JP2011172343A - Driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent excessive electric power from being input to a battery or voltage on an inverter from being larger than that of a step up/down circuit. <P>SOLUTION: When gate is shut off in an inverter due to a failure in a drive system including a motor and the inverter (S100), if the following condition continues for a predetermined time (S110-S140), the inverter controls itself so as to be in a three-phase short-circuit state (S150): a first motor back electromotive force Vbe 1, which is a back electromotive force generated by motor rotation, is higher than a predetermined voltage Vref, and a battery power Pb to be input to a battery is larger than a predetermined power Pref. Excessive power is prevented from being input to the battery, and voltage of a high-voltage system is prevented from being excessively increased. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drive device.

  Conventionally, this type of drive device includes a motor generator driven by three-phase alternating current, an inverter that drives the motor generator, a battery, and a boost converter that boosts the power of the battery and supplies it to the inverter. The upper arm of the boost converter is fixed in the on state and the lower arm is turned off when an abnormality occurs in the overvoltage detection protection unit that detects whether the boosted voltage of the boost converter exceeds a predetermined overvoltage determination value. The thing fixed in a state is proposed (for example, refer to patent documents 1). In this drive device, by controlling in this way, electric power can be supplied from the battery to the inverter and voltage generated by the motor can be supplied to the battery without converting the voltage by the boost converter.

JP 2009-060726 A

  In the drive device described above, if an abnormality occurs in the inverter while the motor generator is rotating at a high rotational speed and the inverter is gate-cut, the electric power generated by the counter electromotive force generated by the rotation of the motor flows to the battery. Depending on the number of rotations of the motor generator, the electric power due to the counter electromotive force increases, and excessive electric power may be input to the battery. In order to eliminate this inconvenience, it is conceivable to block the gate of the boost converter. In this case, however, the voltage on the inverter side of the boost converter may rise beyond the assumed range.

  The drive device of the present invention is mainly intended to suppress excessive electric power being input to the battery or an excessively higher voltage on the inverter side than the buck-boost circuit.

  The drive device of the present invention employs the following means in order to achieve the main object described above.

The drive device of the present invention is
A three-phase AC motor, an inverter that drives the three-phase AC motor by switching a plurality of switching elements, a secondary battery, a battery voltage system to which the secondary battery is connected, and a high-voltage system to which the inverter is connected And a step-up / step-down circuit that exchanges electric power with voltage adjustment between,
When an abnormality occurs in the drive system including the three-phase AC motor and the inverter and the inverter is gate-cut, a back electromotive force generated by the rotation of the three-phase AC motor is a predetermined voltage equal to or higher than the voltage of the high-voltage system. When it is confirmed that the power that is higher than the voltage and the power input to the secondary battery exceeds the maximum allowable power for control when charging the secondary battery, the inverter is in a three-phase short circuit state. Control means for controlling the inverter;
It is a summary to provide.

  In the drive device of the present invention, when an abnormality occurs in the drive system including the three-phase AC motor and the inverter and the inverter is gate-cut, the back electromotive force generated by the rotation of the three-phase AC motor is higher than the voltage of the high voltage system. When it is confirmed that the power input to the secondary battery exceeds the maximum allowable power for control when charging the secondary battery, the inverter is in a three-phase short circuit state. To control. Thereby, it can suppress that the electric power by a counter electromotive force is supplied to the buck-boost circuit side, and can suppress that excessive electric power is input into a secondary battery. Further, it is not necessary to shut off the gate of the step-up / step-down circuit, and the voltage on the inverter side of the step-up / step-down circuit can be suppressed from becoming excessive. Here, when an abnormality occurs in the drive system, there is a case where field-weakening control cannot be performed.

It is a block diagram which shows the outline of a structure of the drive device 20 as an Example of this invention. 4 is a flowchart showing an example of an abnormal time control routine executed by the electronic control unit 50. When an abnormality occurs in the first drive system, the rotational speed Nm1 of the motor MG1, whether it is in a high counter electromotive force state, whether it is in a high power input state, whether the inverter 24 is in a gate cutoff state, whether the inverter 24 is It is explanatory drawing which shows an example of the mode of the time change of whether it is a phase short circuit state.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a drive device 20 as an embodiment of the present invention. The drive device 20 according to the embodiment is mounted on an electric vehicle or a hybrid vehicle, and as shown in the drawing, a known synchronous power generation including a rotor having a permanent magnet attached to an outer surface and a stator around which a three-phase coil is wound. Two motors MG1 and MG2 configured as electric motors, inverters 24 and 25 that drive the motors MG1 and MG2, respectively, and share the power line 28, a battery 26, a power line 27 to which the battery 26 is connected, and an inverter 24, 25 is connected to the power line 28 to which the battery 25 is connected, and the power on the battery 26 side is boosted and supplied to the inverters 24 and 25, or the power on the inverters 24 and 25 is stepped down and supplied to the battery 26 side. The converter 30 and the boost converter 30 are connected in parallel to the inverters 24 and 25 and connected to the inverters 24 and 25 in order to smooth the boosted voltage. Comprises a capacitor 32, a smoothing capacitor 34 connected in parallel the boosting converter 30 viewed from Te to the battery 26 for smoothing the voltage before boosting, the electronic control unit 50 that controls the whole apparatus. Hereinafter, the inverters 24 and 25 side of the boost converter 30 are referred to as a high voltage system, and the battery 26 side of the boost converter 30 is referred to as a battery voltage system.

  The inverters 24 and 25 include transistors T11 to T16 and T21 to 26 as six switching elements, and six diodes D11 to D16 and D21 to D26 connected in parallel to the transistors T11 to T16 and T21 to T26 in the reverse direction. It is comprised by. The transistors T11 to T16 and T21 to T26 are arranged in pairs so that each of the inverters 24 and 25 is on the source side and the sink side with respect to the positive electrode bus and the negative electrode bus shared as the power line 28. Each of the three-phase coils (U-phase, V-phase, W-phase) of the motors MG1, MG2 is connected to each connection point between the transistors. Hereinafter, the transistors T11 to T13 are collectively “first upper arm”, the transistors T14 to T16 are collectively “first lower arm”, the transistors T21 to T23 are collectively “second upper arm”, and the transistors T24 to T26 are collectively. May be referred to as a “second lower arm”.

  Boost converter 30 includes transistors T31 and T32 as two switching elements, two diodes D31 and D32 connected in parallel to transistors T31 and T32 in the reverse direction, and a reactor L. The two transistors T31 and T32 are connected to the positive and negative buses of the power line 28 connected to the inverters 24 and 25, respectively, and the reactor L is connected to the connection point between the transistors T31 and T32.

  The electronic control unit 50 is applied to the rotational positions θm1 and θm2 from the rotational position detection sensors 40 and 41 for detecting the rotational positions of the motors MG1 and MG2 and the V and W phases of the three-phase coils of the motors MG1 and MG2. The voltage from the voltage sensor 44 (high voltage system voltage) attached between the terminals of the phase currents Iv1, Iw1, Iv2, Iw2 and the smoothing capacitor 32 from the current sensors 42V, 42W, 43V, 43W for detecting the phase current VH, the inter-terminal voltage Vb from the voltage sensor 46 installed between the terminals of the battery 26, the charge / discharge current Ib from the current sensor 48 attached to the output terminal of the battery 26, and the like are input. Further, the electronic control unit 50 outputs a switching signal to the switching elements of the inverters 24 and 25, a switching signal to the switching element of the boost converter 30, and the like. The electronic control unit 50 also calculates the electrical angles θe1 and θe2 of the rotors of the motors MG1 and MG2 and the rotational speeds Nm1 and Nm2 of the motor 22 based on the rotational positions θm1 and θm2 from the rotational position detection sensors 40 and 41. ing.

  In the driving apparatus 20 of the embodiment, the electronic control unit 50 controls the inverters 24 and 25 based on the torque commands Tm1 * and Tm2 * as torques to be output from the motors MG1 and MG2, and the torques of the motors MG1 and MG2. Boost converter 30 is controlled based on commands Tm1 *, Tm2 * and rotation speeds Nm1, Nm2. Here, the inverters 24 and 25 are controlled by selecting a sine wave control method or a rectangular wave control method. The sine wave control method is a method of obtaining an output voltage having a sine wave-like fundamental wave component by switching control based on a PWM signal generated using a sine wave voltage command signal and a carrier signal (triangular wave signal) which is a carrier wave. . In addition, the rectangular wave control method is a method for obtaining an output voltage having a fundamental component with a constant amplitude obtained by changing the voltage phase of a rectangular wave voltage having the maximum amplitude according to a torque command. In comparison, the voltage utilization rate can be improved. In the high rotation speed region of the motors MG1 and MG2, the rectangular wave control method is mainly selected. In this case, the high voltage system voltage VH is higher than the counter electromotive force generated by the rotation of the motors MG1 and MG2. Thus, so-called field weakening control for supplying a field weakening current is performed.

  Next, the operation of the drive device 20 of the embodiment configured as described above, particularly, when an abnormality occurs in the first drive system including the motor MG1 and the inverter 24 and the second drive system including the motor MG2 and the inverter 25. Will be described. Hereinafter, as an example, the operation when an abnormality occurs in the first drive system will be described, but the same can be considered when an abnormality occurs in the second drive system. FIG. 2 is a flowchart showing an example of an abnormal time control routine executed by the electronic control unit 50 when an abnormality occurs in the first drive system. Here, when the abnormality occurs in the first drive system, for example, there is a case where field-weakening control cannot be performed.

  When the abnormality control routine is executed, the electronic control unit 50 first determines that there is a possibility that the switching control of the inverter 24 cannot be normally performed, and gates the inverter 24 (step S100).

  Subsequently, the first motor back electromotive force Vbe1 that is the back electromotive force generated by the rotation of the motor MG1 and the battery power Pb that is the power input to the battery 26 (positive on the charging side and negative on the discharging side) are input. (Step S110) The input first motor back electromotive force Vbe1 is compared with the predetermined voltage Vref (Step S120), and the battery power Pb is compared with the predetermined power Pref (charge-side value) (Step S130). Here, the first motor counter electromotive force Vbe1 is determined as the relationship between the rotation speed Nm1 of the motor MG1 and the first motor counter electromotive force Vbe1 such that the higher the rotation speed Nm1, the higher the first motor counter electromotive force Vbe1. A value obtained by applying the rotational speed Nm1 calculated based on the rotational position θm1 from the rotational position detection sensor 40 to the map is input. Further, the battery power Pb is obtained by multiplying the voltage Vb between the terminals of the battery 26 from the voltage sensor 46 by the charge / discharge current Ib of the battery 26 from the current sensor 48 (positive on the charging side and negative on the discharging side). It was supposed to be entered. Further, the predetermined voltage Vref uses a high voltage system voltage VH or a voltage slightly higher than that, and the predetermined power Pref uses the maximum allowable power for control when charging the battery 26. Consider a case where the motor MG1 is rotating with the inverter 24 being gate-cut off. At this time, when the first motor counter electromotive force Vbe1 is equal to or lower than the high voltage system voltage VH, the electric power generated by the first motor counter electromotive force Vbe1 is not supplied to the boost converter 30 side. However, when the first motor back electromotive force Vbe1 is higher than the high voltage system voltage VH, the diode of the inverter 24 functions as a full-wave rectifier circuit, so that the power from the first motor back electromotive force Vbe1 is transferred to the boost converter 30 side. If switching control of the boost converter 30 is performed, excessive power may be input to the battery 26 via the boost converter 30 depending on the magnitude of the first motor back electromotive force Vbe1. . The determinations in steps S120 and S130 are processes for determining whether or not excessive power from the first motor counter electromotive force Vbe1 is input to the battery 26 in this way. In this case, if the boost converter 30 is shut off in order to avoid the input of excessive power to the battery 26, the high voltage system voltage VH may increase excessively.

  When the first motor back electromotive force Vbe1 is equal to or lower than the predetermined voltage Vref, or when the battery power Pb is equal to or lower than the predetermined power Pref even when the first motor back electromotive force Vbe1 is higher than the predetermined voltage Vref, the first motor back electromotive force Vbe1 Even if the electric power is not supplied to the boost converter 30 or supplied, it is determined that no excessive electric power is input to the battery 26, and this routine is terminated. In this case, the gate shutoff of the inverter 24 is continued.

  When the first motor back electromotive force Vbe1 is higher than the predetermined voltage Vref and the battery power Pb is higher than the predetermined power Pref in steps S120 and S130, a predetermined time (for example, 1 second, 2 seconds, etc.) ) (Step S140), and when it is determined that the state has not continued for a predetermined time, the process returns to step S110. In step S140, when it is determined that the state in which the first motor back electromotive force Vbe1 is higher than the predetermined voltage Vref and the battery power Pb is higher than the predetermined power Pref continues for a predetermined time, the state is confirmed. It is determined that the inverter 24 is in a three-phase short circuit (three-phase on) state, and three-phase on control is performed to control the inverter 24 (step S150). Here, the three-phase on control specifically refers to the state where the upper arm (transistors T11 to T13) of the inverter 24 is turned off and the lower arm (transistors T14 to T16) is turned on, or the upper arm is turned on. In addition, the lower arm is turned off. Thereby, it is possible to suppress the supply of electric power from the first motor counter electromotive force Vbe1 to the boost converter 30 side, and it is possible to suppress excessive electric power from being input to the battery 26. Further, it is not necessary to block the boost converter 30 to suppress the input of excessive power to the battery 26, and it is possible to suppress the voltage VH of the high voltage system from becoming excessive. Note that even when an abnormality occurs in the second drive system including the motor MG2 and the inverter 25 and the gate of the inverter 25 is shut off, the second motor counter electromotive force Vbe2, which is a counter electromotive force generated by the rotation of the motor MG2, is a predetermined voltage. When the battery power Pb is higher than Vref and the battery power Pb is larger than the predetermined power Pref, the same effect can be achieved by controlling the inverter 25 so that the inverter 25 is in a three-phase short circuit (three-phase on) state.

  In this way, when the inverter 24 is in a three-phase short circuit state, when the rotational speed Nm1 of the motor MG1 decreases and the first motor back electromotive force Vbe1 reaches a predetermined voltage Vref or lower that is lower than or equal to the predetermined voltage Vref (step S160). Then, the inverter 24 is shut off (step S170), and this routine is finished. In the state where the inverter 24 is in a three-phase short circuit, the torque (the drag torque) corresponding to the counter electromotive force generated by the rotation of the motor MG1 is maximized in a region where the rotation speed Nm1 is relatively low, and therefore the rotation speed Nm1 of the motor MG1 is By blocking the gate of the inverter 24 in a low region where the first motor back electromotive force Vbe1 is low, the influence of the drag torque can be reduced. At this time, since the first motor back electromotive force Vbe1 is equal to or lower than the predetermined voltage Vref, excessive power is not input to the battery 26.

  FIG. 3 shows whether or not the rotational speed Nm1 of the motor MG1 and the first motor back electromotive force Vbe1 are in a high back electromotive force state higher than a predetermined voltage Vref when the abnormality occurs in the first drive system, and the battery power Pb is predetermined. It is explanatory drawing which shows an example of the mode of a time change whether it is a high electric power input state larger than electric power Pref, whether the inverter 24 is a gate interruption | blocking state, and whether the inverter 24 is a three-phase short circuit state. As shown in the figure, an abnormality occurred in the first drive system while the motor MG1 was rotating at a high rotation speed (time t1), and the inverter 24 was shut off at the gate so that a high back electromotive force state and a large power input were obtained. When the state is reached (time t2), when the high back electromotive force state and the high power input state continue for a predetermined time (time t3), the battery 26 is brought into a three-phase short circuit state by setting the inverter 24 in a three-phase short-circuit state. When the high-power input state is canceled by suppressing the supply of power to the side, and then the rotational speed Nm1 of the motor MG1 decreases and is not in the high counter electromotive force state (time t4), the inverter 24 is gated. Cut off.

  According to the drive device 20 of the embodiment described above, when an abnormality occurs in the first drive system including the motor MG1 and the inverter 24 and the gate of the inverter 24 is shut off, the back electromotive force generated by the rotation of the motor MG1. When it is confirmed that a certain first motor back electromotive force Vbe1 is higher than the predetermined voltage Vref and the battery power Pb, which is the power input to the battery 26, is larger than the predetermined power Pref, the inverter 24 is in a three-phase short circuit state. Since the inverter 24 is controlled, it is possible to suppress an excessive amount of electric power from being input to the battery 26 and to suppress an excessive increase in the high voltage system voltage VH.

  In the drive device 20 of the embodiment, when the gate of the inverter 24 is shut off, it is confirmed that the first motor back electromotive force Vbe1 is higher than the predetermined voltage Vref and the battery power Pb is higher than the predetermined power Pref. However, instead of this, when it is confirmed that the first motor back electromotive force Vbe1 is higher than the predetermined voltage Vref and the inter-terminal voltage Vb of the battery 26 is higher than the allowable voltage, the inverter It is good also as what makes 24 the state of a three-phase short circuit.

  In the driving device 20 of the embodiment, when the inverter 24 is in a three-phase short circuit state, the gate of the inverter 24 is cut off when the first motor back electromotive force Vbe1 reaches a predetermined voltage Vref or less. In addition, the inverter 24 may be gate-blocked even when the motor MG1 or the inverter 24 becomes higher than the allowable temperature by setting the inverter 24 in a three-phase short circuit state. By so doing, an excessive temperature rise in the motor MG1 and the inverter 24 can be suppressed.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor MG1 and the motor MG2 correspond to a “three-phase AC motor”, the inverter 24 and the inverter 25 correspond to an “inverter”, the battery 26 corresponds to a “battery”, and the boost converter 30 The first motor counter electromotive force that is a counter electromotive force generated by the rotation of the motor MG1 when an abnormality occurs in the first drive system including the motor MG1 and the inverter 24 and the gate of the inverter 24 is shut off. FIG. 6 is a diagram for controlling the inverter 24 so that the inverter 24 is in a three-phase short circuit state when it is confirmed that Vbe1 is higher than the predetermined voltage Vref and the battery power Pb, which is the power input to the battery 26, is larger than the predetermined power Pref. The electronic control unit 50 that executes the abnormal control routine No. 2 corresponds to a “control unit”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention is applicable to the drive device manufacturing industry.

  20 drive device, 24, 25 inverter, 26 battery, 27, 28 power line, 30 boost converter, 32, 34 smoothing capacitor, 40, 41 rotational position detection sensor, 42V, 42W, 43V, 43W, 48 current sensor, 44, 46 voltage sensor, 50 electronic control unit, D11-D16, D21-D26, D31, D32 diode, L reactor, T11-T16, T21-T26, T31, T32 transistors.

Claims (1)

A three-phase AC motor, an inverter that drives the three-phase AC motor by switching a plurality of switching elements, a secondary battery, a battery voltage system to which the secondary battery is connected, and a high-voltage system to which the inverter is connected And a step-up / step-down circuit that exchanges electric power with voltage adjustment between,
When an abnormality occurs in the drive system including the three-phase AC motor and the inverter and the inverter is gate-cut, a back electromotive force generated by the rotation of the three-phase AC motor is a predetermined voltage equal to or higher than the voltage of the high-voltage system. When it is confirmed that the power that is higher than the voltage and the power input to the secondary battery exceeds the maximum allowable power for control when charging the secondary battery, the inverter is in a three-phase short circuit state. Control means for controlling the inverter;
A drive device comprising:

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