JP5899787B2 - Rotating electrical machine control system - Google Patents

Description

  The present invention relates to a rotating electrical machine control system, and more particularly to a rotating electrical machine control system including a control unit that controls a drive circuit by a PWM control method using current feedback under preset PWM conditions.

  As a method of controlling a rotating electrical machine used as a motor or a generator, it is known to use a sine wave PWM (Pulse Width Modulation) control mode, an overmodulation control mode, and a rectangular wave control mode. The overmodulation control mode may be referred to as an overmodulation PWM control mode.

  For example, Patent Document 1 discloses an electric motor drive control device, in which a target operating point of a motor is included in a predetermined resonance region including a motor operating point when resonance occurs in a boost converter. It describes that the boost converter is controlled so that the voltage becomes higher than the voltage on the battery side, and that the inverter is controlled using a sine wave PWM control system. In this configuration, a resonant circuit is configured by the reactor of the boost converter and the smoothing capacitor connected to the boost converter, and when the operating point of the motor enters a predetermined region, resonance of voltage and current occurs, and the boost converter and The purpose is to prevent an excessive voltage or current from being applied to the smoothing capacitor.

JP 2009-225633 A

  However, when the inverter is controlled using the sine wave PWM control method as described above, there is a possibility that an offset error may be superimposed on the detected current value of the current sensor of the motor that is a rotating electrical machine due to product variation of the sensor. . In this case, since control is performed with the detection value of the current sensor being positive, the d-axis current and the q-axis current, which are actual currents, fluctuate in electrical primary, and power fluctuations that fluctuate in electrical primary occur in the motor. Furthermore, since the LC resonance circuit is configured by the reactor of the boost converter, which is a voltage conversion unit, and the smoothing capacitor, LC resonance occurs. In this case, when the frequency region of the LC resonance and the frequency of the power fluctuation coincide with each other, the high-voltage side voltage VH that is the boosted voltage greatly varies, and the battery current IB that is the battery output current also varies greatly. In particular, when the rotating electrical machine is controlled by sine wave PWM control, the control V is highly followable, and thus the fluctuations in the voltage VH and the current IB become significant. In addition, when the capacity of the smoothing capacitor is small or when the internal resistance of the battery is small, fluctuations in the voltage VH and the current IB become more remarkable. Thus, when both the voltage VH and the current IB are increased and an overcurrent and an overvoltage are generated, an effective measure is required to prevent exceeding a preset design component protection area value. For example, effective measures are required to prevent an overcurrent or overvoltage that exceeds a component protection threshold of a power control unit (PCU) including an inverter and a smoothing capacitor. Therefore, it is desired to realize a rotating electrical machine control system that can effectively prevent the occurrence of overvoltage and overcurrent related to the output voltage VH of the boost converter and the battery current IB.

  An object of the present invention is to effectively prevent the occurrence of an overcurrent and an overvoltage even when an error is superimposed on a detected current value of a current sensor in a rotating electrical machine control system.

A rotating electrical machine control system according to the present invention includes a rotating electrical machine, a voltage converter connected to a DC power source and including a reactor, a drive circuit connected to the rotating electrical machine, and a smoothing capacitor connected to the voltage converter. A control unit that controls the drive circuit in a PWM control method that uses current feedback under preset PWM conditions, and the control unit includes a resonance frequency region of a resonance circuit that includes the reactor and the smoothing capacitor. A gain reduction unit for reducing a feedback gain when current feedback is performed in the PWM control to be lower than a normal gain used in normal times when the frequency and the frequency of output fluctuation of the rotating electrical machine match. The rotating electrical machine control system.

  In the rotating electrical machine control system according to the present invention, it is preferable that the gain reduction unit is configured such that the rotational speed of the rotating electrical machine is within a specific rotational speed range set in advance based on the frequency of the resonance frequency range. In addition, assuming that the frequency in the resonance frequency region and the frequency of the output fluctuation of the rotating electrical machine coincide with each other, the feedback gain is reduced below the normal gain.

In the rotating electrical machine control system according to the present invention, it is preferable that the gain reduction unit is configured such that the rotational speed of the rotating electrical machine is within a specific rotational speed range set in advance based on the frequency of the resonance frequency range. In the case where the absolute value of the output of the rotating electrical machine is larger than a predetermined output set in advance, and the filtered current value obtained by applying a filter that removes the ripple component to the actual current value that is the actual current value, Only when the absolute value of the difference from the actual current value is larger than a predetermined current value set in advance, the feedback gain is reduced below the normal gain.

  According to the rotating electrical machine control system of the present invention, when the frequency in the resonance frequency region of the resonant circuit including the reactor and the smoothing capacitor matches the output fluctuation frequency of the rotating electrical machine, current feedback is performed by PWM control. In this case, since the feedback gain in this case is lower than the normal gain, the control response is deteriorated. For this reason, even when an error is superimposed on the detected current value of the current sensor that detects the current about the rotating electrical machine, the fluctuation of the input current to the voltage conversion unit in the resonance frequency region can be suppressed to a small level. Generation of overvoltage can be effectively prevented.

It is a circuit diagram which shows an example of the rotary electric machine control system of embodiment of this invention. It is a block diagram which shows the structure of the control part of FIG. It is a figure which shows the relationship between the elapsed time in the case of accelerating rotation of a motor generator with constant acceleration, and a battery electric current value in the rotary electric machine control system of a comparative example. It is a flowchart explaining an example of the method of determining the feedback gain of sine wave PWM control using the rotary electric machine control system of embodiment of this invention. 5 is a flowchart showing a subroutine for determining whether a current fluctuation determination flag is ON (= 1) or OFF (= 0) in S10 of FIG. 5 is a flowchart showing a subroutine for determining whether an LC resonance band determination flag is ON (= 1) or OFF (= 0) in S10 of FIG.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, a motor generator mounted on a vehicle will be described as a rotating electrical machine, but a rotating electrical machine used for purposes other than mounting on a vehicle may be used. Further, the rotating electrical machine may be used for an electric vehicle or a fuel cell vehicle mounted on a vehicle that simply functions as a motor.

  In the following, the same or corresponding elements in all drawings are denoted by the same reference numerals, and redundant description is omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a circuit diagram showing an example of a rotating electrical machine control system according to an embodiment of the present invention. The rotating electrical machine control system 10 is used by being mounted on a hybrid vehicle that uses one or both of an engine (not shown) and a motor generator MG2 that is a rotating electrical machine mainly used as a traveling motor as a main drive source. Such a rotating electrical machine control system 10 includes a motor generator MG2, a battery 12 that is a DC power source and a power storage unit, a DC / DC converter 14 that is a voltage conversion unit connected to the battery 12, and a DC / DC converter 14 Are provided with a smoothing capacitor C1 and a second smoothing capacitor C2, an inverter 16 serving as a drive circuit connected between the step-up side of the DC / DC converter 14 and the motor generator MG2, and a control unit 18.

  Note that the hybrid vehicle includes another motor generator MG1 (not shown) that is mainly driven by an engine and is used as a generator, and another inverter that drives another motor generator MG1. The DC converter 14 may be connected in parallel to the inverter 16 on the boost side, and another motor generator MG1 may be connected to another inverter. Although the control part 18 of this embodiment can control another inverter and another motor generator MG1 similarly, in the following description, the case where the inverter 16 and the motor generator MG2 are controlled will be described as a representative.

  Motor generator MG2 is a U-phase, V-phase, and W-phase three-phase rotating electric machine that functions as a motor when electric power is supplied from battery 12 and functions as a generator during braking of the vehicle. The generated electric power is supplied to the battery 12 via the inverter 16.

  The DC / DC converter 14 includes a reactor 20 and two switching elements Sa connected in series with each other. One end of the reactor 20 is connected between the two switching elements Sa, and the other end of the reactor 20 is connected to the positive electrode side of the battery 12 via the system relay SR and the fuse F. The switching element Sa is, for example, a transistor or an IGBT. In the illustrated example, the system relay SR includes a first relay R1 and a second relay R2 connected in parallel to the first relay R1 and having a resistor Rw connected in series. The control unit 18 enables the battery 12 and the DC / DC converter 14 to be electrically connected by controlling one of the first relay R1 and the second relay R2 to be turned on and the other to be turned on.

  A diode Da is connected in antiparallel to each switching element Sa of the DC / DC converter 14, and a negative electrode side of the battery 12 is connected to the switching element Sa on one side (the lower side in FIG. 1) of the two switching elements Sa. A smoothing capacitor C <b> 1 is connected between the other end of the reactor 20 and the negative electrode side of the battery 12. A second smoothing capacitor C <b> 2 is connected between both ends of the two switching elements Sa and the inverter 16.

  In such a DC / DC converter 14, switching of the switching element Sa is controlled by the control unit 18, and the high voltage side voltage VH obtained by boosting the low voltage side voltage VL that is the output side voltage of the battery 12 is supplied to the inverter 16. The high voltage side voltage VH supplied from the inverter 16 side is stepped down and supplied to the battery 12 side. For such control of the DC / DC converter 14, the rotating electrical machine control system 10 uses the low-voltage sensor 22 that detects the low-voltage side voltage VL of the DC / DC converter 14 and the high-voltage side voltage VH of the DC / DC converter 14. And a high-pressure sensor 24 for detection.

  The inverter 16 includes three arms Au, Av, Aw corresponding to the U-phase, V-phase, and W-phase connected in parallel with each other, and each phase arm Au, Av, Aw is connected to each other in series with a transistor, IGBT. The two switching elements Sw are included. A diode Di is connected to each switching element Sw in antiparallel. Switching of each switching element Sw is controlled by the control unit 18 to convert a DC voltage supplied from the high-voltage side of the DC / DC converter 14 into a three-phase AC voltage and output it to the motor generator MG2. When the vehicle is braked, the three-phase AC voltage output from the motor generator MG2 to the inverter 16 is converted into a DC voltage by the inverter 16, and the voltage is stepped down by the DC / DC converter 14 before being supplied to the battery 12. To charge.

  The control unit 18 can be configured with, for example, an in-vehicle computer. The control unit 18 can be configured by one computer, but can also be configured by connecting a plurality of computers with cables or the like. For example, the control unit 18 can be a motor control unit that controls the operation of the motor generator MG2.

  FIG. 2 is a block diagram showing a configuration of the control unit 18 of FIG. As shown in FIG. 2, the rotating electrical machine control system 10 includes a rotation angle sensor MR that is a rotation angle detection unit that detects a rotation angle per predetermined time set in advance of the motor generator MG2. The detection value of the rotation angle sensor MR is input to the control unit 18. Instead of the rotation angle sensor MR, a rotation speed sensor for detecting the rotation speed per predetermined time of the motor generator MG2 may be provided, and the detection value of the rotation speed sensor may be input to the control unit 18. Control unit 18 can also calculate the number of rotations per predetermined time of motor generator MG2 based on the detection value of rotation angle sensor MR. In this case, the rotation angle sensor MR and the rotation speed calculation unit constitute a rotation speed detection unit. The rotating electrical machine control system 10 further includes a current sensor 28 that detects a current flowing through a power line that connects the stator coils 26u, 26v, and 26w of each phase of the motor generator MG2 and the inverter 16. The current sensor 28 will be described in detail later.

  Further, in FIG. 2, a portion of the control unit 18 that performs motor control by sine wave PWM control is divided into functions. That is, the control unit 18 includes a mode switching unit (not shown). The mode switching unit controls the motor generator MG2 according to the modulation degree and the operating point of the motor generator MG2 represented on the dq plane. The control mode, overmodulation control mode, or rectangular wave control mode can be switched.

  In the sine wave PWM control mode, the motor generator MG2 is controlled by sine wave PWM control. In the overmodulation control mode, the motor generator MG2 is controlled by overmodulation control. In the rectangular wave control mode, the motor generator MG2 is controlled by rectangular wave control.

Here, the “modulation degree (= modulation rate)” is the system voltage, and the effective voltage of the line that is the motor generator applied voltage with respect to the high-voltage side voltage VH of the DC / DC converter 14 that is the input voltage of the inverter 16. The ratio of the value J (J / VH). The effective value J of the line voltage of the motor generator MG2 is calculated using the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* as follows: J = {(Vd ^* ) ² + (Vq ^* ) ² } ^{1 /} Given in ² . Therefore, the modulation degree E is obtained by the modulation degree E = [{(Vd ^* ) ² + (Vq ^* ) ² } ^1/2 ] / VH. For example, the PWM control mode is performed until the modulation degree E is 0.61, which satisfies a preset PWM condition, and when the modulation degree E exceeds 0.61, the mode is switched to the over-modulation control mode. Further, when the modulation degree E is 0.78, the rectangular wave control mode is used.

  Here, the sine wave PWM control mode and the overmodulation control mode are current feedback control, which is a control for outputting a PWM signal to the motor generator MG2 by comparing a voltage command value with a carrier wave. In other words, the control unit 18 controls the inverter 16 by a sine wave PWM control method using current feedback under preset PWM conditions.

  On the other hand, the rectangular wave control mode is a control for outputting a one-pulse switching waveform to the motor generator MG2 in accordance with the electrical angle. The voltage amplitude is fixed to the maximum value, and the torque is feedback controlled by controlling the phase. .

  Returning to FIG. 1, since the LC resonance circuit is constituted by the reactor 20 of the DC / DC converter 14 and each of the smoothing capacitors C1 and C2, it is one of the frequencies in the resonance frequency region and the output fluctuation of the motor generator MG2. When the frequency of the power fluctuation matches, when the offset error deviating from the zero point is superimposed on the detection value of the current sensor 28, the fluctuation of the power fluctuation becomes large due to LC resonance. As the fluctuation increases, the battery current IB, which is the output current of the battery 12, and the high-voltage side voltage VH of the inverter, which is the system voltage, may fluctuate greatly, and overcurrent or overvoltage may occur. The present embodiment has been invented to effectively prevent the occurrence of such overcurrent and overvoltage.

  That is, as shown in FIGS. 1 and 2, the control unit 18 includes a gain determination unit 30 that is a gain reduction unit. The gain determination unit 30 performs PWM control when any frequency in the resonance frequency region of the LC resonance circuit including the reactor 20 and each of the smoothing capacitors C1 and C2 matches the frequency of power fluctuation of the motor generator MG2. The feedback gain G in the case of performing current feedback is made lower than the normal time gain Gn used in normal time. That is, when the frequency of the power fluctuation of motor generator MG2 deviates from the frequency in the resonance frequency region of the LC resonance circuit, gain determination unit 30 uses a feedback gain used in PI control unit 32 (FIG. 2) described later. In G, a normal gain Gn to be used in a normal state is determined, that is, input. Further, gain determination unit 30 turns off the current fluctuation determination flag even when any frequency in the resonance frequency region of the LC resonance circuit matches the power fluctuation frequency of motor generator MG2. And the absolute value | PM | of the power of the motor generator MG2 is equal to or less than a predetermined power Pa (kw) that is a predetermined output (| PM | ≦ Pa). When the condition is satisfied, the normal gain Gn is determined as the feedback gain G.

  Here, the “current fluctuation determination flag” is the absolute difference between the actual current value IBa and the filtered current value IBf obtained by applying a filter to remove the ripple component to the actual current value IBa that is the actual battery current value IB. When the value (| IBa−IBf |) is larger than a predetermined current value Ic (A) set in advance (| IBa−IBf |> Ic), it is turned on (that is, becomes 1), otherwise it is turned off. (That is, 0). For this purpose, the detection value of the battery current sensor 33 (FIG. 1) that detects the battery current IB that is the output current of the battery 12 (FIG. 1) is input to the control unit 18.

  On the other hand, gain determination unit 30 is in a state where any frequency in the resonance frequency region of the LC resonance circuit matches the power fluctuation frequency of motor generator MG2, and the current fluctuation determination flag is turned ON (ie, 1), and when the absolute value | PM | of the power of the motor generator MG2 exceeds a predetermined power Pa (kw) (| PM |> Pa), the feedback gain G is smaller than the normal gain Gn. A certain LC resonance band gain GL is determined, that is, input.

Next, a method for controlling motor generator MG2 in sine wave PWM control mode by control unit 18 will be described with reference to FIG. In FIG. 2, the control unit 18 obtains the torque command value T ^* and the rotational angular velocity command value ω ^* from another control unit (not shown). These command values are calculated by estimating the user's required torque and required vehicle speed from an accelerator pedal operation amount, a brake pedal operation amount, etc. of a vehicle (not shown). The control unit 18 includes a current command generation unit 34, a subtractor unit 36, a PI control unit 32, a 3 phase / 2 phase conversion unit 38, and a 2 phase / 3 phase conversion unit 40.

The current command generator 34 compares the actual rotational angular velocity ω of the motor generator MG2 with the rotational angular velocity command value ω ^*, and uses the previously created table or the like to determine the torque command value T ^* as the d-axis current command value Id ^*. And q-axis current command value Iq ^* .

The subtractor unit 36 subtracts the actual d-axis current value Id from the d-axis current command value Id ^* and calculates the d-axis current deviation δId, and the actual subtractor 36 from the q-axis current command value Iq ^*. And an Iq subtractor having a function of calculating a q-axis current deviation δIq by subtracting the q-axis current value Iq.

  The actual d-axis current value Id and the actual q-axis current value Iq in the motor generator MG2 are determined by the function of the three-phase / two-phase converter 38, and the rotation angle θ of the rotor of the motor generator MG2 and 3 of the motor generator MG2. It is calculated based on the detection values Iu, Iv, and Iw of the current sensor 28 that detects the current of the phase. The electrical angle of the rotor is detected by a rotation angle sensor MR such as a resolver. Current values Iu, Iv, Iw connect corresponding phase arms Au, Av, Aw (FIG. 1) of inverter 16 and corresponding phase stator coils 26u, 26v, 26w (FIG. 1) of motor generator MG2. It is obtained by detecting the current flowing through the power line. Since one end of each phase of the stator coils 26u, 26v, 26w of the motor generator MG2 is connected at a neutral point, the current values Iu for the remaining one phase can be calculated by detecting the currents Iv, Iw for two phases. It is. FIG. 1 shows that two of a V-phase current value Iv and a W-phase current value Iw are detected. The remaining U-phase current value Iu is obtained by Iu = − (Iv + Iw). It is also possible to provide current sensors 28 for three phases and directly detect the current values Iu, Iv, Iw for the three phases. The current sensor 28 has an accuracy capable of detecting the resonance frequency of the LC resonance circuit including the reactor 20 (FIG. 1) and the smoothing capacitors C1 and C2 (FIG. 1). Also, the high voltage sensor 24 for detecting the high voltage VH shown in FIG. 1 has an accuracy capable of detecting the resonance frequency of the LC resonance circuit.

The PI control unit 32 performs proportional-integral control on the d-axis current deviation δId and the q-axis current deviation δIq under a predetermined feedback gain G to obtain a control deviation corresponding to these, and d corresponding to the control deviation It has a function of calculating the shaft voltage command value Vd ^* and the q-axis voltage command value Vq ^* . Current subtraction in the PWM control mode is performed by the subtractor unit 36 and the PI control unit 32.

The two-phase / three-phase conversion unit 40 is obtained from the rotation angle θ of the rotor based on the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* input from the PI control unit 32. It has a function of calculating a U-phase voltage Vu, a V-phase voltage Vv, and a W-phase voltage Vw from a predicted angle that is predicted to be located after five control cycles.

  The calculated phase voltages Vu, Vv, Vw are converted into PWM signals by a PWM signal generator (not shown), and the PWM signals are output to a gate circuit (not shown). The gate circuit controls on / off of the switching element Sw by selecting the switching element Sw (FIG. 1) of the inverter 16 to which the control signal is applied.

  The current flowing through the power line connecting each phase arm of inverter 16 and each phase stator coil of motor generator MG2 is fed back to subtractor section 36 via three-phase / two-phase conversion section 38 as described above. . In this way, current feedback in the PWM control mode is performed.

  The above is the basic configuration of current feedback control. In the present embodiment, the control unit 18 further includes a gain determination unit 30. That is, when considering a comparative example that does not have the gain determination unit 30 in the above basic configuration, the comparative example also includes the reactor 20 of the DC / DC converter 14 and the smoothing capacitors C1 and C2 as in the above-described embodiment. Since the LC resonance circuit is configured, if any frequency in the resonance frequency region matches the frequency of the power fluctuation that is the output fluctuation of the motor generator MG2, an overcurrent or an overvoltage may occur.

  FIG. 3 is a diagram showing the relationship between the elapsed time t when accelerating the rotation of the motor generator MG2 at a constant acceleration and the battery current value IB that is the output current value of the battery 12 in the rotating electrical machine control system of the comparative example. is there. Since the horizontal axis in FIG. 3 is the elapsed time t when the rotation of the motor generator MG2 is accelerated with a constant acceleration, it can be replaced with the rotation speed N of the motor generator MG2. The vertical axis in FIG. 3 is the battery 12 current value IB, and shows the change in IB when the rotational speed N is increased. In motor generator MG2, power fluctuation caused by the offset error of current sensor 28 occurs, and furthermore, LC resonance circuit is constituted by reactor 20 of DC / DC converter 14 and each of smoothing capacitors C1 and C2. Occurs. In this case, when the frequency region of the LC resonance coincides with the frequency of the power fluctuation described above, a large fluctuation of the battery current IB based on the LC resonance occurs in the resonance rotational speed band indicated by the arrow L in FIG. In addition, large fluctuations in the high-voltage side voltage VH based on LC resonance also occur in the same resonance rotational speed band. That is, the fluctuation of the battery current IB and the fluctuation of the high-voltage side voltage VH due to the power fluctuation are expanded by the LC resonance phenomenon.

  When the fluctuation of the battery current IB increases and the fluctuation of the high-voltage side voltage VH of the DC / DC converter 14, that is, the fluctuation of the system voltage of the inverter 16 increases, the drive signal by the inverter 16 fluctuates, and the control of the motor generator MG 2 becomes ineffective. Become stable. Further, when the fluctuation of the battery current IB becomes large and exceeds the PCU protection threshold value X shown in FIG. 3, the performance of the components of the power control unit (PCU) including the inverter 16 and the smoothing capacitors C1 and C2 may be reduced. There is sex.

In the present embodiment, in order to solve such a problem in the comparative example, the control unit 18 includes a gain determination unit 30 as shown in FIG. As described above, gain determination unit 30 provides feedback when performing current feedback by PWM control when any frequency in the resonance frequency region of the LC resonance circuit matches the frequency of power fluctuation of motor generator MG2. The gain G is made lower than the normal gain Gn used during normal operation. More preferably, the gain determination unit 30 sets a specific rotation in which the rotation speed per predetermined time of the motor generator MG2, for example, the rotation speed Arpm (= min ⁻¹ ) per minute is preset based on the frequency in the resonance frequency region. When the current fluctuation determination flag is turned on (that is, becomes 1) and the absolute value | PM | of the power of the motor generator MG2 exceeds the predetermined power Pa (kw) (| PM |) > Pa) when the frequency in the resonance frequency region and the frequency of the power fluctuation of the motor generator MG2 coincide. In this case, the gain determining unit 30 determines the LC gain GL for the feedback gain G that is lower than the normal gain Gn. That is, the gain determination unit 30 inputs the LC resonance band gain GL to the feedback gain G of the PI control unit 32. Based on the LC resonance band gain GL, the PI control unit 32 performs proportional-integral control to obtain a control deviation, and a d-axis voltage command value Vd ^* and a q-axis voltage command value Vq ^* corresponding to the control deviation. Is calculated.

In FIG. 2, the gain determination unit 30 also determines the rotational speed Arpm (= min ⁻¹ ) of the motor generator MG2 and the absolute value of power | PM | based on the angular velocity command value ω ^* and the torque command value T ^*. And are calculated. However, the detection value of the rotation angle sensor MR of the motor generator MG2 or the detection value of the rotation speed sensor that detects the rotation speed of the motor generator MG2 by using it instead of the rotation angle sensor MR is set to the rotation speed Arpm (= min ^{− 1} ) and the absolute value of power | PM |.

Further, when the absolute value | PM | of the power of the motor generator MG2 exceeds a predetermined power Pa (kw) (| PM |> Pa), and the rotational speed per predetermined time of the motor generator MG2 is the specific rotational speed. When in the region, the LC resonance band determination flag is turned on (that is, 1), and is otherwise turned off (that is, 0). For example, when it is between revolutions per minute of the motor generator MG2 Arpm (= min ^-1) is the specific rotation speed range T1rpm (= min ^-1) and T2rpm (= min ^-1), i.e. T1 < When | A | <T2, the LC resonance band determination flag is turned ON.

  When the current fluctuation determination flag is turned ON and the LC resonance band determination flag is turned ON, the feedback gain G is determined as the LC resonance band gain GL, and otherwise, the feedback gain G is the normal gain Gn. Is determined.

  Next, an example of a method for determining the feedback gain G of the sine wave PWM control will be described using the flowcharts of FIGS. FIG. 4 is a flowchart for explaining an example of a method for determining the feedback gain G of the sinusoidal PWM control using the rotating electrical machine control system 10 of the present embodiment. FIG. 5 is a flowchart showing a subroutine for determining whether the current fluctuation determination flag is ON (= 1) or OFF (= 0) in S10 of FIG. FIG. 6 is a flowchart showing a subroutine for determining whether the LC resonance band determination flag is ON (= 1) or OFF (= 0) in S10 of FIG.

  When determining the feedback gain G of the sine wave PWM control, first, in step S10 of FIG. 4 (in the following description, “step S” is simply referred to as S), the current fluctuation determination flag is turned ON, and It is determined whether or not the LC resonance band determination flag is turned on. For this purpose, the subroutine for determining the current fluctuation determination flag in FIG. 5 and the subroutine for determining the LC resonance band determination flag in FIG. 6 are executed.

  First, in S20 of FIG. 5, the absolute value (| IBa−IBf |) of the difference between the actual current value IBa, which is the actual battery 12 current value IB, and the filtered current value IBf is a predetermined current value Ic set in advance. It is determined whether it is larger than (A). If the determination result in S20 is affirmative, that is, if (| IBa-IBf |)> Ic, the current fluctuation determination flag is turned on (that is, becomes 1) (S22), and the determination result in S20 is negative. In this case, that is, if (| IBa−IBf |) ≦ Ic, the current fluctuation determination flag is turned off (that is, becomes 0) (S24).

Further, in S30 of FIG. 6, the absolute value | PM | of the power of the motor generator MG2 exceeds the predetermined power Pa (kw) (| PM |> Pa), and is the predetermined time of the motor generator MG2. The number of revolutions Arpm per minute (= min ⁻¹ ) is within a specific revolution number range (ie, between T1 rpm (= min ⁻¹ ) and T2 rpm (= min ⁻¹ )), that is, T1 <| A | < It is determined whether or not T2. When the determination result of S30 of FIG. 6 is affirmative, the LC resonance band determination flag is turned on (that is, becomes 1) (S32), and when the determination result of S30 of FIG. The determination flag is turned off (that is, 0) (S34). Note that the execution order of the subroutines in FIGS. 5 and 6 may be reversed.

Next, when the determination result of S10 of FIG. 4 is affirmative, the feedback gain G is determined to be the LC resonance band gain GL lower than the normal gain Gn (S12), and the determination result of S10 of FIG. Is negative, the feedback gain G is determined as the normal gain Gn (S14). The PI control unit 32 shown in FIG. 2 performs proportional integral control based on the feedback gain G determined as either GL or Gn to obtain a control deviation, and a d-axis voltage command value Vd corresponding to the control deviation. ^* And q-axis voltage command value Vq ^* are calculated. Therefore, when feedback gain G is determined to be LC resonance band gain GL, the responsiveness of feedback control of motor generator MG2 is deteriorated.

  Each function of the control unit 18 described above can be realized by executing software, but part of each function may be realized by hardware.

  According to this embodiment, when any frequency in the resonance frequency region of the LC resonance circuit including the reactor 20 and the smoothing capacitors C1 and C2 matches the frequency of the power fluctuation of the motor generator MG2, When the current feedback is performed by PWM control, the feedback gain G becomes the LC resonance band gain GL that is lower than the normal gain Gn, and the control responsiveness deteriorates. For this reason, even when an offset error is superimposed on the detected current value of the current sensor 28 for the motor generator MG2, fluctuations in the input current to the inverter 16 in the resonance frequency region can be suppressed, and the battery current IB and the high voltage can be reduced. The occurrence of overcurrent and overvoltage can be effectively prevented, such as the side voltage VH can be suppressed.

  In the present embodiment, the gain determination unit 30 is configured such that when the rotational speed of the motor generator MG2 is within a specific rotational speed range set in advance based on the frequency in the resonant frequency range, Assuming that the power fluctuation frequency of the motor generator MG2 coincides, the feedback gain G is reduced below the normal gain Gn. However, the present invention is not limited to such a configuration. For example, the rotational speed per unit time of an output shaft (not shown) or a wheel (not shown) connected to the motor generator MG2 so that power can be transmitted is within another specific rotational speed range that is preset based on the frequency in the resonance frequency range. At some point, the feedback gain G can be made lower than the normal gain Gn, assuming that the frequency in the resonance frequency region and the frequency of the power fluctuation of the motor generator MG2 coincide.

  Further, in the present embodiment, gain determination unit 30 has a rotational speed of motor generator MG2 within a specific rotational speed range set in advance based on the frequency in the resonance frequency range (T1 <| A | <T2). However, when the absolute value | PM | of the power of the motor generator MG2 is larger than the predetermined power Pa (kw) (| PM |> Pa) and the difference between the actual current value IBa and the filtered current value IBf Only when the absolute value | IBa−IBf | is larger than the predetermined current value Ic (| IBa−IBf |> Ic), the feedback gain G is reduced below the normal gain Gn. That is, if | PM |> Pa is not satisfied, the power fluctuation is small, and if | IBa−IBf |> Ic, the fluctuation of the current ripple is small. Therefore, even if the feedback gain G is set to the normal gain Gn, the overcurrent and overvoltage Problems are less likely to occur, and control response can be enhanced. For this reason, it is possible to effectively prevent the feedback gain G from excessively decreasing during control, and to improve the performance of a device such as a vehicle equipped with the motor generator MG2.

  Unlike the present embodiment, the gain determination unit 30 performs the current fluctuation determination in FIG. 5 or determines whether the absolute value of the power of the motor generator MG2 in FIG. 6 is greater than a predetermined power. The LC resonance band in which the feedback gain G is reduced below the normal gain Gn or the normal gain Gn only by determining whether or not the rotation speed A of the motor generator MG2 is within the specific rotation speed region. The gain GL for use can also be determined. In this case, when the rotational speed A of the motor generator MG2 is within the specific rotational speed range, the feedback gain G is determined as the LC resonance band gain GL, and the rotational speed A of the motor generator MG2 is within the specific rotational speed range. If not, the feedback gain G is determined as the normal gain Gn.

  In the above description, the case where the voltage conversion unit is the DC / DC converter 14 having the step-up / step-down function has been described. However, the voltage conversion unit has only a function of boosting the voltage from the battery 12 side to the inverter 16 side. A step-up converter may be used, or a step-down converter having only a function of stepping down the voltage from the inverter 16 side to the battery 12 side.

  The rotating electrical machine control system according to the present invention can be used for controlling rotating electrical machines mounted on fuel cell vehicles, hybrid vehicles, and the like.

  10 rotating electrical machine control system, 12 battery, 14 DC / DC converter, 16 inverter, 18 control unit, 20 reactor, 22 low pressure sensor, 24 high pressure sensor, 26u, 26v, 26w stator coil, 28 current sensor, 30 gain determination unit, 32 PI control unit, 33 battery current sensor, 34 current command generation unit, 36 subtractor unit, 38 3 phase / 2 phase conversion unit, 40 2 phase / 3 phase conversion unit.

Claims (3)

Rotating electrical machinery,
A voltage converter connected to a DC power source and including a reactor;
A drive circuit connected to the rotating electrical machine;
A smoothing capacitor connected to the voltage converter;
A control unit for controlling the drive circuit in a PWM control method using current feedback under preset PWM conditions;
The controller is
When the frequency in the resonance frequency region of the resonance circuit including the reactor and the smoothing capacitor matches the frequency of the output fluctuation of the rotating electrical machine, the feedback gain when performing current feedback by the PWM control is A rotating electrical machine control system comprising a gain lowering unit that lowers the gain at a normal time to be used . In the rotating electrical machine control system according to claim 1,
The gain reduction unit is configured such that when the rotational speed of the rotating electrical machine is within a specific rotational speed range set in advance based on the frequency of the resonant frequency range, the frequency of the resonant frequency range and the output of the rotating electrical machine The rotating electrical machine control system characterized in that the feedback gain is reduced below the normal gain, assuming that the frequency of fluctuation matches. In the rotating electrical machine control system according to claim 2,
The gain reduction unit has a predetermined value in which the absolute value of the output of the rotating electrical machine is preset when the rotational speed of the rotating electrical machine is within a specific rotational speed range set in advance based on the frequency in the resonance frequency range. The absolute value of the difference between the actual current value and the filtered current value obtained by applying a filter that removes the ripple component to the actual current value, which is an actual current value, is set in advance. The rotating electrical machine control system, wherein the feedback gain is reduced below the normal gain only when the current value is larger.

Images