JP2019097224A - Control device of electric vehicle - Google Patents

Abstract

To provide a control device of an electric vehicle capable of suppressing a semiconductor device of an inverter, a buck-boost converter, or a DC/DC converter from becoming hot at the time of discharging of at least one of first and second capacitors.SOLUTION: At the time of discharging of at least one of first capacitor 46 and second capacitor 48, a control device 70 of an electrically-powered vehicle 20 compares the element temperatures of semiconductor elements of at least two of an inverter 34, a buck-boost converter 40, and DC/DC converter 54, and controls a cryogenic device having the lowest element temperature of the at least two devices to operate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an electric vehicle, and more specifically, mounted on an electric vehicle including a motor, an inverter, a storage device, a buck-boost converter, first and second capacitors, and a DC / DC converter. Control device.

  Conventionally, a control device of this type of electric vehicle is mounted on an electric vehicle including a motor (electric motor), an inverter, a power storage device, a buck-boost converter (converter), and first and second capacitors. A thing is proposed (for example, refer to patent documents 1). The inverter has a plurality of semiconductor elements (switching elements) to drive the motor. The buck-boost converter has a plurality of semiconductor elements (switching elements) and a reactor, and is connected to a first power line (power line) to which an inverter is connected and a second power line (power line) to which a power storage device is connected. There is. The first capacitor is attached to the first power line. The second capacitor is attached to the second power line. The control device controls semiconductor elements of an inverter and a buck-boost converter. Then, when the temperature of the semiconductor element of the inverter is lower than a predetermined temperature, the inverter is energized, and when the temperature of the semiconductor element of the inverter exceeds the predetermined temperature, the gate voltage of the semiconductor element constituting the inverter is set to 0 It is assumed that 0. By such control, the first and second capacitors are discharged while suppressing the semiconductor element of the inverter from becoming high temperature.

International Publication No. 2012/160700

  In the above-described control device for an electrically powered vehicle, when the semiconductor element of the inverter reaches a high temperature, the amount of energization of the inverter is set to 0, so that the first and second capacitors can not be discharged. Therefore, when it is necessary to discharge the first and second capacitors promptly, there arises a disadvantage that it can not be dealt with. As a method of avoiding such a problem, a method of operating the buck-boost converter to discharge the first and second capacitors can be considered. However, if the buck-boost converter is operated when the semiconductor device of the buck-boost converter is at a high temperature, the semiconductor device will be at a higher temperature.

  In the control device for an electric vehicle according to the present invention, when discharging at least one of the first and second capacitors, it is mainly to suppress that the semiconductor elements of the inverter, the buck-boost converter and the DC / DC converter become high temperature. To aim.

  The control device for an electric vehicle according to the present invention adopts the following means in order to achieve the above-mentioned main object.

The control device of the electric vehicle of the present invention is
Motor,
An inverter having at least one semiconductor element and driving the motor;
A storage device,
At least one semiconductor element and a reactor, and connected to a first power line to which the inverter is connected and a second power line to which the power storage device is connected, the second power line and the first power line A buck-boost converter that exchanges power with the conversion of voltage between
A first capacitor attached to the first power line;
A second capacitor attached to the second power line;
A DC / DC converter having at least one semiconductor element and connected to the first power line;
A control device for an electrically powered vehicle mounted on an electrically powered vehicle including the inverter, the buck-boost converter, and the DC / DC converter,
When discharging at least one of the first and second capacitors, the element temperature of the semiconductor element of at least two devices among the inverter, the buck-boost converter, and the DC / DC converter is compared, and the at least two Controlling the cryogenic device so that the cryogenic device having the lowest element temperature of the two devices operates.
Make it a gist.

  In the control device for an electric vehicle according to the present invention, when discharging at least one of the first and second capacitors, the element temperatures of the semiconductor elements of at least two of the inverter, the buck-boost converter and the DC / DC converter are compared. In comparison, the cryogenic device is controlled to activate the operation of the cryogenic device having the lowest element temperature of at least two devices. Thereby, when discharging at least one of the first and second capacitors, it is possible to suppress that the semiconductor elements of the inverter, the buck-boost converter, and the DC / DC converter become high temperature.

  In the control device for an electric vehicle according to the present invention, the low temperature device operates such that the low temperature device operates when at least one of the first and second capacitors is discharged by detecting a collision of the electric vehicle. May be controlled. In this way, when the collision of the electric vehicle is detected and at least one of the first and second capacitors is discharged, the semiconductor elements of the inverter, the buck-boost converter, and the DC / DC converter are prevented from becoming hot. Can.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 which mounts the control apparatus as one Example of this invention. 5 is a flowchart showing an example of a control routine executed by the ECU 70.

  Next, modes for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 equipped with a control device as an embodiment of the present invention. As illustrated, the electric vehicle 20 according to the embodiment includes the motor 32, the inverter 34, the main battery 36, the buck-boost converter 40, the capacitors 46 and 48, the accessory battery 50, and the DC / DC converter 54. , System main relay SMR, and an electronic control unit (hereinafter referred to as "ECU") 70.

  The motor 32 is configured as a synchronous generator motor, and includes a rotor in which permanent magnets are embedded, and a stator in which a three-phase coil is wound. The rotor of the motor 32 is connected to a drive shaft 26 connected to drive wheels 22 a and 22 b via a differential gear 24.

  The inverter 34 is connected to the motor 32 and to a high voltage system power line 42 a as a first power line. The inverter 34 includes a plurality of transistors (switching elements) (not shown) which are power semiconductor elements. The motor 32 is rotationally driven by switching control of the plurality of transistors of the inverter 34 by the ECU 70 when a voltage is applied to the high voltage system power line 42 a.

  The main battery 36 is configured, for example, as a lithium ion secondary battery or a nickel hydrogen secondary battery with a rated voltage of 200 V or 250 V, and is connected to a low voltage system power line 42 b as a second power line.

  The buck-boost converter 40 is connected to the high voltage system power line 42 a and the low voltage system power line 42 b. The buck-boost converter has two transistors T31 and T32 which are power semiconductor elements, two diodes D31 and D32 connected in parallel to the transistors T31 and T32, and a reactor L. The transistor T31 is connected to the positive electrode side line of the high voltage system power line 42a. The transistor T32 is connected to the transistor T31 and the negative electrode side line of the high voltage system power line 42a and the low voltage system power line 42b. The reactor L is connected to a connection point between the transistors T31 and T32 and the positive electrode side line of the low voltage system power line 42b. The step-up / down converter 40 boosts the power of the low voltage system power line 42b and supplies it to the high voltage system power line 42a or the high voltage system by adjusting the ratio of the on time of the transistors T31 and T32 by the ECU 70. The power of the power line 42a is stepped down and supplied to the low voltage system power line 42b. The capacitor 46 is attached to the positive electrode side line and the negative electrode side line of the high voltage system power line 42a, and the capacitor 48 is attached to the positive electrode side line and the negative electrode side line of the low voltage system power line 42b.

  For example, the auxiliary battery 50 is configured as a lead storage battery with a rated voltage of 12 V or 14 V, and is connected to the auxiliary power line 42c as a third power line. In addition to the accessory battery 50, a plurality of accessories 52 such as a headlight, a room lamp, an audio system, a power window, a seat heater, and the ECU 70 are connected to the accessory power line 42c.

  The DC / DC converter 54 is configured as a known step-down circuit including a transistor (switching element) which is a power semiconductor element, a transformer, and a rectifier circuit. The DC / DC converter 54 controls the switching of the transistor by the ECU 70 to convert the power from the main battery 36 from direct current to alternating current by the transistor, step down the converted power by the transformer, and rectify the stepped down power by the rectifier circuit. It rectifies and supplies to the auxiliary battery 50 and the auxiliary machine 52.

  System main relay SMR is provided closer to main battery 36 than capacitor 48 in low voltage system power line 42b. The system main relay SMR is on / off controlled by the ECU 70 to connect and disconnect the main battery 36 and the capacitor 48 side.

  The ECU 70 is configured as a microprocessor centered on a CPU (not shown), and includes a ROM for storing processing programs and various maps, a RAM for temporarily storing data, and an input / output port in addition to the CPU.

  Signals from various sensors are input to the ECU 70 through input ports. As a signal input to the ECU 70, for example, the rotational position θm from the rotational position detection sensor 32a that detects the rotational position of the rotor of the motor 32, and the phase from the current sensor that detects the current flowing in each phase of the motor 32 The currents Iu and Iv can be mentioned. In addition, the voltage Vmb of the main battery 36 from the voltage sensor 36a attached between the terminals of the main battery 36 and the current Imb of the main battery 36 from the current sensor 36b attached to the output terminal of the main battery 36 may also be listed. it can. Furthermore, the voltage VH of the capacitor 46 (high voltage system power line 42a) from the voltage sensor 46a attached between the terminals of the capacitor 46 and the capacitor 48 (low voltage) from the voltage sensor 48a attached between the terminals of the capacitor 48 The voltage VL of the system power line 42b and the current IL of the reactor L from the current sensor 40a that detects the current flowing through the reactor L of the buck-boost converter 40 can also be mentioned. In addition, the voltage Vhb of the auxiliary battery 50 from the voltage sensor 50a attached between the terminals of the auxiliary battery 50 can also be mentioned. The element temperature T1 from the temperature sensor 34a that detects the temperature of one of the plurality of transistors of the inverter 34, the element temperature T2 from the temperature sensor 40b that detects the temperature of the transistor T32 in the buck-boost converter 40, and DC The element temperature T3 from the temperature sensor 54a that detects the temperature of the transistor of the DC / DC converter 54 can also be mentioned. In addition, the ignition signal from the ignition switch 80 and the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81 can also be mentioned. In addition, the accelerator opening Acc from the accelerator pedal position sensor 84 for detecting the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, and the vehicle speed sensor 88 The vehicle speed V and the vehicle acceleration α from the acceleration sensor 89 can also be mentioned.

  Various control signals are output from the ECU 70 via the output port. As signals output from the ECU 70, for example, switching control signals to a plurality of transistors (not shown) of the inverter 34, switching control signals to the transistors T31 and T32 of the step-up / down converter 40, transistors to the DC / DC converter 54 Switching control signals can be mentioned. The ECU 70 calculates the electrical angle θe and the rotational speed Nm of the motor 32 based on the rotational position θm of the rotor of the motor 32 from the rotational position detection sensor 32a. Further, the ECU 70 calculates the state of charge SOC of the main battery 36 based on the integrated value of the current Imb of the main battery 36 from the current sensor 36 b. Here, the storage ratio SOC is a ratio of the capacity of power that can be discharged from the main battery 36 to the total capacity of the main battery 36.

  In the electrically powered vehicle 20 of the embodiment configured in this manner, the ECU 70 performs the following travel control. In the traveling control, the required torque Td * required for the drive shaft 26 is set based on the accelerator opening Acc and the vehicle speed V, and the set required torque Td * is set for the torque command Tm * of the motor 32. Performs switching control of a plurality of transistors of the inverter 34 so as to be driven by the torque command Tm *. Further, target voltage VH * of high voltage system power line 42a is set so that motor 32 can be driven at the target operating point (torque command Tm * and rotation speed Nm), and voltage VH of high voltage system power line 42a is the target voltage The switching control of the transistors T31 and T32 of the buck-boost converter 40 is performed so as to be VH *. Furthermore, switching control of the transistors of the DC / DC converter 54 is performed so that the power of the low voltage system power line 42 b is stepped down by the DC / DC converter 54 and supplied to the accessory system power line 42 c.

  Next, the operation of the electrically powered vehicle 20 of the embodiment configured as described above, in particular, the operation when a collision of the vehicle is detected will be described. FIG. 2 is a flowchart showing an example of a control routine executed by the ECU 70. This routine is executed when a vehicle collision is detected. In the embodiment, the ECU 70 detects a collision of the vehicle when the vehicle acceleration α detected by the acceleration sensor 89 reaches less than the negative threshold αref for collision determination.

  When this routine is executed, the CPU of the ECU 70 executes a process of turning off the system main relay SMR (step S100). Subsequently, a process of inputting the element temperatures T1 to T3 is executed (step S110). The element temperatures T1 to T3 are input from the temperature sensors 34a, 40b and 54a.

  Subsequently, the lowest temperature of the element temperatures T1 to T3 is set to the lowest temperature Tmin (step S120), and it is checked in step S120 which temperature of the element temperatures T1 to T3 is set to the lowest temperature Tmin (step S120) S130). When the element temperature T1 is set to the minimum temperature Tmin, torque is not output from the motor 32 (so that d-axis current flows in the motor 32). The capacitor 46 is discharged (motor discharge) by the switching of each transistor and the consumption of electric power by the winding of the motor 32 (step S140), and this routine is finished. At this time, the gates of the transistors T31 and T32 of the buck-boost converter 40 and the transistors of the DC / DC converter 54 are turned off. As described above, since the transistor of the inverter 34 having the transistor at the lowest temperature in step S130 is switching-controlled to discharge the capacitor 48, the transistors T31 and T32 of the buck-boost converter 40 and the transistors of the DC / DC converter 54 are Compared to when switching control is performed, each transistor can be prevented from reaching high temperatures.

  When the element temperature T2 is set to the minimum temperature Tmin in step S130, the transistors T31 and T32 of the buck-boost converter 40 are turned on and off to discharge the capacitors 46 and 48 by the operation of the buck-boost converter 40 (buck-boost converter discharge). Then (step S150), this routine ends. Here, the transistor T31 of the step-up / down converter 40 is turned off and the transistor T32 is turned on to discharge the capacitor 48, and the transistor T31 is turned on and the transistor T32 is turned off to discharge the capacitor 46. At this time, the gates of the transistors of the inverter 34 and the transistors of the DC / DC converter 54 are turned off. As described above, the transistors T31 and T32 of the step-up / down converter 40 having the transistor at the lowest temperature in the process of step S130 are switching-controlled to discharge the capacitors 46 and 48. Compared to switching control of the transistors of the converter 54, each transistor can be prevented from reaching high temperatures.

  When the element temperature T3 is set to the minimum temperature Tmin in step S130, the transistors of the DC / DC converter 54 are repeatedly turned on and off to discharge the capacitor 48 by the operation of the DC / DC converter 54 (DC / DC converter discharge). (Step S160), this routine ends. At this time, the gates of the transistors of the inverter 34 and the transistors T31 and T32 of the buck-boost converter 40 are turned off. As described above, the transistor of the DC / DC converter 54 having the transistor at the lowest temperature in the process of step S130 is switching-controlled to discharge the capacitor 48. Therefore, each transistor of the inverter 34 and the transistor T31 of the buck-boost converter 40 , T32 can be suppressed from reaching high temperatures as compared to when switching control is performed.

  According to the electric vehicle 20 of the embodiment described above, when discharging at least one of the capacitors 46 and 48, the element temperature T1 of the inverter 34, the element temperature T2 of the buck-boost converter 40, and the DC / DC converter 54 By comparing the element temperature T3 and operating the device having the lowest element temperature among the inverter 34, the buck-boost converter 40, and the DC / DC converter 54, the inverter 34, the buck-boost converter 40, and the DC / DC converter 54 are operated. It is possible to suppress that each transistor becomes high temperature.

  In the electrically powered vehicle 20 of the embodiment, the temperature of one of the plurality of transistors is used as the element temperature T1 of the inverter 34. However, the highest one of the temperatures of at least two of the plurality of transistors of the inverter 34 may be the element temperature T1, or the average of the temperatures of at least two of the plurality of transistors of the inverter 34 may be the element temperature T1.

  In the electrically powered vehicle 20 of the embodiment, the temperature of the transistor T32 is the element temperature T2 of the buck-boost converter 40. However, the temperature of the transistor T31 may be the element temperature T2, the higher one of the transistors T31 and T32 may be the element temperature T2, or the average of the temperatures of the transistors T31 and T32 may be the element temperature T3.

  In the electrically powered vehicle 20 of the embodiment, the temperature of the transistor of the DC / DC converter 54 is the element temperature T3. However, when the DC / DC converter 54 includes a plurality of transistors, the temperature of one of the plurality of transistors may be the element temperature T3, or the highest temperature among the temperatures of the plurality of transistors may be the element temperature. The element temperature T3 may be an average of at least two temperatures of a plurality of transistors.

  In the electric vehicle 20 according to the embodiment, the element temperature T1 of the inverter 34, the element temperature T2 of the buck-boost converter 40, and the element temperature T3 of the DC / DC converter 54 are compared. The device with the lowest element temperature among 54 is operated. However, comparing at least two of the element temperature T1 of the inverter 34, the element temperature T2 of the buck-boost converter 40, and the element temperature T3 of the DC / DC converter 54, It is also good.

  In the electric vehicle 20 of the embodiment, when a collision of the vehicle is detected, the control routine illustrated in FIG. 2 is executed. However, execution of the control routine illustrated in FIG. 2 is not limited to detection of a vehicle collision, and may be performed at any time when discharging at least one of the capacitors 46 and 48. I don't care.

  In the electric vehicle 20 of the embodiment, the main battery 36 is used as the power storage device, but any device capable of storing power may be used, and a capacitor or the like may be used.

  In the embodiment, the present invention is applied to an electric powered vehicle that travels with power from a motor without an engine. However, the present invention may be applied to an electric vehicle of a type having an engine and a motor and traveling using power from the engine and power from the motor.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the section of "Means for Solving the Problems" will be described. In the embodiment, the motor 32 corresponds to a "motor", the inverter 34 corresponds to an "inverter", the main battery 36 corresponds to a "power storage device", and the buck-boost converter 40 corresponds to a "buck-boost converter" The capacitor 46 corresponds to the "first capacitor", the capacitor 48 corresponds to the "second capacitor", and the DC / DC converter 54 corresponds to the "DC / DC converter".

  In addition, the correspondence of the main elements of the embodiment and the main elements of the invention described in the section of the means for solving the problem implements the invention described in the column of the means for solving the problem in the example. The present invention is not limited to the elements of the invention described in the section of “Means for Solving the Problems”, as it is an example for specifically explaining the mode for carrying out the invention. That is, the interpretation of the invention described in the section of the means for solving the problem should be made based on the description of the section, and the embodiment is an embodiment of the invention described in the section of the means for solving the problem. 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 by these Examples, In the range which does not deviate from the summary of this invention, it becomes various forms Of course it can be implemented.

  The present invention is applicable to the manufacturing industry of electric vehicles and the like.

  DESCRIPTION OF SYMBOLS 20 electric vehicle, 22a, 22b driving wheel, 24 differential gear, 26 drive shaft, 32 motor, 32a rotational position detection sensor, 34 inverter, 34a, 40b, 54a temperature sensor, 36 main battery, 36a, 46a, 48a, 50a voltage Sensor, 36b, 40a current sensor, 40 buck-boost converter, 42a high voltage system power line, 42b low voltage system power line, 42c accessory system power line, 46, 48 capacitor, 50 accessory battery, 52 accessory, 54 DC / DC converter, 70 electronic control unit (ECU), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position Nsensa, 88 vehicle speed sensor, 89 acceleration sensor, D31, D32 diodes, L reactor, SMR system main relay, T31, T32 transistor.

Claims (1)

Motor,
An inverter having at least one semiconductor element and driving the motor;
A storage device,
At least one semiconductor element and a reactor, and connected to a first power line to which the inverter is connected and a second power line to which the power storage device is connected, the second power line and the first power line A buck-boost converter that exchanges power with the conversion of voltage between
A first capacitor attached to the first power line;
A second capacitor attached to the second power line;
A DC / DC converter having at least one semiconductor element and connected to the first power line;
A control device for an electrically powered vehicle mounted on an electrically powered vehicle including the inverter, the buck-boost converter, and the DC / DC converter,
When discharging at least one of the first and second capacitors, the element temperature of the semiconductor element of at least two devices among the inverter, the buck-boost converter, and the DC / DC converter is compared, and the at least two Controlling the cryogenic device so that the cryogenic device having the lowest element temperature of the two devices operates.
Control device for an electric vehicle.

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