JP7211242B2 - Modulation method switching device - Google Patents

Description

The present invention relates to a modulation scheme switching device for switching modulation schemes when controlling a multi-phase rotating electric machine.

Conventionally, in pulse width modulation of power converters, the modulation method can be seamlessly selected according to the modulation rate (amplitude of voltage command value/amplitude of carrier wave), from 3-phase modulation to 2-phase modulation and over-modulation (1-pulse drive). There is a technique for switching (see Patent Document 1)

JP 2017-212869 A

By the way, when a multi-phase rotating electric machine is driven by a battery voltage applied from a battery, the battery current flowing from the battery fluctuates as the load of the multi-phase rotating electric machine fluctuates. Fluctuations in the battery current cause the battery voltage to fluctuate, which in turn causes the modulation rate to fluctuate. For this reason, in the technique of Patent Document 1, which switches the modulation method according to the modulation rate, the modulation method may be switched inappropriately and the battery current may fluctuate transiently.

The present invention has been made to solve the above problems, and its main object is to provide a modulation scheme switching device for switching a modulation scheme when controlling a multi-phase electric rotating machine driven by a battery voltage, in which a transient To suppress fluctuation of battery current.

The first means for solving the above problems is
A modulation scheme switching device (60) for switching a modulation scheme when controlling a multi-phase electric rotating machine (30) driven by a battery voltage applied from a battery (20),
A first modulation method in which the applied voltage applied to each phase (34U, 34V, 34W, 34UA, 34VA, 34WA, 34UB, 34VB, 34WB) of the multiphase rotating electric machine is limited to a first upper limit voltage or less. A first execution unit (61) that executes
a second execution unit (62) that executes a second modulation scheme in which the applied voltage applied to each phase of the multi-phase rotating electric machine is limited to a second upper limit voltage or less that is higher than the first upper limit voltage;
The induced voltage is reduced from the applied voltage in the second modulation method executed by the second execution unit based on a parameter correlated with the induced voltage induced in each phase as the multiphase rotating electric machine rotates. a switching unit (64) for switching from the first modulation method to the second modulation method on condition that the subtracted phase voltage is lower than a predetermined voltage;
Prepare.

According to the above configuration, the modulation scheme switching device switches the modulation scheme when controlling the multi-phase rotating electric machine driven by the battery voltage. A first execution unit executes a first modulation scheme and a second execution unit executes a second modulation scheme. In the first modulation method, the applied voltage applied to each phase of the multi-phase rotating electrical machine is limited to the first upper limit voltage or less. In the second modulation method, the applied voltage applied to each phase of the multi-phase rotating electric machine is limited to a second upper limit voltage or less, which is higher than the first upper limit voltage. For this reason, the voltage applied to each phase by the second modulation method tends to be higher than the voltage applied to each phase by the first modulation method. battery current may increase.

In this respect, the switching unit converts the applied voltage to the induced voltage in the second modulation method executed by the second execution unit, based on parameters correlated with the induced voltage induced in each phase as the multiphase rotating electric machine rotates. is lower than a predetermined voltage, the first modulation method is switched to the second modulation method. That is, the phase voltage obtained by subtracting the induced voltage from the applied voltage applied to each phase contributes to the current increase. Therefore, by switching from the first modulation method to the second modulation method on condition that the phase voltage becomes lower than the predetermined voltage, it is possible to suppress the transient increase (fluctuation) of the battery current.

The induced voltage induced in each phase as the multi-phase rotating electrical machine rotates changes according to the rotational speed of the multi-phase rotating electrical machine and the magnetic flux density of the magnetic field.

In this regard, in the second means, the parameter includes the rotational speed of the multi-phase rotating electric machine. According to such a configuration, switching from the first modulation method to the second modulation method is performed based on the rotational speed of the multi-phase rotating electric machine. Therefore, even if the induced voltage changes with the change in the rotational speed of the multi-phase rotating electric machine, it is possible to accurately determine that the phase voltage is lower than the predetermined voltage, and switch from the first modulation method to the second modulation method. You can switch.

As the induced voltage induced in each phase increases as the multi-phase rotating electric machine rotates, the maximum value of torque that can be generated by the multi-phase rotating electric machine decreases. Therefore, it is desirable to switch to a modulation method capable of generating a larger torque before the multiple-phase rotating electrical machine becomes unable to generate the required torque.

In this regard, in the third means, the switching unit performs the switching before the maximum value of the torque that can be generated by the multi-phase rotating electric machine in the first modulation method executed by the first execution unit becomes smaller than the required torque. Further, on the condition that , the first modulation scheme is switched to the second modulation scheme. According to such a configuration, it is possible not only to suppress a transient increase in battery current, but also to switch to a modulation method capable of generating a larger torque before the multi-phase rotating electric machine becomes unable to generate the required torque. can be done.

The higher the rotational speed of the multi-phase rotating electrical machine, the higher the induced voltage induced in each phase as the multi-phase rotating electrical machine rotates. For this reason, if hysteresis is provided in the rotation speed for switching from the first modulation method to the second modulation method and the rotation speed for switching from the second modulation method to the first modulation method, the rotation speed for switching from the second modulation method to the first modulation method There is a risk that the applied voltage will increase due to the delay in switching to the system. In that case, the battery current may increase in the second modulation scheme.

In this regard, in the fourth means, the switching unit switches between the first modulation method and the second modulation method based on the rotation speed of the multi-phase rotating electric machine, and switches from the first modulation method to the second modulation method. The rotation speed for switching to the method is the same as the rotation speed for switching from the second modulation method to the first modulation method. According to such a configuration, delay in switching from the second modulation scheme to the first modulation scheme can be suppressed, and an increase in battery current in the second modulation scheme can be suppressed.

In a fifth means, the first execution unit controls Duty, which is a ratio of the time during which the battery voltage is applied to each of the phases in a predetermined period in the first modulation method, and sets the Duty to a first upper limit Duty The second execution unit controls the Duty in the second modulation method, limits the Duty to a second upper limit Duty that is larger than the first upper limit Duty, and the second execution unit , when the first modulation scheme is switched to the second modulation scheme, the Duty is limited to a third upper limit Duty or less, and the third upper limit Duty is gradually increased from the first upper limit Duty to the second upper limit Duty. increase to

According to the above configuration, the first execution unit controls the duty, which is the ratio of the time during which the battery voltage is applied to each phase in the predetermined period in the first modulation method, and limits the duty to the first upper limit duty or less. Therefore, in the first modulation method, the applied voltage can be limited to the voltage corresponding to the first upper limit duty or less. In addition, the second execution unit controls the Duty in the second modulation method and limits the Duty to a second upper limit Duty that is larger than the first upper limit Duty or less. Therefore, in the second modulation method, the applied voltage can be limited to the voltage corresponding to the second upper limit duty or less. Here, since the second upper limit Duty is larger than the first upper limit Duty, the battery current may increase transiently when the first modulation method is switched to the second modulation method.

In this regard, when the first modulation scheme is switched to the second modulation scheme, the second execution unit limits the Duty to the third upper limit Duty or less, and changes the third upper limit Duty from the first upper limit Duty to the second upper limit Duty. gradually increase to Therefore, when the first modulation method is switched to the second modulation method, it is possible to suppress a rapid increase in the applied voltage, and it is possible to suppress a transient increase in the battery current.

In the sixth means, a third execution for executing a third modulation method in which the applied voltage applied to each phase of the multi-phase rotating electric machine is limited to a third upper limit voltage or less that is higher than the second upper limit voltage. a section (63), wherein the predetermined voltage is a first predetermined voltage, and the switching section subtracts the induced voltage from the applied voltage applied to each phase by the third execution section based on the parameter; The second modulation method is switched to the third modulation method on condition that the phase voltage obtained is lower than a second predetermined voltage which is lower than the first predetermined voltage.

According to the above configuration, the third execution section executes the third modulation scheme. In the third modulation method, the applied voltage applied to each phase of the multi-phase rotating electrical machine is limited to a third upper limit voltage or less, which is higher than the second upper limit voltage. For this reason, the voltage applied to each phase by the third modulation method tends to be higher than the voltage applied to each phase by the second modulation method, and there is a transitional voltage when switching from the second modulation method to the third modulation method. battery current may increase.

In this respect, the switching unit makes the phase voltage obtained by subtracting the induced voltage from the applied voltage applied to each phase by the third execution unit lower than a second predetermined voltage lower than the first predetermined voltage based on the parameter. On this condition, the second modulation scheme is switched to the third modulation scheme. Therefore, it is possible to suppress the transient increase (fluctuation) of the battery current. Furthermore, since the modulation scheme switching device includes the third execution section in addition to the first execution section and the second execution section, it is possible to gradually increase the applied voltage. As a result, a transient increase in battery current can be further suppressed.

In the seventh means, the switching unit controls the applied voltage applied to each phase by the second execution unit based on the parameter when the rotational speed of the multi-phase rotating electric machine is lower than a predetermined rotational speed. on the condition that the phase voltage obtained by subtracting the induced voltage from is lower than a predetermined voltage, the first modulation method is switched to the second modulation method, and the rotational speed of the multi-phase rotating electric machine is higher than the predetermined rotational speed. If it is high, the modulation method is switched based on the modulation rate of the applied voltage command value.

When the rotational speed of the multi-phase rotating electrical machine is lower than a predetermined rotational speed, for example, when the engine is started by the multi-phase rotating electrical machine, the battery current tends to increase rapidly, so it is desirable to suppress the rapid increase of the battery current. On the other hand, when the rotational speed of the multi-phase rotating electrical machine is higher than the predetermined rotational speed, for example, when the driving force of the engine is assisted by the multi-phase rotating electrical machine, it is desirable to suppress the fluctuation of the torque generated by the multi-phase rotating electrical machine. .

In this respect, according to the above configuration, when the rotation speed of the multi-phase rotating electric machine is lower than the predetermined rotation speed, the first modulation method is switched to the second modulation method based on the parameter correlated with the induced voltage. Therefore, a rapid increase in battery current can be suppressed. On the other hand, when the rotation speed of the multi-phase rotating electric machine is higher than the predetermined rotation speed, the modulation method is switched based on the modulation rate of the applied voltage command value. Therefore, it is possible to prioritize suppression of torque fluctuations generated by the multi-phase rotating electric machine over suppression of battery current fluctuations.

In the eighth means, a detection unit for detecting a battery current flowing from the battery, and when a state in which the battery current detected by the detection unit is greater than a predetermined current continues for a period longer than a predetermined time, it is determined that there is an abnormality. and a determination unit (66) for determining

According to the above configuration, the determination unit determines that there is an abnormality when the state in which the battery current detected by the detection unit is greater than the predetermined current continues for a period longer than the predetermined time. In such a configuration, it is possible to suppress a transient increase in the battery current, so that it is possible to suppress an erroneous determination that the determination unit is abnormal when switching the modulation scheme.

In the case where a multi-phase rotating electric machine has a plurality of systems having the respective phases, if the modulation schemes are switched simultaneously in the plurality of systems, transient battery current fluctuations may be amplified.

In this respect, in the ninth means, the times for switching the modulation schemes are made different from each other in the plurality of systems. According to such a configuration, even if the multi-phase rotating electric machine includes a plurality of systems having the respective phases, it is possible to suppress amplification of transient battery current fluctuations.

1 is an overall configuration diagram of an in-vehicle system according to a first embodiment; FIG. The figure which shows the drive aspect of a field-energization circuit. FIG. 4 is a block diagram showing torque control when the rotation speed is equal to or lower than the first rotation speed; The block diagram which shows torque control when a rotational speed is higher than a 3rd rotational speed. FIG. 4 is a diagram showing a mode of switching modulation schemes; The figure which shows the definition of a voltage vector. 4 is a time chart showing how the upper limit duty changes. Equivalent circuit describing the phase currents. Graph showing the relationship between rotational speed and torque. Graph showing the relationship between rotational speed, phase voltage, induced voltage, and applied voltage. 4 is a time chart showing switching modes of modulation schemes; The block diagram which shows a part of vehicle-mounted system which concerns on 2nd Embodiment. The figure which shows the spatial phase difference of a 1st, 2nd stator winding group. FIG. 4 is a diagram showing a switch driving mode using 120° energization;

<First embodiment>
A first embodiment embodied in a rotating electric machine and a modulation method switching device mounted on a vehicle will be described below with reference to the drawings.

As shown in FIG. 1, the vehicle includes an engine 10 as a vehicle main engine. The engine 10 includes a fuel injection valve and the like, and generates power by burning fuel such as gasoline or light oil injected from the fuel injection valve. The power generated is output from the output shaft 10 a of the engine 10 .

The vehicle includes a battery 20 as a DC power source, a load 22, and a control system. The battery 20 is, for example, a lithium storage battery or a lead storage battery with a rated voltage of 12V. The control system includes a rotating electric machine 30 that is AC driven. In this embodiment, a wound-field synchronous machine is used as the rotating electric machine 30 (multi-phase rotating electric machine). Further, in the present embodiment, an ISG (Integrated Starter Generator), which is a generator to which the function of an electric motor is added, is used as the rotary electric machine 30 . Note that the rotating electric machine 30 is, for example, a salient pole machine.

The rotating electric machine 30 has a rotor 31 . The rotor 31 has a field winding 32 . The rotating shaft of the rotor 31 can transmit power to the output shaft 10a of the engine 10 via a pulley (not shown) or the like. When the rotating electric machine 30 is driven as a generator, the rotor 31 rotates by the rotational power supplied from the output shaft 10a, and the rotating electric machine 30 generates electric power. The battery 20 is charged with the electric power generated by the rotating electric machine 30 . On the other hand, when the rotary electric machine 30 is driven as an electric motor, the output shaft 10a rotates with the rotation of the rotor 31, and torque is applied to the output shaft 10a. As a result, the engine 10 can be started and the running of the vehicle (driving force of the engine 10) can be assisted. The drive wheels of the vehicle are connected to the output shaft 10a via a transmission or the like.

The rotating electric machine 30 has a stator 33 . The stator 33 has stator windings. The stator windings include U-, V-, and W-phase windings 34U, 34V, and 34W arranged with an electrical angle difference of 120 degrees from each other.

The control system includes a three-phase inverter 40 , a field energization circuit 41 and a capacitor 21 . The inverter 40 includes a series connection of U, V, W phase upper arm switches SUp, SVp, SWp and U, V, W phase lower arm switches SUn, SVn, SWn. U-, V- and W-phase windings 34U, 34V and 34W are provided at connection points between U-, V- and W-phase upper arm switches SUp, SVp and SWp and U-, V and W-phase lower arm switches SUn, SVn and SWn. are connected. The second ends of the U-, V-, and W-phase windings 34U, 34V, and 34W are connected at a neutral point. That is, in this embodiment, the U-, V-, and W-phase windings 34U, 34V, and 34W are star-connected. In this embodiment, IGBTs are used as the arm switches SUp to SWn. U-, V-, W-phase upper arm diodes DUp, DVp, DWp are connected in anti-parallel to the U-, V-, W-phase upper arm switches SUp, SVp, SWp. U-, V- and W-phase lower arm diodes DUn, DVn and DWn are connected in anti-parallel to the U-, V- and W-phase lower arm switches SUn, SVn and SWn.

A positive electrode terminal of the battery 20 is connected to the collectors, which are high potential side terminals of the U-, V-, and W-phase upper arm switches SUp, SVp, and SWp, via a high potential side electric path Lp. The negative terminal of the battery 20 is connected to the emitters, which are the low potential side terminals of the U-, V-, and W-phase lower arm switches SUn, SVn, and SWn, via the low potential side electric path Ln. Each electric path Lp, Ln is a conductive member such as a busbar. A high potential side terminal of a capacitor 21 is connected to the positive terminal side of the battery 20 in the high potential side electric path Lp with respect to the connection point with the collector of each upper arm switch SUp, SVp, SWp. A low potential side terminal of a capacitor 21 is connected to the negative terminal side of the battery 20 with respect to the connection point with the emitters of the lower arm switches SUn, SVn, and SWn in the low potential side electric path Ln.

The field energizing circuit 41 is a full bridge circuit, and includes a series connection of a first upper arm switch SH1 and a first lower arm switch SL1, and a series connection of a second upper arm switch SH2 and a second lower arm switch SL2. It has A first end of the field winding 32 is connected to a connection point between the first upper arm switch SH1 and the first lower arm switch SL1 via a brush (not shown). A second end of the field winding 32 is connected to a connection point between the second upper arm switch SH2 and the second lower arm switch SL2 via a brush (not shown). In this embodiment, IGBTs are used as the arm switches SH1, SL1, SH2, SL2. Diodes DH1, DL1, DH2, and DL2 are connected in anti-parallel to the arm switches SH1, SL1, SH2, and SL2, respectively.

The inverter 40 side of the high potential side electrical path Lp is connected to the high potential side terminal collectors of the first and second upper arm switches SH1 and SH2 from the connection point with the high potential side terminal of the capacitor 21. . The emitters, which are the low potential side terminals of the first and second lower arm switches SL1 and SL2, are connected to the inverter 40 side of the low potential side electric path Ln from the connection point with the low potential side terminal of the capacitor 21. .

The control system includes a voltage detector 50 , a phase current detector 51 , a field current detector 52 and an angle detector 53 . The voltage detection unit 50 detects the terminal voltage of the capacitor 21 as the power supply voltage VDC (battery voltage). The phase current detector 51 detects phase currents flowing through the U-, V-, and W-phase windings 34U, 34V, and 34W. The field current detector 52 detects the field current flowing through the field winding 32 . The angle detector 53 outputs an angle signal that is a signal corresponding to the rotation angle of the rotor 31 . Output signals from the detection units 50 to 53 are input to a control device 60 provided in the vehicle. In this embodiment, the rotary electric machine 30, the inverter 40, the field energization circuit 41, and the control device 60 are integrated to form a mechanical and electrical integrated drive device.

The control device 60 (modulation method switching device) includes a memory 68 corresponding to a storage unit. The memory 68 corresponds to a non-transitory computer readable medium, such as a non-volatile memory. The control device 60 includes a first execution section 61 , a second execution section 62 , a third execution section 63 , a switching section 64 and a determination section 66 . These will be described later.

A part or all of each function of the control device 60 may be configured in hardware by one or a plurality of integrated circuits or the like, for example. Also, each function of the control device 60 may be configured by, for example, software recorded in a non-transitional substantive recording medium and a computer executing the software.

The control device 60 generates a drive signal for each switch that constitutes the inverter 40 and the field energization circuit 41 .

First, the inverter 40 will be explained. The control device 60 acquires the angle signal from the angle detection unit 53, and generates drive signals for turning on/off the switches SUp to SWn forming the inverter 40 based on the acquired angle signal. More specifically, when the rotating electrical machine 30 is driven as an electric motor, the control device 60 converts the DC power output from the battery 20 into AC power and supplies it to the U-, V-, and W-phase windings 34U, 34V, and 34W. , generate drive signals for turning on/off the arm switches SUp to SWn, and supply the generated drive signals to the gates of the arm switches SUp to SWn. On the other hand, when the rotating electrical machine 30 is driven as a generator, the control device 60 converts the AC power output from the U-, V-, and W-phase windings 34U, 34V, and 34W into DC power to A drive signal for turning on/off each of the arm switches SUp to SWn is generated so as to be supplied to at least one of them.

Next, the field energizing circuit 41 will be described. The control device 60 turns on and off each switch that constitutes the field current circuit 41 in order to excite the field winding 32 . Specifically, the control device 60 turns each switch on and off so that the first state shown in FIG. 2(a) and the second state shown in FIG. 2(b) alternately appear. The first state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are turned on, and the second upper arm switch SH2 and the first lower arm switch SL1 are turned off. The second state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are turned off and the second upper arm switch SH2 and the first lower arm switch SL1 are turned on.

Control device 60 calculates electrical angle θe of rotary electric machine 30 and rotational speed Nm of rotor 31 based on the angle signal from angle detection unit 53 . Based on the phase currents flowing through the U-, V-, and W-phase windings 34U, 34V, and 34W detected by the phase current detector and the field current detected by the field current detector 52, the controller 60 A battery current flowing from the battery 20 is detected (estimated). The determination unit 66 determines that there is an abnormality (overcurrent determination) when the detected battery current is greater than the predetermined current Ih for a period longer than a predetermined time. The predetermined current Ih is the maximum current assumed as the battery current that flows when the engine 10 is started in a normal state. The predetermined time is the time during which it can be determined that the battery current is actually flowing, regardless of the influence of noise or the like.

Next, the torque control of the rotary electric machine 30 performed by the control device 60 will be described. 3 and 4 are block diagrams of torque control.

First, the torque control shown in FIG. 3 will be described. This torque control is performed when the rotation speed Nm of the rotary electric machine 30 is equal to or lower than the first rotation speed Nm1, as indicated by "three-phase modulation (duty limit)" in FIG. A method for setting the first rotation speed Nm1 will be described later.

Based on the phase current and the electrical angle θe detected by the phase current detection unit 51, the two-phase conversion unit 70 converts the U-, V-, and W-phase currents IU, IV, and IW in the three-phase fixed coordinate system of the rotary electric machine 30 into Convert to d- and q-axis currents Idr and Iqr in the dq coordinate system, which is a two-phase rotating coordinate system.

The d-axis command setting unit 71 sets the torque of the rotary electric machine 30 to the command torque Trq* based on the command torque Trq* (required torque), the rotation speed Nm, and the power supply voltage VDC detected by the voltage detection unit 50. Set the d-axis command current Id*. Specifically, the d-axis command setting unit 71 sets the d-axis command current Id* based on the map information in which the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC are associated with the d-axis command current Id*. set. This map information is stored in memory 68 .

The q-axis command setting unit 72 sets a q-axis command current Iq* for setting the torque of the rotary electric machine 30 to the command torque Trq* based on the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC. Specifically, the q-axis command setting unit 72 sets the q-axis command current Iq* based on the map information that associates the command torque Trq*, the rotation speed Nm, the power supply voltage VDC, and the q-axis command current Iq*. set. This map information is stored in memory 68 .

The stator control unit 73 calculates a d-axis command voltage Vd* as a manipulated variable for feedback-controlling the d-axis current Idr to the d-axis command current Id*. Specifically, the stator control unit 73 calculates the d-axis current deviation ΔId as a value obtained by subtracting the d-axis current Idr from the d-axis command current Id*, and feedback-controls the calculated d-axis current deviation ΔId to 0. d-axis command voltage Vd* is calculated as the manipulated variable.

The stator control unit 73 calculates a q-axis command voltage Vq* as a manipulated variable for feedback-controlling the q-axis current Iqr to the q-axis command current Iq*. Specifically, the stator control unit 73 calculates the q-axis current deviation ΔIq as a value obtained by subtracting the q-axis current Iqr from the q-axis command current Iq*, and feedback-controls the calculated q-axis current deviation ΔIq to 0. q-axis command voltage Vq* is calculated as the manipulated variable.

In this embodiment, the feedback control used in the stator control section 73 is proportional integral control, for example. Feedback control is not limited to proportional-integral control, and may be proportional-integral-derivative control, for example.

A command voltage vector, which is a command value of the voltage vector in the dq coordinate system, is determined by the d-axis command voltage Vd* and the q-axis command voltage Vq*. Here, the voltage vector Vtr applied to the stator winding has a d-axis voltage Vd as its d-axis component and a q-axis voltage Vq as its q-axis component, as shown in FIG. In this embodiment, the voltage phase δ, which is the phase of the voltage vector Vtr, is defined with the positive direction of the d-axis as a reference, and the counterclockwise direction from this reference as the positive direction.

Based on the d- and q-axis command voltages Vd* and Vq* and the electrical angle θe, the three-phase conversion unit 74 converts the d- and q-axis command voltages Vd* and Vq* into U, V and W in a three-phase fixed coordinate system. Convert to phase command voltages Vu*, Vv*, Vw*. In this embodiment, the U-, V-, and W-phase command voltages Vu*, Vv*, and Vw* have sinusoidal waveforms with a phase shift of 120 degrees in electrical angle.

The stator generation unit 75 turns on and off the switches SUp to SWn of the inverter 40 by sinusoidal PWM control based on the carrier signal (carrier wave), the command voltages Vu*, Vv*, Vw* for each phase, and the power supply voltage VDC. to generate each drive signal. Specifically, the sinusoidal PWM control generates each drive signal based on a value obtained by dividing each phase command voltage Vu*, Vv*, Vw* by "VDC/2" and a magnitude comparison with the carrier signal. is. The carrier signal is a triangular wave signal. Each drive signal is generated as a duty, which is the proportion of time during which the power supply voltage VDC is applied to the U, V, and W phases in a predetermined period. In the "three-phase modulation (duty limitation)", the duty is limited to the first upper limit duty or less. The first upper limit Duty is, for example, 80[%].

In sinusoidal PWM control, the value obtained by dividing the amplitude of each phase command voltage Vu*, Vv*, Vw* by "VDC/2" is equal to or less than the amplitude of the carrier signal. In this embodiment, a value obtained by dividing the amplitude of each phase command voltage Vu*, Vv*, Vw* by "VDC/2" is defined as the modulation factor Mr. In the stator generator 75, the modulation rate Mr is 1 when the rotation speed Nm is equal to the first rotation speed Nm1, and the modulation rate Mr is smaller than 1 when the rotation speed Nm is less than the first rotation speed Nm1. As the modulation rate, a value obtained by dividing the amplitude of the voltage command value by the amplitude of the carrier wave can be used.

According to "three-phase modulation (duty limit)", the actual voltage vector is controlled to the command voltage vector determined by the d and q axis command voltages Vd* and Vq* while the duty is limited to the first upper limit duty or less. .

The field command setting unit 80 sets the field command current If* based on the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC. Specifically, the field command setting unit 80 sets the field command current If* based on the map information in which the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC are associated with the field command current If*. set. This map information is stored in memory 68 .

The field current control unit 81 calculates a field command voltage Vf* as a manipulated variable for feedback-controlling the field current Ifr detected by the field current detection unit 52 to the field command current If*. Specifically, the field current control unit 81 calculates a field current deviation ΔIf as a value obtained by subtracting the field current Ifr from the field command current If*, and performs feedback control to set the calculated field current deviation ΔIf to 0. A field command voltage Vf* is calculated as a manipulated variable for the operation. In this embodiment, the feedback control used in the field current control section 81 is proportional integral control, for example. Feedback control is not limited to proportional-integral control, and may be proportional-integral-derivative control, for example.

The field generation unit 82 converts the applied voltage of the field winding 32 to the field command voltage based on a magnitude comparison between the value obtained by dividing the field command voltage Vf* by the power supply voltage VDC and the carrier signal, which is a triangular wave signal. Each drive signal for each of the switches SH1 to SL2 of the field energization circuit 41 for controlling to Vf* is generated.

Next, torque control shown in FIG. 4 will be described. This torque control is performed when the rotation speed Nm of the rotary electric machine 30 is equal to or higher than the third rotation speed Nm3 (>Nm2>Nm1), as indicated by "overmodulation" in FIG. Control from "three-phase modulation (duty limit)" to "overmodulation" is performed when the engine 10 is started. A method for setting the third rotation speed Nm3 will be described later.

Based on the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC, the phase information setting unit 90 sets the command voltage phase δ*, which is the command value of the voltage phase δ for setting the torque of the rotary electric machine 30 to the command torque Trq*. set. Specifically, the phase information setting unit 90 sets the command voltage phase δ* based on the map information in which the command torque Trq*, the rotational speed Nm, and the power supply voltage VDC are associated with the command voltage phase δ*. . This map information is stored in memory 68 .

The amplitude information setting unit 91 sets a command modulation rate Mr*, which is a command value of the modulation rate Mr, based on the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC. Specifically, the amplitude information setting unit 91 sets the command modulation rate Mr* based on the map information that associates the command torque Trq*, the rotation speed Nm, the power supply voltage VDC, and the command modulation rate Mr*. . This map information is stored in memory 68 . The command modulation factor Mr* has a positive correlation with the voltage amplitude, which is the magnitude of the command voltage vector. The command modulation rate Mr* is used, for example, to determine the ON period Ton in rectangular wave control (overmodulation control). The ON period Ton is a period during which the switches SUp to SWn of the inverter 40 are turned on. The ON period Ton is set, for example, between 120° and 180° in electrical angle.

Based on the command voltage phase δ*, the command modulation rate Mr*, and the electrical angle θe, the pattern generator 92 generates drive signals for the switches SUp to SWn of the inverter 40 for driving the rotating electrical machine 30 by rectangular wave control. Generate. In the rectangular wave control, in each phase, the electric power of the rotating electric machine 30 is divided into a state in which the upper arm switch is turned on and the lower arm switch is turned off, and a state in which the upper arm switch is turned off and the lower arm switch is turned on. It appears once in one period of the angle. Further, in the rectangular wave control, the switching of the upper arm switch to the off state is shifted by 120 degrees in electrical angle for each phase. In rectangular wave control, the torque of rotating electric machine 30 is controlled to command torque Trq* by controlling the voltage phase while fixing the amplitude of the fundamental wave component of the phase voltage of each phase winding.

In the memory 68, for each of the three phases, a first signal for turning ON only the upper arm switch and a second signal for turning ON only the lower arm switch are associated with the electrical angle θe. A pulse pattern, which is map information, is stored. The pulse pattern is stored in the memory 68 in association with the command modulation rate Mr* and the command voltage phase δ*. Pattern generator 92 selects a pulse pattern corresponding to command modulation rate Mr* and command voltage phase δ*, and generates a drive signal for each switch of inverter 40 based on the selected pulse pattern. In this embodiment, when the rotation speed Nm is equal to or higher than the third rotation speed Nm3, the modulation factor Mr becomes the upper limit value of 1.27.

4, the field command setting section 80, the field current control section 81 and the field generation section 82 are the same as those shown in FIG.

According to the rectangular wave control, the actual voltage vector is controlled to the command voltage vector determined by the command modulation rate Mr* and the command voltage phase δ*.

Next, torque control when the rotation speed Nm is higher than the first rotation speed Nm1 and lower than the third rotation speed Nm3 will be described.

As shown in FIG. 5, when the rotational speed Nm of the rotary electric machine 30 is higher than the first rotational speed Nm1 and equal to or lower than the second rotational speed Nm2 (>Nm1), "two-phase modulation (duty limit)" is performed. will be The two-phase modulation method is well known as described in WO2010/119929, etc., and the description thereof is omitted here by citing the contents described in the same publication. A method for setting the second rotation speed Nm2 will be described later.

In the "two-phase modulation (duty limitation)" of the present embodiment, the duty is limited to the second upper limit duty (>first upper limit duty) or less while executing the two-phase modulation method. The second upper limit Duty is, for example, 90[%].

Furthermore, when switched from "three-phase modulation (Duty limit)" to "two-phase modulation (Duty limit)", the Duty is limited to the third upper limit Duty or less, and the third upper limit Duty is changed from the first upper limit Duty to the third 2 Gradually increase up to the upper limit duty. For example, as shown in FIG. 7 , when switching from “three-phase modulation (duty limit)” to “two-phase modulation (duty limit)” at time t11, the third upper limit duty shifts from the first upper limit duty at a constant speed over time. Duty is increased, and the third upper limit Duty is set to the second upper limit Duty at time t12.

As shown in FIG. 5, when the rotation speed Nm of the rotary electric machine 30 is higher than the second rotation speed Nm2 and equal to or lower than the third rotation speed Nm3 (>Nm2), "two-phase modulation" is performed. In "two-phase modulation", the duty is not limited, that is, the upper limit of the duty is 100[%].

Further, when switched from "two-phase modulation" to "two-phase modulation (Duty limit)", the Duty is limited to the fourth upper limit Duty or less, and the fourth upper limit Duty is changed from 100 [%] to the second upper limit Duty gradually decrease to For example, when switched from “two-phase modulation” to “two-phase modulation (Duty limit)”, the fourth upper limit Duty is decreased at a constant speed from 100 [%] over time, and the fourth upper limit Duty is changed to the second upper limit Duty.

In each modulation method described above, the applied voltage applied to each phase of the U, V, and W phases is limited to the upper limit voltage or less according to the principle of each modulation method and the upper limit duty. The upper limit voltage of "three-phase modulation (duty limit)" is the lowest, followed by "two-phase modulation (duty limit)," "two-phase modulation," and "overmodulation." Highest upper limit voltage.

Here, a modulation method in which the applied voltage is limited to a first upper limit voltage or less is defined as a first modulation method, and a modulation method in which an applied voltage is limited to a second upper limit voltage or less, which is higher than the first upper limit voltage, is defined as a second modulation method. A third modulation method is defined as a modulation method in which the applied voltage is limited to a third upper limit voltage or less, which is higher than the second upper limit voltage. At this time, in the control device 60, the part that executes the first modulation scheme is the first execution section 61 (see FIG. 1), the section that executes the second modulation scheme is the second execution section 62, and the third modulation The part that executes the method is the third execution unit 63 .

For example, if "three-phase modulation (duty limit)" is the first modulation method, any one of "two-phase modulation (duty limit)," "two-phase modulation," and "overmodulation" is the second modulation method. . For example, if “two-phase modulation (duty limitation)” is the second modulation method, either “two-phase modulation” or “overmodulation” is the third modulation method. Further, for example, if "two-phase modulation" is the first modulation method, "overmodulation" is the second modulation method.

Here, in the second modulation method, the applied voltage applied to each phase of the rotary electric machine 30 is limited to the second upper limit voltage or less, which is higher than the first upper limit voltage. For this reason, the voltage applied to each phase by the second modulation method tends to be higher than the voltage applied to each phase by the first modulation method. battery current may increase. In this case, the determination unit 66 may erroneously determine that the rotating electric machine 30, the inverter 40, and the field energization circuit 41 are abnormal even though they are not abnormal. In order to suppress such erroneous determination, in the present embodiment, the first to third rotation speeds Nm1 to Nm3 are set as follows.

FIG. 8 is an equivalent circuit illustrating phase currents. Here, an applied voltage Vu applied to the U phase and a phase current Iu flowing in the U phase will be described as an example.

The U phase has resistance R and inductance L. An induced voltage ωφcos θ is generated in the U phase as the rotor 31 of the rotary electric machine 30 rotates. ω is the angular velocity of the rotor 31, and φ is the magnetic flux passing through the U-phase winding 34U. θ=ωt and t is time. Therefore, it can be expressed as Vu=(L+R)Iu+ωφcosθ. Then, it can be expressed as Iu=(Vu-ωφcosθ)/(L+R). From this equation, it can be seen that the higher the angular velocity ω of the rotor 31, that is, the rotational speed Nm of the rotary electric machine 30, the lower the U-phase phase voltage (Vu−ωφcos θ) and the smaller the phase current Iu.

Therefore, when switching from the first modulation method to the second modulation method, the first to third rotation speeds Nm1 are adjusted so that the phase voltage (Vu−ωφcosθ) of the U phase in the second modulation method becomes lower than the predetermined voltage V1. ~Nm3 is set. That is, the switching unit 64 (see FIG. 1) determines that the phase voltage obtained by subtracting the induced voltage ωφ cos θ from the applied voltage Vu in the second modulation method becomes lower than the predetermined voltage V1 based on the rotation speed Nm of the rotary electric machine 30. on the condition that the first modulation scheme is switched to the second modulation scheme. Based on the rotation speed Nm of the rotary electric machine 30, the switching unit 64 determines that the phase voltage obtained by subtracting the induced voltage ωφcosθ from the applied voltage Vu in the third modulation method is lower than a predetermined voltage V2 (<V1) lower than the predetermined voltage V1. The second modulation method is switched to the third modulation method on the condition that the .DELTA. Note that the rotation speed Nm of the rotating electric machine 30 corresponds to a parameter that correlates with the induced voltage induced in each phase as the rotating electric machine 30 rotates.

FIG. 9 is a graph showing the relationship between rotational speed Nm and torque of rotating electric machine 30. In FIG. Here, a case of switching from the first modulation method to the second modulation method at the switching rotation speed Nm12 will be described as an example. A solid line indicates the command torque Trq*, a dashed line indicates the maximum torque Trq1 in the first modulation method, and a dashed line indicates the maximum torque Trq2 in the second modulation method. The maximum torque Trq1 is the maximum value of torque that the rotating electric machine 30 can generate in the first modulation method. The maximum torque Trq2 is the maximum value of torque that the rotating electric machine 30 can generate in the second modulation method.

When rotation speed Nm exceeds switching rotation speed Nm12, maximum torque Trq1 in the first modulation method becomes smaller than command torque Trq*, and command torque Trq* cannot be output in the first modulation method. Therefore, the switching unit 64 switches from the first modulation method to the second modulation method when the rotation speed Nm reaches the switching rotation speed Nm12, that is, before the maximum torque Trq1 in the first modulation method becomes smaller than the command torque Trq*. switch to

The maximum torque Trq2 in the second modulation method is larger than the command torque Trq* even when the rotational speed Nm exceeds the switching rotational speed Nm12. Therefore, in the second modulation method, even if the rotation speed Nm exceeds the switching rotation speed Nm12, the command torque Trq* can be output.

FIG. 10 is a graph showing the relationship among the rotational speed Nm, phase voltage (Vu-ωφcosθ), induced voltage ωφcosθ, and applied voltage Vu. Here, a case similar to that of FIG. 9 will be described as an example. In FIG. 10(c), the solid line indicates the U-phase command voltage Vu*, the dashed line indicates the maximum applied voltage Vu1 in the first modulation method, and the dashed line indicates the maximum applied voltage Vu2 in the second modulation method. there is The maximum applied voltage Vu1 is the maximum voltage that can be applied to the U phase in the first modulation method. The maximum applied voltage Vu2 is the maximum voltage that can be applied to the U phase in the second modulation method.

When the rotation speed Nm exceeds the switching rotation speed Nm12, the maximum applied voltage Vu1 in the first modulation method becomes lower than the U-phase command voltage Vu*, and the U-phase command voltage Vu* can be output in the first modulation method. Gone. Therefore, when the rotation speed Nm reaches the switching rotation speed Nm12, that is, before the maximum applied voltage Vu1 in the first modulation method becomes lower than the U-phase command voltage Vu*, the switching unit 64 switches from the first modulation method to the first modulation method. 2 Switch to the modulation method. At this time, as shown in FIG. 10A, the phase voltage Vc of the U phase at the switching rotation speed Nm12 is lower than the predetermined voltage V1. That is, by switching from the first modulation method to the second modulation method on the condition that the rotation speed Nm reaches the switching rotation speed Nm12, the phase voltage of the U phase in the second modulation method is made lower than the predetermined voltage V1. be able to. Therefore, it is possible to suppress an increase in the phase current Iu when switching from the first modulation method to the second modulation method.

The maximum applied voltage Vu2 in the second modulation method is higher than the U-phase command voltage Vu* even when the rotation speed Nm exceeds the switching rotation speed Nm12. Therefore, in the second modulation method, the U-phase command voltage Vu* can be output even if the rotational speed Nm exceeds the switching rotational speed Nm12.

Note that the induced voltage ωφcos θ induced in the U-phase as the rotating electric machine 30 rotates increases as the rotation speed Nm of the rotating electric machine 30 increases. For this reason, if a hysteresis is provided in the rotation speed Nm12 for switching from the first modulation method to the second modulation method and the rotation speed Nm21 for switching from the second modulation method to the first modulation method, the rotation speed Nm21 for switching from the second modulation method to the first modulation method will be changed. There is a risk that the applied voltage Vu (see Vu2 in FIG. 10(c)) will increase due to the delay in switching to the 1 modulation method. In that case, the battery current may increase in the second modulation scheme. Therefore, in the present embodiment, the rotation speed Nm12 for switching from the first modulation method to the second modulation method and the rotation speed Nm21 for switching from the second modulation method to the first modulation method are the same. Similarly, the rotation speed Nm23 for switching from the second modulation method to the third modulation method and the rotation speed Nm32 for switching from the third modulation method to the second modulation method are the same.

Further, as shown in FIG. 5, when the rotational speed Nm of the rotating electric machine 30 is higher than the predetermined rotational speed Nm4 (>Nm3), for example, when the driving force of the engine 10 is assisted by the rotating electric machine 30, the rotating electric machine 30 It is desirable to suppress fluctuations in the generated torque. Modulation method switching based on the modulation factor Mr can suppress variations in the torque generated by the rotating electrical machine 30 more than modulation method switching based on the rotation speed Nm of the rotating electrical machine 30 described above.

Therefore, in the present embodiment, when the driving force of the engine 10 is assisted by the rotating electric machine 30, that is, when the rotation speed Nm of the rotating electric machine 30 is higher than the predetermined rotation speed Nm4, the modulation method is determined based on the command modulation factor Mr*. switch. Specifically, when the command modulation rate Mr* is equal to or less than the first modulation rate Mr1, "three-phase modulation assist (with neutral point shift)" is performed. When the command modulation rate Mr* is greater than the first modulation rate Mr1 and is equal to or less than the second modulation rate Mr2 (>Mr1), "for two-phase modulation assist" is performed. When the command modulation rate Mr* is greater than the second modulation rate Mr2, "for overmodulation assist" is performed. The upper limit voltage for "3-phase modulation assist (with neutral point shift)" is the lowest, and the upper limit voltage increases in order for "2-phase modulation assist" and "over-modulation assist". has the highest upper voltage limit.

FIG. 11 is a time chart showing how modulation schemes are switched.

As time elapses, the modulation method is switched from "3-phase modulation (duty limit)" to "2-phase modulation (duty limit)", "2-phase modulation", and "overmodulation" in order. Specifically, the rotation speed Nm is switched to “two-phase modulation (duty limit)” at the first rotation speed Nm1, switched to “two-phase modulation” at the second rotation speed Nm2, and switched to “two-phase modulation” at the third rotation speed Nm3. It is switched to "Overmodulation". Further, the upper limit value of Duty is increased in order as the rotation speed Nm increases. The battery current is smaller than the predetermined current Ih, so that the determination unit 66 can avoid erroneous determination of abnormality.

The embodiment detailed above has the following advantages.

In the second modulation method executed by the second execution unit 62, the switching unit 64 performs The first modulation method is switched to the second modulation method under the condition that the phase voltage obtained by subtracting the induced voltage ωφ cos θ from the applied voltage Vu (Vv, Vw) becomes lower than the predetermined voltage V1. That is, the phase voltage obtained by subtracting the induced voltage ωφ cos θ from the applied voltage Vu applied to each phase 34U (34V, 34W) contributes to the current increase. Therefore, by switching from the first modulation method to the second modulation method on the condition that the phase voltage becomes lower than the predetermined voltage V1, it is possible to suppress the transient increase (fluctuation) of the battery current. .

The induced voltage ωφ cos θ induced in each phase as the rotating electrical machine 30 rotates changes according to the rotation speed Nm of the rotating electrical machine 30 and the magnetic flux density of the magnetic field. In general, the change speed of the rotation speed Nm of the rotating electric machine 30 is higher than the change speed of the magnetic flux density due to the field current flowing through the field winding 32 . In this regard, the parameters include the rotation speed Nm of the rotating electric machine 30 . According to such a configuration, switching from the first modulation method to the second modulation method is performed based on the rotation speed Nm of the rotary electric machine 30, which generally has a higher changing speed than the magnetic flux density. Therefore, even if the induced voltage ωφcosθ changes with the change in the rotational speed Nm of the rotary electric machine 30, it is accurately determined that the phase voltage is lower than the predetermined voltage V1, and the first modulation method to the second modulation method is performed. method can be switched.

When the induced voltage ωφcosθ induced in each phase increases as the rotating electrical machine 30 rotates, the maximum torque that the rotating electrical machine 30 can generate decreases. Therefore, it is desirable to switch to a modulation method capable of generating a larger torque before the rotating electric machine 30 becomes unable to generate the command torque Trq*. In this respect, the switching unit 64 is further conditional on the condition that the maximum value of torque that can be generated by the rotating electrical machine 30 in the first modulation method executed by the first execution unit 61 is before it becomes smaller than the command torque Trq*. , to switch from the first modulation scheme to the second modulation scheme. According to such a configuration, not only is it possible to suppress the transient increase in battery current, but before the rotating electric machine 30 becomes unable to generate the command torque Trq*, it switches to a modulation method that can generate a larger torque. be able to.

The switching unit 64 switches between the first modulation method and the second modulation method based on the rotation speed Nm of the rotary electric machine 30, and switches from the rotation speed Nm12 from the first modulation method to the second modulation method, and from the second modulation method. It is the same as the rotation speed Nm21 for switching to the first modulation method. According to such a configuration, delay in switching from the second modulation scheme to the first modulation scheme can be suppressed, and an increase in battery current in the second modulation scheme can be suppressed.

- When the first modulation scheme is switched to the second modulation scheme, the second execution unit 62 limits the Duty to the third upper limit Duty or less, and sets the third upper limit Duty from the first upper limit Duty to the second upper limit Duty. Increase gradually. Therefore, when the first modulation method is switched to the second modulation method, it is possible to suppress a rapid increase in the applied voltage Vu and a transient increase in the battery current.

Based on the above parameters, the switching unit 64 selects a second predetermined voltage V2 that is lower than the first predetermined voltage V1 when the phase voltage obtained by subtracting the induced voltage ωφcos θ from the applied voltage Vu applied to each phase by the third execution unit 63 is switched from the second modulation scheme to the third modulation scheme on the condition that it becomes lower than . Therefore, it is possible to suppress the transient increase (fluctuation) of the battery current. Furthermore, since the modulation scheme switching device includes the third execution section 63 in addition to the first execution section 61 and the second execution section 62, the applied voltage Vu can be gradually increased. As a result, a transient increase in battery current can be further suppressed.

When the rotation speed Nm of the rotating electric machine 30 is lower than the predetermined rotation speed Nm4, the first modulation method is switched to the second modulation method based on a parameter correlated with the induced voltage ωφcosθ. Therefore, a rapid increase in battery current can be suppressed. On the other hand, when the rotation speed Nm of the rotary electric machine 30 is higher than the predetermined rotation speed Nm4, the modulation method is switched based on the modulation rate of the command value of the applied voltage Vu (command modulation rate Mr*). Therefore, it is possible to give priority to suppressing fluctuations in the torque generated by the rotating electric machine 30 over suppressing fluctuations in the battery current.

- The determination unit 66 determines that there is an abnormality when the estimated battery current is greater than the predetermined current Ih for a period longer than a predetermined time. In such a configuration, it is possible to suppress a transient increase in battery current, so that it is possible to suppress erroneous determination by the determination unit 66 that there is an abnormality when the modulation scheme is switched.

<Second embodiment>
The second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in FIG. 12, the rotating electrical machine includes two stator winding groups (systems). For this purpose, the control system comprises a first inverter 40A and a second inverter 40B. In addition, in FIG. 12, the same reference numerals are assigned to the same configurations as those shown in FIG. 1 for convenience. Also, in FIG. 12, illustration of the field energization circuit 41, the control device 60, and the like is omitted.

A stator 33 of the rotary electric machine includes a first stator winding group and a second stator winding group. The first stator winding group (first system) includes first U-, V-, and W-phase windings 34UA, 34VA, and 34WA that are shifted by 120 electrical degrees from each other. The second stator winding group (second system) includes second U-, V-, and W-phase windings 34UB, 34VB, and 34WB that are 120 degrees apart in electrical angle. In this embodiment, as shown in FIG. 13, the spatial phase difference Δθ, which is the angle between the first stator winding group and the second stator winding group, is 30 degrees in electrical angle.

The first inverter 40A includes a series connection of first U, V, W phase upper arm switches SUp1, SVp1, SWp1 and first U, V, W phase lower arm switches SUn1, SVn1, SWn1. First U-, V- and W-phase upper arm diodes DUp1, DVp1 and DWp1 are connected in anti-parallel to the first U-, V- and W-phase upper arm switches SUp1, SVp1 and SWp1. First U-, V- and W-phase lower arm diodes DUn1, DVn1 and DWn1 are connected in anti-parallel to the first U-, V- and W-phase lower arm switches SUn1, SVn1 and SWn1.

The second inverter 40B includes a series connection of second U, V, W phase upper arm switches SUp2, SVp2, SWp2 and second U, V, W phase lower arm switches SUn2, SVn2, SWn2. Second U-, V- and W-phase upper arm diodes DUp2, DVp2 and DWp2 are connected in anti-parallel to the second U-, V- and W-phase upper arm switches SUp2, SVp2 and SWp2. Second U-, V- and W-phase lower arm diodes DUn2, DVn2 and DWn2 are connected in anti-parallel to the second U-, V- and W-phase lower arm switches SUn2, SVn2 and SWn2.

The collectors of the upper arm switches SUp1 to SWp2 are connected to the positive terminal of the battery 20 via the high potential side electric path Lp. The emitters of the lower arm switches SUn1 to SWn2 are connected to the negative terminal of the battery 20 through the low potential side electric path Ln. A high potential side terminal of a capacitor 21 is connected to the positive terminal side of the battery 20 in the high potential side electric path Lp from the connection point with the collectors of the upper arm switches SUp1 to SWp2. A low potential side terminal of a capacitor 21 is connected to the negative terminal side of the battery 20 with respect to the connection point with the emitters of the lower arm switches SUn1 to SWn2 in the low potential side electric path Ln.

When a rotating electrical machine has a plurality of stator winding groups, switching the modulation schemes in the plurality of stator winding groups at the same time may amplify transient battery current fluctuations.

Therefore, in the present embodiment, the times at which the modulation schemes are switched in the plurality of stator winding groups are made different from each other. For example, when the rotational speed Nm reaches the switching rotational speed Nm12, the first stator winding group switches from the first modulation method to the second modulation method, and after a predetermined delay period has passed, the second stator winding group Switch from the first modulation scheme to the second modulation scheme. According to such a configuration, even if the rotating electrical machine includes a plurality of stator winding groups, it is possible to suppress amplification of transient battery current fluctuations.

<Other embodiments>
Each of the above-described embodiments can be modified and implemented as follows. In addition, description is abbreviate|omitted by attaching|subjecting the same code|symbol about the same part as each said embodiment.

- The driving state of the rotary electric machine 30 associated with each command value stored in the memory 68 is not limited to all of the command torque Trq*, the rotation speed Nm, and the power supply voltage VDC. At least one of command torque Trq*, rotational speed Nm, and power supply voltage VDC may be used as the drive state.

・The configuration is not limited to that each command value is stored in the memory 68 . For example, each command value may be calculated for each control cycle based on the acquired command torque Trq*, rotation speed Nm, and power supply voltage VDC.

- The control performed when the modulation factor is greater than 1 is not limited to the rectangular wave control shown in FIG. For example, the 120° energization control shown in FIG. 14 may be used.

Controls performed when the modulation rate is greater than 1 include a state in which the upper arm switch is turned on and the lower arm switch is turned off, and a state in which the upper arm switch is turned off and the lower arm switch is turned off. is not limited to appearing once in one cycle of the electrical angle of the rotating electric machine. For example, for the purpose of reducing the harmonic components contained in each phase voltage, the amplitude of the fundamental wave component contained in each phase voltage is set to the amplitude corresponding to the modulation factor of rectangular wave control, and the upper arm switch is turned on. The state in which the lower arm switch is turned off and the state in which the upper arm switch is turned off and the lower arm switch is turned on may occur multiple times in one electrical angle cycle.

The switching unit 64 switches between the first modulation method and the second modulation method based on the rotation speed Nm of the rotary electric machine 30, and switches from the rotation speed Nm12 from the first modulation method to the second modulation method, and from the second modulation method. It is also possible to employ a configuration in which the rotation speed Nm21 for switching to the first modulation method is not the same.

The switching unit 64 performs the first modulation after the maximum value of the torque that the rotating electric machine 30 can generate by the first modulation method executed by the first execution unit 61 becomes smaller than the command torque Trq* (required torque). It is also possible to switch from the method to the second modulation method. That is, the switching unit 64 determines that the maximum value of the torque that can be generated by the rotating electric machine 30 by the first modulation method executed by the first execution unit 61 is before becoming smaller than the command torque Trq*. It is also possible to delete from the conditions for switching from the scheme to the second modulation scheme.

- The control device 60 may only switch the modulation method and may not limit the upper limit of the duty. Even in this case, in each modulation method, the applied voltage applied to each phase of the U, V, and W phases is limited to the upper limit voltage or less according to the principle of each modulation method.

・The control device 60 is not limited to having the first to third execution units that execute the first to third modulation schemes, and the applied voltage applied to each phase of the rotating electric machine 30 is higher than the third upper limit voltage. A fourth execution unit that executes a fourth modulation scheme that is limited to a high fourth upper limit voltage or less may be provided. Based on the rotation speed Nm of the rotary electric machine 30, the switching unit 64 selects a third phase voltage obtained by subtracting the induced voltage from the applied voltage applied to each phase by the fourth execution unit, which is lower than the second predetermined voltage V2. The third modulation method may be switched to the fourth modulation method on condition that the voltage is lower than the predetermined voltage V3. Also, the control device 60 may include only the first and second execution units that execute the first and second modulation schemes.

- The magnetic flux density of the magnetic field may be included as a parameter that correlates with the induced voltage induced in each phase as the rotary electric machine 30 rotates. The magnetic flux density can be calculated based on the field current detected by the field current detector 52 and flowing through the field winding 32 .

- The switches used in the inverter 40 and the field energization circuit 41 may be, for example, N-channel MOSFETs.

- The rotating electric machine is not limited to a star-connected one, and may be, for example, a delta-connected one.

- The rotating electrical machine 30 (multi-phase rotating electrical machine) is not limited to a three-phase rotating electrical machine, and may be a four-phase or more rotating electrical machine. The rotating electric machine 30 is not limited to a field type rotating electric machine, and may be a permanent magnet type rotating electric machine. Further, the rotating electric machine 30 may not have the function of a generator, and may have only the function of an electric motor. If the rotating electrical machine 30 is a permanent magnet type rotating electrical machine, the temperature of the permanent magnet may be included as a parameter that correlates with the induced voltage induced in each phase as the rotating electrical machine 30 rotates.

20... Battery, 30... Rotary electric machine, 60... Control device, 61... First execution unit, 62... Second execution unit, 64... Switching unit.

Claims (9)

A modulation scheme switching device (60) for switching a modulation scheme when controlling a multi-phase electric rotating machine (30) driven by a battery voltage applied from a battery (20),
A first modulation method in which the applied voltage applied to each phase (34U, 34V, 34W, 34UA, 34VA, 34WA, 34UB, 34VB, 34WB) of the multiphase rotating electric machine is limited to a first upper limit voltage or less. A first execution unit (61) that executes
a second execution unit (62) that executes a second modulation scheme in which the applied voltage applied to each phase of the multi-phase rotating electric machine is limited to a second upper limit voltage or less that is higher than the first upper limit voltage;
The induced voltage is reduced from the applied voltage in the second modulation method executed by the second execution unit based on a parameter correlated with the induced voltage induced in each phase as the multiphase rotating electric machine rotates. a switching unit (64) for switching from the first modulation method to the second modulation method on condition that the subtracted phase voltage is lower than a predetermined voltage;
A modulation scheme switching device comprising: 2. The modulation scheme switching device according to claim 1, wherein said parameter includes a rotational speed of said multi-phase rotating electric machine. Further, the switching unit performs the 3. The modulation scheme switching device according to claim 1, wherein the modulation scheme is switched from the first modulation scheme to the second modulation scheme. The switching unit switches between the first modulation method and the second modulation method based on the rotation speed of the multi-phase rotating electric machine, and switches the rotation speed from the first modulation method to the second modulation method; 4. The modulation scheme switching device according to any one of claims 1 to 3, wherein the rotation speed for switching from the second modulation scheme to the first modulation scheme is the same. The first execution unit controls Duty, which is a ratio of the time for applying the battery voltage to each phase in a predetermined period in the first modulation method, and limits the Duty to a first upper limit Duty or less,
The second execution unit controls the Duty in the second modulation scheme, limits the Duty to a second upper limit Duty that is greater than the first upper limit Duty, and
The second execution unit, when switched from the first modulation scheme to the second modulation scheme, limits the Duty to a third upper limit Duty or less, and increases the third upper limit Duty from the first upper limit Duty to the The modulation scheme switching device according to any one of claims 1 to 4, wherein the duty is gradually increased up to the second upper limit duty. a third execution unit (63) for executing a third modulation scheme in which the applied voltage applied to each phase of the multi-phase rotating electric machine is limited to a third upper limit voltage higher than the second upper limit voltage or less; ,
the predetermined voltage is a first predetermined voltage;
The switching unit, based on the parameter, determines that a phase voltage obtained by subtracting the induced voltage from the applied voltage applied to each phase by the third execution unit is higher than a second predetermined voltage lower than the first predetermined voltage. 6. The modulation scheme switching device according to any one of claims 1 to 5, wherein said second modulation scheme is switched to said third modulation scheme on condition that the modulation scheme is lowered. The switching unit subtracts the induced voltage from the applied voltage applied to each phase by the second execution unit based on the parameter when the rotational speed of the multi-phase rotating electric machine is lower than a predetermined rotational speed. Switching from the first modulation method to the second modulation method on the condition that the phase voltage obtained is lower than a predetermined voltage, and when the rotation speed of the multi-phase rotating electric machine is higher than the predetermined rotation speed, the application The modulation scheme switching device according to any one of claims 1 to 6, wherein the modulation scheme is switched based on the modulation rate of the voltage command value. a detection unit that detects a battery current flowing from the battery;
A determination unit (66) that determines an abnormality when the state in which the battery current detected by the detection unit is greater than a predetermined current continues for a period longer than a predetermined time. 2. The modulation scheme switching device according to item 1. The multi-phase rotating electric machine includes a plurality of systems having the phases,
The modulation scheme switching device according to any one of claims 1 to 8, wherein timings for switching modulation schemes in a plurality of said systems are made different from each other.

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