JP2011155787A - Rotating electric control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly switch control modes while reducing load caused by extra arithmetic operation in a control part of a rotating electric control system. <P>SOLUTION: The rotating electric control system 10 controls a rotating electric machine 17 while smoothly switching modes between a PWM control mode and a rectangular-wave control mode. The rotating electric control system 10 includes a control part 21 that executes the operation of each control mode of the PWM control mode and the rectangular-wave control mode when a rotation number of the rotating electric machine 17 is smaller than a predetermined threshold of the rotation number, and executes the operation of the rectangular-wave control mode and stops the operation of the PWM control mode when the rotation number of the rotating electric machine 17 is larger than predetermined threshold of the rotating number. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine control system, and more particularly to a rotating electrical machine control system that smoothly switches between a PWM control mode and a rectangular wave control mode.

  An electric vehicle, a hybrid vehicle, a fuel cell vehicle, and the like drive a vehicle by a driving force of a rotating electric machine. As a rotating electrical machine used for traveling, a three-phase AC motor is generally employed. In the rotating electrical machine control system, DC power from a main battery is supplied to an inverter, and the inverter converts the DC power into AC power. Controls a phase AC motor.

  The rotating electrical machine control method in the rotating electrical machine control system includes a rectangular wave control mode in which the PWM duty ratio is fixed to the maximum value, a sine wave PWM control mode, and a rectangular wave control mode in addition to a general sine wave PWM control mode. And an overmodulation PWM control mode using an intermediate voltage waveform. In this rotating electrical machine control method, control is performed by switching three modes of a sine wave PWM control mode, an overmodulation PWM control mode, and a rectangular wave control mode according to operating conditions such as the rotational speed and torque of the rotating electrical machine. Thus, a large output can be obtained in the middle rotation region and the high rotation region of the rotating electrical machine.

  As a technique related to the present invention, for example, Patent Document 1 discloses a command value calculation processing unit that calculates a command value based on an electric machine, an electric machine target torque representing a target value of the electric machine torque, and an electric machine rotation speed. And a plurality of signal generation processing means for generating drive signals based on the command values are disclosed. Furthermore, a voltage saturation variable calculation processing means for calculating a voltage saturation variable representing the likelihood of occurrence of voltage saturation and a switching condition for switching control between asynchronous PWM control and synchronous PWM control based on the voltage saturation variable are established. Control switching determination processing means for determining whether or not control has been performed, and control switching processing for selecting and outputting the drive signal based on a determination result by the control switching determination processing means, and switching control between asynchronous PWM control and synchronous PWM control A configuration having a means is disclosed.

  As another technique related to the present invention, for example, Patent Document 2 discloses an inverter that converts a DC voltage into an AC voltage for driving an AC motor, and the DC voltage input to the inverter is a voltage. A converter that is variably controlled according to the command value, and a variable that is related to the operating state of the AC motor and that includes at least the torque command value so that the AC motor outputs torque according to the torque command value. And the structure provided with the 1st motor control part comprised so that the phase of the rectangular wave voltage applied to the said AC motor from the said inverter may be set.

  Further, in Patent Document 2, the first motor control unit is configured to calculate the one variable from the plurality of variables based on characteristics normalized with respect to some of the plurality of variables excluding the torque command value. There is disclosed a configuration including a normalized value setting unit configured to set the reference value of the phase corresponding to the values of the remaining variables excluding the part variables. And a correction processing unit configured to set the command value of the phase by correcting the reference value set by the normalized value setting unit based on the values of some of the variables. Containing configurations are disclosed.

Japanese Patent Laying-Open No. 2005-073307 JP 2009-201250 A

  By the way, when the rotating electrical machine is controlled by switching the three modes of the sine wave PWM control mode, the overmodulation PWM control mode, and the rectangular wave control mode, the PWM control mode that combines the sine wave PWM control mode and the overmodulation PWM control mode. Therefore, the calculation for the rectangular wave control mode and the calculation for the rectangular wave control mode are always performed, and the mode switching of the control mode can be performed smoothly. However, depending on the operating conditions of the rotating electrical machine, it may not be necessary to always perform a total of two calculations, that is, a calculation for the PWM control mode and a calculation for the rectangular wave control mode. If it performs, it will become a processing load unnecessary for control parts, such as CPU, and excessive heat dissipation may generate | occur | produce.

  An object of the present invention is to smoothly switch control modes while reducing a load caused by an extra calculation process in a control unit of a rotating electrical machine control system.

  A rotating electrical machine control system according to the present invention is a rotating electrical machine control system that controls a rotating electrical machine while smoothly switching between a PWM control mode and a rectangular wave control mode. The rotational speed of the rotating electrical machine is lower than a predetermined rotational speed threshold. When the rotation speed is small, the calculation for each control mode of the PWM control mode and the rectangular wave control mode is performed. When the rotation speed of the rotating electrical machine is larger than the predetermined rotation speed threshold, the calculation for the rectangular wave control mode is performed. And a controller for stopping the calculation for the PWM control mode.

  In the rotating electrical machine control system according to the present invention, it is preferable that the control unit includes a calculation unit that calculates a predetermined rotation speed threshold based on the torque of the rotating electrical machine.

  In the rotating electrical machine control system according to the present invention, the control unit includes a calculating unit that calculates a predetermined rotational speed threshold based on the torque of the rotating electrical machine and a system voltage that is a voltage across the inverter that drives the rotating electrical machine. It is preferable to have.

  According to the rotating electrical machine control system configured as described above, when the rotational speed of the rotating electrical machine is larger than a predetermined rotational speed threshold, it is determined that the control in the rectangular wave control mode is performed, and the calculation for the PWM control mode is performed. Can be stopped. Thereby, in the rotation speed region that can be determined when the control in the rectangular wave control mode is performed, the load due to the extra calculation processing can be reduced in the control unit, and in the rotation speed region that cannot be determined when the control in the rectangular wave control mode is performed, Smooth control mode switching can be performed by performing calculations for both control modes.

In embodiment of this invention, it is a figure which shows the structure of a rotary electric machine control system. In embodiment of this invention, it is a figure which shows the control map currently recorded on the control part of the rotary electric machine control system. In the embodiment of the present invention, it is a flowchart which shows the procedure for performing the operation for each control mode efficiently. It is a flowchart which shows the procedure for performing the calculation for each control mode efficiently in the 1st modification of embodiment of this invention. It is a flowchart which shows the procedure for performing the calculation for each control mode efficiently in the 2nd modification of embodiment of this invention.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, the same elements are denoted by the same reference symbols in all the drawings, and redundant description is omitted.

  FIG. 1 is a diagram illustrating a configuration of a rotating electrical machine control system 10. The rotating electrical machine control system 10 operates with a battery 11, a system main relay (SR1, SR2), a converter 15 that boosts the voltage of the battery 11, a smoothing capacitor (C1, C2), an inverter 16, and a three-phase AC. A rotating electric machine 17, a control unit 21 that controls them, voltage sensors 22 and 24, a current sensor 23, and a resolver 25 connected to the control unit 21.

  Converter 15 includes a reactor L1, a power semiconductor switching element (switching elements Q1, Q2), and diodes D1, D2. As the power semiconductor switching element, an IGBT (Insulated Gate Bipolar Transistor), a power MOS transistor, a power bipolar transistor, or the like can be used.

  Reactor L1 is connected between a connection node of switching elements Q1, Q2 and power line 12. Further, the smoothing capacitor C <b> 1 is connected between the power line 12 to which the battery voltage from the battery 11 is supplied and the ground line 13. The smoothing capacitor C <b> 2 is connected between the high voltage power line 14 and the ground line 13.

  Inverter 16 connected to converter 15 is provided between power line 14 and ground line 13, and includes U-phase arm 18, V-phase arm 19, and W-phase arm 20, and switching control is performed by control unit 21. Has been.

  The rotating electrical machine 17 is a three-phase AC motor, and one end of three coils of U, V, and W phases connected to the inverter 16 is commonly connected at a midpoint.

  During the boosting operation, converter 15 boosts the battery voltage supplied from battery 11 to increase the voltage, and supplies it to inverter 16 as a system voltage. Further, during the step-down operation, converter 15 can charge battery 11 by stepping down the system voltage supplied from inverter 16 via smoothing capacitor C2. The system voltage can be continuously varied by the boost ratio of the converter 15.

  The controller 21 includes a torque command value Trqcom input from an external electronic control unit (ECU), a battery voltage VB detected by the voltage sensor 22, a current value IB detected by the current sensor 23, and a voltage sensor 24. The system voltage VH, the V-phase arm current value iv, the W-phase arm current value iw, the rotation angle θ from the resolver 25, and the like are input. Based on these input signals, the controller 21 calculates the rotational speed of the rotating electrical machine 17 and the output torque of the rotating electrical machine 17 by calculation. Then, converter 15 and inverter 16 are controlled such that rotating electric machine 17 outputs a torque according to torque command value Trqcom.

  FIG. 2 is a diagram showing a control map recorded in the control unit 21 of the rotating electrical machine control system 10. The control unit 21 controls the converter 15 and the inverter 16 by switching the three control modes of the sine wave PWM control mode, the overmodulation PWM control mode, and the rectangular wave control mode based on the input signal and the control map described above. To do. Here, the sine wave PWM control mode and the overmodulation PWM control mode are simply referred to as a PWM control mode.

  In the rotating electrical machine 17 that is an AC motor, the induced voltage increases as the number of rotations and output torque increase, and thus the required motor voltage that overcomes the induced voltage and rotates the motor also increases. Therefore, the system voltage VH supplied by the converter 15 needs to be set higher than the required motor voltage. On the other hand, the system voltage VH has a limit value, and the maximum system voltage VH is referred to as a VH maximum voltage.

  Therefore, in the low rotation speed region (PWM control mode region indicated by the region a (sine wave PWM control mode region) and region b (overmodulation PWM control mode region)) shown in the left half of FIG. In the region where the required motor voltage is lower than the VH maximum voltage, the maximum torque control by the sine wave PWM control mode or the overmodulation PWM control mode is applied, and the output torque is controlled by the motor current control based on the vector control.

  Further, in the high rotation speed region (rectangular wave control mode region indicated by region c) shown in the right half of FIG. 2, when the required motor voltage reaches the VH maximum voltage, the system voltage VH is maintained and field weakening control is performed. The rectangular wave control mode is applied. In the rectangular wave control mode, since the amplitude of the fundamental wave component is fixed, the output torque is controlled according to the deviation between the output torque (actual value) obtained by power calculation and the torque command value.

  The characteristics according to the three control modes described above can be expressed by a modulation rate that is a ratio of the motor required voltage (induced voltage) to the system voltage VH. In the sine wave PWM control mode, on / off of the switching element in each phase arm is controlled by voltage comparison between a sine wave voltage command value and a carrier wave. Thereby, the duty ratio is controlled so that the fundamental wave component becomes a sine wave within a predetermined period. With such control, in the sine wave PWM control mode, for example, the fundamental wave component amplitude can be increased to 0.61 times (modulation rate) of the system voltage VH.

  The overmodulation PWM control mode performs PWM control similar to the sine wave PWM control mode by reducing the amplitude of the carrier wave. By this control, the fundamental wave component is distorted, so that, for example, the modulation rate can be increased to a range of 0.61 to 0.78.

  On the other hand, in the rectangular wave control mode, one pulse of a rectangular wave having a one-to-one ratio of on / off of the switch element is applied to the AC motor within a predetermined period. Thereby, for example, the modulation rate can be increased to 0.78.

  Here, a characteristic function of the control unit 21 will be described. The control unit 21 includes a rotation speed threshold setting processing unit 212 and a control mode processing unit 214.

  The rotation speed threshold setting processing unit 212 uses a rotation speed threshold obtained in advance by simulation, experiment, or the like (a threshold at which the control mode can be determined as the rectangular wave control mode at a rotation speed larger than the rotation speed threshold) as the rotation speed threshold. Has the function to set. For example, in FIG. 2, if the rotation speed of the rotating electrical machine 17 is larger than the rotation speed threshold value (rotation speed r), the rectangular wave control mode can be determined, so the rotation speed r is set as the rotation speed threshold value.

  The control mode processing unit 214 has a function of determining whether or not the rotational speed of the rotating electrical machine 17 is greater than the rotational speed threshold set by the rotational speed threshold setting processing unit 212. Further, when the rotational speed of the rotating electrical machine 17 is smaller than the rotational speed threshold, the control mode processing unit 214 performs an operation for the PWM control mode that combines the sine wave PWM control mode and the overmodulation PWM control mode, and a rectangular wave. Perform calculations for the control mode. Then, when the rotation speed of the rotating electrical machine 17 is larger than the rotation speed threshold, the control mode processing unit 214 stops the calculation for the PWM control mode and performs only the calculation for the rectangular wave control mode.

  Here, the calculation for the PWM control mode means that a switching pattern for controlling the converter 15 and the inverter 16 is obtained by calculation in the sine wave PWM control mode or the overmodulation PWM control mode. In addition, the calculation for the rectangular wave control mode means that a switching pattern for controlling the converter 15 and the inverter 16 is obtained by calculation in the rectangular wave control mode.

  Next, the operation of the rotating electrical machine control system 10 having the above configuration will be described with reference to FIGS. FIG. 3 is a flowchart showing a procedure for causing the control unit 21 to efficiently execute the calculation for each control mode. When the calculation efficiency improvement program is started in the control unit 21, first, a rotation speed threshold for determining whether or not the calculation for the PWM control mode can be stopped is set (S10). This step is executed by the function of the rotation speed threshold setting processing unit 212 of the control unit 21.

  Next, it is determined whether or not the rotational speed of the rotating electrical machine 17 is greater than a rotational speed threshold value (S12). This step is executed by the function of the control mode processing unit 214 of the control unit 21. If it is determined in S12 that the rotation speed of the rotating electrical machine 17 is greater than the rotation speed threshold, the calculation for the PWM control mode is stopped and only the calculation for the rectangular wave control mode is executed (S14). This step is executed by the function of the control mode processing unit 214 of the control unit 21. After S14, the process proceeds to return processing.

  If it is determined in S12 that the rotation speed of the rotating electrical machine 17 is smaller than the rotation speed threshold value, the calculation for the PWM control mode and the rectangular wave control mode is executed (S16). This step is executed by the function of the control mode processing unit 214 of the control unit 21. After S16, the process proceeds to return processing. Thus, if the rotational speed of the rotating electrical machine 17 is in a region larger than the rotational speed threshold value, there is no possibility of control by the PWM control mode, and it can be determined that control by the rectangular wave control mode is performed. Stop the computation for. Thereby, in the rotation speed region where it can be determined that the control in the rectangular wave control mode is performed, the load due to unnecessary calculation processing in the control unit 21 can be reduced, and the heat radiation by the control unit 21 can also be reduced. In addition, in the rotation speed region where the control in the rectangular wave control mode cannot be determined and the calculation for the PWM control mode and the calculation for the rectangular wave control mode are always performed, a smooth control mode switching is performed. It can be performed.

  Next, a first modification of the rotating electrical machine control system 10 will be described. The difference between the first modification of the rotating electrical machine control system 10 and the rotating electrical machine control system 10 is only the function of the rotation speed threshold value setting processing unit 212, and will be described mainly.

  The rotation speed threshold value setting processing unit 212 obtains the output torque of the rotating electrical machine 17 based on the current value iv of the V-phase arm, the current value iw of the W-phase arm, the rotation angle θ from the resolver 25, and the like. 2), and a function of setting the calculated rotation speed threshold value as the threshold value. In the above description, the rotation speed threshold value is calculated based on the output torque of the rotating electrical machine 17 and the control map. However, the rotation speed threshold value may be calculated based on the torque command value Trqcom and the control map.

  Next, the operation of the first modification of the rotating electrical machine control system 10 will be described with reference to FIG. FIG. 4 is a flowchart showing a procedure for efficiently executing computation for each control mode in the control unit 21 of the first modification of the rotating electrical machine control system 10. When the calculation efficiency improvement program is started in the control unit 21, first, a rotation speed threshold value is calculated based on the output torque of the rotating electrical machine 17 and the control map (S8). This step is executed by the function of the rotation speed threshold setting processing unit 212 of the control unit 21.

  Next, the rotation speed threshold value calculated in step S8 is set as the threshold value (S10). This step is executed by the function of the rotation speed threshold setting processing unit 212 of the control unit 21. And about S12-S16 which are the post process of S10, since the process similar to the rotary electric machine control system 10 is performed, detailed description is abbreviate | omitted.

  Thus, according to the first modification of the rotating electrical machine control system 10, it is possible to reset the rotation speed threshold in consideration of the state of the output torque of the rotating electrical machine 17. It can be changed to a rotation speed threshold value suitable for the operating conditions. Therefore, according to the first modified example of the rotating electrical machine control system 10, it is possible to more smoothly perform the control mode switching while reducing the load caused by the extra arithmetic processing in the control unit 21.

  Next, a second modification of the rotating electrical machine control system 10 will be described. The difference between the second modified example of the rotating electrical machine control system 10 and the rotating electrical machine control system 10 is only the function of the rotation speed threshold value setting processing unit 212, and will be mainly described.

  The rotation speed threshold value setting processing unit 212 acquires the system voltage VH that continuously varies depending on the boost ratio of the converter 15 from the voltage sensor 24, and acquires the current value iv of the V-phase arm, the current value iw of the W-phase arm, and the resolver 25. The output torque of the rotating electrical machine 17 is obtained from the rotation angle θ of The rotation speed threshold value setting processing unit 212 calculates a rotation speed threshold value based on the system voltage VH, the output torque of the rotating electrical machine 17, and the control map, and sets the calculated rotation speed threshold value as the threshold value. Have

  Next, the operation of the second modification of the rotating electrical machine control system 10 will be described with reference to FIG. FIG. 5 is a flowchart showing a procedure for efficiently executing computation for each control mode in the control unit 21 of the second modification of the rotating electrical machine control system 10. When the calculation efficiency improvement program is started in the control unit 21, first, a rotation speed threshold value is calculated based on the system voltage VH, the output torque of the rotating electrical machine 17, and the control map (S9). This step is executed by the function of the rotation speed threshold setting processing unit 212 of the control unit 21.

  Next, the rotation speed threshold value calculated in step S9 is set as the threshold value (S10). This step is executed by the function of the rotation speed threshold setting processing unit 212 of the control unit 21. And about S12-S16 which are the post process of S10, since the process similar to the rotary electric machine control system 10 is performed, detailed description is abbreviate | omitted.

  Thus, according to the second modification of the rotating electrical machine control system 10, in addition to the state of the output torque of the rotating electrical machine 17, the rotation speed threshold is set in consideration of the system voltage VH. It is possible to calculate a rotation speed threshold suitable for the operating conditions. Therefore, according to the second modified example of the rotating electrical machine control system 10, it is possible to more smoothly switch the control mode while reducing the load caused by the extra arithmetic processing in the control unit 21.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine control system, 11 Battery, 12, 14 Power line, 13 Ground line, 15 Converter, 16 Inverter, 17 Rotating electrical machine, 18 U-phase arm, 19 V-phase arm, 20 W-phase arm, 21 Control part, 22, 24 Voltage sensor, 23 Current sensor, 25 Resolver, 212 Rotation speed threshold setting processing unit, 214 Control mode processing unit.

Claims (3)

In the rotating electrical machine control system that controls the rotating electrical machine while smoothly switching between the PWM control mode and the rectangular wave control mode,
When the rotation speed of the rotating electrical machine is smaller than a predetermined rotation speed threshold value, the calculation for each control mode of the PWM control mode and the rectangular wave control mode is performed,
A rotating electrical machine control, comprising: a control unit that performs computation for the rectangular wave control mode and stops computation for the PWM control mode when the rotational speed of the rotating electrical machine is greater than a predetermined rotational speed threshold value system. In the rotating electrical machine control system according to claim 1,
The control unit
A rotating electrical machine control system comprising a calculating means for calculating a predetermined rotational speed threshold based on torque of the rotating electrical machine. In the rotating electrical machine control system according to claim 1,
The control unit
A rotating electrical machine control system comprising: a calculating means for calculating a predetermined rotational speed threshold value based on a torque of the rotating electrical machine and a system voltage that is a voltage across the inverter that drives the rotating electrical machine.

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