and the voltage smoothed by the capacitor 131 is supplied from the DC power supply 2. The output side of the main circuit 111 is connected to the first winding of the multi-phase motor 3. The current sensor 141 detects the current flowing from the main circuit 111 to the first winding of the multi-phase electric motor 3. The main circuit 111 supplies single-phase AC power to the first winding of the multi-phase electric motor 3 based on the gate pulse GP1 supplied from the current control circuit 121 described later.

The single-phase inverter 102 includes, for example, a main circuit 112 (second main circuit), a current control circuit 122 (second control unit), a capacitor 132, and a current sensor 142.

The main circuit 112 is an example of the second main circuit. The main circuit 112 and the main circuit 11N described later are configured in the same manner as the main circuit 111.

The input side of the main circuit 112 is connected to the DC power supply 2, and a voltage smoothed by a capacitor 132 connected in parallel is supplied from the DC power supply 2. The output side of the main circuit 112 is connected to the second winding of the polyphase motor 3. The current sensor 142 detects the current flowing from the main circuit 112 to the second winding of the multi-phase motor 3. The main circuit 112 supplies single-phase AC power to the second winding of the multi-phase motor 3 based on the second PWM signal modulated by the PWM method.

The single-phase inverter 10N includes, for example, a main circuit 11N, a current control circuit 12N, a capacitor 13N, and a current sensor 14N.

The input side of the main circuit 11N is connected to the DC power supply 2, and a voltage smoothed by a capacitor 13N connected in parallel is supplied from the DC power supply 2. The output side of the main circuit 11N is connected to the Nth winding of the multi-phase motor 3. The current sensor 14N detects the current flowing from the main circuit 11N to the Nth winding of the polyphase motor 3. The main circuit 11N supplies single-phase AC power to the Nth winding of the multi-phase motor 3 based on the Nth PWM signal modulated by the PWM method.

Hereinafter, when the single-phase inverter 101, the single-phase inverter 102, ..., And the single-phase inverter 10N are collectively shown, they are referred to as a single-phase inverter 10i. i indicates an integer from 1 to N, and N is an integer of 2 or more. Similarly, when the main circuit 111, the main circuit 112, ..., And the main circuit 11N are collectively shown, it is referred to as the main circuit 11i. When the current control circuit 121, the current control circuit 122, ..., And the current control circuit 12N are collectively shown, it is referred to as a current control circuit 12i.

The synchronization signal generation circuit 150 generates a carrier synchronization signal and supplies the generated carrier synchronization signal to each current control circuit of each single-phase inverter 10i. The carrier synchronization signals include the carrier synchronization signal CSS1 supplied to the current control circuit 121, the carrier synchronization signal CSS2 (FIG. 4) supplied to the current control circuit 122, and the carrier synchronization signal CSSN supplied to the current control circuit 12N (FIG. 5). ) Etc. may be included. In the following description, the carrier synchronization signal supplied to each single-phase inverter 10i will be described by exemplifying the carrier synchronization signal CSS1 as a common signal, but the present invention is not limited thereto. For example, the carrier synchronization signal CSS1 and the carrier synchronization signal CSS2 may be independent signals, or the carrier synchronization signal CSS1 and the carrier synchronization signal CSS2 and the carrier synchronization signal CSSN may be synchronized with each other and have different waveforms. There may be. The above synchronization may include a relationship that includes an acceptable phase difference.

The speed phase control circuit 160 receives the speed command and the angle detection value (mechanical angle) from the rotation angle detector 170 described later, and receives the current command peak value, the phase angle θ (electric angle), and the speed detection value ω. Is generated, and the current command peak value, the phase angle θ, and the speed detection value ω are supplied to the single-phase inverter 10i. The current command peak value is a control target value for driving the multi-phase electric motor 3 at the speed of the speed command value set as the speed command. Details of the speed phase control circuit 160 will be described later.

The rotation angle detector 170 detects the rotation angle of the multi-phase electric motor 3 and outputs an angle detection value (mechanical angle). Note that sensorless control may be used without providing the rotation angle detector 170.

The relationship between the multi-phase electric motor 3 and each single-phase inverter 10i will be described with reference to FIG. FIG. 2 is a diagram for explaining the relationship between the multi-phase electric motor 3 of the embodiment and each single-phase inverter 10i. A single-phase inverter 10i is arranged corresponding to the winding of each phase. The windings of each phase of the polyphase motor 3 are not electrically connected, but are magnetically coupled because the magnetic paths of the windings of different phases overlap.

As a result, the multi-phase electric motor 3 is driven by each single-phase inverter 10i provided corresponding to each phase.

An example of the multi-phase electric motor drive device 1 of the embodiment will be described with reference to FIGS. 3 to 5. FIG. 3 is a configuration diagram of a main part of the multi-phase electric motor drive device 1 of the embodiment.

The details of the speed phase control circuit 160 will be described.
The speed phase control circuit 160 includes, for example, a subtractor 161, a speed control circuit 162, a phase control circuit 163, and a speed detection circuit 164. The subtractor 161 calculates the speed deviation between the speed command value by the speed command and the speed detection value ω detected by the speed detection circuit 164 described later. The speed control circuit 162 generates a current command peak value such that the speed deviation calculated by the subtractor 161 becomes zero, and outputs the generated current command peak value to each single-phase inverter 10i. The speed detection circuit 164 differentiates the angle detection value (mechanical angle) detected by the rotation angle detector 170 to generate the speed detection value ω. The phase control circuit 163 generates a phase angle θ (electrical angle) based on the angle detection value (mechanical angle) detected by the rotation angle detector 170, and outputs the phase angle θ to each single-phase inverter 10i.

As described above, the speed phase control circuit 160 sets the current command peak value such that the rotation speed of the multi-phase motor 3 becomes a speed command based on the angle detection value detected by the rotation angle detector 170, for each single-phase inverter 10i. Is instructed to supply the phase angle θ used for control to each single-phase inverter 10i.

The details of the current control circuit 121 will be described.
The current control circuit 121 includes, for example, a sine value generator 1211 (Sin), a multiplier 1212, a subtractor 1213, a current control circuit main body 1214, and a PWM control circuit 1215 (first PWM unit, notation in the figure is PWM. ), The phase comparator 1216 (first phase comparator), the carrier generation circuit 1217 (first carrier generation unit), the carrier phase correction circuit 1218 (first phase correction unit), and the phase correction determination unit 1218c (. It is provided with a first phase determining unit).

The sine value generator 1211 generates a sine value of the phase based on the phase angle θ supplied from the speed phase control circuit 160 and the phase difference defined based on the winding configuration of the polyphase motor 3. The sine values generated by the sine value generator 1211 are different from each other for each corresponding winding.

The multiplier 1212 multiplies the current command peak value supplied from the speed phase control circuit 160 with the sine value generated by the sine value generator 1211 to obtain the current command value ICMD1.

The subtractor 1213 subtracts the current detection value IDET1 detected by the current sensor 141 from the current command value ICMD1 calculated by the multiplier 1212 to obtain the current deviation ΔI1.

The current control circuit main body 1214 calculates a voltage command value ER1 that sets the current deviation ΔI1 to 0, and supplies the voltage command value ER1 to the PWM control circuit 1215.

The phase comparator 1216 receives the first carrier wave from the carrier generation circuit 1217, compares the phase of the carrier synchronization signal CSS1 (first synchronization signal) with the phase of the first carrier wave, and values according to the phase difference. Output PD1.

The carrier generation circuit 1217 adjusts the carrier frequency fH by a predetermined amount based on the above phase difference PD1 so that the phase of the carrier synchronization signal CSS1 and the phase of the first carrier match.

The carrier phase correction circuit 1218 corrects the phase of the first carrier wave of the carrier frequency fH adjusted by the carrier generation circuit 1217 based on the phase correction command supplied from the phase correction determination unit 1218c described later, and corrects the phase of the first carrier wave to the first carrier signal. CS1 is generated, and the result is output as the first carrier signal CS1.

The phase correction determination unit 1218c may determine the phase of the first carrier signal CS1 (first reference carrier) based on, for example, the speed detection value ω of the polyphase electric motor 3. Further, the phase correction determination unit 1218c may determine the phase of the first carrier signal CS1 by adjusting the magnitude of the phase difference of the first predetermined amount based on the speed detection value ω of the polyphase electric motor 3. The phase correction determination unit 1218c is an example of the first phase determination unit. For example, the phase difference of the first predetermined amount is defined as the phase difference of the phase of the first carrier signal CS1 with respect to the phase of the carrier synchronization signal CSS1 (first synchronization signal). The phase of the first carrier signal CS1 (first reference carrier) may be determined to a predetermined value regardless of the speed detection value ω of the multi-phase electric motor 3. The same applies hereinafter.

The phase comparator 1216 and the carrier generation circuit 1217 form a first PLL (Phase Locked Loop).

The PWM control circuit 1215 generates a gate pulse GP1 for controlling the main circuit 111 by PWM control based on the voltage command value ER1 and the first carrier signal CS1. For example, the PWM control circuit 1215 uses the first carrier signal CS1 to modulate the voltage command value ER1 (reference signal) of the first phase of the multi-phase electric motor 3, and the modulated PWM signal GP1 (first PWM signal). Is supplied to the main circuit 111 (first main circuit).

The current control circuit 121 configured as described above generates a first carrier signal CS1 that is synchronized with the carrier synchronization signal CSS1 and has a first predetermined amount of phase difference with respect to the phase of the carrier synchronization signal CSS1. The current control circuit 121 modulates the voltage command value ER1 (reference signal) of the first phase of the multi-phase electric motor 3 by using the first carrier signal CS1, and transmits the first PWM signal obtained by modulating the voltage command value ER1 (reference signal) to the main circuit 111. Supply.

The single-phase inverter 102 and the single-phase inverter 10N are shown in the attached sheet.

The current control circuit 122 of the single-phase inverter 102 according to the embodiment will be described with reference to FIG. FIG. 4 is a configuration diagram of the current control circuit 122 of the embodiment. The current control circuit 122 is provided in association with the main circuit 112 (second main circuit).

The current control circuit 122 (second control unit) includes, for example, a sine value generator 1221 (Sin), a multiplier 1222, a subtractor 1223, a current control circuit main body 1224, and a PWM control circuit 1225 (second PWM unit, The notation in the figure is PWM.), The phase comparator 1226 (second phase comparator), the carrier generation circuit 1227 (second carrier generation unit), the carrier phase correction circuit 1228 (second phase correction unit), and the like. It is provided with a phase correction determination unit 1228c (second phase determination unit). Although detailed description is omitted, the sine value generator 1221, the multiplier 1222, the subtractor 1223, the current control circuit main body 1224, the PWM control circuit 1225, the phase comparator 1226, the carrier generation circuit 1227, and the like. The carrier phase correction circuit 1228 and the phase correction determination unit 1228c include the above-mentioned sine value generator 1211, multiplier 1212, subtractor 1213, current control circuit main body 1214, PWM control circuit 1215, and phase comparator 1216. The carrier generation circuit 1217, the carrier phase correction circuit 1218, and the phase correction determination unit 1218c are configured in the same manner.

The generation of the second carrier signal CS2 will be described.
The phase comparator 1226 receives the second carrier wave from the carrier generation circuit 1227, compares the phase of the carrier synchronization signal CSS2 with the phase of the second carrier wave, and outputs a value PD2 corresponding to the phase difference.

The carrier generation circuit 1227 adjusts the carrier frequency fH of the second carrier wave by a predetermined amount based on the above phase difference PD2 so that the phase of the carrier synchronization signal CSS2 and the phase of the second carrier wave match.

The carrier phase correction circuit 1228 corrects the phase of the second carrier wave of the carrier frequency fH adjusted by the carrier generation circuit 1227 based on the phase correction command supplied from the phase correction determination unit 1228c described later, and corrects the phase of the second carrier wave to the second carrier signal. CS2 is generated, and the result is output as a second carrier signal CS2.

The phase correction determination unit 1228c may determine the phase of the second carrier signal CS2 (second reference carrier) based on, for example, the speed detection value ω of the multi-phase electric motor 3. Further, the phase correction determination unit 1228c may determine the phase of the second carrier signal CS2 by adjusting the magnitude of the phase difference of the second predetermined amount based on the speed detection value ω of the polyphase electric motor 3. The phase correction determination unit 1218c is an example of the first phase determination unit. For example, the phase difference of the second predetermined amount is defined as the phase difference of the phase of the second carrier signal CS2 with respect to the phase of the carrier synchronization signal CSS1.

The phase comparator 1226 and the carrier generation circuit 1227 form a second PLL.

The PWM control circuit 1225 generates a gate pulse GP2 for controlling the main circuit 112 by PWM control based on the voltage command value ER2 and the second carrier signal CS2. For example, the PWM control circuit 1225 uses the second carrier signal CS2 to modulate the voltage command value ER2 (reference signal) of the second phase of the multi-phase electric motor 3, and the modulated PWM signal GP2 (second PWM signal). Is supplied to the main circuit 112 (second main circuit).

The current control circuit 122 configured as described above generates a second carrier signal CS2 that is synchronized with the carrier synchronization signal CSS2 and has a phase difference of a second predetermined amount with respect to the phase of the carrier synchronization signal CSS2. The current control circuit 122 modulates the voltage command value ER2 (reference signal) of the second phase of the multi-phase electric motor 3 using the second carrier signal CS2, and transmits the second PWM signal obtained by modulating the second PWM signal to the main circuit 112. Supply.

The current control circuit 12N of the single-phase inverter 10N in the embodiment will be described with reference to FIG. FIG. 5 is a block diagram of the current control circuit 12N of the embodiment. The current control circuit 12N is provided in association with the main circuit 11N.

The current control circuit 12N includes, for example, a sine value generator 12N1 (Sin), a multiplier 12N2, a subtractor 12N3, a current control circuit main body 12N4, and a PWM control circuit 12N5 (NPWM unit, notation in the figure is PWM. ), The phase comparator 12N6 (Nth phase comparator), the carrier generation circuit 12N7 (Nth carrier generation unit), the carrier phase correction circuit 12N8 (Nth phase correction unit), and the phase correction determination unit 12N8c (. The Nth phase determining unit) is provided. Although detailed description is omitted, the sine value generator 12N1, the multiplier 12N2, the subtractor 12N3, the current control circuit main body 12N4, the PWM control circuit 12N5, the phase comparator 12N6, the carrier generation circuit 12N7, and the like. The carrier phase correction circuit 12N8 and the phase correction determination unit 12N8c are the above-mentioned sine value generator 1211, multiplier 1212, subtractor 1213, current control circuit main body 1214, PWM control circuit 1215, and phase comparator. It is configured in the same manner as the 1216, the carrier generation circuit 1217, the carrier phase correction circuit 1218, and the phase correction determination unit 1218c. For a detailed description of the current control circuit 12N, see the current control circuit 121 described above.

The current control circuit 12N generates an Nth carrier signal CSN that is synchronized with the carrier synchronization signal CSSN and has an Nth predetermined amount of phase difference with respect to the phase of the carrier synchronization signal CSSN. The current control circuit 12N modulates the voltage command value ERN (reference signal) of the Nth phase of the multi-phase electric motor 3 using the Nth carrier signal CSN, and modulates the gate pulse GPN of the NPWM signal obtained by modulating the voltage command value ERN (reference signal). It is supplied to the main circuit 11N.

Next, with reference to FIG. 6, the gate signal including the gate pulse of each phase when PWM control in which the carrier signals of each phase are synchronized is performed by the multi-phase electric motor drive device 1 of the embodiment will be described. FIG. 6 is a diagram for explaining a gate signal generated by PWM control in which carrier signals of each phase of the embodiment are synchronized. What is illustrated here is the case of three phases. The carrier signal of each phase is the above-mentioned first carrier signal CS1, second carrier signal CS2, Nth carrier signal CSN, and the like. In the following description, the phase of the carrier signal may be referred to as the carrier phase. The period of the carrier signal is sometimes called the carrier period.

In the four waveform diagrams shown in FIG. 6, the degree of modulation of the PWM control input signal is different from each other. The modulation degrees in the waveform diagrams (a) to (d) of FIG. 6 are 0.01, 0.2, 0.6, and 1, respectively.
The carrier signal of a certain phase and the input signal of the PWM control of the three phases are superimposed on the upper side of each waveform diagram, and the gate signal including the gate pulse of each phase generated by the PWM control is shown on the lower side of the carrier signal. Shown.

From this figure, when the degree of modulation is small, the time zones in which the gate pulses of each phase are generated are aligned, but it can be seen that the time zones in which the gate pulses of each phase are generated vary as the degree of modulation increases.
When the modulation factor is close to 0, the period in which the gate pulses of each phase are output overlaps is long. When the modulation factor becomes 0, the output of the gate pulse of each phase overlaps, and the switch of each phase is turned on.

Next, the potential fluctuation between the main circuit and the ground will be described with reference to FIGS. 7 and 8. 7 and 8 are diagrams for explaining the potential fluctuation between the main circuit of the embodiment and the ground.
By the way, if the time zones in which the gate pulses of each phase are generated are the same, the potentials between the main circuit and the ground may fluctuate because the timings at which the switches of each phase are turned on match. is there. The modulation factor is set to 0 for the sake of simplicity. For example, the outputs of the single-phase inverter 101 are called U-phase and V-phase.

FIG. 7 shows the circuit operation when the P-side element of the single-phase inverter is turned on (ON) and the N-side element is turned off (OFF). For example, the P-side element is switches S1 and S2. The N-side element is the switches S3 and S4.

It is assumed that the single-phase inverter 101, the DC power supply 2, and the multi-phase electric motor 3 are insulated from the frame E. In this case, there is a stray capacitance between the single-phase inverter 101, the DC power supply 2, the multi-phase electric motor 3, and the frame E.

For example, the stray capacitance between the P side of the DC link near the single-phase inverter 101 and the frame E is called SC11. The stray capacitance between the N side of the DC link near the single-phase inverter 101 and the frame E is called SC12. The stray capacitance between the P side of the DC link near the DC power supply 2 and the frame E is called SC21. The stray capacitance between the N side of the DC link near the DC power supply 2 and the frame E is called SC22.

There are stray capacitances SC31 and SC32 between the U-phase and V-phase connected to the internal winding of the multi-phase motor 3 and the housing of the multi-phase motor 3. Further, there is a stray capacitance (not shown) between the housing of the polyphase motor 3 and the frame E.

The stray capacitances SC11, SC12, SC21, and SC22 are sufficiently smaller than the stray capacitances SC31 and SC32 of the polyphase motor 3. According to this, the potential of the frame E on the multi-phase motor 3 side becomes close to the P potential, and the potential difference between the potential of the frame E on the main circuit side and the N potential becomes substantially equal to the difference between the P potential and the N potential. ..

In the above case, no current flows between the U-phase and V-phase of the output of the single-phase inverter, that is, in the path of the normal mode, but as shown in FIG. 7, there are many currents in the U-phase and V-phase of the output of the single-phase inverter. A common mode current flows in the path via the stray capacitances SC31 and SC32 on the phase electric motor 3 side.

FIG. 8 shows the circuit operation when the N-side element of the single-phase inverter is turned ON.
Taking the potential fluctuation between the main circuits NE (earth) as an example, as shown in FIG. 8, when the N-side element is on, the potential (earth potential) of the frame E and the N potential become substantially the same potential. The potential difference between NE becomes 0.
Further, as shown in FIG. 7, when the P-side element is on, the ground potential and the P potential are substantially the same potential, so that the potential difference between NE and E becomes equal to the DC voltage.

The result of the simulation simulating this is shown in FIG. FIG. 9 is a diagram for explaining the potential fluctuation between NE and E when the modulation factor is 0. As a condition of this simulation, as described above, the stray capacitance on the main circuit side is set to be sufficiently smaller than the stray capacitances SC31 and SC32 on the polyphase motor 3 side. The potential fluctuation between NE shown in FIG. 9 is synchronized with the carrier cycle.

Next, an example for reducing the common mode current will be described.
For example, an example in which the number of windings (the number of phases) of the multi-phase electric motor 3 is set to two is shown, and the operation of this example is verified by simulation. In this case, the main circuit is formed by connecting the single-phase inverters 101 and 102 to the DC power supply 2 as shown in FIG. 1, and the number of the single-phase inverters 101 and 102 is two. One end of a capacitor simulating the stray capacitance SC31 and SC32 on the multi-phase electric motor 3 side shown in FIG. 7 is connected to the outputs of the single-phase inverters 101 and 102, and the other end of the capacitor is connected to the frame. The output of the single-phase inverter 101 and the output of the single-phase inverter 102 are coupled to each other via a capacitor simulating the stray capacitances SC31 and SC32.

Next, with reference to FIG. 10, the carrier phase of the single-phase inverters 101 and 102 and the potential fluctuation between the main circuit and the ground (frame) will be described. FIG. 10 is a diagram for explaining the result of the simulation of the embodiment. For simplification, the modulation factor is set to 0 as described above. The values of the stray capacitances SC31 and SC32 on the multi-phase electric motor 3 side may be determined according to the type of the multi-phase electric motor 3 actually used.

When the carrier signals of the single-phase inverters 101 and 102 are synchronized with each other between the single-phase inverters 101 and 102 and their respective phases are aligned, the switching timing of the switches S1-S4 in each single-phase inverter Are the same, and the positions of the switching switches in the switches S1-S4 of each single-phase inverter are the same. Therefore, the behavior is the same as that shown in FIGS. 7 and 8 described above.

On the other hand, even if the carrier signals of the single-phase inverters 101 and 102 are synchronized with each other, if the carrier phases of the single-phase inverters 101 and 102 shift between the two, the single-phase inverters 101 and 102 The positions of the switches (elements) that switch within are not aligned with each other. For example, while the switches S1 and S2, which are the P-side elements of the single-phase inverter 101, are on, a period during which the switches S3 and S4, which are the N-side elements of the single-phase inverter 102, are turned on occurs.

During the above period, the P potential and N potential of the main circuit are divided by the stray capacitances SC31 and SC32 defined for each winding of the multi-phase motor 3, and the single-phase inverters 101 and 102 When the stray capacitances on the multi-phase motor 3 side are equal, the potential of the frame E becomes 0.

From FIGS. 10A to 10E, the results of the simulation when the phase difference between the carrier signals of the single-phase inverters 101 and 102 are increased in order are shown. The phase differences between the carrier signals in the waveform diagrams (a) to (e) of FIG. 10 are 0 degrees, 45 degrees, 90 degrees, 135 degrees, and 180 degrees, respectively. In addition, one cycle of the carrier cycle is set to 360 degrees.

The upper side shown in the results of each of the above simulations shows the potential fluctuation between the main circuit and the ground (hereinafter referred to as the main circuit-to-ground potential fluctuation), and the lower side thereof is included in the waveform of the potential fluctuation. Indicates the frequency component to be used. The lower graph is a semi-logarithmic graph. In the frequency component, in addition to the fundamental wave component, the harmonic component can be confirmed.

From the results of each simulation shown in FIG. 10, it can be confirmed that when the phase difference between the carrier signals is small, the magnitude of each frequency component included in the waveform of the potential fluctuation is relatively large. Further, as the phase difference between the carrier signals becomes larger, the magnitude of each frequency component included in the waveform of the potential fluctuation tends to become smaller.

When the phase difference between the carrier signals of the single-phase inverters 101 and 102 is 180 degrees, that is, when the phases are opposite, for example, the period during which the P-side element of the single-phase inverter 101 is on and The period during which the N-side element of the single-phase inverter 102 is turned on overlaps. As a result, the potential fluctuation caused by turning on the P-side element of the single-phase inverter 101 and the potential fluctuation caused by turning on the N-side element of the single-phase inverter 102 cancel each other out. Is constant without fluctuation. The potential of the frame can be regarded as the ground potential.

According to the result of this simulation, it was clarified that the potential fluctuation between the main circuit and the ground can be reduced by shifting the carrier phase between the single-phase inverters 101 and 102 by a predetermined amount. From the results of this simulation, it was confirmed that noise due to the potential fluctuation between the main circuit and the ground can be suppressed.

Next, with reference to FIGS. 11 to 16, a method of setting a phase difference between the carrier signals by shifting the carrier phase between the single-phase inverters corresponding to the adjacent phases of the multi-phase electric motor 3 by a predetermined amount will be described.

First, the phase difference between carrier signals is defined.
11 and 12 are diagrams for explaining an example in which the phases of the carrier signals of the single-phase inverter corresponding to the adjacent phases of the multi-phase electric motor 3 of the embodiment are shifted at equal intervals.

As shown in FIG. 11, when the phases of the carrier signals are shifted by 360 / N degrees at equal intervals in the adjacent phases of N single-phase inverters, the line voltage waveform of each phase of the multi-phase motor 3 is shown in FIG. As shown in (a) and (b), the center position of the square wave of each phase is shifted by 360 / N degrees. That is, a phase difference of 360 / N degrees can be provided in the phase of the carrier signal in the adjacent phases.

Further, when the above phase difference is provided, the phases of the carrier signals may be shifted by 180 / N degrees at equal intervals in adjacent phases of N single-phase inverters. Also in the above case, vibration of the voltage and current of the DC power supply 2 can be suppressed.

13 and 14 are diagrams for explaining an example in which the phases of the carrier signals of the single-phase inverter corresponding to each phase of the multi-phase electric motor 3 of the embodiment are aligned.

When the phases of the carrier signals of the single-phase inverters of each phase are aligned as shown in FIG. 13, the line voltage waveforms of each phase of the multi-phase motor 3 are as shown in FIGS. 14 (a) and 14 (b). The center positions of the square waves of each phase are aligned. The waveform in this case is different from the case where the phase difference is provided in the phases of the carrier signals shown in FIGS. 11 and 12 described above.

Next, with reference to FIG. 15, a process for adjusting the carrier phase between the single-phase inverters corresponding to the adjacent phases of the multi-phase electric motor 3 will be described. FIG. 15 is a flowchart of a process for adjusting the carrier phase between the single-phase inverters of the embodiment. This process uses the rotation speed of the multi-phase electric motor 3. The rotation speed of the multi-phase electric motor 3 is an example of a physical quantity whose value changes depending on the operating status of the multi-phase electric motor 3.

First, the speed detection circuit 164 calculates the speed detection value ω based on the angle detection value detected by the rotation angle detector 170 (step SA11).

Next, the phase correction determination unit 1218c determines the magnitude of the calculated speed detection value ω (step SA12), and if the speed detection value ω is less than the first threshold value, the phase difference is predetermined. The upper limit value MAX is determined (step SA14), and the process proceeds to step SA20. When the speed detection value ω exceeds the second threshold value, the phase correction determination unit 1218c determines the phase difference to 0 (step SA16), and proceeds to the process in step SA20. When the speed detection value ω is equal to or greater than the first threshold value and is equal to or less than the second threshold value, the phase correction determination unit 1218c determines the magnitude of the phase difference using a function that takes the speed detection value ω as a variable (step SA18). , The process proceeds to step SA20. For example, the above function is specified so that the phase difference becomes smaller as the velocity detection value ω becomes larger. A more specific example will be described later.

When the processing of steps SA14, SA16, and SA18 is completed, the carrier phase correction circuit 1218 outputs the first carrier signal CS1 whose phase is adjusted to the determined phase difference (step SA20). Next, the PWM control unit 1215 generates a gate pulse GP1 based on the voltage command value ER1 and the first carrier signal CS1 and supplies it to the main circuit 111 (step SA22). The main circuit 111 outputs power based on the gate pulse GP1.

Through the above processing, the single-phase inverter 101 supplies electric power to the windings of the multi-phase electric motor 3 under the control of the current control circuit 121 to drive the multi-phase electric motor 3. The same applies to the other single-phase inverters 102, ..., 10N. As a result, the multi-phase electric motor 3 is driven by each single-phase inverter with a phase difference based on the speed detection value.

Although the above procedure has been described by exemplifying the phase correction determination unit 1218c, the same procedure may be applied to the phase correction determination unit 1228c, the phase correction determination unit 12N8c, and the like.

Next, with reference to FIG. 16, an example of a predetermined function for defining the phase difference of the embodiment will be described. FIG. 16 is a diagram for explaining a predetermined function for defining the phase difference of the embodiment. In the example shown in FIG. 16, when the speed detection value ω is less than the first threshold value and when the speed detection value ω exceeds the second threshold value, the phase difference is set to 0 or a fixed value of the upper limit value. Further, when the speed detection value ω is in the range of the first threshold value or more and the second threshold value or less, a function that takes the speed detection value ω as a variable is applied. The function shown in the figure is a function in which the velocity detection value ω is used as a variable and the solution value monotonously decreases as the velocity detection value ω increases. The function shown in the figure is a linear function, but the one shown in the figure is not limited and may be changed as appropriate.

For example, although FIG. 16 illustrates a value different from 0 for the first threshold value, the first threshold value may be set to 0.

Further, in the above embodiment, the case where the first threshold value and the second threshold value are set to different values is illustrated, but instead, the first threshold value and the second threshold value may be set to the same value. The control in this case is switching control (ON / OFF control) for whether or not to provide a phase difference.

According to the above embodiment, the current control circuit 121 (first control unit) is provided in association with the main circuit 111 (first main circuit), and the carrier synchronization signal CSS1 is provided based on the speed of the multi-phase electric motor 3. Determines the magnitude of the first predetermined amount of phase difference with respect to the phase (reference phase) of. The current control circuit 121 supplies the main circuit 111 with a first PWM signal whose phase is determined with respect to the phase (reference phase) of the carrier synchronization signal CSS1. The detection speed value ω of the multi-phase motor 3 may be applied to the speed of the multi-phase motor 3.

The current control circuit 122 (second control unit) is provided in association with the main circuit 112 (second main circuit), and is provided at a second location with respect to the phase of the carrier synchronization signal CSS1 based on the speed of the multiphase motor 3. Determine the magnitude of the quantitative phase difference. The current control circuit 122 supplies the main circuit 112 with a second PWM signal whose phase is determined with respect to the phase (reference phase) of the carrier synchronization signal CSS1.

When the speed of the multi-phase electric motor 3 is relatively high, the current control circuit 121 and the current control circuit 122 reduce the phase difference of the first predetermined amount and the phase difference of the second predetermined amount to a large number. When the speed of the phase electric motor 3 is relatively slow, it is preferable to increase the phase difference of the first predetermined amount and the phase difference of the second predetermined amount. As a result, the multi-phase electric motor drive device 1 reduces the potential fluctuation between the main circuit and the ground that may occur when a current is passed through the plurality of windings of the multi-phase electric motor 3.

The current control circuit 121 generates a first carrier wave that is synchronized with the carrier synchronization signal CSS1 (first synchronization signal) and has a first predetermined amount of phase difference with respect to the phase of the carrier synchronization signal CSS1. The current control circuit 121 modulates the reference signal of the first phase of the multi-phase electric motor 3 using the generated first carrier wave to obtain the first PWM signal. The current control circuit 121 supplies the first PWM signal obtained thereby to the main circuit 111. Such a current control circuit 121 can generate a first carrier signal CS1 having a first predetermined amount of phase difference with respect to the phase of the carrier synchronization signal CSS1.

The current control circuit 122 generates a second carrier wave that is synchronized with the carrier synchronization signal CSS1 (first synchronization signal) and has a second predetermined amount of phase difference with respect to the phase of the carrier synchronization signal CSS1. The current control circuit 122 modulates the reference signal of the second phase of the multi-phase electric motor 3 using the generated second carrier wave to obtain the second PWM signal. The current control circuit 122 supplies the second PWM signal obtained thereby to the main circuit 112. Such a current control circuit 122 can generate a second carrier signal CS2 having a phase difference of a second predetermined amount with respect to the phase of the carrier synchronization signal CSS1.

The current control circuit 121 and the current control circuit 122 determine the magnitudes of the first predetermined amount of phase difference and the second predetermined amount of phase difference, respectively, based on the speed of the multi-phase electric motor 3. For example, when the speed of the multi-phase motor 3 is relatively high, the phase difference between the first predetermined amount and the second predetermined amount is reduced so that the speed of the multi-phase motor 3 is relatively slow. Increases the phase difference of the first predetermined amount and the phase difference of the second predetermined amount.

The synchronization signal generation circuit 150 supplies, for example, the carrier synchronization signal CSS1 to the current control circuit 121 and the current control circuit 122. According to this, the multi-phase electric motor drive device 1 can drive the multi-phase electric motor 3 by using the first carrier signal CS1 and the second carrier signal CS2 synchronized with the carrier synchronization signal CSS1, and the multi-phase electric motor 3 can be driven. It is possible to reduce the potential fluctuation between the main circuit and the ground that may occur when a current is passed through a plurality of windings.

In the above embodiment, the case of two single-phase inverters has been described by exemplifying the single-phase inverters 101 and 102, but the above description may be applied to a configuration including an even number of single-phase inverters. Good. In that case, the odd-numbered single-phase inverter and the even-numbered single-phase inverter may be applied to the above-mentioned single-phase inverters 101 and 102, respectively. By the same carrier signal phase adjustment method as described above, the same result as described above can be obtained even in the case of a configuration including a plurality of single-phase inverters.

In the above embodiment, each carrier signal used for PWM control as described above (for example, the first carrier signal CS1 and the second carrier signal) while maintaining the phase continuity of the signal generated by the PLL of each single-phase inverter. The phase of the CS2, the third carrier signal CS3, the fourth carrier signal CS4, etc.) can be provided with a phase difference, or the phase difference can be eliminated or switched, and the magnitude thereof can be adjusted. In order to reduce the influence of the discontinuous switching of the phase at the time of the switching, a rate control process for adjusting the rate of change when changing from the first phase to the second phase so as to fall within a predetermined range is performed. It may be added to the processing performed by the phase correction determination unit 1218c.

By synchronizing the carrier signals of each single-phase inverter provided for the windings of each phase of the multi-phase motor 3, the timings of the PWM pulses input to the windings of the adjacent phases match, and the PWM The harmonic current component caused by the pulse is reduced, and the loss and temperature rise of the multi-phase motor 3 can be reduced. The effect of reducing the loss and temperature rise of the multi-phase motor 3 is remarkable when the load of the multi-phase motor 3 is high, but is not noticeable when the load is low.

When the above embodiment is applied to an application such as a square torque load in which the load characteristics of the multi-phase motor 3 are low speed and light load and high speed and high load, the carrier phase is shifted at low speed to affect the influence of noise. It is desirable to synchronize the carrier phase in the high speed range where the temperature rise of the multi-phase motor 3 becomes relatively high.

(First modification)
A first modification of the embodiment will be described. In the function shown in FIG. 16 described above, when the velocity detection value ω is in the range of the first threshold value or more and the second threshold value or less, the function in which the solution value monotonously decreases as the velocity detection value ω increases is illustrated. .. Instead of this, in this modification, the above function is set so that the switching of the speed detection value ω has hysteresis.

FIG. 17 is a diagram for explaining a predetermined function for defining the phase difference according to the first modification. In the example shown in FIG. 17, when the speed detection value ω is less than the first threshold value, the phase difference is set to a fixed upper limit value as in FIG. 16 described above, and the speed detection value ω exceeds the second threshold value. In this case, the phase difference is set to 0 as in FIG. 16 described above. Further, when the velocity detection value ω is in the range of the first threshold value or more and the second threshold value or less, a function for forming hysteresis while maintaining a fixed value of 0 or an upper limit value is applied. For example, when the speed detection value ω is less than the first threshold value and falls within the range of the first threshold value or more and the second threshold value or less, the fixed value of the upper limit value is maintained, and when the second threshold value is exceeded, it is 0. To. Further, when the speed detection value ω exceeds the second threshold value and is in the range of the first threshold value or more and the second threshold value or less, 0 is maintained, and when the first threshold value is not satisfied, the upper limit value is fixed. To. The function shown in the figure is an example of a function that sets hysteresis for switching based on the speed detection value ω.

If the system becomes unstable when all single-phase inverters are switched together at the time of the above switching, divide all single-phase inverters into multiple groups and switch step by step in group units. It may be. For example, it is preferable to divide the inverters into groups so that the number of single-phase inverters in each group is the same or close to each other. More specifically, it is divided into an odd-numbered first group and an even-numbered second group among all single-phase inverters. For example, when the control device 10 provides the above phase difference in the first group and provides the above phase difference in the second group after a lapse of a predetermined time, the two phases of the first phase and the second phase are switched in order. Good. As described above, the first phase and the second phase may be the upper limit value and 0.

In the phase shift control, when switching between two phases from the first phase to the second phase, in order to reduce the influence of the discontinuous switching of the phases, when changing from the first phase to the second phase. A rate control process for limiting the rate of change of the above may be added to the process of the phase correction determination unit 1218c.

According to the first modification described above, in addition to achieving the same effect as that of the embodiment, the phase between each phase of the number of phases can be made into a size obtained by evenly dividing the phase based on the number of phases. it can.

(Second modification)
A second modification of the above embodiment will be described. In this modification, a case where the phase difference is adjusted based on a detection value other than the speed detection value ω of the multi-phase motor 3 instead of the speed detection value ω (rotational speed) of the multi-phase motor 3 will be described.

Examples of the detected values other than the speed detected value ω of the multi-phase electric motor 3 include the following.
・ Current value flowing through the ground electrode (magnitude of ground current)
-The magnitude of the potential (DC component) of the frame E with respect to the ground electrode-The magnitude of the potential fluctuation of the frame E with respect to the ground electrode-The temperature of the semiconductor element or the heat sink of the semiconductor element-Calculation of the loss calculated based on the output current Value ・ The magnitude (peak value) of the voltage reference of PWM control calculated based on the feedback signal of feedback control.

When using the above "current value flowing through the ground electrode (magnitude of the earth current)", when using the "magnitude of the potential (DC component) of the frame E with respect to the ground electrode", and when using the "frame with respect to the ground electrode" When "the magnitude of the potential fluctuation of E" is used, it is directly or indirectly detected that the potential of the frame E is unstable and a difference from the potential of the grounding electrode is generated, and the detection result is obtained. May be used as a control condition. When using these detected values, if a state in which the above current value and voltage value are large is detected, a phase difference is provided. Further, the larger the size, the larger the phase difference may be.

When the above "temperature of the semiconductor element or the heat sink of the semiconductor element" is used, and when the "calculated value of the loss calculated based on the output current" is used, the loss in the semiconductor element is indirectly detected. , The detection result may be used as a control condition. When a state in which a large loss is detected in the semiconductor element is detected when these detected values are used, a phase difference is provided. Further, the larger the magnitude of the loss, the larger the phase difference may be.

When using the above "magnitude (peak value) of the PWM control voltage reference calculated based on the feedback signal of the feedback control", the gate pulses of the PWM control of each phase must be aligned. May be detected and the detection result may be used as a control condition. When the magnitude of the voltage reference of the PWM control is used, if a state in which the magnitude of the voltage reference is larger than a predetermined value is detected, a phase difference is provided. Further, the larger the magnitude of the voltage reference, the larger the phase difference may be.

Also in the case of the above modification, as in the embodiment, the potential fluctuation between the main circuit and the ground that may occur when the multi-phase motor drive device 1 passes a current through a plurality of windings of the multi-phase motor 3 is reduced. Can be made to.

At least according to the above embodiment, the multi-phase electric motor drive device 1 includes a main circuit 111, a main circuit 112, a current control circuit 121, and a current control circuit 122. The polyphase motor 3 includes a plurality of windings including at least a first winding and a second winding, and the windings are electrically insulated from each other and magnetically coupled to each other. The main circuit 111 is connected to the first winding and supplies AC power to the first winding based on the first PWM signal modulated by the single-phase pulse width modulation method. The main circuit 112 is connected to the second winding and supplies AC power to the second winding based on the second PWM signal modulated by the PWM method. The current control circuit 121 is provided in association with the main circuit 111, and supplies the first PWM signal whose phase is determined with respect to the reference phase based on the speed of the multi-phase electric motor 3 to the main circuit 111. The current control circuit 122 is provided in association with the main circuit 112, and supplies the second PWM signal whose phase is determined with respect to the reference phase based on the speed of the multi-phase electric motor 3 to the main circuit 112. As a result, it is possible to reduce the potential fluctuation between the main circuit and the ground that may occur when the multi-phase motor drive device 1 passes a current through a plurality of windings of the multi-phase motor 3.

The current control circuit 12i of the multi-phase electric motor drive device 1 may be realized by a software function unit that functions by executing a program by a processor such as a CPU, and all of the current control circuit 12i may be realized by an LSI or the like. It may be realized by the hardware function part.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

For example, in the description of the above embodiment, the phase of the carrier wave is defined as 0 to 360 degrees, but the angle at which the phase difference is calculated is not limited to 360 degrees and is set to another value. You can. For example, if the phase difference between the phases becomes large, the loss of the multi-phase motor 3 increases and the temperature rise becomes large. Therefore, in a trade-off with the generated noise, the angle is set to 360 degrees based on an angle lower than 360 degrees. Alternatively, the angle divided by the number of inverter phases may be set as the phase shift amount. For example, 270 degrees divided by the number of inverter phases may be set as the phase shift amount.

Further, the main circuit 11i may be separate from the current control circuit 12i.
The number of phases of the multi-phase electric motor 3 described above is not limited to the number of phases shown in the embodiment, and may be arbitrarily set.

1 ... Multi-phase electric motor drive device, 2 ... DC power supply, 3 ... Multi-phase electric motor, 10 ... Control device, 101, 102, 10N, 10i ... Single-phase inverter, 150 ... Synchronous signal generation circuit, 160 ... Speed phase control circuit, 170 ... Rotation angle detector, 111 ... Main circuit (first main circuit), 112 ... Main circuit (second main circuit), 11N, 11i ... Main circuit, 121 ... Current control circuit (first control unit), 122 ... Current control circuit (second control unit), 12N, 12i ... current control circuit, 1215 ... PWM control circuit (first PWM unit), 1216 ... phase comparator (first phase comparator), 1217 ... carrier generation circuit (first) Carrier generation unit), 1218 ... Carrier phase correction circuit (first carrier phase correction circuit), 1218c ... Phase correction determination unit, 1225 ... PWM control circuit (second PWM unit), 1226 ... Phase comparator (second phase comparator) , 1227 ... Carrier generation circuit (second carrier generation unit), 1228 ... Carrier phase correction circuit, 1228c ... Phase correction determination unit, carrier phase correction circuit (second carrier phase correction circuit), 12N5 ... PWM control circuit (NPWM unit) ), 12N6 ... Phase comparator (Nth phase comparator), 12N7 ... Carrier generation circuit (Nth carrier generation unit), 12N8 ... Carrier phase correction circuit (Nth carrier phase correction circuit), 12N8c ... Phase correction determination unit, 131, 132, 13N ... Condenser, 141, 142, 14N ... Current sensor, 150 ... Synchronous signal generation circuit, 160 ... Speed phase control circuit

Claims (10)

A polyphase motor comprising a plurality of windings including at least a first winding and a second winding, each winding being electrically insulated and magnetically coupled to each other.
A first main circuit connected to the first winding and supplying AC power to the first winding based on a first PWM signal modulated by a single-phase pulse width modulation (hereinafter referred to as PWM) method.
A second main circuit connected to the second winding and supplying AC power to the second winding based on a second PWM signal modulated by a PWM method.
A first control unit provided in association with the first main circuit and supplying the first PWM signal whose phase with respect to the reference phase is determined based on the speed of the multi-phase electric motor to the first main circuit.
A second control unit provided in association with the second main circuit and supplying the second PWM signal whose phase with respect to the reference phase is determined based on the speed of the multi-phase electric motor to the second main circuit.
Multi-phase electric motor drive device equipped with. A synchronization signal generation circuit for supplying a first synchronization signal whose reference phase is defined as a predetermined phase to the first control unit and the second control unit is provided.
The first control unit
A first reference carrier that is synchronized with the first synchronization signal and has a phase difference of a first predetermined amount with respect to the phase of the first synchronization signal is generated, and the generated first reference carrier is used to generate the multiple. The first PWM signal obtained by modulating the reference signal of the first phase of the phase electric motor is supplied to the first main circuit.
The second control unit
A second reference carrier that is synchronized with the first synchronization signal and has a phase difference of a second predetermined amount with respect to the phase of the first synchronization signal is generated, and the generated second reference carrier is used to generate the multiple. The second PWM signal obtained by modulating the reference signal of the second phase of the phase electric motor is supplied to the second main circuit.
The multi-phase electric motor drive device according to claim 1. The first control unit
The magnitude of the phase difference of the first predetermined amount is adjusted based on the speed detection value of the multi-phase electric motor.
The multi-phase electric motor drive device according to claim 2. The second control unit
The magnitude of the phase difference of the second predetermined amount is adjusted based on the speed detection value of the multi-phase electric motor.
The multi-phase electric motor drive device according to claim 2 or 3. The first control unit
A first phase determining unit for determining the phase of the first reference carrier wave based on the speed detection value of the multi-phase electric motor is provided.
The second control unit
A second phase determining unit for determining the phase of the second reference carrier wave based on the speed detection value of the multi-phase electric motor is provided.
The multi-phase electric motor drive device according to claim 2. The first control unit
A first carrier generation unit that generates the first reference carrier so that the phase of the supplied first synchronization signal and the phase of the first reference carrier are aligned with each other.
A first phase correction unit that adjusts the phase of the first reference carrier wave based on the determined phase of the first reference carrier wave to generate the first reference carrier wave, and
The multi-phase electric motor driving device according to claim 5, further comprising a first PWM unit that modulates a reference signal of the first phase of the multi-phase electric motor using the first reference carrier wave. The first phase correction unit is
When changing from the first phase of the second reference carrier wave to the second phase, the phase of the first reference carrier wave is not changed.
The multi-phase electric motor drive device according to claim 6. The second control unit
A second carrier generation unit that generates the second reference carrier so that the phase of the supplied first synchronization signal and the phase of the second reference carrier are aligned with each other.
A second phase correction unit that generates the second reference carrier and
The multi-phase electric motor driving device according to claim 5 or 6, further comprising a second PWM unit that modulates a reference signal of the second phase of the multi-phase electric motor using the second reference carrier wave. The second phase correction unit is
The phase of the second reference carrier wave is adjusted so that the rate of change of the phase when changing from the first phase to the second phase of the second reference carrier wave falls within a predetermined predetermined range.
The multi-phase electric motor drive device according to claim 8. The second phase correction unit is
Based on the first phase and the second phase of the second reference carrier, the first phase of the second reference carrier is changed to the second phase.
The multi-phase electric motor drive device according to claim 8.

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