JP2023057811A - Power conversion device, control unit for generator motor, and electrically-driven power steering device - Google Patents

Abstract

To obtain a power conversion device, a control unit for a generator motor, and an electrically-driven power steering device that can further reduce phase current ripple.SOLUTION: A first offset operator 8a subtracts a first offset voltage from a first voltage command so that one of three applied voltages corresponding to three phases in a first applied voltage matches the maximum value or the minimum value of a first reference signal. A second offset operator 8b subtracts a second offset voltage from a second voltage command so that one of three applied voltages corresponding to three phases in a second applied voltage matches the maximum value or the minimum value of a second reference signal. A control unit 6 adjusts a phase difference between a first voltage vector at the timing when the first reference signal becomes maximum or minimum and a second voltage vector at the timing when the second reference signal becomes maximum or minimum to 30 degrees, or controls at least one of the first voltage vector and the second voltage vector to be a zero voltage vector.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a power conversion device, a control device for a generator motor, and an electric power steering device.

In a conventional power converter, voltage is applied to two winding sets using two inverters. Also, when the third harmonic is superimposed on the voltage command, each carrier signal in the two inverters is offset by 90 degrees from each other to avoid that the two inverters become effective voltage vectors at the same time (e.g., patent Reference 1).

JP 2012-50252 A

In the conventional power conversion device as described above, due to the mutual inductance of the two winding sets, when the first set is outputting an effective voltage vector, the current change of the second set occurs, and the second set is effective. A first set of current changes occurs when outputting a voltage vector. For this reason, the conventional power converter has a problem that the phase current ripple becomes large.

The present disclosure has been made in order to solve the above-described problems, and aims to obtain a power conversion device, a control device for a generator motor, and an electric power steering device that can further reduce the phase current ripple. aim.

A power conversion device according to the present disclosure has a plurality of first switching elements, converts a DC voltage from a DC power supply into a first AC voltage, and applies it to a first three-phase winding of an AC rotating machine. A first power converter, a second power converter having a plurality of second switching elements, converting a DC voltage into a second AC voltage, and applying the voltage to a second three-phase winding of an AC rotary machine; By comparing the first applied voltage obtained by subtracting the first offset voltage from the first voltage command, which is the voltage command for the first three-phase winding, with the first reference signal, the plurality of first switching elements A second applied voltage obtained by subtracting a second offset voltage from a second voltage command, which is a voltage command for a second three-phase winding, and a second reference signal. , and the phase difference between the first three-phase winding and the second three-phase winding is 30 degrees. , the first reference signal and the second reference signal are either the first carrier signal or the second carrier signal, the phase difference between the first carrier signal and the second carrier signal is 180 degrees, and the control unit is , subtracting the first offset voltage from the first voltage command such that at least one of the three applied voltages corresponding to the three phases in the first applied voltage matches the maximum value or the minimum value of the first reference signal; Subtracting the second offset voltage from the second voltage command such that at least one of the three applied voltages corresponding to the three phases in the two applied voltages matches the maximum value or the minimum value of the second reference signal, and the first on/off signal The phase difference between the first voltage vector obtained based on and the second voltage vector obtained based on the second on-off signal is 30 degrees, or at least one of the first voltage vector and the second voltage vector be the zero voltage vector.

According to the power conversion device, generator motor control device, and electric power steering device according to the present disclosure, the phase current ripple can be further reduced.

1 is a configuration diagram showing a power converter according to Embodiment 1; FIG. FIG. 2 is a diagram showing the relationship between the phase of the first three-phase winding and the phase of the second three-phase winding in FIG. 1; Figure 2 shows a first voltage vector output by the first power converter of Figure 1; It is a figure which shows the relationship between several 1st on-off signals and a 1st voltage vector. Figure 2 shows a second voltage vector output by the second power converter of Figure 1; It is a figure which shows the relationship between several 2nd on-off signals and a 2nd voltage vector. FIG. 2 is a flow chart showing an offset calculation routine executed by a first offset calculator in FIG. 1; FIG. 3 is a diagram for explaining the operation of the first on/off signal generator of FIG. 1; FIG. FIG. 2 is a diagram showing an example of carrier wave signal switching in the first on/off signal generator of FIG. 1; It is a figure for demonstrating the operation|movement of the 1st on-off signal generator as a comparative example. FIG. 2 is a diagram showing an example of carrier wave signal switching in the first on/off signal generator of FIG. 1; FIG. 12 is a diagram for explaining the operation of the first on/off signal generator when the switching timing of the carrier wave signal is not appropriately set as a comparative example with respect to FIG. 11; FIG. 2 is a diagram showing an example of carrier wave signal switching in the first on/off signal generator of FIG. 1; 2 is a flow chart showing a carrier signal selection routine executed by the first on/off signal generator of FIG. 1; 4 is a flow chart showing an offset calculation routine executed by a second offset calculator in FIG. 1; 2 is a flow chart showing a carrier signal selection routine executed by the second on/off signal generator of FIG. 1; 2 is a diagram showing an example of carrier signal switching in the second on/off signal generator of FIG. 1; FIG. FIG. 5 is a diagram showing a relationship between a coupling coefficient and a sum of squares of DC components of differential values of six-phase currents; FIG. 5 is a diagram showing an example of a combination of a first voltage vector and a second voltage vector in a power conversion device as a comparative example; 2 is a diagram showing an example of a combination of a first voltage vector and a second voltage vector in the power converter of FIG. 1; FIG. 3 is a diagram showing another example of a combination of the first voltage vector and the second voltage vector in the power converter of FIG. 1; FIG. FIG. 2 is a configuration diagram showing an application example of the power conversion device of FIG. 1 to a generator motor; FIG. 2 is a configuration diagram showing an application example of the power conversion device of FIG. 1 to an electric motor for an electric power steering device; FIG. 2 is a configuration diagram showing a power conversion device according to Embodiment 2; FIG. 25 is a diagram showing combinations of modulation methods, carrier signals, and effective voltage vector sections in the power converter of FIG. 24; FIG. 12 is a diagram showing 12 regions obtained by dividing the voltage phase; FIG. 25 is a diagram showing a first example of carrier wave signal switching in the first on/off signal generator and the second on/off signal generator of FIG. 24; It is a figure which shows the 1st example of a 1st applied voltage waveform and a 2nd applied voltage waveform. FIG. 4 is a diagram showing a first example of a combination of first voltage vectors in a voltage phase range of 0 degrees to 60 degrees; FIG. 25 is a diagram showing a second example of carrier wave signal switching in the first on/off signal generator and the second on/off signal generator of FIG. 24; 25 is a diagram showing a third example of carrier wave signal switching in the first on/off signal generator and the second on/off signal generator of FIG. 24; FIG. It is a figure which shows the 2nd example of a 1st applied voltage waveform and a 2nd applied voltage waveform. FIG. 10 is a diagram showing a second example of a combination of a first voltage vector and a second voltage vector in a voltage phase range of 0 degrees to 60 degrees; FIG. 25 is a diagram showing a fourth example of carrier wave signal switching in the first on/off signal generator and the second on/off signal generator of FIG. 24; FIG. 10 is a diagram showing a third example of a first applied voltage waveform and a second applied voltage waveform; FIG. 11 is a diagram showing a third example of a combination of the first voltage vector and the second voltage vector in the voltage phase range from 0 degrees to 60 degrees; FIG. 25 is a diagram showing a fifth example of carrier wave signal switching in the first on/off signal generator and the second on/off signal generator of FIG. 24; FIG. 10 is a diagram showing a fourth example of the first applied voltage waveform and the second applied voltage waveform; FIG. 12 is a diagram showing a fourth example of a combination of the first voltage vector and the second voltage vector in the voltage phase range from 0 degrees to 120 degrees; FIG. 25 is a diagram showing a sixth example of carrier wave signal switching in the first on/off signal generator and the second on/off signal generator of FIG. 24; FIG. 11 is a diagram showing a fifth example of the first applied voltage waveform and the second applied voltage waveform; FIG. 10 is a diagram showing a fifth example of a combination of the first voltage vector and the second voltage vector in the voltage phase range from 0 degrees to 120 degrees; FIG. 2 is a configuration diagram showing a first example of a processing circuit that implements the functions of the power converters of Embodiments 1 and 2; FIG. 4 is a configuration diagram showing a second example of a processing circuit that implements the functions of the power converters of the first and second embodiments;

Embodiments will be described below with reference to the drawings.
Embodiment 1.
FIG. 1 is a configuration diagram showing a power converter according to Embodiment 1. FIG. The power converter includes a smoothing capacitor 3 , a first power converter 4 a , a second power converter 4 b , a first current detector 5 a , a second current detector 5 b and a controller 6 .

An AC rotating machine 1 as a load and a DC power supply 2 as a power supply are connected to the power converter. The power converter converts the DC voltage Vdc from the DC power supply 2 into an AC voltage and applies it to the AC rotating machine 1 .

The AC rotating machine 1 is a three-phase AC rotating machine. The AC rotating machine 1 has a first three-phase winding and a second three-phase winding. The first three-phase winding and the second three-phase winding are housed in the stator inside the AC rotating machine 1 without being electrically connected to each other. A first three-phase winding includes winding U1, winding V1, and winding W1. The winding U1, the winding V1, and the winding W1 are the U1-phase winding, the V1-phase winding, and the W1-phase winding, respectively. A second three-phase winding includes winding U2, winding V2, and winding W2. Winding U2, winding V2, and winding W2 are the U2-phase winding, the V2-phase winding, and the W2-phase winding, respectively.

Examples of the AC rotating machine 1 include a permanent magnet synchronous rotating machine, an induction rotating machine, and a synchronous reluctance rotating machine. Any of the above rotating machines may be used as the AC rotating machine 1 as long as it has two three-phase windings.

A DC power supply 2 is connected to a first power converter 4a and a second power converter 4b. The DC power supply 2 outputs a DC voltage Vdc to the first power converter 4a and the second power converter 4b. As the DC power supply 2, for example, a battery, a DC-DC converter, a diode rectifier, or a PWM (Pulse Width Modulation) rectifier is used.

The smoothing capacitor 3 is connected in parallel with the DC power supply 2 . That is, one end of the smoothing capacitor 3 is connected to the positive terminal of the DC power supply 2 and the other end of the smoothing capacitor 3 is connected to the negative terminal of the DC power supply 2 . The smoothing capacitor 3 suppresses fluctuations in the bus line current of the first power converter 4a and the second power converter 4b, and stabilizes the DC current. Although not shown, the smoothing capacitor 3 has an equivalent series resistance Rc and a lead inductance Lc in addition to the true capacitor capacitance C. FIG.

The first power converter 4a has a plurality of first switching elements. The first power converter 4 a converts the DC voltage Vdc from the DC power supply 2 into a first AC voltage and applies it to the first three-phase winding of the AC rotary machine 1 . The plurality of first switching elements includes three first high potential side switching elements Sup1, Svp1 and Swp1 and three first low potential side switching elements Sun1, Svn1 and Swn1.

The first high potential side switching elements Sup1, Svp1 and Swp1 correspond to the U1 phase, V1 phase and W1 phase, respectively. The first low potential side switching elements Sun1, Svn1 and Swn1 correspond to the U1 phase, V1 phase and W1 phase, respectively.

The U1-phase first high potential side switching element Sup1 and the U1-phase first low potential side switching element Sun1 are connected in series with each other. The first high potential side switching element Svp1 of the V1 phase and the first low potential side switching element Svn1 of the V1 phase are connected in series with each other. The W1-phase first high potential side switching element Swp1 and the W1-phase first low potential side switching element Swn1 are connected in series with each other. A plurality of first switching elements Sup1 to Swn1 constitute an inverter circuit.

As a result, the U1-phase current Iu1, the V1-phase current Iv1, and the W1-phase current Iw1 flow through the first three-phase winding.

The second power converter 4b has a plurality of second switching elements. The second power converter 4b converts the DC voltage Vdc from the DC power supply 2 into a second AC voltage and applies it to the second three-phase winding of the AC rotating machine 1 . The plurality of second switching elements includes three second high potential side switching elements Sup2, Svp2 and Swp2 and three second low potential side switching elements Sun2, Svn2 and Swn2.

The second high potential side switching elements Sup2, Svp2 and Swp2 correspond to the U2 phase, V2 phase and W2 phase, respectively. The second low potential side switching elements Sun2, Svn2 and Swn2 correspond to the U2 phase, V2 phase and W2 phase, respectively.

The U2-phase second high potential side switching element Sup2 and the U2-phase second low potential side switching element Sun2 are connected in series with each other. The V2-phase second high potential side switching element Svp2 and the V2-phase second low potential side switching element Svn2 are connected in series with each other. The W2-phase second high-potential side switching element Swp2 and the W2-phase second low-potential side switching element Swn2 are connected in series with each other. A plurality of second switching elements Sup2 to Swn2 form an inverter circuit.

As a result, the U2-phase current Iu2, the V2-phase current Iv2, and the W2-phase current Iw2 flow through the second three-phase winding.

A combination of an IGBT (Insulated Gate Bipolar Transistor) and a diode is used for each of the plurality of first switching elements Sup1 to Swn1 and the plurality of second switching elements Sup2 to Swn2. In this combination, an IGBT and a diode are connected in anti-parallel. Also, instead of IGBTs, for example, bipolar transistors or MOS (Metal Oxide Semiconductor) power transistors may be used.

The first current detector 5a is provided between the first power converter 4a and the first three-phase winding. The first current detector 5a detects the values of the U1-phase current Iu1, V1-phase current Iv1, and W1-phase current Iw1 as current detection values Iu1s, Iv1s, and Iw1s, respectively.

The first current detector 5a can constantly detect the values of the U1-phase current Iu1, the V1-phase current Iv1, and the W1-phase current Iw1 regardless of the ON/OFF states of the plurality of first switching elements Sup1 to Swn1. Therefore, the power converter according to the first embodiment can detect each of the first power converter 4a without considering whether the values of the U1-phase current Iu1, the V1-phase current Iv1, and the W1-phase current Iw1 can be detected. It can be determined whether the first switching element is turned on or off.

The second current detector 5b is provided between the second power converter 4b and the second three-phase winding. The second current detector 5b detects the values of the U2-phase current Iu2, V2-phase current Iv2, and W2-phase current Iw2 as current detection values Iu2s, Iv2s, and Iw2s, respectively.

The second current detector 5b can constantly detect the values of the U2-phase current Iu2, the V2-phase current Iv2, and the W2-phase current Iw2 regardless of the ON/OFF states of the plurality of second switching elements Sup2 to Swn2. Therefore, the power converter according to Embodiment 1 can detect each of the second power converter 4b without considering whether the values of the U2-phase current Iu2, the V2-phase current Iv2, and the W2-phase current Iw2 can be detected. It can be determined whether the second switching element is turned on or off.

The control unit 6 has a voltage command calculator 7, a first offset calculator 8a, a second offset calculator 8b, a first on/off signal generator 9a, and a second on/off signal generator 9b.

The voltage command calculator 7 calculates a first voltage command based on the control command for the AC rotary machine 1, and inputs the calculated first voltage command to the first offset calculator 8a. The first voltage command includes a voltage command Vu1 for the U1 phase, a voltage command Vv1 for the V1 phase, and a voltage command Vw1 for the W1 phase.

Also, the voltage command calculator 7 calculates a second voltage command based on the control command for the AC rotary machine 1, and inputs the calculated second voltage command to the second offset calculator 8b. The second voltage command includes a voltage command Vu2 for the U2 phase, a voltage command Vv2 for the V2 phase, and a voltage command Vw2 for the W2 phase.

The voltage command calculator 7 calculates the first voltage command and the second voltage command by current feedback control or V/F (Voltage/Frequency) control, for example.

In the case of current feedback control, the voltage command calculator 7 sets a current command for the AC rotating machine 1 as the control command, and determines the amplitude of the voltage command based on the set current command. More specifically, the voltage command calculator 7 calculates the first voltage command by proportional integral control so that the deviation between the current command for the AC rotating machine 1 and the current detection values Iu1s, Iv1s, Iw1s becomes zero. Calculate. Further, the voltage command calculator 7 calculates a second voltage command by proportional-integral control so that the deviation between the current command for the AC rotary machine 1 and the current detection values Iu2s, Iv2s, Iw2s becomes zero.

In the case of V/F control, the voltage command calculator 7 sets a speed command or frequency command for the AC rotating machine 1 as a control command, and determines the amplitude of the voltage command based on the set speed command or frequency command. do.

Since the V/F control is feedforward control, the voltage command calculator 7 calculates U1-phase current Iu1, V1-phase current Iv1, W1-phase current Iw1, U2-phase current Iu2, V2-phase current Iv2, and W2-phase current Iw2 information is not required. Therefore, in the case of V/F control, information on the U1 phase current Iu1, V1 phase current Iv1, W1 phase current Iw1, U2 phase current Iu2, V2 phase current Iv2, and W2 phase current Iw2 is input to the voltage command calculator 7. you don't have to.

The first offset calculator 8a calculates a first offset voltage Voffset1. The first offset calculator 8a obtains the first applied voltage by subtracting the first offset voltage Voffset1 from the first voltage command. The first offset calculator 8a outputs the obtained first applied voltage to the first on/off signal generator 9a.

The first applied voltage includes three applied voltages corresponding to each phase, that is, applied voltage Vu1′ corresponding to U1 phase, applied voltage Vv1′ corresponding to V1 phase, and applied voltage Vw1′ corresponding to W1 phase. include. That is, the first applied voltage is represented by the following formula (1).

A second offset calculator 8b calculates a second offset voltage Voffset2. The second offset calculator 8b obtains the second applied voltage by subtracting the second offset voltage Voffset2 from the second voltage command. The second offset calculator 8b outputs the obtained second applied voltage to the second on/off signal generator 9b.

The second applied voltage includes three applied voltages corresponding to each phase, that is, applied voltage Vu2′ corresponding to U2 phase, applied voltage Vv2′ corresponding to V2 phase, and applied voltage Vw2′ corresponding to W2 phase. include. That is, the second applied voltage is represented by the following formula (2).

The first on/off signal generator 9a generates a plurality of first on/off signals Qup1, Qun1, Qvp1, Qvn1, Qwp1 for the plurality of first switching elements Sup1 to Swn1 by comparing the first applied voltage and the first reference signal. , and Qwn1. The first reference signal is a carrier signal. The first on/off signal generator 9a outputs the calculated plurality of first on/off signals Qup1 to Qwn1 to the first power converter 4a.

The plurality of first on/off signals Qup1, Qvp1, Qwp1, Qun1, Qvn1, and Qwn1 turn on and off the plurality of first switching elements Sup1, Svp1, Swp1, Sun1, Svn1, and Swn1, respectively.

When the values of the plurality of first on/off signals Qup1 to Qwn1 are "1", the first on/off signal generator 9a outputs signals for turning on the corresponding plurality of first switching elements Sup1 to Swn1. Output to the converter 4a. When the values of the plurality of first on/off signals Qup1 to Qwn1 are "0", the first on/off signal generator 9a outputs signals for turning off the corresponding plurality of first switching elements Sup1 to Swn1. Output to the converter 4a.

The second on/off signal generator 9b generates a plurality of second on/off signals Qup2, Qun2, Qvp2, Qvn2, Qwp2 for the plurality of second switching elements Sup2 to Swn2 by comparing the second applied voltage and the second reference signal. , and Qwn2. The second reference signal is a carrier signal. The second on/off signal generator 9b outputs the calculated plurality of second on/off signals Qup2 to Qwn2 to the second power converter 4b.

The plurality of second on/off signals Qup2, Qvp2, Qwp2, Qun2, Qvn2, and Qwn2 turn on and off the plurality of second switching elements Sup2, Svp2, Swp2, Sun2, Svn2, and Swn2, respectively.

When the values of the plurality of second on/off signals Qup2-Qwn2 are "1", the second on-off signal generator 9b generates signals for turning on the corresponding plurality of second switching elements Sup2-Swn2. Output to the converter 4b. When the values of the plurality of second on/off signals Qup2-Qwn2 are "0", the second on-off signal generator 9b generates a signal for turning off the corresponding plurality of second switching elements Sup2-Swn2. Output to the converter 4b.

FIG. 2 is a diagram showing the relationship between the phases of the first three-phase windings U1, V1, W1 and the phases of the second three-phase windings U2, V2, W2 in FIG. The phase difference between the first three-phase windings U1, V1, W1 and the second three-phase windings U2, V2, W2 is 30 electrical degrees. More specifically, the phase of the U2 winding leads the phase of the U1 winding by 30 degrees. The phase of the V2-phase winding leads the phase of the V1-phase winding by 30 degrees. The phase of the W2-phase winding leads the phase of the W1-phase winding by 30 degrees.

FIG. 3 is a diagram showing the first voltage vector output by the first power converter 4a of FIG. The first power converter 4a outputs one of the eight first voltage vectors according to the ON/OFF states of the plurality of first switching elements Sup1 to Swn1. The eight first voltage vectors are V0(1), V1(1), V2(1), V3(1), V4(1), V5(1), V6(1), and V7(1) .

where V0(1) and V7(1) are zero voltage vectors. When the first power converter 4a outputs the zero voltage vector, the first bus current Iinv1, which is the bus current of the first power converter 4a, becomes zero. Also, V1(1), V2(1), V3(1), V4(1), V5(1), and V6(1) are effective voltage vectors. When the first power converter 4a is outputting the effective voltage vector, the first bus current Iinv1 is the current value of each phase or its inverted value.

FIG. 4 is a diagram showing the relationship between the plurality of first on/off signals Qup1-Qwn1 and the first voltage vector. As shown in FIG. 4, there are eight combinations of values of the plurality of first on/off signals Qup1 to Qwn1. For example, when Qup1 is "0", Qun1 is "1", Qvp1 is "0", Qvn1 is "1", Qwp1 is "0", and Qwn1 is "1", the first power converter 4a Output V0(1) as one voltage vector.

FIG. 5 is a diagram showing the second voltage vector output by the second power converter 4b of FIG. Also, in FIG. 5, the first voltage vector of FIG. 3 is represented by a dashed line for comparison. The second power converter 4b outputs any one of the eight second voltage vectors according to the ON/OFF states of the plurality of second switching elements Sup2 to Swn2. The eight second voltage vectors are V0(2), V1(2), V2(2), V3(2), V4(2), V5(2), V6(2), and V7(2) .

where V0(2) and V7(2) are zero voltage vectors. When the second power converter 4b is outputting the zero voltage vector, the second bus current Iinv2, which is the bus current of the second power converter 4b, becomes zero. Also, V1(2), V2(2), V3(2), V4(2), V5(2), and V6(2) are effective voltage vectors. When the second power converter 4b is outputting the effective voltage vector, the second bus line current Iinv2 becomes the current value of each phase or its inverted value.

Since the phase difference between the first three-phase winding and the second three-phase winding is 30 degrees, V1(1) and V1(2), V2(1) and V2(2), V3(1) and V3(2), V4(1) and V4(2), V5(1) and V5(2), and V6(1) and V6(2) are out of phase with each other by 30 degrees. For example, the phase of the second voltage vector V1(2) leads the phase of the first voltage vector V1(1) by 30 degrees, but the phase of the first voltage vector V2(1) leads by 30 degrees. Running late.

FIG. 6 is a diagram showing the relationship between the plurality of second on/off signals Qup2-Qwn2 and the second voltage vector. As shown in FIG. 6, there are eight combinations of values of the plurality of second on/off signals Qup2 to Qwn2. For example, when Qup2 is "0", Qun2 is "1", Qvp2 is "0", Qvn2 is "1", Qwp2 is "0", and Qwn2 is "1", the second power converter 4b Output V0(2) as a two-voltage vector.

FIG. 7 is a flow chart showing an offset calculation routine executed by the first offset calculator 8a of FIG. The first offset calculator 8a calculates the first offset voltage Voffset1 according to the routine of FIG. The routine of FIG. 7 is executed, for example, each time the first voltage commands Vu1, Vv1, Vw1 arrive at the first offset calculator 8a.

Here, each phase in the first voltage command is called a first voltage maximum phase, a first voltage intermediate phase, and a first voltage minimum phase in descending order of voltage command. The voltage command for the first voltage maximum phase is called Vmax1, the voltage command for the first voltage intermediate phase is called Vmid1, and the voltage command for the first voltage minimum phase is called Vmin1. Among the first voltage commands Vu1, Vv1, and Vw1, the phase having the maximum absolute value is called the first voltage absolute value maximum phase.

When the routine of FIG. 7 is started, the first offset calculator 8a determines whether or not the first voltage absolute value maximum phase and the first voltage maximum phase match in step S130.

If the first voltage absolute value maximum phase and the first voltage maximum phase match, the first offset calculator 8a converts the first offset voltage Voffset1 to the voltage command Vmax1 for the first voltage maximum phase in step S131. It is set to the difference Vmax1-Vdc from the power supply voltage Vdc. Next, the first offset computing unit 8a once terminates this routine. That is, in this case, the applied voltage corresponding to the first voltage maximum phase matches the maximum value of the first reference signal.

On the other hand, if the first voltage absolute value maximum phase and the first voltage maximum phase do not match, that is, if the first voltage absolute value maximum phase and the first voltage minimum phase match, the first offset calculator In step S132, 8a sets the first offset voltage Voffset1 to the voltage command Vmin1 for the first voltage minimum phase, and temporarily terminates this routine. That is, in this case, the applied voltage corresponding to the first voltage minimum phase matches the minimum value of the first reference signal. Note that the fact that the first voltage absolute value maximum phase and the first voltage maximum phase do not match means that the first voltage absolute value maximum phase and the first voltage minimum phase match.

That is, the first offset calculator 8a calculates the offset from the first voltage command so that any one of the three applied voltages corresponding to the three phases in the first applied voltage matches the maximum value or the minimum value of the first reference signal. Subtract the first offset voltage Voffset1.

FIG. 8 is a diagram for explaining the operation of the first on/off signal generator 9a of FIG. In FIG. 8, the voltage command Vu1 for the U1 phase, the voltage command Vv1 for the V1 phase, and the voltage command Vw1 for the W1 phase have a relationship of Vu1>Vv1>Vw1. This corresponds to the case where the first voltage absolute value maximum phase and the first voltage maximum phase match in FIG. C1 is the first carrier signal. C2 is the second carrier signal. The first carrier wave signal C1 and the second carrier wave signal C2 are both triangular wave signals with a minimum value of 0, a maximum value of Vdc, and a period of Tc. The phase difference between the first carrier signal C1 and the second carrier signal C2 is 180 degrees.

The first on/off signal generator 9a compares the first carrier wave signal C1 as the first reference signal with the U1-phase applied voltage Vu1'. When the U1-phase applied voltage Vu1' is greater than or equal to the first carrier wave signal C1, the first on/off signal generator 9a outputs "1" and "0" as Qup1 and Qun1, respectively, to the first power converter 4a. When the U1-phase applied voltage Vu1' is smaller than the first carrier wave signal C1, the first on/off signal generator 9a outputs "0" and "1" as Qup1 and Qun1, respectively, to the first power converter 4a.

Here, the first applied voltage Vu1' is equal to the power supply voltage Vdc. That is, the first applied voltage Vu1' matches the maximum value of the first reference signal. Therefore, Qup1 always outputs "1" and Qun1 always outputs "0" in one period Tc of the carrier wave signal. Therefore, during the period shown in FIG. 8, the switching operation of the U1-phase switching element is stopped. The U1 phase in this case is called the first switching stop phase. Thus, the first switching stop phase is a phase in which the first applied voltage is matched with the maximum value or minimum value of the first reference signal.

Since the U1 phase is the first switching stop phase, modulation is substantially performed by two phases, the V1 phase and the W1 phase. Such modulation is called first flat biphasic modulation. That is, the first flat two-phase modulation is modulation in which the first offset voltage Voffset1 is subtracted from the first voltage command so that the applied voltage corresponding to the first voltage maximum phase matches the maximum value of the first reference signal. be.

As a result, the first power converter 4a outputs V2(1) from t1 to t2, V1(1) from t2 to t3, V6(1) from t3 to t5, and V1(1) from t5 to t6 as the first voltage vector. 1) and V2(1) at t6 to t7, respectively. During power running, the power factor angle is often 0 degrees or close to 0 degrees.

In addition, in FIG. 7, when the first voltage absolute value maximum phase and the first voltage maximum phase do not match, the control unit 6 performs the first two-phase modulation. That is, the first flat two-phase modulation is a modulation that subtracts the first offset voltage Voffset1 from the first voltage command so that the applied voltage corresponding to the first voltage minimum phase matches the minimum value of the first reference signal. be.

FIG. 9 is a diagram showing an example of carrier wave signal switching in the first on/off signal generator 9a of FIG. In FIG. 9, the hatched portion corresponds to the first switching stop phase. For example, in the voltage phase range of 0 degrees to 30 degrees, the first voltage absolute value maximum phase is the U1 phase. Also, the first voltage maximum phase is the U1 phase. In this case, since the first voltage absolute value maximum phase and the first voltage maximum phase match, the applied voltage Vu1′ of the U1 phase is determined by the first offset calculator 8a as the maximum voltage of the first carrier wave signal C1. made equal. Therefore, the U1-phase switching elements Sup1 and Sun1 do not turn on or off in the voltage phase range of 0 degrees to 30 degrees. That is, the U1 phase becomes the first switching stop phase in the voltage phase range of 0 degrees to 30 degrees.

For the U1 phase, the output results of Qup1 and Qun1 do not change regardless of which of the first carrier signal C1 and the second carrier signal C2 is selected as the first reference signal. It is hung. The first carrier signal C1 is selected as the first reference signal corresponding to the V1 phase, and the second carrier signal C2 is selected as the first reference signal corresponding to the W1 phase.

For example, when the power factor angle is 0 degrees and the voltage phase is 25 degrees, different carrier signals are selected as the first reference signals for the two phases other than the first switching stop phase, as shown in FIG. A voltage vector such as Different carrier signals are selected as the first reference signals of the two phases means that the first carrier signal C1 is selected as the first reference signal of one phase and the second carrier signal is selected as the first reference signal of the other phase. C2 is selected.

At this time, voltage vectors V1(1), V2(1), and V6(1) are output, and the bus line currents are Iu1, -Iw1, and -Iv1, respectively. Here, since Iu1>0, Iv1<0, and Iw1<0, a positive current always flows through the bus.

10 is a diagram showing a first on/off signal and a first voltage vector in a power conversion device as a comparative example with respect to FIG. 8. FIG. That is, FIG. 10 is a diagram for explaining the operation of the first on/off signal generator 9a as a comparative example. On the other hand, when the same carrier wave signal is selected as the first reference signals of the two phases other than the first switching stop phase, voltage vectors such as those shown in FIG. 10 are output. The selection of the same carrier wave signal as the first reference signals of the two phases means that the first carrier signal C1 is selected at the same time as the first reference signals of the two phases, or the second carrier wave signal C2 is selected at the same time. or

At this time, voltage vectors V1(1), V2(1), and V7(1) are output, and bus line currents are Iu1, -Iw1, and 0, respectively. Here, since Iu1>0 and Iw1<0, there are cases where a positive current flows through the bus and cases where no current flows.

Therefore, in order to reduce the capacitor current, the phases of the carrier signals selected in the two phases other than the first switching stop phase should differ by 180 degrees. When switching the carrier wave signal every 60 degrees in accordance with the change of the first switching stop phase, it is necessary to first switch the carrier wave signal at the voltage phase of 30 degrees in the V1 phase. When the voltage phase is 30 degrees, since the V1 phase is the first voltage intermediate phase, it does not become the first switching stop phase.

FIG. 11 is a diagram for explaining the operation of the first on/off signal generator 9a of FIG. FIG. 11 shows changes in Qup1, Qvp1, and Qwp1 when the carrier signal is ideally switched. The applied voltage Vv1' of the V1 phase is compared with the first carrier wave signal C1 from t10 to t12, and with the second carrier wave signal C2 from t12 to t14. Since the calculation of the first applied voltage after t12 is normally completed before t12, it is known before t12 whether or not the carrier signal needs to be switched.

FIG. 12 is a diagram for explaining the operation of the first on/off signal generator 9a when the switching timing of the carrier wave signal is not appropriately set as a comparative example with respect to FIG. For example, if the calculation of the first applied voltage is completed at t15 and the carrier wave signal is switched at that time, the first on/off signal generator 9a should be controlled to change Qvp from "0" to "1" at t15. becomes unenforceable. Therefore, the applied voltage Vv1' of the V1 phase, which should be output from t10 to t12, is not properly output, thereby disturbing the three-phase current.

In order to avoid such a problem and appropriately output the first applied voltage as shown in FIG. 11, it is necessary to synchronize the switching of the carrier wave signal and the output of the first applied voltage at t12. There is However, if an inexpensive microcomputer is used, it may be difficult to synchronize.

FIG. 13 is a diagram showing an example of carrier wave signal switching in the first on/off signal generator 9a of FIG. According to this, even if the switching of the carrier wave signal and the reflection of the first applied voltage are not synchronized, it is possible to avoid the problem that the applied voltage Vv1' of the V1 phase is not properly output. If the carrier wave signal is set as shown in FIG. 9, it is necessary to switch the carrier wave signal in the first voltage intermediate phase. However, by setting the carrier wave signal as shown in FIG. can do.

In the U1 phase, the first carrier signal C1 is selected between 210 degrees and 330 degrees, and the second carrier signal C2 is selected between 30 degrees and 150 degrees. In the V1 phase, the first carrier signal C1 is selected at 0 to 90 degrees and 330 to 360 degrees, and the second carrier signal C2 is selected at 150 to 270 degrees. In the W1 phase, the first carrier signal C1 is selected between 90 degrees and 210 degrees, and the second carrier signal C2 is selected between 0 degrees and 30 degrees and between 270 degrees and 360 degrees.

In one phase, a section serving as a first switching stop phase is interposed between a section in which the first carrier signal C1 is selected and a section in which the second carrier signal C2 is selected.

In one period of the carrier wave signal, the first on/off signal in the phase that is the first switching stop phase does not change. Therefore, even if the carrier wave signal is switched in the first switching stop phase, the first on/off signal does not change.

In the present embodiment 1, if the direction of rotation changes from left to right in FIG. A second carrier signal C2 is selected at 360 degrees or from 0 to 30 degrees. As the first reference signal in the V1 phase, the first carrier signal C1 is selected between 270 degrees and 330 degrees, and the second carrier signal C2 is selected between 90 degrees and 150 degrees. As the first reference signal in the W1 phase, the first carrier signal C1 is selected between 30 degrees and 90 degrees, and the second carrier signal C2 is selected between 210 degrees and 270 degrees.

FIG. 14 is a flow chart showing a carrier wave signal selection routine executed by the first on/off signal generator 9a of FIG. The first on/off signal generator 9a selects a carrier wave signal as follows. The routine of FIG. 14 is executed, for example, each time the first applied voltages Vu1', Vv1', Vw1' arrive at the first on/off signal generator 9a.

When the routine of FIG. 14 is started, the first on/off signal generator 9a determines whether or not the first voltage absolute value maximum phase and the first voltage maximum phase match in step S140.

When the first voltage absolute value maximum phase and the first voltage maximum phase match, in step S141, the first on/off signal generator 9a selects the second carrier signal C2 as the carrier signal of the first voltage absolute value maximum phase. to exit this routine.

On the other hand, if the first voltage absolute value maximum phase and the first voltage maximum phase do not match, in step S142, the first on/off signal generator 9a selects the first carrier wave as the carrier wave signal of the first voltage absolute value maximum phase. The signal C1 is selected, and this routine is temporarily terminated.

Although not shown, the first on/off signal generator 9a holds the previously selected carrier wave signal as the carrier wave signal in two phases other than the first voltage absolute value maximum phase.

In other words, the first on/off signal generator 9a controls, in one of the three phases, when the state of the phase is the switching stop state, when the applied voltage matches the maximum value of the carrier wave signal, or when the applied voltage Switch the carrier signal when it meets the minimum value of . This suppresses the disturbance of the applied voltage caused by the switching of the carrier wave signal.

FIG. 15 is a flow chart showing an offset calculation routine executed by the second offset calculator 8b of FIG. The second offset calculator 8b calculates the second offset voltage Voffset2 according to the routine of FIG. The routine of FIG. 15 is executed, for example, each time the second voltage commands Vu2, Vv2, Vw2 arrive at the second offset calculator 8b.

Here, each phase in the second voltage command is called a second maximum voltage phase, a second intermediate voltage phase, and a second minimum voltage phase in descending order of voltage command. The voltage command for the second voltage maximum phase is called Vmax2, the voltage command for the second voltage intermediate phase is called Vmid2, and the voltage command for the second voltage minimum phase is called Vmin2. Among the second voltage commands Vu2, Vv2, and Vw2, the phase having the maximum absolute value is called the second voltage maximum absolute value phase.

When the routine of FIG. 15 is started, the second offset calculator 8b determines whether or not the second voltage absolute value maximum phase and the second voltage maximum phase match in step S150.

If the second voltage absolute value maximum phase and the second voltage maximum phase match, the second offset calculator 8b converts the second offset voltage Voffset2 to the voltage command Vmax2 for the second voltage maximum phase in step S151. It is set to the difference Vmax2-Vdc from the power supply voltage Vdc. Next, the second offset computing unit 8b once terminates this routine. That is, in this case, the applied voltage corresponding to the second voltage maximum phase matches the maximum value of the second reference signal.

On the other hand, if the second voltage absolute value maximum phase and the second voltage maximum phase do not match, that is, if the second voltage absolute value maximum phase and the second voltage minimum phase match, the second offset calculator In step S152, 8b sets the second offset voltage Voffset2 to the voltage command Vmin2 for the second voltage minimum phase, and temporarily ends this routine. That is, in this case, the applied voltage corresponding to the second voltage minimum phase matches the minimum value of the second reference signal. Note that the fact that the second voltage absolute value maximum phase and the second voltage minimum phase do not match means that the second voltage absolute value maximum phase and the second voltage minimum phase match.

That is, the second offset computing unit 8b calculates from the second voltage command such that any one of the three applied voltages corresponding to the three phases in the second applied voltage matches the maximum value or the minimum value of the second reference signal. Subtract the second offset voltage Voffset2.

FIG. 16 is a flow chart showing a carrier wave signal selection routine executed by the second on/off signal generator 9b of FIG. When the first on/off signal generator 9a selects the carrier signal as shown in FIG. 14, the second on/off signal generator 9b selects the carrier signal as shown in FIG. The routine of FIG. 16 is executed, for example, each time the second applied voltages Vu2', Vv2', Vw2' arrive at the second on/off signal generator 9b.

When the routine of FIG. 16 is started, the second on/off signal generator 9b determines whether or not the second voltage absolute value maximum phase and the second voltage maximum phase match in step S160.

If the second voltage absolute value maximum phase and the second voltage maximum phase match, in step S161, the second on/off signal generator 9b selects the second carrier signal C2 as the carrier signal of the second voltage absolute value maximum phase. to exit this routine.

On the other hand, if the second voltage absolute value maximum phase and the second voltage maximum phase do not match, the second on/off signal generator 9b selects the first carrier wave as the carrier wave signal of the first voltage absolute value maximum phase in step S162. The signal C1 is selected, and this routine is temporarily terminated.

Although not shown, the second on/off signal generator 9b holds the previously selected carrier wave signal as the carrier wave signal in two phases other than the second voltage absolute value maximum phase.

In other words, the second on/off signal generator 9b, in a certain phase of the three phases, when the state of the phase is the switching stop state, when the applied voltage matches the maximum value of the carrier wave signal, or when the applied voltage Switch the carrier signal when it meets the minimum value of . This suppresses the disturbance of the applied voltage caused by the switching of the carrier wave signal.

Note that when the second voltage absolute value maximum phase and the second voltage maximum phase match, the control unit 6 performs the second flat two-phase modulation. That is, the second flat two-phase modulation is modulation in which the second offset voltage Voffset2 is subtracted from the second voltage command so that the applied voltage corresponding to the second voltage maximum phase matches the maximum value of the second reference signal. be.

Further, when the second voltage absolute value maximum phase and the second voltage maximum phase do not match, the control unit 6 performs the second flat two-phase modulation. That is, the second flat two-phase modulation is modulation in which the second offset voltage Voffset2 is subtracted from the second voltage command so that the applied voltage corresponding to the second voltage minimum phase matches the minimum value of the second reference signal. be. A phase in which the second applied voltage is matched to the maximum value or minimum value of the second reference signal is called a second switching stop phase.

FIG. 17 is a diagram showing an example of carrier wave signal switching in the second on/off signal generator 9b of FIG. A second voltage vector is determined to correspond to the first voltage vector. That is, it is necessary to set the second voltage vector in accordance with the first voltage vector. For example, step S141 and step S142 in FIG. 14 may be interchanged, but in that case, step S161 and step S162 in FIG. 16 need to be interchanged so that the second voltage vector corresponds to the first voltage vector. There is

Next, the difference in phase current ripple due to the combination of the first voltage vector and the second voltage vector will be explained. Here, to simplify the explanation, the resistance component and the induced voltage component are assumed to be 0, but the case where the resistance component and the induced voltage component are not 0 can also be explained based on the same idea.

The d-axis voltage of the first power converter 4a is the first d-axis voltage Vd1, the q-axis voltage of the first power converter 4a is the first q-axis voltage Vq1, and the d-axis voltage of the second power converter 4b is the second d-axis voltage Vd2. , the q-axis voltage in the second power converter 4b is defined as a second q-axis voltage Vq2. At this time, the following formula (3) holds.

Assuming that the d-axis self-inductance is Ld, the d-axis mutual inductance is Md, the q-axis self-inductance is Lq, the q-axis mutual inductance is Mq, the electrical angle is θ, and the differential operator is p, differential values piu1 to piw2 of the six-phase current are obtained. can be represented by the following formula (4).

Let k be the coupling coefficient, and simplify as shown in Equation (5). Below, the differential value of the six-phase current is expressed as a ratio to the differential value pibase of the base current represented by Equation (6).

When the first power converter 4a outputs V1(1) as the first voltage vector and the second power converter 4b outputs V0(2) as the second voltage vector, the DC component of the differential value of the six-phase current piu1_dc to piw2_dc are given by the following equation (7). The efficiency of the AC rotating machine 1 is affected by phase current ripples of all six phases. Therefore, in order to improve the efficiency of the AC rotating machine 1, the square sum of the DC components of the differential values of the six-phase currents should be minimized. In this case, the sum of squares of the DC components of the differential values of the six-phase currents is represented by the following equation (8). The "sum of squares of the DC components of the differential values of the six-phase currents" is hereinafter abbreviated as "sum of squares of the differential DC".

When the first power converter 4a outputs V1(1) as the first voltage vector and the second power converter 4b outputs V1(2) as the second voltage vector, the DC component of the differential value of the six-phase current is given by the following equation (9). In this case, the differential DC sum of squares is represented by the following equation (10).

When the first power converter 4a outputs V1(1) as the first voltage vector and the second power converter 4b outputs V2(2) as the second voltage vector, the DC component of the differential value of the six-phase current is given by the following equation (11). In this case, the differential DC sum of squares is represented by the following equation (12).

When the first power converter 4a outputs V1(1) as the first voltage vector and the second power converter 4b outputs V3(2) as the second voltage vector, the DC component of the differential value of the six-phase current is given by the following equation (13). In this case, the differential DC sum of squares is represented by the following equation (14).

FIG. 18 is a diagram showing the relationship between the coupling coefficient k and the differential DC sum of squares. The differential DC sum of squares is determined by the phase difference between the first voltage vector and the second voltage vector. Therefore, the differential DC sum of squares when V1(1) and V4(2) are output simultaneously is equal to the differential DC sum of squares when V1(1) and V3(2) are output simultaneously.

Further, the differential DC sum of squares when V1(1) and V5(2) are output at the same time is equal to the differential DC sum of squares when V1(1) and V2(2) are output at the same time. Also, the differential DC sum of squares when V1(1) and V6(2) are output at the same time is equal to the differential DC sum of squares when V1(1) and V1(2) are output at the same time.

Thus, when V1(1) is output as the first voltage vector, there are two second voltage vectors, V6(2) and V1(2), that minimize the differential DC sum of squares. In this embodiment, the phase difference between the first three-phase winding and the second three-phase winding is 30 degrees. is 0 degrees, only V1(2) exists as the second voltage vector that minimizes the sum of differential DC squares. Therefore, by setting the phase difference between the first three-phase winding and the second three-phase winding to 30 degrees, it is possible to increase the options for the combination of the first voltage vector and the second voltage vector.

When V1(1) is output as the first voltage vector, in a region where the coupling coefficient k is greater than 0.32, V1 By outputting (2) or V6(2), the change in phase current can be made smaller. Both of the two second voltage vectors V1(2) and V6(2) are vectors having a phase difference of 30 degrees from the first voltage vector V1(1).

On the other hand, when V1(1) is output as the first voltage vector, V2(2) has a phase difference of 90 degrees from V1(1) and V3(2) has a phase difference of 150 degrees from V1(1). is output as the second voltage vector, the change in phase current increases. Therefore, in order to reduce the phase current ripple, it is desirable that V1(1) is output at the same time as V1(2) or V6(2).

Here, only the second voltage vector combined with the first voltage vector V1(1) is described, but the second voltage vectors combined with the other first voltage vectors V2(1) to V6(1) are also described. You can think of it in the same way. In other words, it is desirable that the first voltage vectors V2(1) to V6(1) are output simultaneously with the second voltage vector having a phase difference of 30 degrees.

FIG. 19 is a diagram showing an example of a combination of a first voltage vector and a second voltage vector in a power converter as a comparative example. In the power conversion device of the comparative example, unlike the first embodiment, when the current absolute value maximum phase matches the voltage maximum phase or the voltage minimum phase, the switching of the current absolute value maximum phase is stopped. . In addition, in the example of the combination of FIG. 19, the power converter has a modulation factor of 0.9 and a power factor angle of 60 degrees. The voltage phase range shown in FIG. 19 is from 0 degrees to 60 degrees. Also, the length of the horizontal axis corresponds to one period Tc of the carrier wave signal.

For example, the combinations of the first voltage vector and the second voltage vector at a voltage phase of 50 degrees are V6(1) and V0(2), V6(1) and V1(2), V1(1) and V1(2) , V2(1) and V1(2), and V2(1) and V2(2). In this way, since there is a section in which voltage vectors with a phase difference of 90 degrees are output, the phase current is relatively large in the comparative example.

20 is a diagram showing an example of a combination of the first voltage vector and the second voltage vector in the power converter of FIG. 1. FIG. As in FIG. 19, the power converter has a modulation factor of 0.9, a power factor angle of 60 degrees, and a voltage phase range of 0 degrees to 60 degrees.

For example, the combinations of the first voltage vector and the second voltage vector at a voltage phase of 50 degrees are V1(1) and V6(2), V1(1) and V1(2), V2(1) and V1(2) , V2(1) and V2(2), and V3(1) and V2(2). In any of the above combinations, since the phase difference between the first voltage vector and the second voltage vector is 30 degrees, the phase current ripple can be further reduced.

FIG. 21 is a diagram showing another example of a combination of the first voltage vector and the second voltage vector in the power converter of FIG. 1. FIG. FIG. 21 shows combinations of voltage vectors when the modulation factor of the power converter is 0.4.

For example, the combinations of the first voltage vector and the second voltage vector at a voltage phase of 50 degrees are V1(1) and V6(2), V1(1) and V7(2), V0(1) and V7(2) , V0(1) and V2(2), and V3(1) and V2(2). In any of the above combinations, since the phase difference between the first voltage vector and the second voltage vector is 30 degrees, the phase current ripple can be further reduced.

That is, in the power conversion device of Embodiment 1, among the four phases other than the first switching stop phase and the second switching stop phase, the first reference signal and the second The same carrier signal is chosen as a reference signal. That is, the first carrier wave signal C1 or the second carrier wave signal C2 is simultaneously selected as the first reference signal and the second reference signal in the two phases with the smallest phase difference. Thereby, the phase current ripple can be further reduced.

Here, when carrier signals with a phase difference of 180 degrees are selected as the carrier signals of the two phases other than the first switching stop phase, the effective voltage vector is output. Further, even when carrier signals having phases different by 180 degrees are selected as the carrier signals of the two phases other than the second switching stop phase, the effective voltage vector is output. Therefore, suppressing the change in the phase current at the timing described above is effective in reducing the phase current ripple.

Therefore, in the power conversion device of Embodiment 1, the first voltage vector obtained at the timing when the first reference signal is maximum and minimum, and the second voltage vector obtained at the timing when the second reference signal is maximum and minimum The phase difference with the vector is set to 30 degrees. Alternatively, at least one of the first voltage vector and the second voltage vector is the zero voltage vector. Thereby, the phase current ripple can be reduced. That is, current detection error can be suppressed by performing current detection at time t4.

When the first power converter 4a is overmodulated, both the state of the first voltage maximum phase and the state of the first voltage minimum phase are the switching stop state. Thus, two of the three applied voltages corresponding to the three phases of the first applied voltage may match the maximum or minimum value of the first reference signal. That is, at least one of the three applied voltages corresponding to the three phases in the first applied voltage matches the maximum value or minimum value of the first reference signal.

Similarly, when the second power converter 4b is overmodulated, both the state of the second maximum voltage phase and the state of the second minimum voltage phase are switching stop states. In this way, two of the three applied voltages corresponding to the three phases of the second applied voltage may match the maximum or minimum value of the second reference signal. That is, at least one of the three applied voltages corresponding to the three phases in the second applied voltage matches the maximum value or minimum value of the second reference signal.

FIG. 22 is a configuration diagram showing an application example of the power converter of FIG. 1 to a generator motor. Since the configuration of the power converter is as described with reference to FIG. 1, the description thereof is omitted here. The generator motor is, for example, a vehicle generator motor. The generator motor has an AC rotating machine 1 and an internal combustion engine 801 . The generator motor is mounted on a vehicle (not shown).

As an auxiliary machine of the internal combustion engine 801 , the AC rotating machine 1 generates driving force for wheels provided on the vehicle via a drive system component (not shown), and also generates power using the rotation of the internal combustion engine 801 .

The closer the rotational speed of internal combustion engine 801 is to the idling rotational speed, the more frequently AC rotating machine 1 performs the power generation operation. In addition, when the engine is operated at a relatively low rotation speed near the idle rotation speed, the iron loss has a relatively large effect on the power generation efficiency.

According to the power converter of Embodiment 1, the phase current ripple in the power generation operation of the AC rotating machine 1 which is frequently performed near the idling speed of the internal combustion engine 801 is suppressed. As a result, iron loss is reduced and more efficient power generation is performed. Similarly, when the driving force is assisted by power running, the iron loss is reduced and efficient driving is performed, thereby further improving the fuel efficiency of the vehicle.

FIG. 23 is a configuration diagram showing an application example of the power conversion device of FIG. 1 to an electric motor for an electric power steering device. Since the configuration of the power converter is as described with reference to FIG. 1, the description thereof is omitted here. The AC rotary machine 1 is connected to an electric power steering device (not shown) of a vehicle.

The vehicle has a steering wheel 901 , front wheels 902 , a torque detector 903 , gears 904 and a control command generator 905 . The driver of the vehicle steers the front wheels 902 by turning the steering wheel 901 left and right. Torque detector 903 detects a steering torque Ts of the steering system and outputs the detected steering torque Ts to control command generator 905 .

Control command generator 905 calculates a control command for controlling AC rotating machine 1 based on steering torque Ts output from torque detector 903 . The calculated control command is input to the voltage command calculator 7 of the control section 6 . The control command generation unit 905 calculates a torque current command Iq_tgt as the control command using the following equation (15). where ka is a constant.

By using the power conversion device according to Embodiment 1 for the electric motor for the electric power steering device, the phase current ripple is reduced, and vibrations uncomfortable for the driver are suppressed from being transmitted to the driver via the steering wheel 901. be done. In addition, the noise transmitted into the passenger compartment is reduced.

Note that the constant ka may be set so as to change according to the steering torque Ts or the running speed of the vehicle. Here, the torque current command Iq_tgt is determined using equation (15), but the torque current command Iq_tgt may be determined based on known compensation control according to the steering situation. Here, for simplification, only the torque current command Iq_tgt for the q-axis current is determined. good.

As described above, the power converter according to Embodiment 1 includes the first power converter 4a, the second power converter 4b, and the controller 6. FIG. The first power converter 4a has a plurality of first switching elements Sup1 to Swn1, converts the DC voltage Vdc from the DC power supply 2 into a first AC voltage, and converts the first three-phase Applies to windings U1, V1, W1. The second power converter 4b has a plurality of second switching elements Sup2 to Swn2, converts the DC voltage Vdc into a second AC voltage, and converts the second three-phase windings U2, V2 of the AC rotary machine 1 to the second AC voltage. , W2.

The control unit 6 compares the first applied voltages Vu1', Vv1', Vw1' obtained by subtracting the first offset voltage Voffset1 from the first voltage commands Vu1, Vv1, Vw1 with the first reference signal. Thereby, the control unit 6 calculates a plurality of first on/off signals Qup1 to Qwn1 for the plurality of first switching elements Sup1 to Swn1. The first voltage commands Vu1, Vv1, Vw1 are voltage commands for the first three-phase windings U1, V1, W1.

The control unit 6 compares the second applied voltages Vu2', Vv2', Vw2' obtained by subtracting the second offset voltage Voffset2 from the second voltage commands Vu2, Vv2, Vw2 with the second reference signal. Thereby, the control unit 6 calculates a plurality of second on/off signals Qup2 to Qwn2 for the plurality of second switching elements Sup2 to Swn2. The second voltage commands Vu2, Vv2, Vw2 are voltage commands for the second three-phase windings U2, V2, W2.

Here, the phase difference between the first three-phase winding and the second three-phase winding is 30 degrees. Also, the first reference signal and the second reference signal are either the first carrier wave signal C1 or the second carrier wave signal C2, and the phase difference between the first carrier wave signal C1 and the second carrier wave signal C2 is 180 degrees. .

The control unit 6 changes the first offset voltage Voffset1 from the first voltage command so that at least one of the three applied voltages corresponding to the three phases in the first applied voltage matches the maximum value or minimum value of the first reference signal. Subtract. At the same time, the control unit 6 controls the second voltage command so that at least one of the three applied voltages corresponding to the three phases in the second applied voltage matches the maximum value or the minimum value of the second reference signal. 2 Subtract the offset voltage Voffset2.

The control unit 6 sets the phase difference between the first voltage vector obtained based on the first on/off signal and the second voltage vector obtained based on the second on/off signal to 30 degrees, or sets the first voltage vector and Let at least one of the second voltage vectors be a zero voltage vector.

According to this, the phase difference between the first voltage vector and the second voltage vector can be minimized, thereby further reducing the phase current ripple.

Further, the control unit 6 adjusts the phase difference between the first voltage vector obtained at the timing when the first reference signal reaches its maximum and minimum and the second voltage vector obtained at the timing when the second reference signal reaches its maximum and minimum. 30 degrees, or both the first voltage vector and the second voltage vector are zero voltage vectors.

According to this, the phase difference between the first voltage vector and the second voltage vector can be minimized, thereby further reducing the phase current ripple.

Further, when the first voltage absolute value maximum phase and the first voltage maximum phase match, the control section 6 performs the first flat two-phase modulation. The first voltage absolute value maximum phase is the phase with the maximum absolute value among the three voltage commands corresponding to the three phases in the first voltage command. The first flat two-phase modulation is modulation that subtracts the first offset voltage Voffset1 from the first voltage command so that the applied voltage corresponding to the first voltage maximum phase matches the maximum value of the first reference signal.

When the first voltage absolute value maximum phase and the first voltage minimum phase match, the control unit 6 performs the first flat two-phase modulation. The first flat two-phase modulation is modulation that subtracts the first offset voltage Voffset1 from the first voltage command so that the applied voltage corresponding to the first voltage minimum phase matches the minimum value of the first reference signal.

The control unit 6 selects the first carrier wave signal C1 as the first reference signal for one of the two phases other than the phase in which the first applied voltage matches the maximum value or minimum value of the first reference signal. , select the second carrier signal C2 as the first reference signal of the other phase.

Further, when the second voltage absolute value maximum phase and the second voltage maximum phase match, the control unit 6 performs the second flat two-phase modulation. The second voltage absolute value maximum phase is the maximum phase among the absolute values of the three voltage commands corresponding to the three phases in the second voltage command. The second flat top two-phase modulation is modulation that subtracts the second offset voltage Voffset2 from the second voltage command so that the applied voltage corresponding to the second voltage maximum phase matches the maximum value of the second reference signal.

When the second voltage absolute value maximum phase and the second voltage minimum phase match, the control unit 6 performs the second flat two-phase modulation. The second flat two-phase modulation is modulation that subtracts the second offset voltage Voffset2 from the second voltage command so that the applied voltage corresponding to the second voltage minimum phase matches the minimum value of the second reference signal.

The control unit 6 selects the first carrier wave signal C1 as the second reference signal for one of the two phases other than the phase in which the second applied voltage matches the maximum value or minimum value of the second reference signal. , select the second carrier signal C2 as the second reference signal for the other phase.

The control unit 6 controls four phases other than the phase in which the first upper solid two-phase modulation or the first lower solid two-phase modulation is performed and the phase in which the second upper solid two-phase modulation or the second lower solid two-phase modulation is performed. The same signal of either the first carrier wave signal C1 or the second carrier wave signal C2 is selected as the first reference signal and the second reference signal in the two phases with the smallest phase difference.

According to this, the phase difference between the first voltage vector and the second voltage vector can be minimized, thereby further reducing the phase current ripple.

Further, when performing the first flat two-phase modulation, the control unit 6 selects the first carrier wave signal C1 as the first reference signal for the first voltage maximum phase, the first voltage intermediate phase and the first voltage minimum phase. maintains the previous first reference signal as the first reference signal of When performing the first flat bottom two-phase modulation, the control unit 6 selects the second carrier signal C2 as the first reference signal of the first voltage minimum phase, and selects the second carrier signal C2 of the first voltage maximum phase and the first voltage intermediate phase. The previous first reference signal is maintained as the No. 1 reference signal.

When performing the second flat two-phase modulation, the control unit 6 selects the first carrier wave signal C1 as the second reference signal for the second voltage maximum phase, and selects the first carrier signal C1 for the second voltage intermediate phase and the second voltage minimum phase. The previous second reference signal is maintained as the second reference signal. When performing the second flat two-phase modulation, the control unit 6 selects the second carrier signal C2 as the second reference signal for the second voltage minimum phase, and selects the second carrier signal C2 for the second voltage maximum phase and the second voltage intermediate phase. The previous second reference signal is maintained as the second reference signal.

According to this, the frequency of switching the carrier wave signal can be reduced, and the carrier wave signal can be switched in the switching stop state. This suppresses the disturbance of the applied voltage caused by the switching of the carrier wave signal.

Further, the first power converter 4a and the second power converter 4b are further provided with current detectors 5a and 5b. The current detectors 5a and 5b detect the first three-phase winding and the second three-phase winding at least one of timing when the first reference signal and the second reference signal are maximum and minimum. Detects current flow. The control unit 6 calculates a first voltage command and a second voltage command based on the first detected current and the second detected current obtained by the current detectors 5a and 5b.

According to this, the phase current is detected at the timing when the current change is small. As a result, phase current detection errors are suppressed.

Further, the generator motor control device includes the power conversion device according to the first embodiment.

According to this, iron loss in the generator-motor is reduced, and efficient power generation is possible. Therefore, when applied to a vehicle generator-motor, the fuel consumption of the vehicle can be improved.

Also, the electric power steering system includes the power converter according to the first embodiment.

According to this, by reducing the phase current ripple of the power conversion device, the vibration transmitted to the driver via the steering wheel is suppressed, and the noise in the vehicle interior is reduced.

In the first embodiment, the first carrier signal C1 is a triangular wave that is convex upward in one cycle of the carrier signal, and the second carrier signal C2 is a triangular wave that is convex downward in one cycle of the carrier signal. The relationship may be the opposite.

Embodiment 2.
24 is a configuration diagram showing a power converter according to Embodiment 2. FIG. The power conversion device of FIG. 24 is provided with a first on/off signal generator 9a1 instead of the first on/off signal generator 9a of FIG. 24 is provided with a second on/off signal generator 9b1 instead of the second on/off signal generator 9b in FIG.

Configurations other than the above are the same as those of the power conversion apparatus in FIG. Hereinafter, the description of the same configuration as that of the power converter of FIG. 1 will be omitted.

In the first on/off signal generator 9a of FIG. 1, carrier signals having phases different from each other by 180 degrees are used as the first reference signals in the two phases other than the switching stop phase. Similarly, in the second on/off signal generator 9b, carrier signals with phases 180 degrees out of phase are used as the second reference signals in the two phases other than the switching stop phase.

On the other hand, the first on/off signal generator 9a1 of FIG. 24 uses the same carrier wave signal as the first reference signals in the two phases other than the switching stop phase. Similarly, the second on/off signal generator 9b1 of FIG. 24 uses the same carrier wave signal as the second reference signal in the two phases other than the switching stop phase.

When flat two-phase modulation is implemented, the effective voltage vector interval appears near the maximum value of the carrier signal, as in the case shown in FIG. The effective voltage vector section is the section in which the effective voltage vector is output. Therefore, when the applied voltage and the first carrier wave signal C1 are compared, the effective voltage vector section appears in the middle of one period of the first carrier wave signal C1. When the applied voltage and the second carrier wave signal C2 are compared, the effective voltage vector sections appear at both ends of one period of the second carrier wave signal C2.

On the other hand, when bottom-bottom biphasic modulation is performed, the effective voltage vector interval appears near the minimum value of the carrier signal. Therefore, when the applied voltage and the first carrier wave signal C1 are compared, the effective voltage vector sections appear at both ends of one period of the first carrier wave signal C1. When the applied voltage and the second carrier signal C2 are compared, the effective voltage vector section appears in the middle of one cycle of the second carrier signal C2.

In order to reduce the phase current ripple, the phase of the first voltage vector based on the first switching signal and the second voltage vector based on the second switching signal is adjusted at the timing when the carrier signal is maximized or the carrier signal is minimized. The phase difference should be reduced.

Specifically, the phase current ripple is reduced by setting the phase difference between the first voltage vector and the second voltage vector to 30 degrees at the timing when the carrier wave signal is maximized and the carrier wave signal is minimized. can be done.

Alternatively, the phase current ripple can be reduced by setting at least one of the first voltage vector and the second voltage vector as a zero voltage vector.

Further, current detection accuracy can be improved by detecting the current of each phase at least one of the timing at which the carrier wave signal reaches its maximum and the timing at which the carrier wave signal reaches its minimum.

25 is a diagram showing combinations of modulation methods, carrier signals, and effective voltage vector sections in the power converter of FIG. 24. FIG. FIG. 25 shows eight combinations of A to H.

In combination A, the two-phase modulation described above is implemented as the modulation method in the first power converter 4a, and the first carrier signal C1 is used as the carrier signal. In this case, the effective voltage vector section appears in the middle of one period of the first carrier signal C1. In combination A, the two-phase modulation described above is performed as the modulation method in the second power converter 4b, and the first carrier signal C1 is used as the carrier signal. In this case, the effective voltage vector section appears in the middle of one period of the first carrier signal C1.

In combination B, the two-phase modulation described above is performed as the modulation method in the first power converter 4a, and the first carrier signal C1 is used as the carrier signal. Further, in combination B, two-phase modulation is performed as the modulation method in the second power converter 4b, and the second carrier signal C2 is used as the carrier signal.

In combination C, the two-phase modulation described above is implemented as the modulation method in the first power converter 4a, and the second carrier signal C2 is used as the carrier signal. Further, in combination C, the two-phase modulation described above is performed as the modulation method in the second power converter 4b, and the second carrier signal C2 is used as the carrier signal.

In combination D, the two-phase modulation described above is implemented as the modulation method in the first power converter 4a, and the second carrier signal C2 is used as the carrier signal. Further, in combination D, two-phase modulation is performed as the modulation method in the second power converter 4b, and the first carrier signal C1 is used as the carrier signal.

In combination E, flat two-phase modulation is implemented as the modulation method in the first power converter 4a, and the first carrier signal C1 is used as the carrier signal. Further, in combination D, the two-phase modulation described above is performed as the modulation method in the second power converter 4b, and the second carrier signal C2 is used as the carrier signal.

In combination F, flat two-phase modulation is implemented as the modulation method in the first power converter 4a, and the first carrier signal C1 is used as the carrier signal. Further, in combination F, two-phase modulation is performed as the modulation method in the second power converter 4b, and the first carrier signal C1 is used as the carrier signal.

In combination G, the two-phase modulation described above is implemented as the modulation method in the first power converter 4a, and the second carrier signal C2 is used as the carrier signal. Moreover, in the combination G, the two-phase modulation described above is performed as the modulation method in the second power converter 4b, and the first carrier signal C1 is used as the carrier signal.

In combination H, flat two-phase modulation is implemented as the modulation method in the first power converter 4a, and the second carrier signal C2 is used as the carrier signal. In addition, in combination H, two-phase modulation is performed as the modulation method in the second power converter 4b, and the second carrier signal C2 is used as the carrier signal.

The phase difference between the first voltage vector and the second voltage vector is 30 degrees, or at least one of the first voltage vector and the second voltage vector, by selecting the modulation method and the carrier signal according to combinations A through H. One can be a zero voltage vector. In addition, the current detection accuracy is improved by detecting the current of each phase at least one of the timing at which the carrier wave signal is maximized and the timing at which the carrier wave signal is minimized.

FIG. 26 is a diagram showing 12 regions obtained by dividing the voltage phase. Here, the voltage phase range from 0 degrees to 360 degrees is equally divided into regions a to l by 30 degrees. A region between voltage vectors V1(1) and V1(2) is defined as region a, and regions b, regions c, .

That is, region a is the region between voltage vectors V1(1) and V1(2). Region b is the region between voltage vectors V1(2) and V2(1). Region c is the region between voltage vectors V2(1) and V2(2). Region d is the region between voltage vectors V2(2) and V3(1). Region e is the region between voltage vectors V3(1) and V3(2). Region f is the region between voltage vectors V3(2) and V4(1).

Region g is the region between voltage vectors V4(1) and V4(2). Region h is the region between voltage vectors V4(2) and V5(1). Region i is the region between voltage vectors V5(1) and V5(2). Region j is the region between voltage vectors V5(2) and V6(1). Region k is the region between voltage vectors V6(1) and V6(2). Region l is the region between voltage vectors V6(2) and V1(1).

In region a, the first power converter 4a outputs voltage vectors V1(1) and V2(1). Voltage vectors V1(1) and V2(1) are both effective voltage vectors. Also, in region a, the second power converter 4b outputs voltage vectors V6(2) and V1(2). Voltage vectors V6(2) and V1(2) are both effective voltage vectors.

Of the four voltage vectors output in region a, the voltage vectors with the closest directions are V1(1) and V1(2). Therefore, the first voltage maximum phase is the U1 phase and the second voltage maximum phase is the U2 phase. The phase difference between the U1 phase and the U2 phase is 30 degrees. In region a, the voltage vectors with the second closest directions are V2(1) and V6(2). Therefore, the first voltage minimum phase is the W1 phase and the second voltage minimum phase is the V2 phase. The phase difference between the W1 phase and the V2 phase is 90 degrees.

When the combination of modulation method and carrier wave signal is combination A, voltage vectors V1(1) and V1(2) with a phase difference of 30 degrees are output simultaneously, but voltage vector V2(1) with a phase difference of 90 degrees is output at the same time. and V6(2) are also output at the same time. On the other hand, when the combination of modulation method and carrier wave signal is combination B, the voltage vectors V1(1) and V6(1) with a phase difference of 30 degrees are simultaneously output, and the voltage vector V2 ( 1) and V1(2) are output simultaneously.

In the case of the combinations D, E, and G as well, voltage vectors with a phase difference of 30 degrees are simultaneously output from the first power converter 4a and the second power converter 4b, so the phase current ripple is reduced.

Also, in the region c, the region e, the region g, the region i, and the region k, when the combinations B, D, E, and G are selected, the positions in the first power converter 4a and the second power converter 4b Voltage vectors with a phase difference of 30 degrees are simultaneously output.

In region b, the first power converter 4a outputs voltage vectors V1(1) and V2(1). Voltage vectors V1(1) and V2(1) are both effective voltage vectors. Also, in region b, the second power converter 4b outputs voltage vectors V1(2) and V2(2). Voltage vectors V1(2) and V2(2) are both effective voltage vectors.

Of the four voltage vectors output in region b, the voltage vectors with the closest directions are V2(1) and V1(2). Therefore, the first voltage maximum phase is the U1 phase and the second voltage maximum phase is the U2 phase. The phase difference between the U1 phase and the U2 phase is 30 degrees. In region b, the voltage vectors with the second closest directions are V1(1) and V2(2). Therefore, the first voltage minimum phase is the W1 phase and the second voltage minimum phase is the W2 phase. The phase difference between the W1 phase and the W2 phase is 30 degrees.

When the modulation method and carrier signal combination is combination B, the voltage vectors V2(1) and V1(2) with a phase difference of 30 degrees are output simultaneously, but the voltage vector V1(1) with a phase difference of 90 degrees is output. and V2(2) are also output at the same time. On the other hand, when the combination of modulation method and carrier wave signal is combination A, voltage vectors V1(1) and V1(2) with a phase difference of 30 degrees are simultaneously output, and voltage vector V2 ( 1) and V2(2) are output simultaneously.

Also, in the region d, the region f, the region h, the region j, and the region l, when the combinations A, C, F, and H are selected, the positions in the first power converter 4a and the second power converter 4b are Voltage vectors with a phase difference of 30 degrees are simultaneously output.

In this way, by changing the combination of the modulation method and the carrier wave signal according to the voltage phase region, the phase difference between the first voltage vector and the second voltage vector can be set to 30 degrees in the entire voltage phase range. can be done. Specific examples are shown below.

FIG. 27 is a diagram showing a first example of carrier wave signal switching in the first on/off signal generator 9a1 and the second on/off signal generator 9b1 of FIG. Also, FIG. 28 is a diagram showing a first example of the first applied voltage waveform and the second applied voltage waveform. The modulation factor of the power converter at this time is 0.6.

FIG. 29 is a diagram showing a first example of a combination of the first voltage vector and the second voltage vector in the voltage phase region from 0 degrees to 60 degrees. For example, the combination of the first voltage vector and the second voltage vector at voltage phases of 20 degrees is V7(1) and V0(2), V2(1) and V0(2), V2(1) and V1(2 ), V1(1) and V1(2), V1(1) and V6(2). Any combination has a phase difference of 30 degrees or at least one of which is a zero voltage vector.

Also, for example, the combinations of the first voltage vector and the second voltage vector at voltage phases of 50 degrees are V2(1) and V2(2), V2(1) and V1(2), V1(1) and V1 (2), V0(1) and V1(2), V0(1) and V0(2). Any combination has a phase difference of 30 degrees or at least one of which is a zero voltage vector.

FIG. 30 is a diagram showing a second example of carrier wave signal switching in the first on/off signal generator 9a1 and the second on/off signal generator 9b1 in FIG. In the example shown in FIG. 30, the second carrier signal C2 is selected in the voltage phase in which the first carrier signal C1 is selected in FIG. Carrier signal C1 is selected. In this case as well, the combination of the first voltage vector and the second voltage vector has a phase difference of 30 degrees, and the effect of reducing the phase current ripple is the same as in the example shown in FIG.

That is, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the control unit 6 implements the first flat biphasic modulation. When the first on/off signal generator 9a1 selects one of the first carrier signal C1 and the second carrier signal C2 as the first reference signal, the control unit 6 performs the second flat two-phase modulation. do. Also, the second on/off signal generator 9b1 selects the same signal as the signal selected as the first reference signal as the second reference signal.

Further, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the control unit 6 implements the first flattened biphasic modulation. When the first on/off signal generator 9a1 selects one of the first carrier wave signal C1 and the second carrier wave signal C2 as the first reference signal, the control unit 6 performs the second flat two-phase modulation. do. Also, the second on/off signal generator 9b1 selects the same signal as the signal selected as the first reference signal as the second reference signal.

Further, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or when the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 , performs the first flat-top bi-phase modulation. When the first on/off signal generator 9a1 selects one of the first carrier wave signal C1 and the second carrier wave signal C2 as the first reference signal, the control unit 6 performs the second flat two-phase modulation. do. Also, the second on/off signal generator 9b1 selects a signal different from the signal selected as the first reference signal as the second reference signal.

Further, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or when the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 , implements the first flattened biphasic modulation. When the first on/off signal generator 9a1 selects one of the first carrier signal C1 and the second carrier signal C2 as the first reference signal, the control unit 6 performs the second flat two-phase modulation. do. Also, the second on/off signal generator 9b1 selects a signal different from the signal selected as the first reference signal as the second reference signal.

FIG. 31 is a diagram showing a third example of carrier wave signal switching in the first on/off signal generator 9a1 and the second on/off signal generator 9b1 in FIG. According to the method shown in FIG. 27, the first non-switching phase was switched six times and the second non-switching phase was switched eleven times in the voltage phase range from 0 degrees to 360 degrees. According to the method shown in FIG. 31, the number of switching of the switching stop phase by the first power converter 4a can be reduced to three.

FIG. 32 is a diagram showing a second example of the first applied voltage waveform and the second applied voltage waveform. The modulation factor is 0.6. Also, FIG. 33 is a diagram showing a second example of a combination of the first voltage vector and the second voltage vector in the region where the voltage phase is from 0 degrees to 60 degrees. For example, when the voltage phase is 20 degrees, the combinations of the first voltage vector and the second voltage vector are V7(1) and V0(2), V2(1) and V0(2), V2(1) and V1 (2), V1(1) and V1(2), V1(1) and V6(2). Any combination has a phase difference of 30 degrees or at least one of which is a zero voltage vector.

When the voltage phase is 50 degrees, the combinations of the first voltage vector and the second voltage vector are V7(1) and V7(2), V7(1) and V2(2), V2(1) and V2 (2), V2(1) and V1(2), V1(1) and V1(2). In this case also, any combination has a phase difference of 30 degrees or at least one of which is a zero voltage vector.

In this case, at the end of one period Tc of the carrier signal, there is a section where both the first power converter 4a and the second power converter 4b output zero voltage vectors. In the section where both the first power converter 4a and the second power converter 4b output the zero voltage vector, by switching the carrier wave signal, it is necessary to synchronize the reflection of the applied voltage and the switching timing of the carrier wave signal. Gone. Therefore, the above method is suitable for mounting on an inexpensive microcomputer.

That is, the control unit 6 performs the first flat two-phase modulation, and the first on/off signal generator 9a1 selects the first carrier signal C1 as the first reference signal. Here, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the control unit 6 implements a second flat biphasic modulation. Also, the second on/off signal generator 9b1 selects the first carrier wave signal C1 as the second reference signal.

On the other hand, if the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or if the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 2 A flat biphasic modulation is implemented. Also, the second on/off signal generator 9b1 selects the second carrier wave signal C2 as the second reference signal. As a result, the number of times the switching stop phase is switched is reduced, and the phase current ripple is reduced.

FIG. 34 is a diagram showing a fourth example of carrier wave signal switching in the first on/off signal generator 9a1 and the second on/off signal generator 9b1 in FIG. According to the method shown in FIG. 34, the number of switching times of the first switching stop phase can be reduced to three.

FIG. 35 is a diagram showing a third example of the first applied voltage waveform and the second applied voltage waveform. The modulation factor is 0.6. Also, FIG. 36 is a diagram showing a third example of a combination of the first voltage vector and the second voltage vector in the region where the voltage phase is from 0 degrees to 60 degrees. For example, when the voltage phase is 20 degrees, the combinations of the first voltage vector and the second voltage vector are V2(1) and V1(2), V1(1) and V1(2), V1(1) and V6 (2), V1(1) and V7(2), and V0(1) and V7(2). Any combination has a phase difference of 30 degrees or at least one of which is a zero voltage vector.

When the voltage phase is 50 degrees, the combinations of the first voltage vector and the second voltage vector are V2(1) and V2(2), V2(1) and V1(2), V1(1) and V1 (2), V0(1) and V1(1), V0(1) and V0(2). In this case also, any combination has a phase difference of 30 degrees or at least one of which is a zero voltage vector.

In this case, there is a section in which both the first power converter 4a and the second power converter 4b output zero voltage vectors at the center of one cycle Tc of the carrier signal. Current detection accuracy is improved by performing current detection in a section where both the first power converter 4a and the second power converter 4b output zero voltage vectors.

That is, the control unit 6 performs the first bottom-bottom two-phase modulation, and the first on/off signal generator 9a1 selects the first carrier wave signal C1 as the first reference signal. Here, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the control unit 6 implements a second flattened biphasic modulation. Also, the second on/off signal generator 9b1 selects the first carrier wave signal C1 as the second reference signal.

On the other hand, if the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or if the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 2 A flat two-phase modulation is implemented. Also, the second on/off signal generator 9b1 selects the second carrier wave signal C2 as the second reference signal. As a result, the number of times the switching stop phase is switched is reduced, and the phase current ripple is reduced.

FIG. 37 is a diagram showing a fifth example of carrier wave signal switching in the first on/off signal generator 9a1 and the second on/off signal generator 9b1 of FIG. According to the method shown in FIG. 27, the first non-switching phase was switched six times and the second non-switching phase was switched 11 times in the voltage phase range of 0 degrees to 360 degrees. According to the method shown in FIG. 37, the number of switching times of the second switching stop phase can be reduced to six.

38 is a diagram showing a fourth example of the first applied voltage waveform and the second applied voltage waveform in the power converter of FIG. 24. FIG. The modulation factor is 0.6. Also, FIG. 39 is a diagram showing a fourth example of a combination of the first voltage vector and the second voltage vector in the region where the voltage phase is from 0 degrees to 120 degrees. Regardless of the voltage phase, when both the first power converter 4a and the second power converter 4b output effective voltage vectors, the phase difference between the first voltage vector and the second voltage vector is 30 degrees. It has become.

In other words, when the three voltage commands corresponding to the three phases in the first voltage command are in any of the following order in descending order, the control section 6 performs the first flat two-phase modulation. The first on/off signal generator 9a1 selects the first carrier wave signal C1 as the first reference signal.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

Moreover, when the three voltage commands corresponding to the three phases in the first voltage command are not in any of the following orders in descending order, the control unit 6 carries out the first flat bottom two-phase modulation. The first on/off signal generator 9a1 selects the second carrier wave signal C2 as the first reference signal.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

Further, when the three voltage commands corresponding to the three phases in the second voltage command are in any of the following order in descending order, the control unit 6 performs the second flat two-phase modulation. The second on/off signal generator 9b1 selects the first carrier wave signal C1 as the second reference signal.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

Moreover, when the three voltage commands corresponding to the three phases in the second voltage command are not in any of the following orders in descending order, the control unit 6 performs the second flat two-phase modulation. The second on/off signal generator 9b1 selects the second carrier wave signal C2 as the second reference signal.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

FIG. 40 is a diagram showing a sixth example of carrier wave signal switching in the first on/off signal generator 9a1 and the second on/off signal generator 9b1 in FIG. Also by the method shown in FIG. 40, the number of times of switching the second switching stop phase can be reduced to 6 times.

FIG. 41 is a diagram showing a fifth example of the first applied voltage waveform and the second applied voltage waveform. The modulation factor is 0.6. Also, FIG. 42 is a diagram showing a fifth example of a combination of the first voltage vector and the second voltage vector in the region where the voltage phase is from 0 degrees to 120 degrees. In any voltage phase, when both the first power converter 4a and the second power converter 4b output effective voltage vectors, the phase difference between the first voltage vector and the second voltage vector is 30 degrees. ing.

In other words, when the three voltage commands corresponding to the three phases in the first voltage command are in any of the following order in descending order, the control unit 6 performs the first flat two-phase modulation. The first on/off signal generator 9a1 selects the second carrier wave signal C2 as the first reference signal.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

Moreover, when the three voltage commands corresponding to the three phases in the first voltage command are not in any of the following orders in descending order, the control unit 6 performs the first flat two-phase modulation. The first on/off signal generator 9a1 selects the first carrier wave signal C1 as the first reference signal.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

Further, when the three voltage commands corresponding to the three phases in the second voltage command are in any of the following order in descending order, the control unit 6 performs the second flat two-phase modulation. The second on/off signal generator 9b1 selects the second carrier wave signal C2 as the second reference signal.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

Further, when the three voltage commands corresponding to the three phases in the second voltage command are not in any of the following orders in descending order, the control unit 6 performs the second flat two-phase modulation. The second on/off signal generator 9b1 selects the first carrier wave signal C1 as the second reference signal.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

As described above, in the power converter according to Embodiment 2, modulation is performed as follows. When the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the control unit 6 Modulation is performed by a combination of 1 upper-solid two-phase modulation and a second upper-solid two-phase modulation or a combination of the first lower-solid two-phase modulation and a second lower-solid two-phase modulation.

Here, each phase in the first voltage command is called a first voltage maximum phase, a first voltage intermediate phase, and a first voltage minimum phase in descending order of voltage command, and each phase in the second voltage command is called They are called a second maximum voltage phase, a second intermediate voltage phase, and a second minimum voltage phase in descending order.

The first flat two-phase modulation is modulation that subtracts the first offset voltage Voffset1 from the first voltage command so that the applied voltage corresponding to the first voltage maximum phase matches the maximum value of the first reference signal. The second flat top two-phase modulation is modulation that subtracts the second offset voltage Voffset2 from the second voltage command so that the applied voltage corresponding to the second voltage maximum phase matches the maximum value of the second reference signal.

The first flat two-phase modulation is modulation that subtracts the first offset voltage Voffset1 from the first voltage command so that the applied voltage corresponding to the first voltage minimum phase matches the minimum value of the first reference signal. The second flat two-phase modulation is modulation that subtracts the second offset voltage Voffset2 from the second voltage command so that the applied voltage corresponding to the second voltage minimum phase matches the minimum value of the second reference signal.

When the control unit 6 performs the first flat two-phase modulation and selects one of the first carrier signal C1 and the second carrier signal C2 as the first reference signal, the second flat two-phase modulation is performed. and selecting the same signal as the signal selected as the first reference signal as the second reference signal.

Further, when the control unit 6 performs the first lower solid two-phase modulation and selects one of the first carrier wave signal C1 and the second carrier wave signal C2 as the first reference signal, the second lower solid two-phase modulation is performed. A phase modulation is performed and a second reference signal is selected that is identical to the signal selected as the first reference signal.

On the other hand, if the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or if the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 Modulation is performed by a combination of 1 upper-solid two-phase modulation and a second lower-solid two-phase modulation or a combination of the first lower-solid two-phase modulation and a second upper-solid two-phase modulation.

When the control unit 6 performs the first upper flat two-phase modulation and selects one of the first carrier signal C1 and the second carrier signal C2 as the first reference signal, the second lower flat two-phase modulation is performed. and select a signal different from the signal selected as the first reference signal as the second reference signal.

Further, when the control unit 6 performs the first bottom solid two-phase modulation and selects one of the first carrier wave signal C1 and the second carrier wave signal C2 as the first reference signal, the second top plane two-phase modulation is performed. A phase modulation is performed and a signal different from the signal selected as the first reference signal is selected as the second reference signal.

According to this, the phase difference between the first voltage vector and the second voltage vector can be minimized, thereby further reducing the phase current ripple.

The control unit 6 also performs the first flat two-phase modulation and selects the first carrier signal C1 as the first reference signal. Further, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, , performs a second flattened bi-phase modulation and selects the first carrier signal C1 as the second reference signal. On the other hand, if the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or if the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 2. Perform flat-to-bottom bi-phase modulation and select a second carrier signal as a second reference signal.

According to this, the number of times the switching stop phase is switched is reduced, and the phase current ripple is reduced.

The control unit 6 also performs the first bottom-bottom two-phase modulation and selects the first carrier signal C1 as the first reference signal. Further, when the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, , performs a second flattened bi-phase modulation and selects the first carrier signal C1 as the second reference signal. On the other hand, if the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or if the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the control unit 6 2, a flat-top two-phase modulation is performed and a second carrier signal is selected as a second reference signal.

According to this, the number of times the switching stop phase is switched is reduced, and the phase current ripple is reduced.

When each phase of the first three-phase winding is U1 phase, V1 phase, and W1 phase, and each phase of the second three-phase winding is U2 phase, V2 phase, and W2 phase, U1 phase and U2 phase , the phase difference between the V1 phase and the V2 phase, and the phase difference between the W1 phase and the W2 phase are each set to 30 degrees.

When the three voltage commands corresponding to the three phases in the first voltage command are in any of the following order in descending order, the control unit 6 performs the first top-bottom two-phase modulation, and uses the first reference signal as the first reference signal. 1 carrier signal C1 is selected.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

If the three voltage commands corresponding to the three phases in the first voltage command are not in any of the following order in descending order, the control unit 6 performs the first flat two-phase modulation, and uses the second reference signal as the first reference signal. Select carrier signal C2.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

When the three voltage commands corresponding to the three phases in the second voltage command are in any of the following order in descending order, the control unit 6 performs the second flat two-phase modulation, and uses the second reference signal as the second reference signal. 1 carrier signal C1 is selected.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

If the three voltage commands corresponding to the three phases in the second voltage command are not in any of the following order in descending order, the control unit 6 performs the second flat two-phase modulation, and uses the second reference signal as the second reference signal. Select carrier signal C2.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

According to this, the number of times the switching stop phase is switched is reduced, and the phase current ripple is reduced.

When each phase of the first three-phase winding is U1 phase, V1 phase, and W1 phase, and each phase of the second three-phase winding is U2 phase, V2 phase, and W2 phase, U1 phase and U2 phase , the phase difference between the V1 phase and the V2 phase, and the phase difference between the W1 phase and the W2 phase are each set to 30 degrees.

When the three voltage commands corresponding to the three phases in the first voltage command are in any of the following order in descending order, the control unit 6 performs the first flat two-phase modulation, and uses the first reference signal as the first reference signal. A two-carrier signal C2 is selected.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

If the three voltage commands corresponding to the three phases in the first voltage command are not in any of the following order in descending order, the control unit 6 performs the first flat two-phase modulation and uses the first reference signal as the first reference signal. Select carrier signal C1.
・U1 phase voltage command, V1 phase voltage command, W1 phase voltage command ・V1 phase voltage command, W1 phase voltage command, U1 phase voltage command ・W1 phase voltage command, U1 phase voltage command, V1 phase voltage reference

If the three voltage commands corresponding to the three phases in the second voltage command are in any of the following order in descending order, the control unit 6 performs the second flat two-phase modulation and uses the second reference signal as the second reference signal. A two-carrier signal C2 is selected.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

If the three voltage commands corresponding to the three phases in the second voltage command are not in any of the following order in descending order, the control unit 6 performs the second flat two-phase modulation, and uses the first reference signal as the second reference signal. Select carrier signal C1.
・U2 phase voltage command, V2 phase voltage command, W2 phase voltage command ・V2 phase voltage command, W2 phase voltage command, U2 phase voltage command ・W2 phase voltage command, U2 phase voltage command, V2 phase voltage reference

According to this, the number of times the switching stop phase is switched is reduced, and the phase current ripple is reduced.

Note that the first carrier signal C1 was defined as a signal that is maximum at the center of one cycle of the carrier signal and minimum at both ends of one cycle of the carrier signal. Further, the second carrier wave signal C2 was defined as a signal having a minimum value at the center of one cycle of the carrier signal and a maximum value at both ends of one cycle of the carrier signal. However, even if the definitions of the first carrier wave signal C1 and the second carrier wave signal C2 are interchanged, the same effect can be obtained.

Also, the functions of the power converters of the first and second embodiments are implemented by a processing circuit. FIG. 43 is a configuration diagram showing a first example of a processing circuit that implements the functions of the power converters of the first and second embodiments. The processing circuit 100 of the first example is dedicated hardware.

Further, the processing circuit 100 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. Applicable.

Also, FIG. 44 is a configuration diagram showing a second example of a processing circuit that implements the functions of the power converters of the first and second embodiments. The second example processing circuit 200 comprises a processor 201 and a memory 202 .

In the processing circuit 200, the functions of the power converter are realized by software, firmware, or a combination of software and firmware. Software and firmware are written as programs and stored in memory 202 . The processor 201 implements functions by reading and executing programs stored in the memory 202 .

It can also be said that the program stored in the memory 202 causes the computer to execute the procedure or method of each part described above. Here, the memory 202 is a non-volatile memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read Only Memory). volatile or volatile semiconductor memory. The memory 202 also includes magnetic disks, flexible disks, optical disks, compact disks, mini disks, DVDs, and the like.

It should be noted that the functions of the power conversion device described above may be partially realized by dedicated hardware and partially realized by software or firmware.

Thus, the processing circuitry may implement the functionality of the power conversion device described above through hardware, software, firmware, or a combination thereof.

1 AC rotating machine 2 DC power supply 4a first power converter 4b second power converter 5a first current detector 5b second current detector 6 control unit Sup1 to Swn1 first switching element Sup1 , Svp1, Swp1 First high potential side switching elements Sun1, Svn1, Swn1 First low potential side switching elements Sup2 to Swn2 Second switching elements Sup2, Svp2, Swp2 Second high potential side switching elements Sun2, Svn2, Swn2 Second low-side switching element, U1, V1, W1 First three-phase winding, U2, V2, W2 Second three-phase winding.

Claims (12)

A first power converter that has a plurality of first switching elements, converts a DC voltage from a DC power supply into a first AC voltage, and applies it to a first three-phase winding of an AC rotating machine;
a second power converter having a plurality of second switching elements, converting the DC voltage into a second AC voltage, and applying the DC voltage to a second three-phase winding of the AC rotating machine; and By comparing a first applied voltage obtained by subtracting a first offset voltage from a first voltage command, which is a voltage command for three-phase windings, with a first reference signal, a plurality of A second applied voltage obtained by subtracting a second offset voltage from a second voltage command, which is a voltage command for the second three-phase winding, and a second reference signal. A control unit that calculates a plurality of second on/off signals for the plurality of second switching elements by comparison,
A phase difference between the first three-phase winding and the second three-phase winding is 30 degrees,
The first reference signal and the second reference signal are either a first carrier signal or a second carrier signal,
A phase difference between the first carrier signal and the second carrier signal is 180 degrees,
The control unit
subtracting the first offset voltage from the first voltage command such that at least one of three applied voltages corresponding to three phases in the first applied voltage matches the maximum value or minimum value of the first reference signal; and the second offset voltage from the second voltage command such that at least one of three applied voltages corresponding to three phases in the second applied voltage matches the maximum value or minimum value of the second reference signal Subtract and
A phase difference between a first voltage vector obtained based on the first on/off signal and a second voltage vector obtained based on the second on/off signal is set to 30 degrees, or the first voltage vector and the second A power conversion device in which at least one of two voltage vectors is a zero voltage vector. The control unit controls the positions of the first voltage vector obtained at timings at which the first reference signal is maximized and minimized and the second voltage vector obtained at timings at which the second reference signal is maximized and minimized. The power converter according to claim 1, wherein the phase difference is 30 degrees, or both the first voltage vector and the second voltage vector are zero voltage vectors. Each phase in the first voltage command is set to a first voltage maximum phase, a first voltage intermediate phase, and a first voltage minimum phase in descending order of voltage command, and each phase in the second voltage command is set in descending order of voltage command. , second voltage maximum phase, second voltage intermediate phase, and second voltage minimum phase,
The control unit
When the first voltage absolute value maximum phase, which is the maximum phase among the absolute values of the three voltage commands corresponding to the three phases in the first voltage command, and the first voltage maximum phase match, the first voltage maximum Performing a first flat two-phase modulation that is modulation for subtracting the first offset voltage from the first voltage command so that the applied voltage corresponding to the phase matches the maximum value of the first reference signal,
When the first voltage absolute value maximum phase and the first voltage minimum phase match, the applied voltage corresponding to the first voltage minimum phase matches the minimum value of the first reference signal. Performing a first flat two-phase modulation that is modulation for subtracting the first offset voltage from the voltage command,
selecting the first carrier wave signal as the first reference signal for one of two phases other than the phase in which the first applied voltage is matched to the maximum value or the minimum value of the first reference signal; selecting the second carrier signal as the first reference signal for the phase of
When the second voltage maximum phase, which is the maximum phase among the absolute values of the three voltage commands corresponding to the three phases in the second voltage command, matches the second voltage maximum phase, the second voltage maximum performing second flat two-phase modulation, which is modulation for subtracting the second offset voltage from the second voltage command, such that the applied voltage corresponding to the phase matches the maximum value of the second reference signal;
When the second voltage absolute value maximum phase and the second voltage minimum phase match, the applied voltage corresponding to the second voltage minimum phase matches the minimum value of the second reference signal. Performing a second flat two-phase modulation that is modulation for subtracting the second offset voltage from the voltage command,
selecting the first carrier signal as the second reference signal for one of the two phases other than the phase in which the second applied voltage is matched to the maximum value or the minimum value of the second reference signal; selecting the second carrier signal as the second reference signal for the phase of
Four phases other than the phase in which the first upper solid two-phase modulation or the first lower solid two-phase modulation is performed and the phase in which the second upper solid two-phase modulation or the second lower solid two-phase modulation is performed one of the first carrier signal and the second carrier signal is selected as the first reference signal and the second reference signal in the two phases with the smallest phase difference. The power converter according to claim 1 or 2. The control unit
When performing the first flat top two-phase modulation, selecting the first carrier signal as the first reference signal for the first voltage maximum phase, and selecting the first carrier signal for the first voltage intermediate phase and the first voltage minimum phase. maintaining the previous first reference signal as the first reference signal;
Selecting the second carrier signal as the first reference signal for the first voltage minimum phase, and selecting the second carrier signal for the first voltage maximum phase and the first voltage intermediate phase when performing the first flat bottom two-phase modulation. maintaining the previous first reference signal as the first reference signal;
selecting the first carrier signal as the second reference signal for the second voltage maximum phase and the second voltage intermediate phase and the second voltage minimum phase when performing the second flat two-phase modulation; maintaining the previous second reference signal as a second reference signal;
selecting the second carrier signal as the second reference signal for the second voltage minimum phase and the second voltage maximum phase and the second voltage intermediate phase for performing the second flattened two-phase modulation; The power converter according to claim 3, wherein the previous second reference signal is maintained as the second reference signal. Each phase in the first voltage command is set to a first voltage maximum phase, a first voltage intermediate phase, and a first voltage minimum phase in descending order of voltage command, and each phase in the second voltage command is set in descending order of voltage command. , a second voltage maximum phase, a second voltage intermediate phase, a second voltage minimum phase,
The control unit
When the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees, and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees,
A first flat two-phase modulation that is modulation for subtracting the first offset voltage from the first voltage command such that the applied voltage corresponding to the first voltage maximum phase matches the maximum value of the first reference signal. and selecting either one of the first carrier signal and the second carrier signal as the first reference signal, the applied voltage corresponding to the second voltage maximum phase is that of the second reference signal A second flat two-phase modulation is performed by subtracting the second offset voltage from the second voltage command so as to match the maximum value, and the second reference signal is selected as the first reference signal. select a signal that is identical to the
First flat two-phase modulation that is modulation for subtracting the first offset voltage from the first voltage command such that the applied voltage corresponding to the first voltage minimum phase matches the minimum value of the first reference signal. and selecting either one of the first carrier signal and the second carrier signal as the first reference signal, the applied voltage corresponding to the second voltage minimum phase is the second reference signal A second flat two-phase modulation is performed by subtracting the second offset voltage from the second voltage command so as to match the minimum value, and the second reference signal is selected as the first reference signal. select a signal that is identical to the
When the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees, or when the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees,
When performing the first top-bottom two-phase modulation and selecting either one of the first carrier signal and the second carrier signal as the first reference signal, performing the second bottom-bottom two-phase modulation and selecting a signal different from the signal selected as the first reference signal as the second reference signal,
When performing the first bottom flat bi-phase modulation and selecting either one of the first carrier signal and the second carrier wave signal as the first reference signal, performing the second top flat bi-phase modulation and a signal different from the signal selected as the first reference signal is selected as the second reference signal. The control unit
performing the first top-bottom two-phase modulation and selecting the first carrier signal as the first reference signal;
When the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the first 2 performing flat-top biphasic modulation and selecting the first carrier signal as the second reference signal;
When the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or when the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the second lower 6. The power converter of claim 5, wherein solid two-phase modulation is performed and the second carrier signal is selected as the second reference signal. The control unit
performing the first bottom-bottom bi-phase modulation and selecting the first carrier signal as the first reference signal;
When the phase difference between the first voltage maximum phase and the second voltage maximum phase is 30 degrees and the phase difference between the first voltage minimum phase and the second voltage minimum phase is 30 degrees, the first 2 performing flat biphasic modulation and selecting the first carrier signal as the second reference signal;
When the phase difference between the first voltage maximum phase and the second voltage maximum phase is not 30 degrees or when the phase difference between the first voltage minimum phase and the second voltage minimum phase is not 30 degrees, the second upper 6. The power converter of claim 5, wherein solid two-phase modulation is performed and the second carrier signal is selected as the second reference signal. When the phases of the first three-phase winding are U1 phase, V1 phase, and W1 phase, and the phases of the second three-phase winding are U2 phase, V2 phase, and W2 phase,
The phase difference between the U1 phase and the U2 phase, the phase difference between the V1 phase and the V2 phase, and the phase difference between the W1 phase and the W2 phase are each set to 30 degrees,
The control unit
The three voltage commands corresponding to the three phases in the first voltage command are the U1 phase voltage command, the V1 phase voltage command, the W1 phase voltage command in descending order, the V1 phase voltage command, the If any of the order of the W1 phase voltage command and the U1 phase voltage command, or the order of the W1 phase voltage command, the U1 phase voltage command, and the V1 phase voltage command, the first upper solid performing biphasic modulation and selecting the first carrier signal as the first reference signal;
The three voltage commands corresponding to the three phases in the first voltage command are the U1 phase voltage command, the V1 phase voltage command, the W1 phase voltage command in descending order, the V1 phase voltage command, the If neither the order of the W1 phase voltage command and the U1 phase voltage command nor the order of the W1 phase voltage command, the U1 phase voltage command, and the V1 phase voltage command, the first bottom two performing phase modulation and selecting the second carrier signal as the first reference signal;
The three voltage commands corresponding to the three phases in the second voltage command are, in descending order, the U2 phase voltage command, the V2 phase voltage command, the W2 phase voltage command, the V2 phase voltage command, and the V2 phase voltage command. If the order of the W2-phase voltage command and the U2-phase voltage command, or the order of the W2-phase voltage command, the U2-phase voltage command, and the V2-phase voltage command, the second upper solid performing biphasic modulation and selecting the first carrier signal as the second reference signal;
The three voltage commands corresponding to the three phases in the second voltage command are, in descending order, the U2 phase voltage command, the V2 phase voltage command, the W2 phase voltage command, the V2 phase voltage command, and the V2 phase voltage command. If the order of the W2-phase voltage command and the U2-phase voltage command is neither the order of the W2-phase voltage command, the U2-phase voltage command, nor the V2-phase voltage command, the second bottom two 6. The power converter of claim 5, wherein phase modulation is performed and the second carrier signal is selected as the second reference signal. When the phases of the first three-phase winding are U1 phase, V1 phase, and W1 phase, and the phases of the second three-phase winding are U2 phase, V2 phase, and W2 phase,
The phase difference between the U1 phase and the U2 phase, the phase difference between the V1 phase and the V2 phase, and the phase difference between the W1 phase and the W2 phase are each set to 30 degrees,
The control unit
The three voltage commands corresponding to the three phases in the first voltage command are the U1 phase voltage command, the V1 phase voltage command, the W1 phase voltage command in descending order, the V1 phase voltage command, the If the order of the W1-phase voltage command and the U1-phase voltage command, or the order of the W1-phase voltage command, the U1-phase voltage command, and the V1-phase voltage command, the first bottom performing biphasic modulation and selecting the second carrier signal as the first reference signal;
The three voltage commands corresponding to the three phases in the first voltage command are the U1 phase voltage command, the V1 phase voltage command, the W1 phase voltage command in descending order, the V1 phase voltage command, the If the order of the W1-phase voltage command and the U1-phase voltage command is neither the order of the W1-phase voltage command, the U1-phase voltage command, nor the V1-phase voltage command, the first upper solid two performing phase modulation and selecting the first carrier signal as the first reference signal;
The three voltage commands corresponding to the three phases in the second voltage command are, in descending order, the U2 phase voltage command, the V2 phase voltage command, the W2 phase voltage command, the V2 phase voltage command, and the V2 phase voltage command. If the order of the W2-phase voltage command and the U2-phase voltage command, or the order of the W2-phase voltage command, the U2-phase voltage command, and the V2-phase voltage command, the second bottom performing biphasic modulation and selecting the second carrier signal as the second reference signal;
The three voltage commands corresponding to the three phases in the second voltage command are, in descending order, the U2 phase voltage command, the V2 phase voltage command, the W2 phase voltage command, the V2 phase voltage command, and the V2 phase voltage command. If the order of the W2-phase voltage command and the U2-phase voltage command is neither the order of the W2-phase voltage command, the U2-phase voltage command, nor the V2-phase voltage command, the second upper solid two 6. The power converter of claim 5, wherein phase modulation is performed and the first carrier signal is selected as the second reference signal. The first power converter and the second power converter operate at least one of a timing at which the first reference signal and the second reference signal are maximized and a timing at which the first reference signal and the second reference signal are minimized. further comprising a current detector for detecting current flowing through the line and the second three-phase winding;
10. Any one of claims 1 to 9, wherein the control unit calculates the first voltage command and the second voltage command based on the first detected current and the second detected current obtained by the current detector. 1. The power converter according to claim 1. A generator-motor control device comprising the power conversion device according to any one of claims 1 to 10. An electric power steering device comprising the power conversion device according to any one of claims 1 to 10.

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