POWER CONVERSION DEVICE AND A CONTROL DEVICE FOR A VEHICLE GENERATOR MOTOR

Abstract

A control unit of a conversion unit of this disclosure controls such that, when an AC rotating machine is in a power-running operating state, a first carrier wave signal and a second carrier wave signal are distinct from each other. Furthermore, the control unit controls such that, when the AC rotating machine is in a regeneration operating state, the first carrier wave signal and the second carrier wave signal are the same, and controls a first power converter and a second power converter in a region where a generated current flowing from the AC rotating machine to a DC power supply increases monotonically with respect to a regeneration torque.

Description

Technical area

[0001] This disclosure relates to a power conversion device and a control device for a vehicle generator motor. State of the art

[0002] Heretofore, it has been known that in a power conversion device, fluctuations in bus current are suppressed and a ripple current (or ripple current) of a capacitor is reduced by shifting a generation period of an effective voltage vector of a first inverter and a generation period of an effective voltage vector of a second inverter (see, for example, Patent Literature 1). Citation listPatent literature

[0003] [PTL 1] JP 2012-050252 A Summary of the inventionTechnical problem

[0004] In the power conversion device disclosed in Patent Literature 1, considering the mutual inductance of the two sets of windings of a three-phase rotating electric machine, a current change occurs in the second set of windings when an effective voltage vector of the first set of windings is output, and a current change occurs in the first set of windings when an effective voltage vector of the second set of windings is output. In other words, the effective voltage vector section appears to increase, and therefore there is a problem that phase current ripple and loss increase.

[0005] This disclosure has been made to solve the above-mentioned problem, and it is an object of this disclosure to provide a power conversion device (or power conversion device) and a control device for a vehicle generator motor capable of reducing a phase current ripple while suppressing a bus current ripple. Solution to the problem

[0006] According to one embodiment of this disclosure, a power conversion device and a control device for a vehicle generator motor are provided, comprising: a first power converter (or power transformer) configured to apply an AC voltage converted from a DC voltage from a DC power supply to the first m-phase windings of first m-phase windings and second m-phase windings included in an AC rotating machine; a second power converter (or power transformer) configured to apply the AC voltage from which the DC voltage was converted to the second m-phase windings; and a control unit configured to control each of the first power converter and the second power converter, where "m" is a natural number of 2 or more, the control unit being configured tocalculate a first applied voltage for each phase of the first m-phase windings and a second applied voltage for each phase of the second m-phase windings based on an external control instruction, wherein the control unit is configured to output a first switching signal to the first power converter by comparing a first carrier wave signal and the first applied voltage, and output a second switching signal to the second power converter by comparing a second carrier wave signal and the second applied voltage, wherein the first power converter is controlled based on the first switching signal, wherein the second power converter is controlled based on the second switching signal, and wherein the control unit is configured to: control that, when the AC rotating machine is in a power running operating state,the first carrier wave signal and the second carrier wave signal are different from each other; and to control that, when the AC rotating machine is in a regeneration mode, the first carrier wave signal and the second carrier wave signal are equal, and to control that the first power converter and the second power converter are controlled in a range in which a generated current flowing from the AC rotating machine to the DC power supply increases monotonically with respect to a regenerative torque. Advantageous effects of the invention

[0007] According to the power conversion device and the control device for a vehicle generator motor of this disclosure, it is possible to reduce the phase current ripple while suppressing the bus current ripple. Short description of the drawings Fig. 1 is a schematic diagram illustrating a power conversion device according to a first embodiment of this disclosure. Fig. 2 is a schematic diagram showing a difference of a phase of a voltage vector for each phase of an AC rotating machine of Fig. 1. Fig. 3 is a table showing a relationship between the state of each first switch in a first power converter of Fig. 1 and an output vector. Fig. 4 is a table showing a relationship between the state of each second switch in the second power converter of Fig. 1 and an output vector. Fig. Fig. 5 is a schematic diagram showing an operating state of an on / off signal generator for the first power converter of Fig. 1. Fig. 6 is a diagram showing a relationship between an output torque and a phase current effective value given when the AC rotating machine of Fig. 1 is in a regeneration mode. Fig. 7 is a graph showing a relationship between the output torque and a power factor given when the AC rotating machine of Fig. 1 is in regeneration mode. Fig. 8 is a graph showing a relationship between the output torque and a generated current given when the AC rotating machine of Fig. 1 is in regeneration mode. Fig. 9 is a diagram showing a relationship between a current phase and a first three-phase current and a relationship between the current phase and a first voltage command given when a power factor angle in the regeneration operation state is 165 degrees in the AC rotating machine of Fig. 1. Fig. 10 is a diagram showing a relationship between a current phase and a first three-phase current and a relationship between the current phase and a first voltage command given when a power factor angle in the regeneration operation state is 135 degrees in the AC rotating machine of Fig. 1. Fig. 11 is a diagram showing a relationship between a current phase and a first three-phase current and a relationship between the current phase and a first current command given when a power factor angle in the regeneration operation state is 105 degrees in the AC rotating machine of Fig. 1. Fig. 12 is a diagram showing a relationship between a coupling coefficient and a phase current ripple of the AC rotating machine of Fig. 1. Fig. Fig. 13 is a schematic diagram showing an operating state of an on / off signal generator for the second converter of Fig. 1. Fig. 14 is a diagram showing a relationship between an output torque and a phase current effective value given when the AC rotating machine of Fig. 1 is in a power run operating state. Fig. 15 is a diagram showing a relationship between the output torque and a power factor given when the AC rotating machine of Fig. 1 is in power run mode. Fig. 16 is a diagram showing a relationship between the output torque and a driving current given when the AC rotating machine of Fig. 1 is in power run mode. Fig. Fig. 17 is a schematic diagram showing an operating state of the on / off signal generator for the first power converter, which is given when an average value of a first applied voltage and an average value of a second applied voltage are calculated in an offset calculator of Fig. 1 matches 0. Fig. Fig. 18 is a schematic diagram showing an operating state of the on / off signal generator for the second power converter, which is when the average value of the first applied voltage and the average value of the second applied voltage in the offset calculator of Fig. 1 0 and a difference between a first carrier wave signal and a second carrier wave signal is 90 degrees. Fig. Fig. 19 is a schematic diagram showing an operating state of the on / off signal generator for the first power converter, which is when a minimum value of the first applied voltage and a minimum value of the second applied voltage are determined in the offset calculator of Fig. 1 matches 0. Fig. Fig. 20 is a schematic diagram showing an operating state of the on / off signal generator for the second converter, which is when the minimum value of the first applied voltage and the minimum value of the second applied voltage in the offset calculator of Fig. 1 and 0 and the difference between a first carrier wave and a second carrier wave is 180 degrees. Fig. 21 is a schematic diagram illustrating a control device for a vehicle generator motor according to a third embodiment of this disclosure. Fig. 22 is a configuration diagram illustrating a first example of a processing circuit that implements functions of the power conversion devices of the first embodiment to the third embodiment. Fig. 23 is a configuration diagram illustrating a second example of the circuit that implements the functions of the power conversion devices of the first embodiment to the third embodiment. Description of the embodiments

[0008] Embodiments of this disclosure will now be described with reference to the drawings. First embodiment

[0009] Fig. 1 is a schematic diagram illustrating a power conversion device 1 (or power conversion apparatus 1) according to a first embodiment of this disclosure. The power conversion device 1 is connected to a DC power supply 20 serving as a power supply. An AC rotating machine 30 is connected to the power conversion device 1 as a load. The power conversion device 1 converts (or converts) a DC voltage from the DC power supply 20 into an AC voltage and supplies the AC voltage to the AC rotating machine 30.

[0010] The AC rotating machine 30 is a three-phase AC rotating machine having first three-phase windings U1, V1, and W1 and second three-phase windings U2, V2, and W2. The first three-phase windings U1 to W1 and the second three-phase windings U2 to W2 are each housed in a stator of the AC rotating machine 30. The first three phase windings U1 to W1 and the second three phase windings U2 to W2 are not electrically connected to each other.

[0011] Fig. 2 is a schematic diagram showing a phase difference of a voltage vector for each phase of the AC rotating machine 30 of Fig. 1. As in Fig. 2, in the first embodiment, there is no difference between the phases of the first and second three-phase windings in the AC rotating machine 30.

[0012] In the AC rotating machine 30 of the first embodiment, the phase difference between the first three-phase winding U1 to W1 and the second three-phase winding U2 to W2 is 0 degrees. Therefore, the voltage vectors 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), V6(1) and V6(2) are correspondingly equal.

[0013] The AC rotating machine 30 is a generator motor. Examples of the AC rotating machine 30 include rotating machines such as a permanent magnet synchronous rotating machine, an induction rotating machine, and a synchronous reluctance rotating machine. Any AC rotating machine can be used in the AC rotating machine 30 in the first embodiment, as long as the AC rotating machine has two windings with three phases.

[0014] The description of the power conversion device 1 will now be made with reference to Fig. 1. The power conversion device 1 comprises a smoothing capacitor 3, a first converter 4a, a second converter 4b, a first detector 5a, a second detector 5b, and a control unit 10.

[0015] The smoothing capacitor 3 is connected in parallel to the DC power supply 20. The first power converter 4a is connected between the DC power supply 20 and the first three phases of the windings U1 to W1 of the AC rotating machine 30. The second power converter 4b is connected between the DC power supply 20 and the second three phases of the windings U2 to W2 of the AC rotating machine 30. The first power converter 4a and the second power converter 4b are inverse conversion circuits (inverters).

[0016] The first power converter 4a has six first switching elements Sup1, Svp1, Swp1, Sun1, Svn1, and Swn1. Of the six first switching elements Sup1 to Swn1, the three switching elements Sup1, Svp1, and Swp1 are high-potential side switching elements. Of the six first switching elements Sup1 to Swn1, the three switching elements Sun1, Svn1, and Swn1 are low-potential side switching elements.

[0017] The high-potential-side switching element Sup1 and the low-potential-side switching element Sun1 are connected in series and connected to the DC power supply 20. The high-potential-side switching element Svp1 and the low-potential-side switching element Svn1 are connected in series and connected to the DC power supply 20. The high-potential-side switching element Swp1 and the low-potential-side switching element Swn1 are connected in series and connected to the DC power supply 20.

[0018] The series-connected high-potential-side switching element Sup1 and the low-potential-side switching element Sun1 are connected in parallel with the series-connected high-potential-side switching element Svp1 and the low-potential-side switching element Svn1. The series-connected high-potential-side switching element Svp1 and the low-potential-side switching element Svn1 are connected in parallel with the series-connected high-potential-side switching element Swp1 and the low-potential-side switching element Swn1. The series-connected high-potential-side switching element Swp1 and the low-potential-side switching element Swn1 are connected in parallel with the series-connected high-potential-side switching element Sup1 and the low-potential-side switching element Sun1.

[0019] The U1 phase of the first three-phase windings is connected between the high-potential switching element Sup1 and the low-potential switching element Sun1. The V1 phase of the first three-phase windings is connected between the high-potential switching element Svp1 and the low-potential switching element Svn1. The W1 phase of the first three-phase windings is connected between the high-potential switching element Swp1 and the low-potential switching element Swn1.

[0020] Fig. 3 is a table showing a relationship between the state of each of the first switching elements Sup1 to Swn1 in the first power converter 4a of Fig. 1 and a vector of the output. If in Fig. 3 the value corresponding to a first switching element is 1, this indicates that the first switching element is switched on. If in Fig. 3 the value corresponding to a first switching element is 0, this indicates that the first switching element is switched off.

[0021] Each of the first switching elements Sup1 to Swn1 is turned on or off based on the first switching signals Qup1, Qun1, Qvp1, Qvn1, Qwp1, and Qwn1 input from the outside. The first power converter 4a can convert a DC voltage Vdc input from the DC power supply 20 into electric power and apply a voltage corresponding to the state of each of the first switching elements Sup1 to Swn1 to the first three phase windings U1 to W1. When a voltage is applied to each of the first three phases U1 to W1, electric current having current values ​​Iu1, Iv1, and Iw1 flows.

[0022] The first switching signals Qup1 to Qwn1, corresponding to the first switching elements Sup1 to Swn1, are the input to the first power converter 4a. Each of the first switching signals Qup1 to Qwn1 is an on / off signal for turning on or off a corresponding one of the first switching elements Sup1 to Swn1.

[0023] For each of the first switching signals Qup1 to Qwn1, when the value is 1, a signal for turning on the corresponding first switching element is output, and when the value is 0, a signal for turning on the corresponding switch is output.

[0024] As in Fig. As shown in Figure 3, eight voltage vectors can be output by the first switching signals Qup1 to Qwn1. The first switching signals Qup1 to Qwn1 will be described later.

[0025] The description will now be made with reference to Fig. 1. The second power converter 4b comprises six second switching elements Sup2, Svp2, Swp2, Sun2, Svn2, and Swn2. Of the six second switching elements Sup2 to Swn2, the three switching elements Sup2, Svp2, and Swp23 are high-potential switching elements. Of the six second switching elements Sup2 to Swn2, the three switching elements Sun2, Svn2, and Swn23 are low-potential switching elements.

[0026] The high-potential-side switching element Sup2 and the low-potential-side switching element Sun2 are connected in series and connected to the DC power supply 20. The high-potential-side switching element Svp2 and the low-potential-side switching element Svn2 are connected in series and connected to the DC power supply 20. The high-potential-side switching element Swp2 and the low-potential-side switching element Swn2 are connected in series and connected to the DC power supply 20.

[0027] The series-connected high-potential-side switching element Sup2 and the low-potential-side switching element Sun2 are connected in parallel with the series-connected high-potential-side switching element Svp2 and the low-potential-side switching element Svn2. The series-connected high-potential-side switching element Svp2 and the low-potential-side switching element Svn2 are connected in parallel with the series-connected high-potential-side switching element Swp2 and the low-potential-side switching element Swn2. The series-connected high-potential-side switching element Swp2 and the low-potential-side switching element Swn2 are connected in parallel with the series-connected high-potential-side switching element Sup2 and the low-potential-side switching element Sun2.

[0028] The U2 phase of the second three-phase windings is connected between the high-potential switching element Sup2 and the low-potential switching element Sun2. The V2 phase of the second three-phase windings is connected between the high-potential switching element Svp2 and the low-potential switching element Svn2. The W2 phase of the second three-phase windings is connected between the high-potential switching element Swp2 and the low-potential switching element Swn2.

[0029] Fig. 4 is a table showing a relationship between the state of each of the second switching elements Sup2 to Swn2 in the second power converter 4b of Fig. 1 and a vector of the output. If in Fig. 4 the value corresponding to a second switching element is 1, this indicates that the second switching element is switched on. If in Fig. 4 the value corresponding to a second switching element is 0, this indicates that the second switching element is switched off.

[0030] Each of the second switching elements Sup2 to Swn2 is turned on or off based on the second switching signals Qup2, Qun2, Qvp2, Qvn2, Qwp2, and Qwn2 input from the outside. The second power converter 4b can convert the DC voltage Vdc input from the DC power supply 20 into electrical power and apply a voltage corresponding to the state of each of the second switching elements Sup2 to Swn2 to the second three phases of the windings U2 to W2. When a voltage is applied to each of the second three phases U2 to W2, a current with the current values ​​Iu2, Iv2, and Iw2 flows.

[0031] The second switching signals Qup2 to Qwn2 corresponding to the second switching elements Sup2 to Swn2 are respectively used as input to the second power converter 4b. Each of the second switching signals Qup2 to Qwn2 is an on / off signal for turning on or off a corresponding one of the second switching elements.

[0032] For each of the second switching signals Qup2 to Qwn2, when the value is 1, a signal for turning on the corresponding second switching element is output, and when the value is 0, a signal for turning on the corresponding switch is output.

[0033] As in Fig. As shown in Figure 4, eight voltage vectors can be output by the second switching signals Qup2 to Qwn2. The second switching signals Qup2 to Qwn2 will be described later.

[0034] The description will now be made with reference to Fig. 1. The first current detector 5a detects the current flowing through each of the first three phase windings U1 to W1. The first current detector 5a detects the current values ​​Iu1 to Iw1 of the electric current flowing through the first three phase windings U1 to W1 as current detection values ​​Iu1s, Iv1s, and Iw1s, respectively. The first current detector 5a detects the electric current flowing through each of the first three phase windings U1 to W1 downstream of the first power converter 4a.

[0035] The second current detector 5b detects the current flowing through each of the second three-phase windings U2 to W2 of the AC rotating machine 30. The second current detector 5b detects the current values ​​Iu2 to Iw2 of the electric current flowing through the second three-phase windings U2 to W2 as current detection values ​​Iu2s, Iv2s, and Iw2s, respectively. The second current detector 5b detects the electric current flowing through each of the second three-phase windings U2 to W2 downstream of the second power converter 4b.

[0036] The control unit 10 includes a control instruction limiter 6, a voltage instruction calculator 7, an offset calculator 8, and an on / off signal generator 9.

[0037] A control instruction (or control command) is input from the outside to the control instruction limiter 6. In response to the externally input control instruction, the control instruction limiter 6 outputs a limited control instruction in which a limit based on a relationship between a regenerative torque and a generated current is applied to the control instruction calculator 7. Details will be described later.

[0038] The limited control instruction is input from the control instruction limiter 6 to the voltage instruction calculator 7. The current detection values ​​Iu1s to Iw1s output from the first current detector 5a are input to the voltage instruction calculator 7. The current detection values ​​Iu2s to Iw2s output from the second current detector 5b are input to the voltage instruction calculator 7.

[0039] The first current detector 5a continuously detects the current flowing through each of the first three-phase windings U1 to W1, regardless of the state of the first switching elements. The second current detector 5b continuously detects the current flowing through each of the second three-phase windings U2 to W2, regardless of the state of the second switching elements. Therefore, the control unit 10 can determine whether a switching element should be turned on or off without considering whether or not an electric current can be detected in the first three-phase windings and the second three-phase windings.

[0040] The voltage command calculator 7 calculates current commands based on the limited control command. The voltage command calculator 7 calculates voltage commands, which are command values ​​of the voltage for driving the AC rotating machine 30, based on the calculated current commands. The voltage commands include the first three-phase voltage commands Vu1, Vv1, and Vw1, which concern the voltages to be applied to the first three-phase windings U1 to W1, and the second three-phase voltage commands Vu2, Vv2, and Vw2, which concern the voltages to be applied to the second three-phase windings U2 to W2.

[0041] The voltage command calculator 7 calculates the first three-phase voltage commands Vu1 to Vw1 and the second three-phase voltage commands Vu2 to Vw2 using, for example, proportional-integral control to zero any deviation between the current detection values ​​Iu1s to Iw2s and the respective current command values. A publicly known current feedback control method is used for the calculation. The first three-phase voltage commands Vu1 to Vw1 and the second three-phase voltage commands Vu2 to Vw2, which are the calculated voltage commands, are output to the offset calculator 8.

[0042] The offset calculator 8 subtracts an offset voltage Voffset1 from each of the first three-phase voltage commands Vu1 to Vw1 to calculate the first three-phase applied voltages Vu1', Vv1' and Vw1'.

[0043] The offset calculator 8 subtracts an offset voltage Voffset2 from each of the second three-phase voltage commands Vu2 to Vw2 to calculate the second three-phase applied voltages Vu2', Vv2', and Vw2'. Details of the method for setting the offset voltages Voffset1 and Voffset2 in each control state will be described later.

[0044] The on / off signal generator 9 outputs the first switching signals Qup1 to Qwn1 based on the first three-phase applied voltages Vu1' to Vw1'. Furthermore, the on / off signal generator 9 outputs the second switching signals Qup2 to Qwn2 based on the second three-phase applied voltages Vu2' to Vw2'.

[0045] Fig. Fig. 5 is a schematic diagram showing an operating state of the on / off signal generator 9 for the first power converter 4a of Fig. 1. In Fig. Figure 5 illustrates an operation of the on / off signal generator 9 in a range where the first three phases, the applied voltages Vu1' to Vw1', satisfy Vu1'>Vv1'>Vw1'. In the first embodiment, a first carrier wave signal C1 is a triangular wave of a period Tc having a minimum value of -Vdc / 2 and a maximum value of Vdc / 2.

[0046] The on / off signal generator 9 compares the first carrier wave signal C1 with the applied power Vu1' for the U phase of the first three-phase applied power, and if Vu1' is larger, outputs a first switching signal where "Qup1=1 and Qun1=0." The on / off signal generator 9 compares the first carrier wave signal C1 with the applied power Vu1' in the U phase of the first three-phase power, and if Vu1' is smaller, outputs a first switching signal where "Qup1=0 and Qun1=1."

[0047] The on / off signal generator 9 compares the first carrier wave signal C1 with the power Vv1' applied to the V phase of the first three-phase power, and outputs a first switching signal at a larger value of Vv1' where Qvp1=1 and Qvn1=0. The on / off signal generator 9 compares the first carrier wave signal C1 with the power Vv1' applied to the V phase of the first three-phase power, and outputs a first switching signal at a smaller value of Vv1' where Qvp1=0 and Qvn1=1.

[0048] The on / off signal generator 9 compares the first carrier wave signal C1 with the power Vw1' applied to the W phase of the first three-phase power, and outputs a first switching signal at a larger value of Vw1' where "Qwp1=1 and Qwn1=0." The on / off signal generator 9 compares the first carrier wave signal C1 with the power Vw1' applied to the W phase of the first three-phase power, and outputs a first switching signal at a smaller value of Vw1' where "Qwp1=0 and Qwn1=1."

[0049] As in Fig. As shown in Figure 5, the voltage vector output is V7 during the periods from t1 to t2 and from t8 to t9, V2 during the periods from t2 to t3 and from t7 to t8, V1 during the periods from t3 to t4 and from t6 to t7, and V0 during a period from t4 to t6. When the voltage vector is V1 and V2, which are effective voltage vectors, the current value Iu1 increases according to the applied voltage, and when the voltage vector is V0 and V7, which are zero voltage vectors, the current value Iu1 changes toward 0.

[0050] The increase and decrease periods in one cycle of the carrier wave signal are divided into two, and thus phase current ripple can be reduced. Meanwhile, when the power factor angle at which the current value satisfies Iu1>Iv1>Iw1 is 0 degrees, the bus current Iinv1 changes within the current value range of 0 to Iu1, and therefore the bus current ripple amplitude is within the range of 0 to Iu1. Details of the method for adjusting the second control signal in each control state will be described later.

[0051] Fig. Fig. 6 is a diagram showing a relationship between an output torque and a phase current effective value given when the AC rotating machine 30 is Fig. 1 is in a regeneration mode. Fig. Fig. 7 is a diagram showing a relationship between the output torque and a power factor given when the AC rotating machine 30 is Fig. 1 is in regeneration mode. Fig. Fig. 8 is a graph showing a relationship between the output torque and a generated current given when the AC rotating machine 30 of Fig. 1 is in regeneration mode.

[0052] The output torque on the horizontal axis is expressed in terms of a maximum value of the torque that can be output by the AC rotating machine 30 at a certain speed of 100. The generated current corresponds to 1 times the sum of the bus current Iinv1 and a bus current Iinv2, as shown in Fig. 1 shown.

[0053] The phase current rms value and the power factor decrease monotonically according to the output torque. However, the generated current has a local maximum value. Assuming that the output torque, which is given when the generated current has a local maximum value, is a local maximum torque Ta, the regenerative torque increases when the output torque <lokales Maximaldrehmoment Ta erfüllt ist, der erzeugte Strom nimmt jedoch nicht zu. Aus diesem Grund nimmt die Effizienz der Leistungserzeugung in einem Bereich, in dem der Leistungsfaktor kleiner als 0,5 ist, erheblich ab. Bei hohen Drehgeschwindigkeiten vergrößert sich die induzierte Spannung und es kommt zur Spannungssättigung. Dafür hat der erzeugte Strom bei Überschreitung eines vorbestimmten Wertes der Drehgeschwindigkeit die Charakteristik einer monotonen Verkleinerung entsprechend dem Ausgangsdrehmoment.

[0054] Fig. 9 is a diagram showing a relationship between a current phase and a first three-phase current and a relationship between the current phase and a first voltage command given when the power factor angle in the regeneration operation state is 165 degrees in the AC rotating machine 30 of Fig. 1. In the range where the current phase is between 195 degrees and 255 degrees, Vu1>Vv1>Vw1 is satisfied. Therefore, the bus current Iinv1 has three outputs: current values ​​Iu1, -Iw1, and 0. At this time, the current value Iu1<0 and Iw1>0, and therefore the bus current Iinv1 is always a negative current or a current of 0.

[0055] Fig. 10 is a diagram showing a relationship between a current phase and a first three-phase current and a relationship between the current phase and a first current command given when the power factor angle in the regeneration operation state is 135 degrees in the AC rotating machine 30 of Fig. 1. In the range where the current phase is between 225 degrees and 285 degrees, Vu1>Vv1>Vw1 is satisfied. For this, the bus current Iinv1 has three outputs: current values ​​Iu1, -Iw1, and 0.

[0056] From 225 degrees to 270 degrees, the current value Iu1<0 and Iw1>0, and thus the bus current Iinv1 becomes a negative current, or 0. Meanwhile, from 270 degrees to 285 degrees, the current value Iu1>0 and Iw1>0, and thus the bus current Iinv1 changes from negative to positive. In other words, the bus current ripple becomes larger during a period of 1 / 4 of an electrical angular cycle.

[0057] Fig. 11 is a diagram showing a relationship between a current phase and a first three-phase current and a relationship between the current phase and a first current command given when the power factor angle in the regeneration operation state is 105 degrees in the AC rotating machine 30 of Fig. 1. In the range where the current phase is between 255 degrees and 315 degrees, Vu1>Vv1>Vw1 is satisfied. Therefore, the bus current Iinv1 has three outputs: current values ​​Iu1, -Iw1, and 0.

[0058] From 255 degrees to 270 degrees, the current value Iu1<0 and Iw1>0, and thus the bus current Iinv1 becomes a negative current, or 0. Meanwhile, from 270 degrees to 315 degrees, the current value Iu1>0 and Iw1>0, and thus the bus current Iinv1 changes from negative to positive. In other words, the bus current ripple becomes larger during a period of 3 / 4 of an electrical angular period. In particular, at 300 degrees, the current value Iu1 is in a state of maximum amplitude, and therefore the bus current ripple deteriorates.

[0059] In other words, the bus current ripple can be suppressed by limiting the range of regenerative operation to 120 degrees or more and 240 degrees or less, which is the power factor angle where Vu1>Vv1>Vw1 is satisfied in the range where the current phase is from 240 degrees to 300 degrees.

[0060] From the above, upon receiving a control instruction to enter the regeneration operation state, the control instruction limiter 6 determines the limited control instruction such that the generated current flowing from the AC rotating machine 30 to the DC power supply 20 decreases monotonically with respect to the output torque. That is, upon receiving a control instruction to enter the regeneration operation state, the control instruction limiter 6 determines the limited control instruction such that the generated current flowing from the AC rotating machine 30 to the DC power supply 20 is limited to the range in which the generated current increases monotonically with respect to the regenerative torque.

[0061] For example, if the control command is a torque command, the torque command is released at a lower limit value Tliml. Here, the lower limit value Tliml is given by Equation (1) with a margin specified as α. The margin α can be determined taking into account various types of fluctuations. Tliml=Ta+α

[0062] Fig. 12 is a diagram showing a relationship between a coupling coefficient and a phase current ripple of the AC rotating machine 30 of Fig. 1. The coupling coefficient of Fig. 12 is the ratio of mutual inductance to self-inductance. In the graph of Fig. Figure 12 shows the relationship between the coupling coefficient and the phase current ripple, which is determined by a combination of voltage vectors. To improve power efficiency, it is necessary to reduce the phase current ripple during the effective voltage vector generation period.

[0063] Therefore, in a case where the coupling coefficient is large, when a voltage vector V1(1) is output, the change in current can be reduced by outputting the voltage vector V1(1) at the same time as V1(2) which has the same phase, instead of at the same time as V0(2) which is a zero voltage vector.

[0064] If the voltage vector V1(1) is output and the voltage vector V1(1) is output at the same time as V3(2), which has a phase difference of 120 degrees, the phase current ripple becomes very large. Therefore, to reduce the phase current ripple, it is necessary to avoid outputting the voltage vector V1(1) at least at the same time as V3(2), which has a phase difference of 120 degrees, and V4(2), which has a phase difference of 180 degrees.

[0065] A case of combination with V1(1) is described here, but the same effects can also be achieved for V2(1) to V6(1). That is, the generation periods of the effective voltage vectors of the first power converter 4a and the second power converter 4b are overlapped. As a result, the phase current ripple can be reduced and the power generation efficiency can be improved.

[0066] Fig. Fig. 13 is a schematic diagram illustrating an operating state of the on / off signal generator 9 for the second power converter 4b of Fig. 1. As in Fig. As shown in Figure 13, in the regeneration mode, the average value of the first applied voltage and the average value of the second applied voltage are aligned by adjusting the offset voltages Voffset1 and Voffset2. The second switching signals are determined by adjusting the average value of the second applied voltage with the average value of the first applied voltage and comparing the first carrier wave signal with the second three-phase applied voltages Vu2' to Vw2'.

[0067] At this time, assuming that the voltage commands Vu1, Vv1, and Vw1 have a maximum value of Vmax1 and a minimum value of Vmin1, and the voltage commands Vu2, Vv2, and Vw2 have a maximum value of Vmax2 and a minimum value of Vmin2, the offset voltages Voffset1 and Voffset2 are given by Equation (2). Since the average value of the first applied voltage and the average value of the second applied voltage are brought into balance, the phase current ripple can be reduced and the power generation efficiency can be improved in the regeneration operation state. In Equation (2), β is a constant. {Voffset1=(Vmax1+Vmin1)2−βVoffset2=(Vmax2+Vmin2)2−β

[0068] Furthermore, setting β in equation (2) to 0 causes the average value of the first applied voltage and the average value of the second applied voltage to be equalized to 0, which corresponds to the average value of the output voltage range of the DC power supply 20. As a result, the generation periods of the zero-sequence voltage vectors that frame the generation periods of the effective voltage vectors are evenly distributed, and therefore, it is possible to reduce the phase current ripple.

[0069] Fig. Fig. 14 is a diagram showing a relationship between an output torque and a phase current effective value given when the AC rotating machine 30 is Fig. 1 is in a power run operating state. Fig. Fig. 15 is a diagram showing a relationship between the output torque and a power factor given when the AC rotating machine 30 is Fig. 1 is in power run mode. Fig. Fig. 16 is a diagram showing a relationship between the output torque and a driving current given when the AC rotating machine 30 of Fig. 1 is in power run mode.

[0070] The drive current corresponds to the sum of the bus current Iinv1 and the bus current Iinv2, which are Fig. 1. The phase current effective value and the drive current increase monotonically with respect to the output torque. The power factor decreases monotonically with respect to the output torque. The change amount of the power factor changes by approximately 0.3 in the power run mode. In the regeneration mode, as shown in Fig. As shown in Figure 7, the power factor changes by about 0.7.

[0071] As with regard to Fig. 9 to Fig. As described in Figure 11, when the power factor angle is 0 degrees or more and 60 degrees or less, or 300 degrees or more and 360 degrees or less, the bus current is 0 or takes a positive value during a portion of at least one half of an electrical angle cycle. Therefore, the bus current ripple of each of the bus currents Iinv1 and Iinv2 is suppressed.

[0072] In the power run mode, the operating range expands to a larger phase current effective value than in the regeneration mode, and therefore the bus current ripple increases with the same output method as in the regeneration mode. Therefore, in the power run mode, the bus current ripple is reduced by suppressing an overlap between the generation period of the effective voltage vector of the first power converter 4a and the generation period of the effective voltage vector of the second power converter 4b.

[0073] Fig. Fig. 17 is a schematic diagram showing an operating state of the on / off signal generator 9 for the first power converter 4a, which is given when an average value of a first applied voltage and an average value of a second applied voltage in the offset calculator 8 of Fig. Compare 1 with 0. In Fig. Figure 17 illustrates an operating state in the power run mode. In the power run mode, the on / off signal generator 9 compares each of the first three-phase applied voltages Vu1' to Vw1' with the first carrier wave signal C1.

[0074] As in Fig. As shown in Figure 17, in the power running state, the on / off signal generator 9 compares the first three phases of the applied voltages Vu1' to Vw1' with the first carrier wave signal C1 and outputs the first switching signals Qup1 to Qwn1. At this time, in the first power converter 4a, the generation periods of the effective voltage vectors appear around t2 and t4, and the generation periods of the zero voltage vectors appear around t1, t3, and t5.

[0075] Fig. Fig. 18 is a schematic diagram showing an operating condition of the on / off signal generator 9 for the second power converter 4b, which is when the average value of the first applied voltage and the average value of the second applied voltage in the offset calculator 8 are Fig. 1 and 0 and a difference between a first carrier wave signal and a second carrier wave signal is 90 degrees. In Fig. 18, the second three-phase applied voltages Vu2' to Vw2' and the second carrier wave signal C2 are compared. The second carrier wave signal C2 is a carrier wave signal having a phase different by 90 degrees from that of the first carrier wave signal C1.

[0076] As in Fig. As shown in Figure 18, the second switching signals Qup2, Qun2, Qvp2, Qvn2, Qwp2, and Qwn2 are output based on the comparison between the second three-phase applied voltages Vu2' to Vw2' and the second carrier wave signal C2. At this time, the generation periods of the effective voltage vectors of the second power converter 4b appear around t1, t3, and t5. The generation periods of the zero-voltage vectors appear around t2 and t4.

[0077] In other words, at a low modulation rate, during a period in which one of the first power converters 4a or the second power converter 4b generates an effective voltage vector, the other power converter generates a zero voltage vector. Therefore, an instantaneous increase in the bus current can be suppressed and the bus current ripple can be reduced.

[0078] At a high modulation rate, during a period in which one of the first power converters 4a or the second power converter 4b generates a zero voltage vector, the other power converter generates an effective voltage vector. This prevents the bus current from briefly dropping to zero, and the bus current ripple can be reduced.

[0079] Furthermore, the effect of reducing bus current ripple can be maximized by setting the center of the generation periods of the effective voltage vectors of the first power converter 4a to t2 and t4 and the center of the generation periods of the zero voltage vectors of the second power converter 4b to t2 and t4. Specifically, the average value of the first applied voltage and the average value of the second applied voltage are adjusted to 0, which corresponds to the average value of the range of the output of the DC power supply 20.

[0080] As a result, the bus current ripple can be suppressed, and by setting an upper limit value Tlimh for the torque to 100, it becomes possible to operate in all ranges where the output torque is between 0 and 100. When the output torque is 100, the absolute value of a lower limit value for the torque Tlimh in a range where the rotational speed is equal to or lower than the rotational speed at which each of the first power converter 4a and the second power converter 4b does not cause voltage saturation is set to be smaller than the absolute value of the upper limit value for the torque Tlimh. By setting this value, it becomes possible to both improve the efficiency of the generated power and reduce the ripple current of the smoothing capacitor 3.

[0081] As in Fig. As shown in Figure 18, the difference between the phase of the first carrier wave signal C1 and the phase of the second carrier wave signal C2 of the on / off signal generator 9 is 90 degrees. However, the difference between the phase of the first carrier wave signal C1 and the phase of the second carrier wave signal C2 may be, for example, 180 degrees.

[0082] Fig. Fig. 19 is a schematic diagram showing an operating state of the on / off signal generator 9 for the first power converter 4a, which is when a minimum value of the first applied voltage and a minimum value of the second applied voltage in the offset calculator 8 of Fig. 1 are matched with 0. Fig. Fig. 20 is a schematic diagram showing an operating state of the on / off signal generator for the second power converter 4b, which is given when the minimum value of the first applied voltage and the minimum value of the second applied voltage in the offset calculator 8 of Fig. 1 0 and the phase difference between a first carrier wave signal and a second carrier wave signal is 180 degrees.

[0083] The phase difference between the first carrier wave signal C1 and the second carrier wave signal C2 is 180 degrees. At this time, the offset direction of the first applied voltage in the first voltage command and the offset direction of the second applied voltage in the second voltage command are set to be the same.

[0084] For example, as shown in equation (3), an offset voltage is applied such that the minimum value of the first applied voltage is 0 and the minimum value of the second applied voltage is 0. {Voffset1=Vmin1Voffset2=Vmin2

[0085] In Fig. 19 shows a first applied voltage and first switching signals, and in Fig. 20 shows a second applied voltage and second switching signals. The generation periods of the effective voltage vectors of the first power converter 4a are immediately after t2 and immediately before t4. The generation periods of the effective voltage vectors of the second power converter 4b are immediately before t2 and immediately after t4. As a result, the generation periods of the effective voltage vectors of the first power converter 4a and the generation periods of the effective voltage vectors of the second power converter 4b can be made continuous without overlap.

[0086] As shown in equation (4), an offset voltage can be applied such that the maximum value of the first applied voltage is 0 and the maximum value of the second applied voltage is 0.

[0087] In equation (3), if the difference between Vmax1 and Vmin1 or the difference between Vmax2 and Vmin2 exceeds Vdc / 2, the DC power supply 20 cannot output an applied voltage that exceeds the maximum output voltage value Vdc / 2. For this reason, the applied voltage is limited to the maximum voltage value Vdc / 2 that the DC power supply 20 can output. In equation (4), if the difference between Vmax1 and Vmin1 or the difference between Vmax2 and Vmin2 exceeds Vdc / 2, the DC power supply 20 cannot output an applied voltage that exceeds the minimum output voltage value -Vdc / 2. For this reason, the applied voltage is limited to the minimum voltage value -Vdc / 2 that the DC power supply 20 can output. As a result, as shown in equation (5), it is preferable to apply an offset voltage such that the minimum value of the first applied voltage is -Vdc / 2 and the minimum value of the second applied voltage is -Vdc / 2.

[0088] For this purpose, the switching of one phase is maintained in both the first power converter 4a and the second power converter 4b, and thus it is possible to reduce the loss due to switching. {Voffset1=Vmin1+Vdc2Voffset2=Vmin2+Vdc2

[0089] As shown in equation (6), the offset voltage can be applied such that the maximum value of the first applied voltage is Vdc / 2 and the maximum value of the second applied voltage is Vdc / 2. {Voffset1=Vmax1+Vdc2Voffset2=Vmax2+Vdc2

[0090] To reduce the unevenness of heat generation, equation (5) and equation (6) can be periodically changed and used.

[0091] In the power conversion device 1 according to the first embodiment, the control unit 10 controls so that the first carrier wave signal C1 and the second carrier wave signal C2 are different from each other when the AC rotating machine 30 is in the power running mode. Further, the control unit 10 controls so that the first carrier wave signal C1 and the second carrier wave signal C2 are equal to each other when the AC rotating machine 30 is in the regeneration mode. In addition, the control unit 10 controls the first power converter and the second power converter in a range where the generated current flow from the AC rotating machine 30 to the DC power supply 20 monotonically increases with respect to the regenerative torque.As a result, in the regeneration operation state, the operation of the power conversion device 1 is limited to a range where the generated current increases monotonically with respect to the regenerative torque. Therefore, the bus current ripple can be suppressed. In other words, when the smoothing capacitor 3 is used, unnecessary increases in the ripple current of the smoothing capacitor 3 can be suppressed. Furthermore, the overlap of the generation periods of the effective voltage vectors can be promoted. Therefore, by reducing the phase current ripple, it is possible to suppress the losses caused by the high-frequency current flowing through the first m-phase windings and the second m-phase windings and improve the power generation efficiency.Furthermore, in the power-running operation state, the bus current ripple can be suppressed by shifting the generation periods of the effective voltage vectors, and when the smoothing capacitor 3 is used, the ripple current of the smoothing capacitor 3 can be reduced. As a result, by reducing the loss in the smoothing capacitor 3, it is possible to suppress heat generation by the smoothing capacitor 3. That is, while suppressing the ripple current of the smoothing capacitor 3 in the regeneration operation state, it is possible to reduce the iron loss and reduce the ripple current of the smoothing capacitor 3 in the power-running operation state.

[0092] In the power conversion device 1 according to the first embodiment, when the AC rotating machine 30 is in the power running state, the control unit 10 controls the phase of the second carrier wave signal C2 to be 90 degrees different from the phase of the first carrier wave signal C1. Furthermore, the control unit 10 calculates the first applied voltage such that the average value of the first applied voltage coincides with the average value of the output voltage range of the DC power supply 20, and calculates the second applied voltage such that the average value of the second applied voltage coincides with the average value of the output voltage range of the DC power supply 20. As a result, at a low modulation rate, an instantaneous increase in the bus current can be suppressed, and the bus current ripple can be suppressed.Furthermore, at a high modulation rate, the bus current can be prevented from becoming instantaneous zero, and bus current ripple can be suppressed. When smoothing capacitor 3 is used, the ripple current of smoothing capacitor 3 can be suppressed by suppressing bus current ripple by avoiding overlap in the effective voltage vector sections. As a result, by reducing the loss in smoothing capacitor 3, it is possible to suppress heat generation by smoothing capacitor 3.

[0093] In the power conversion device 1 according to the first embodiment, the control unit 10 calculates a first voltage command for each phase of the first m-phase windings based on a control command and calculates a first applied voltage by offsetting the first voltage command by an offset voltage. Further, the control unit 10 calculates a second voltage command for each phase of the second m-phase windings based on a control command and calculates a second applied voltage by offsetting the second voltage command by an offset voltage. In addition, when the AC rotating machine 30 is in the power running operation state, the control unit 10 controls such that the phase of the second carrier wave signal C2 differs from the phase of the first carrier wave signal C1 by 180 degrees.Furthermore, the offset direction of the first applied voltage in the first voltage instruction and the offset direction of the second applied voltage in the second voltage instruction are the same. As a result, the generation periods of the effective voltage vectors of the first power converter 4a and the generation periods of the effective voltage vectors of the second power converter 4b can be made continuous without overlap. Therefore, the bus current ripple can be suppressed, and when the smoothing capacitor 3 is used, the ripple current of the smoothing capacitor 3 can be suppressed. As a result, by reducing the loss in the smoothing capacitor 3, it is possible to suppress heat generation by the smoothing capacitor 3.

[0094] In the power conversion device 1 according to the first embodiment, when the AC rotating machine 30 is in the power running operation state, the control unit 10 sets the maximum value of the first applied voltage to the maximum value of the first carrier wave signal C1. Further, the control unit 10 sets the maximum value of the second applied voltage to the maximum value of the second carrier wave signal C2. As a result, the switching of one phase is stopped in both the first power converter 4a and the second power converter 4b. Therefore, it becomes possible to reduce switching losses. As a result, heat generation by the first power converter 4a and the second power converter 4b can be suppressed.

[0095] In the power conversion device 1 according to the first embodiment, the control unit 10 sets the minimum value of the first applied voltage to the minimum value of the first carrier wave signal C1 when the AC rotating machine 30 is in the power running operation state. Further, the control unit 10 sets the minimum value of the second applied voltage to the minimum value of the second carrier wave signal C2. As a result, the switching of a phase is stopped in both the first power converter 4a and the second power converter 4b. As a result, heat generation by the first power converter 4a and the second power converter 4b can be suppressed.

[0096] In the power conversion device 1 according to the first embodiment, when the AC rotating machine 30 is in the regeneration operation state, the control unit 10 controls so that the average value of the first applied voltage and the average value of the second applied voltage are consistent. As a result, the neutral points of the first applied voltage and the second applied voltage are aligned, and it is possible to promote the overlap of the generation periods of the effective voltage vectors. Therefore, the phase current ripple can be reduced. As a result, the losses caused by the high-frequency current flowing through the first m-phase windings and the second m-phase windings can be suppressed, and the power generation efficiency can be improved.

[0097] In the power conversion device 1 according to the first embodiment, when the AC rotating machine 30 is in the regeneration operation state, the control unit 10 controls so that the average value of the first applied voltage and the average value of the second applied voltage coincide with the average value of the output voltage range of the DC power supply 20. As a result, by setting the neutral point between the first applied voltage and the second applied voltage as the average value of the input voltage, the generation periods of the zero-sequence voltage vectors can be evenly distributed. Therefore, the phase current ripple can be reduced. As a result, the iron losses (or core losses) caused by the high-frequency current flowing through the first m-phase windings and the second m-phase windings can be suppressed, and the power generation efficiency can be improved.

[0098] In the power conversion device 1 according to the first embodiment, the upper limit value Tlimh and the lower limit value Tliml of the output torque of the AC rotating machine 30 are determined based on the rotational speed of the AC rotating machine 30. Further, when the output torque is the torque limit value Tlimh, in a range where the rotational speed is equal to or lower than the rotational speed at which neither the first power converter 4a nor the second power converter 4b causes voltage saturation, the absolute value of the torque limit value Tliml is smaller than the absolute value of the torque limit value Tlimh.

[0099] As a result, by setting the absolute value of the lower torque limit Tliml to a small value at low rotation speeds, it is possible to operate in a range where the generated power increases monotonically according to the regenerative torque. As a result, losses due to reactive power can be reduced. Second embodiment

[0100] In the power conversion device 1 according to a second embodiment of this disclosure, in the power running operation state, the on / off signal generator 9 sets the offset direction of the first applied voltage in the first voltage command and the offset direction of the second applied voltage in the second voltage command to be different from each other. In this respect, the power conversion device 1 according to the second embodiment differs from the power conversion device 1 of the first embodiment. Other points are the same as in the first embodiment, and therefore, their description is omitted here.

[0101] For example, as shown in equation (7), an offset voltage is applied such that the minimum value of the first applied voltage is 0 and the maximum value of the second applied voltage is 0. {Voffset1=Vmin1Voffset2=Vmax2

[0102] At this time, the generation periods of the effective voltage vectors of the first power converter 4a are immediately after t2 and immediately before t4. The generation periods of the effective voltage vectors of the second power converter 4b are immediately before t2 and immediately after t4. The generation periods of the effective voltage vectors of the first power converter 4a and the generation periods of the effective voltage vectors of the second power converter 4b can be made continuous without overlap.

[0103] In equation (7), when the difference between Vmax1 and Vmin1 exceeds Vdc / 2, the DC power supply 20 cannot output an applied voltage exceeding the maximum output voltage value Vdc / 2. Therefore, the applied voltage is limited to the maximum value Vdc / 2 that the DC power supply 20 can output. Furthermore, when the difference between Vmax2 and Vmin2 exceeds Vdc / 2, the DC power supply 20 cannot output an applied voltage exceeding the minimum value of the output voltage -Vdc / 2. Therefore, the applied voltage is limited to the minimum value -Vdc / 2 that the DC power supply 20 can output. As a result, as shown in equation (8), an offset voltage is applied so that the minimum value of the first applied voltage is -Vdc / 2 and the maximum value of the second applied voltage is Vdc / 2.

[0104] In both the first power converter 4a and the second power converter 4b, the switching of a phase is stopped, which can reduce losses due to switching. {Voffset1=Vmin1+Vdc2Voffset2=Vmax2−Vdc2

[0105] To reduce the uneven heat generation, equation (8) and equation (9) can be switched and used periodically. {Voffset1=Vmax1−Vdc2Voffset2=Vmin2+Vdc2

[0106] In the power conversion device 1 according to the second embodiment, the control unit 10 sets the first carrier wave signal C1 and the second carrier wave signal C2 to be equal. The first power converter 4a is controlled based on the first switching signals, and the second power converter 4b is controlled based on the second switching signals. When the AC rotating machine 30 is in the power running operation state, the control unit 10 controls so that the offset direction of the first applied voltage in the first voltage command and the offset direction of the second applied voltage in the second voltage command are different from each other.In addition, when the AC rotating machine 30 is in the regeneration operation state, the control unit 10 controls the first power converter 4a and the second power converter 4b in a range where the generated current flowing from the AC rotating machine 30 to the DC power supply 20 monotonically increases with respect to the regenerative torque. As a result, in the power running operation state, the offset direction of the first applied voltage in the first voltage command and the offset direction of the second applied voltage in the second voltage command are different from each other. Therefore, the bus current ripple can be suppressed by shifting the generation periods of the effective voltage vectors. As a result, when the smoothing capacitor 3 is used, the ripple current of the smoothing capacitor 3 can be reduced.By reducing the losses in the smoothing capacitor 3, heat generation by the smoothing capacitor 3 can be suppressed. Furthermore, in the regeneration operating state, by operating in a range where the generated current flow from the AC rotating machine 30 to the DC power supply 20 increases monotonically with respect to the regenerative torque, it is possible to suppress an unnecessary increase in the bus current ripple, that is, the ripple current of the smoothing capacitor 3. At the same time, it is possible to promote the overlap of the generation periods of the effective voltage vectors. Therefore, by reducing the phase current ripple, it is possible to suppress heat generation by the smoothing capacitor 3 by suppressing the iron losses caused by the high-frequency current flowing through the first m-phase windings and the second m-phase windings.

[0107] In the power conversion device 1 according to the second embodiment, when the AC rotating machine 30 is in the power running operation state, the control unit 10 sets the applied voltage of the minimum phase among the first applied voltages as the minimum value of the first carrier wave signal C1, and the applied voltage of the maximum phase among the second applied voltages as the maximum value of the second carrier wave signal C2. As a result, the switch of one phase is maintained in both the first power converter 4a and the second power converter 4b. Therefore, switching losses can be reduced. As a result, heat generation by the first power converter 4a and the second power converter 4b can be suppressed.

[0108] In the power conversion device 1 according to the second embodiment, when the AC rotating machine 30 is in the regeneration operation state, the control unit 10 controls so that the average value of the first applied voltage and the average value of the second applied voltage are aligned. As a result, the neutral points of the first applied voltage and the second applied voltage are aligned, and it is possible to promote the overlap of the effective voltage vector sections. Therefore, the phase current ripple can be reduced. As a result, the iron losses caused by the high-frequency current flowing through the first m-phase windings and the second m-phase windings can be suppressed, and the power generation efficiency can be improved.

[0109] In the power conversion device 1 according to the second embodiment, when the AC rotating machine 30 is in the regeneration operation state, the control unit 10 controls so that the average value of the first applied voltage and the average value of the second applied voltage coincide with the average value of the output voltage range of the DC power supply 20. As a result, by setting the neutral point between the first applied voltage and the second applied voltage as the average value of the input voltage, the generation periods of the zero-sequence voltage vectors can be evenly distributed. Therefore, the phase current ripple can be reduced. As a result, the iron losses caused by the high-frequency current flowing through the first m-phase windings and the second m-phase windings can be suppressed, and the power generation efficiency can be improved.

[0110] In the power conversion device 1 according to the second embodiment, the upper limit value Tlimh and the lower limit value Tliml of the output torque of the AC rotating machine 30 are determined based on the rotational speed of the AC rotating machine 30. Further, when the output torque is the upper limit value Tlimh of the torque, in a range where the rotational speed is equal to or lower than the rotational speed at which neither the first power converter 4a nor the second power converter 4b causes voltage saturation, the absolute value of the lower limit value Tliml of the torque is smaller than the absolute value of the upper limit value Tlimh of the torque.As a result, by setting the absolute value of the lower torque limit Tliml to a small value at low rotation speeds, it is possible to operate in a range where the generated power increases monotonically according to the regenerative torque. As a result, losses due to reactive power can be reduced. Third embodiment

[0111] Fig. 21 is a schematic diagram illustrating a control device for a vehicle generator motor according to a third embodiment of this disclosure. The control device for a vehicle generator motor includes the power conversion device 1 according to the first embodiment and a control unit (not shown). The AC rotating machine 30 is connected to an internal combustion engine 100 via a belt 101. The AC rotating machine 30 and the internal combustion engine 100 are mounted on a vehicle (not shown). In this embodiment, the AC rotating machine 30 is the vehicle generator motor.

[0112] In this embodiment, the configuration of each of the power conversion device 1, the DC power supply 20, and the AC rotating machine 30 is the same as in the first embodiment, and therefore, the description thereof is omitted here.

[0113] The AC rotating machine 30 is controlled by a control unit (not shown). The control unit outputs control instructions to the power conversion device 1. The AC rotating machine 30 is an auxiliary machine of the internal combustion engine 100.

[0114] When the engine 100 restarts the engine from a shut-down state, referred to as an "idle stop," to an operating state, the AC rotating machine 30 outputs an output torque to rotate the engine 100. The AC rotating machine 30 generates electrical power using the rotation of the engine 100 and the torque output.

[0115] The power generation frequency is high near the rotational speed specified when the engine 100 is idling, but the rotational speed is relatively low in the operating range of the engine 100 when the engine 100 restarts. Therefore, iron losses tend to affect the power generation efficiency in the AC rotating machine 30. When the power conversion device 1 of the first embodiment is used in a vehicle generator motor, phase current ripple can be reduced during frequently performed power generation operations, and electric power can be generated efficiently while reducing iron losses.

[0116] Further, when the engine 100 is restarted from idle, a large torque is output due to a large current by power operation, but by suppressing the bus current ripple, an effect of reducing the ripple current of the smoothing capacitor 3 can be achieved.

[0117] The control device for a vehicle generator motor according to the third embodiment includes the power conversion device 1 of this disclosure. As a result, during power generation, that is, during a regeneration operation, it is possible to improve power generation efficiency by suppressing iron loss while operating within a control range that can suppress an unnecessary increase in bus current ripple. Further, during power operation, when the smoothing capacitor 3 is used, heat generation by the smoothing capacitor 3 can be suppressed by reducing the ripple current of the smoothing capacitor 3. In addition, by utilizing the power conversion device of this disclosure to suppress losses, it is possible to reduce the size of the vehicle generator motor and extend the continuous operation period of the vehicle generator motor.

[0118] The control device according to the third embodiment includes the power conversion device 1 of the first embodiment. However, the control device according to the third embodiment is not limited thereto. The control device according to the third embodiment may include the power conversion device 1 of the second embodiment.

[0119] Furthermore, an AC rotating machine 30 in which there is no difference between the phases of the first three-phase windings and the phases of the second three-phase windings is connected to the power conversion device 1 according to the first embodiment to the third embodiment. However, the AC rotating machine 30 is not limited to this. An AC rotating machine 30 with a difference between the phases of the first three-phase windings and the second three-phase windings can be connected to the power conversion device 1.

[0120] Furthermore, an AC rotating machine 30 having two sets of three-phase windings is connected to the power conversion device 1 according to the first embodiment to the third embodiment. However, the AC rotating machine 30 is not limited to this. An AC rotating machine 30 having two or more sets of m-phase windings may be connected to the power conversion device 1. However, "m" is a natural number of 2 or more.

[0121] Furthermore, in the power conversion device 1 according to the first embodiment to the third embodiment, a triangular wave is used as the carrier wave signal. However, the carrier wave signal is not limited to this. The carrier wave signal may have a shape other than a triangular wave, such as a sawtooth wave.

[0122] Furthermore, the power conversion device 1 according to the first embodiment to the third embodiment includes the smoothing capacitor 3. However, the power conversion device 1 is not limited to this. The smoothing capacitor 3 may be omitted. Even if the smoothing capacitor 3 is omitted, the power conversion device 1 can suppress bus current ripple and reduce loss in a functional component used as a replacement.

[0123] The functions of the power conversion device 1 according to the first embodiment to the third embodiment are implemented by a processing circuit. Fig. 22 is a configuration diagram illustrating a first example of a processing circuit that implements the functions of the power conversion device of the first embodiment to the third embodiment. A processing circuit 200 of the first example is dedicated hardware.

[0124] The processing circuit 200 corresponds, for example, to a single circuit, a complex circuit, a programmed processor, a parallel program processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof.

[0125] Fig.23 is a circuit diagram illustrating a second example of the processing circuit that implements the functions of the power conversion device 1 of the first embodiment to the third embodiment. A processing circuit 210 of the second example includes a processor 211 and a memory 212.

[0126] In the processing circuit 210, the functions of the power conversion devices 1 are implemented through software, firmware, or a combination of software and firmware. The software and firmware are described as programs stored in the memory 212. The processor 211 reads and executes the programs stored in the memory 212 to thereby implement the functions.

[0127] The programs stored in memory 212 can also be considered programs that cause a computer to execute the procedure or method of each of the aforementioned units. In this case, memory 212 corresponds, for example, to a non-volatile or volatile semiconductor memory, such as random access memory (RAM), read-only memory (ROM), flash memory, erasable programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM). A magnetic disk, a flexible disk, an optical disk, a compact disk, a MiniDisc, or a DVD may also correspond to memory 212.

[0128] The functions of the above-mentioned power conversion devices 1 can be implemented partly by dedicated hardware and partly by software or firmware.

[0129] In this way, the processing circuit can implement the functions of the above-mentioned power conversion devices 1 through hardware, software, firmware, or a combination thereof.

[0130] The control unit 10 in the first embodiment to the third embodiment includes, for example, the processing circuit 210 that performs arithmetic processing, a ROM that serves as the memory 212, and a RAM. The ROM stores data such as program data and read-only data. The RAM stores various types of data such as calculation results.

[0131] The various types of data stored in the RAM are updated and rewritten sequentially. In the control unit 10, a microcomputer reads and executes the program data stored in the ROM. As a result, the functions of each of the control instruction limiter 6, the voltage instruction calculator 7, the offset calculator 8, and the on / off signal generator 9 of the control unit 10 are implemented. List of reference symbols

[0132] 1 Power conversion device, 3 Smoothing capacitor, 4a First power converter, 4b Second power converter, 5a First current detector, 5b Second current detector, 6 Control instruction limiter, 7 Voltage instruction calculator, 8 Offset calculator, 9 On / off signal generator, 10 Control unit, 20 DC power supply, 30 AC rotating machine, 100 Internal combustion engine, 101 Belt, 200 Processing circuit, 210 Processing circuit, 211 Processor, 212 Memory QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2012-050252 A

[0003]

Claims

[1] Power conversion device comprising: a first power converter configured to apply an AC voltage converted from a DC voltage from a DC power supply to the first m-phase windings, of first m-phase windings and second m-phase windings included in an AC rotating machine; a second power converter configured to apply the AC voltage converted from the DC voltage to the second m-phase windings; and a control unit configured to control each of the first power converter and the second power converter, where “m” is a natural number of 2 or more, wherein the control unit is configured to calculate a first applied voltage for each phase of the first m-phase windings and a second applied voltage for each phase of the second m-phase windings based on an external control instruction, wherein the control unit is configured to output a first switching signal to the first power converter by comparing a first carrier wave signal and the first applied voltage, and to output a second switching signal to the second power converter by comparing a second carrier wave signal and the second applied voltage, wherein the first power converter is controlled based on the first switching signal, wherein the second power converter is controlled based on the second switching signal, and wherein the control unit is configured to: Controlling such that when the AC rotating machine is in a power running operating state, the first carrier wave signal and the second carrier wave signal are different from each other; and Controlling such that, when the AC rotating machine is in a regenerative operation state, the first carrier wave signal and the second carrier wave signal are equal, and controlling the first power converter and the second power converter in a range in which a generated current flowing from the AC rotating machine to the DC power supply monotonically increases with respect to a regenerative torque. [2] The power conversion device according to claim 1, wherein the control unit is configured to: Controlling such that, when the AC rotating machine is in the power running operating state, a phase of the second carrier wave signal differs from a phase of the first carrier wave signal by 90 degrees; Calculating the first applied voltage such that an average value of the first applied voltage matches an average value of an output voltage range of the DC power supply; and Calculating the second applied voltage such that an average value of the second applied voltage matches the average value of the output voltage range of the DC power supply. [3] Power conversion device according to claim 1, wherein the control unit is configured to calculate a first voltage command for each phase of the first m-phase windings based on the external control command and to calculate the first applied voltage by offsetting the first voltage command by an offset voltage, wherein the control unit is configured to calculate a second voltage command for each phase of the second m-phase windings based on the external control command and to calculate the second applied voltage by offsetting the second voltage command by the offset voltage, wherein the control unit is configured to control such that, when the AC rotating machine is in the power running operating state, a phase of the second carrier wave signal differs from a phase of the first carrier wave signal by 180 degrees, and wherein an offset direction of the first applied voltage in the first voltage instruction and an offset direction of the second applied voltage in the second voltage instruction are the same. [4] The power conversion device according to claim 3, wherein the control unit is configured to, when the AC rotating machine is in the power running operation state, set a maximum value of the first applied voltage to a maximum value of the first carrier wave signal and set a maximum value of the second applied voltage to a maximum value of the second carrier wave signal. [5] The power conversion device according to claim 3, wherein the control unit is configured to, when the AC rotating machine is in the power running operation state, set a minimum value of the first applied voltage to a minimum value of the first carrier wave signal and set a minimum value of the second applied voltage to a minimum value of the second carrier wave signal. [6] Power conversion device comprising: a first power converter configured to apply an AC voltage converted from a DC voltage from a DC power supply to the first m-phase windings, of first m-phase windings and second m-phase windings included in an AC rotating machine; a second power converter configured to apply the AC voltage converted from the DC voltage to the second m-phase windings; and a control unit configured to control each of the first power converter and the second power converter, where “m” is a natural number of 2 or more, wherein the control unit is configured to calculate a first voltage command for each phase of the first m-phase windings based on an external control command and to calculate a first applied voltage for each phase of the first m-phase windings by offsetting the first voltage command by an offset voltage, wherein the control unit is configured to calculate a second voltage command for each phase of the second m-phase windings based on the external control command and to calculate a second applied voltage for each phase of the second m-phase windings by offsetting the second voltage command by the offset voltage, wherein the control unit is configured to output a first switching signal to the first power converter by comparing a first carrier wave signal and the first applied voltage, and to output a second switching signal to the second power converter by comparing a second carrier wave signal and the second applied voltage, wherein the control unit is configured to control such that the first carrier wave signal and the second carrier wave signal are equal, wherein the first power converter is controlled based on the first switching signal, wherein the second power converter is controlled based on the second switching signal, and wherein the control unit is configured to: Controlling such that, when the AC rotating machine is in a power running operating state, an offset direction of the first applied voltage in the first voltage instruction and an offset direction of the second applied voltage in the second voltage instruction are different from each other; and Controlling, when the AC rotating machine is in a regenerative operation state, the first power converter and the second power converter in a range in which a generated current flow from the AC rotating machine to the DC power supply monotonically increases with respect to a regenerative torque. [7] The power conversion device according to claim 6, wherein the control unit is configured to, when the AC rotating machine is in the power running operation state, set a minimum value of the first applied voltage to a minimum value of the first carrier wave signal and set a maximum value of the second applied voltage to a maximum value of the second carrier wave signal. [8] The power conversion device according to any one of claims 1 to 7, wherein the control unit is configured to cause an average value of the first applied voltage and an average value of the second applied voltage to correspond to each other when the AC rotating machine is in the regeneration operation state. [9] The power conversion device according to claim 8, wherein the control unit is configured to cause, when the AC rotating machine is in the regeneration operation state, the average value of the first applied voltage and the average value of the second applied voltage to coincide with an average value of an output voltage range of the DC power supply. [10] Power conversion device according to one of claims 1 to 9, wherein an upper limit torque and a lower limit torque of an output torque of the AC rotating machine are determined based on a rotational speed of the AC rotating machine, and wherein, when the output torque is at the upper limit value of the torque, an absolute value of the lower limit value of the torque is set to be smaller than an absolute value of the upper limit value of the torque in a range of the rotational speed equal to or smaller than the rotational speed at which each of the first power converter and the second power converter does not cause voltage saturation to occur. [11] A control device for a vehicle generator motor comprising the power conversion device according to any one of claims 1 to 10.

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