JP2022054480A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device capable of suppressing reduction in a power generation amount of a motor generator.SOLUTION: A control ECU 14 as a vehicle control device can execute a torque mode of commanding and performing a request torque and a voltage mode of commanding and performing a request voltage in output control of outputting predetermined power to a motor generator 3, as a control mode of a motor generator 3, and executes the torque mode when an absolute value of a maximum charging amount Win of a high pressure side battery 11 is larger than a first threshold TH1, and executes the voltage mode when the absolute value is equal to or smaller than the first threshold TH1.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a vehicle control device.

In a power system of a hybrid vehicle including an engine as a vehicle drive source and a motor generator driven and connected to the engine, the power system has a high voltage side used for the motor generator and a low voltage side used for other electrical systems. There is known a configuration in which a DCDC converter is provided between a high voltage side and a low voltage side, and the voltage is stepped down by the DCDC converter to output to the low voltage side (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-137270

In the above power supply system, the power that can be used by the motor generator is within the range of the allowable power (maximum charge amount (lower limit value), maximum discharge amount (upper limit value)) of the high-voltage side battery that exchanges power with the motor generator. It is calculated to fit in. Here, due to the influence of the communication lag between the motor generator and the control ECU, there may be a difference between the actual rotation speed of the motor generator and the rotation speed read in the ECU. Due to this difference, even if the above-mentioned calculated target value of power is constant, the power actually output by the motor generator may fluctuate, and the power may be out of the allowable power range.

As a method to keep the output power of the motor generator within the allowable power range of the high-voltage side battery and protect the allowable power, a margin is taken from the upper limit value and the lower limit value of the allowable power to the range of the target value of the output power, and the output is performed. A method of narrowing the range of the target value of power to the range of allowable power can be mentioned. However, the permissible power of the battery varies depending on the environment, and the upper limit and the lower limit of the permissible power become smaller at low temperatures, for example. At this time, the margin amount of the output power may exceed the allowable power range, and in this case, the motor generator such as power generation cannot operate. As a result, the amount of power generated by the motor generator is reduced.

It is an object of the present disclosure to provide a vehicle control device capable of suppressing a decrease in the amount of power generated by a motor generator.

The vehicle control device according to one aspect of the embodiment of the present invention is a vehicle control device including an engine, a motor generator, and a high-voltage side battery connected to the motor generator, and is a control mode of the motor generator. As an output control for outputting a predetermined power to the motor generator, it is possible to execute a torque mode in which a required torque is commanded and a voltage mode in which a required voltage is commanded, and the maximum charge amount of the high-voltage side battery. The torque mode is executed when the absolute value of is larger than the first threshold value, and the voltage mode is executed when the absolute value is equal to or less than the first threshold value.

According to the present disclosure, it is possible to provide a vehicle control device capable of suppressing a decrease in the amount of power generated by a motor generator.

Schematic configuration diagram of the power supply system of the hybrid vehicle according to the embodiment Time chart showing an example of torque mode behavior The figure which shows the 1st example of the margin setting from the conventional battery allowable power. The figure which shows the 2nd example of the margin setting from the conventional battery allowable power The figure explaining the switching of the control mode in this embodiment. Diagram illustrating an overview of batteryless mode Flow chart of the first example of the control mode switching process Flowchart of the second example of the control mode switching process Flow chart of the third example of the control mode switching process

Hereinafter, embodiments will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals as possible in the drawings, and duplicate description is omitted.

FIG. 1 is a schematic configuration diagram of a power supply system system 1 of a hybrid vehicle according to an embodiment. As shown in FIG. 1, the hybrid vehicle equipped with the power supply system 1 includes an engine (ENG) 2, a motor generator (MG) 3, an air conditioner (A / C) compressor 4, and a transmission (T / M). It includes a 5, a starter 6, and another electric load 7.

The engine 2 and the MG 3 are power sources for the hybrid vehicle, and the MG 3 also functions as a power generation device. The A / C compressor 4 is a compressor of an in-vehicle air conditioner, and is driven by transmitting the power of the engine 2 or the MG 3 as shown in FIG. 1, for example. The T / M5 is a group of parts that transmit the power of the engine 2 to the wheels. The starter 6 is a device for forcibly rotating the engine 2, and is installed in, for example, a T / M 5. The electric load 7 is a device or the like mounted on a hybrid vehicle other than the MG 3 and the starter 6.

The power supply system 1 supplies electric power to an electric load 7 or the like mounted on a hybrid vehicle. The power supply system 1 includes a high-voltage side battery 11, a low-voltage side battery 12, a DCDC converter 13, and a control ECU 14 (vehicle control device).

The DCDC converter 13 is connected between the high-voltage side battery 11 and the low-voltage side battery 12, and exchanges electric power between the high-voltage side battery 11 and the low-voltage side battery 12. The high-voltage side battery 11 is also connected to the MG3 and can charge the electric power generated by the MG3. The low-voltage side battery 12 is also connected to the starter 6 and the electric load 7, and can supply the charged electric power to the starter 6 and the electric load 7.

The DCDC converter 13 steps down the power supplied from the high voltage side including the high voltage side battery 11 and outputs it to the low voltage side including the low voltage side battery 12. The voltage value of the high-voltage side battery 11 is, for example, 48V, and the voltage value of the low-voltage side battery 12 is, for example, 12V. The high-voltage side battery 11 and the low-voltage side battery 12 may have a relative voltage difference across the DCDC converter 13, and the voltage values may be other than 48V and 12V, respectively.

The DCDC converter 13 can step down the power by switching the on / off operation of the switching element, for example.

The control ECU 14 controls the operation of the power supply system 1. Further, the control ECU 14 controls the operation of the motor generator 3.

The control ECU 14 determines the allowable power (maximum charge amount (input) of the high-voltage side battery 11 based on various conditions such as the internal state (internal resistance, SOC, input / output current, etc.) of the high-voltage side battery 11 and environmental information such as outside temperature. Calculate the limit value, lower limit value) Win, and maximum discharge amount (output limit value, upper limit value) Wout).

The control ECU 14 and the motor generator 3 are connected so as to be able to transmit and receive signals by communication such as CAN. The control ECU 14 determines the required torque of the motor generator 3 based on the allowable power of the high-voltage side battery 11 and the rotation speed Nmg of the motor generator 3. The control of the motor generator 3 by the control ECU 14 can also be expressed as calculating the power that can be used by the motor generator 3 in order to protect the allowable power of the high-voltage side battery 11. Alternatively, it can be expressed that the output power of the motor generator 3 is controlled so as to be within the allowable power range of the high-voltage side battery 11.

In particular, in the present embodiment, the control ECU 14 sets the control mode of the motor generator 3 to the "torque mode" in which the output control for outputting a predetermined power to the motor generator 3 is performed by commanding the above-mentioned required torque, and the required voltage. It is possible to execute a "voltage mode" that commands and performs. The control ECU 14 executes the "torque mode" when the absolute value of the maximum charge amount Win of the high-voltage side battery 11 is larger than the first threshold value TH1 (see FIG. 5 and the like), and executes the "torque mode" when the first threshold value TH1 or less. Is executed. Further, the control ECU 14 can execute a "batteryless mode" as a control mode of the motor generator 3 to stop power transfer between the motor generator 3 and the high-voltage side battery 11. The control ECU 14 executes the batteryless mode when the absolute value of the maximum charge amount Win of the high-voltage side battery 11 is smaller than the first threshold value TH1 and is equal to or less than the second threshold value TH2.

The control ECU 14 is physically an electronic circuit mainly composed of a well-known microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an interface. Each function of the control ECU 14 described above is to operate various devices in the vehicle under the control of the CPU by loading the application program held in the ROM into the RAM and executing the application program in the RAM, and also in the RAM and the ROM. It is realized by reading and writing data.

The problems of the conventional torque mode will be described with reference to FIGS. 2 to 4. FIG. 2 is a time chart showing an example of the behavior of the torque mode. FIG. 2 shows the actual rotation speed of the motor generator 3 (actual Nmg), the rotation speed of the motor generator 3 acquired by the control ECU 14 (Nmg in the ECU), the required torque calculated by the control ECU 14, and the required torque. Based on the above, the time transition with the power (MG power) actually output by the motor generator 3 is shown.

As shown in the graph of the actual Nmg in FIG. 2, the rotation speed of the motor generator 3 has a fluctuation range even in the steady state. Further, as shown in the graph of Nmg in the ECU of FIG. 2, the information on the rotation speed arrives at the control ECU 14 with a delay of communication. That is, the Nmg in the ECU has a time delay with respect to the actual Nmg.

As shown in the graph of the required torque in FIG. 2, the required torque fluctuates even when the required power is constant. Then, as shown in the graph of MG power in FIG. 2, the deflection of MG power may be amplified depending on the timing of the actual Nmg and the required torque. Even if the required torque is smoothed and constant, the fluctuation of the actual Nmg remains in the behavior of MG power.

Such a fluctuation of MG power can be caused by, for example, a configuration in which the motor generator 3 transmits power to the engine 2 via a belt as shown in FIG. 1, or a play portion (the motor generator 3 can move) in the tensioner of this belt. However, the engine 2 does not work) is likely to occur in the presence of the configuration.

As described above, the MG power needs to be controlled so as to fall within the allowable power range of the high voltage side battery 11, that is, between the maximum discharge amount Wout and the maximum charge amount Win. This is because when the MG power exceeds the allowable power range, the high-voltage side battery 11 is over-discharged or over-charged, which causes deterioration of the battery. As a method for satisfying this requirement (MG power falls within the allowable power range of the high-voltage side battery 11) in consideration of the variation due to the fluctuation of MG power, the upper limit value (maximum discharge amount Wout) and the lower limit value (maximum discharge amount Wout) of the allowable power (maximum discharge amount Wout) and the lower limit value ( A method of taking a margin from the maximum charge amount Win) to the range of MG power and narrowing the range of MG power within the range of allowable power and narrower than the range of allowable power can be mentioned.

FIG. 3 is a diagram showing a first example of margin setting from the conventional battery allowable power. The vertical axis of FIG. 3 indicates electric power, and the horizontal axis indicates time. In the following description of the present embodiment including FIG. 3, the maximum discharge amount Wout is represented as a positive value, and the maximum charge amount Win is represented as a negative value. In the example of FIG. 3, a predetermined amount of margin is set in the positive direction from the position of the maximum charge amount Win of the lower limit value of the allowable power, and the power value obtained by taking the margin from the maximum charge amount Win is shown by a dotted line. By taking this margin larger than the fluctuation width of the MG power, it is possible to prevent the MG power from exceeding the allowable power of the high-voltage side battery 11 even when the MG power swings.

FIG. 4 is a diagram showing a second example of margin setting from the conventional battery allowable power. The outline of the axes and the like in FIG. 4 is the same as that in FIG. In FIG. 4, the positions of the maximum discharge amount Wout and the maximum charge amount Win are closer to 0 as compared with FIG. That is, the absolute values of the maximum discharge amount Wout and the maximum charge amount Win are small.

In the method shown in FIG. 3, the larger the variation in MG power, the more the allowable power is to be protected by the margin. If you try to protect it, you need a larger margin amount. That is, the position of the margin moves in the more positive direction from the position of the maximum charge amount Win of the lower limit value of the allowable power.

On the other hand, the allowable power of the battery tends to fluctuate depending on the environment. For example, at low temperature, the upper limit value (maximum discharge amount Wout) and lower limit value (maximum charge amount Win) of the allowable power are relatively small as shown in FIG. Become. At this time, if the margin amount of MG power is the same as in FIG. 3, the position of the margin with respect to the maximum charge amount Win, which is the lower limit value, becomes a value larger than the maximum discharge amount Wout, which is the upper limit value, as shown in FIG. , The allowable power range may be exceeded. In this case, since the MG power cannot satisfy the requirement of the allowable power of the battery, the motor generator 3 such as power generation cannot be operated. As a result, the amount of power generated by the motor generator 3 decreases due to the period during which the motor generator 3 cannot generate power. Similarly, there may be a period during which the motor generator 3 cannot be driven as an electric motor.

The output control of the motor generator 3 according to the present embodiment will be described with reference to FIGS. 5 to 9. FIG. 5 is a diagram illustrating switching of control modes in the present embodiment. The outline of the axes and the like in FIG. 5 is the same as in FIGS. 3 and 4. As described with reference to FIG. 4, when the output control of the motor generator 3 is performed in the torque mode, the upper limit value (maximum discharge amount Wout) and the lower limit value (maximum charge amount Win) of the allowable power are relative to each other, for example, at low temperature. When it becomes smaller, that is, when the absolute values of the maximum discharge amount Wout and the maximum charge amount Win become small and the electric power approaches 0, a situation may occur in which the motor generator 3 cannot operate only by the method of providing a margin to the MG power.

Therefore, in the present embodiment, the torque mode is executed when the maximum charge amount Win (negative value), which is the lower limit of the allowable power, is small, that is, when it is large in the negative direction (when the absolute value of the maximum charge amount Win is large). As shown in FIG. 5, when the maximum charge amount Win is equal to or higher than the first threshold value TH1, that is, when the absolute value of the maximum charge amount Win is equal to or less than the absolute value of the first threshold value TH1 and the power is close to 0, the torque mode is used. Run voltage mode without running. When controlled in the voltage mode, the torque is generated by calculating inside the MG so that the required power can be realized, so that the output control of the MG power can be realized with the accuracy equivalent to that of the conventional technology.

Further, as shown in FIG. 5, when the maximum charge amount Win is larger than the first threshold TH1 and the second threshold TH2 or more, that is, the absolute value of the maximum charge amount Win is smaller than the absolute value of the first threshold TH1. When the value becomes TH2 or less and the power becomes closer to 0, the voltage mode cannot be used, so the batteryless mode is executed without executing the voltage mode.

FIG. 6 is a diagram illustrating an outline of the batteryless mode. As shown in FIG. 6, in the batteryless mode, the allowable power of the high-voltage side battery 11 cannot be maintained. Therefore, the relay of the high-voltage side battery 11 is turned off and disconnected, and the portion consumed by the DCDC converter 13 is consumed by the motor generator 3. Switch to control to generate electricity. Since no current flows through the high-voltage side battery 11, the vehicle can generate electricity while maintaining the allowable electric power.

The mode switching of the output control of the motor generator 3 may be only the switching between the torque mode and the voltage mode among the three-stage configuration shown in FIG.

FIG. 7 is a flowchart of a first example of the control mode switching process. In the example of FIG. 7, two types of mode switching between the torque mode and the voltage mode are performed.

In step S101, it is determined whether or not the maximum charge amount Win is smaller than the first threshold value TH1 (whether or not the absolute value of the maximum charge amount Win is larger than the absolute value of the first threshold value TH1). When the maximum charge amount Win is smaller than the first threshold value TH1 (YES in step S101), the process proceeds to step S102, the torque mode is executed, and the torque request is made in consideration of the margin. On the other hand, when the maximum charge amount Win is equal to or higher than the first threshold value TH1 (the absolute value of the maximum charge amount Win is equal to or less than the absolute value of the first threshold value TH1) (NO in step S101), the process proceeds to step S103 and the voltage mode is executed. Will be done.

As described above, in the present embodiment, the torque mode is executed when the absolute value of the maximum charge amount Win of the high-voltage side battery 11 is larger than the absolute value of the first threshold value TH1, and when it is equal to or less than the absolute value of the first threshold value TH1. Run voltage mode. In the voltage mode, the fluctuation of the power of the motor generator 3 is reduced as compared with the torque mode, so that the margin (the margin amount of the output power (MG power) of the motor generator 3 with respect to the allowable power range of the high voltage side battery 11) is set. Can be made smaller. Therefore, even in a situation where the allowable power range of the high-voltage side battery 11 is narrowed and the motor generator 3 cannot operate in the conventional torque mode, the motor generator 3 can be operated by executing the voltage mode instead of the torque mode. It will be possible. As a result, the period during which the motor generator 3 cannot generate power can be reduced, so that it is possible to suppress a decrease in the amount of power generated by the motor generator 3.

FIG. 8 is a flowchart of a second example of the control mode switching process. In the example of FIG. 8, three types of mode switching, a torque mode, a voltage mode, and a batteryless mode, are performed.

In step S201, it is determined whether or not the maximum charge amount Win is smaller than the first threshold value TH1 (whether or not the absolute value of the maximum charge amount Win is larger than the absolute value of the first threshold value TH1). When the maximum charge amount Win is smaller than the first threshold value TH1 (YES in step S201), the process proceeds to step S202, the torque mode is executed, and the torque request is made in consideration of the margin.

On the other hand, when the maximum charge amount Win is equal to or higher than the first threshold value TH1 (NO in step S201), the process proceeds to step S203, and whether or not the maximum charge amount Win is smaller than the second threshold value TH2 (absolute value of the maximum charge amount Win). Is greater than the absolute value of the second threshold TH2)) is determined. If the maximum charge amount Win is smaller than the second threshold value TH2 (YES in step S203), the process proceeds to step S204, and the voltage mode is executed.

On the other hand, when the maximum charge amount Win is the second threshold value TH2 or more (NO in step S203), the process proceeds to step S205, and control is performed in the batteryless mode.

As described above, in the present embodiment, when the absolute value of the maximum charge amount Win of the high-voltage side battery 11 is smaller than the absolute value of the first threshold TH1 and equal to or less than the absolute value of the second threshold TH2, the battery is not used instead of the voltage mode. Run the mode. With this configuration, even in a situation where the MG power cannot be prevented from exceeding the allowable power range of the high-pressure side battery 11 in the torque mode or the voltage mode, the electric connection between the motor generator 3 and the high-pressure side battery 11 is cut off by the batteryless mode. By doing so, it becomes possible to generate power of the motor generator 3 while suppressing the influence on the high voltage side battery 11. As a result, the period during which the motor generator 3 cannot generate power can be further reduced, so that the decrease in the amount of power generated by the motor generator 3 can be further suppressed.

FIG. 9 is a flowchart of a third example of the control mode switching process. In the flowchart of FIG. 9, when the maximum charge amount Win excess is detected, the torque mode is switched to the voltage mode, and when the excess is detected in the voltage mode, the batteryless mode is switched.

In step S301, it is determined whether or not the current control mode is the torque mode. In the case of the torque mode (YES in step S301), the process proceeds to step S302, and in the case of not the torque mode (NO in step S301), the process proceeds to step S305.

In step S302, it is determined whether or not the MG power exceeds the maximum charge amount Win during the execution of the torque mode. The excess determination can be determined, for example, when the MG power exceeds the maximum charge amount Win when the time during which the excess state continues is a predetermined value or more.

If the MG power does not exceed the maximum charge amount Win during execution of the torque mode (NO in step S302), the process proceeds to step S303, the torque mode is continued, and the torque request is made in consideration of the margin. On the other hand, if the MG power exceeds the maximum charge amount Win during the execution of the torque mode (YES in step S302), the process proceeds to step S304 and the mode is switched to the voltage mode.

In step S305, it is determined whether or not the current control mode is the voltage mode. In the case of the voltage mode (YES in step S305), the process proceeds to step S306, and in the case of not the voltage mode (NO in step S305), the process proceeds to step S307, and the batteryless mode is continued.

In step S306, it is determined whether or not the MG power exceeds the maximum charge amount Win during the execution of the voltage mode. The excess determination can be performed by the same method as in step S302.

If the MG power does not exceed the maximum charge amount Win during execution of the voltage mode (NO in step S306), the process proceeds to step S304, and the voltage mode is continued. On the other hand, if the MG power exceeds the maximum charge amount Win during the execution of the voltage mode (YES in step S306), the process proceeds to step S307 and the mode is switched to the batteryless mode.

In this way, by performing control to switch the control mode each time when the maximum charge amount Win excess of the MG power is detected, it is possible to continuously maintain the state in which the MG power is within the allowable power range of the high-voltage side battery 11. As a result, the period during which the motor generator 3 cannot generate power can be reduced, so that it is possible to suppress a decrease in the amount of power generated by the motor generator 3.

Further, in addition to the processing of the flowchart of FIG. 9, the processing of recovering from the batteryless mode to the voltage mode and the torque control may be performed with the recovery of the maximum charge amount Win.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. These specific examples with appropriate design changes by those skilled in the art are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element provided in each of the above-mentioned specific examples, its arrangement, conditions, a shape, and the like are not limited to those exemplified, and can be appropriately changed. The combinations of the elements included in each of the above-mentioned specific examples can be appropriately changed as long as there is no technical contradiction.

1 Power supply system 2 Engine 3 Motor generator 11 High-voltage side battery 14 Control ECU (Vehicle control unit)

Claims (2)

With the engine
With a motor generator
The high-voltage side battery connected to the motor generator and
Is a vehicle control device equipped with
As the control mode of the motor generator, it is possible to execute an output control in which a predetermined power is output to the motor generator, a torque mode in which a required torque is commanded and a voltage mode in which a required voltage is commanded.
The torque mode is executed when the absolute value of the maximum charge amount of the high-voltage side battery is larger than the first threshold value, and the voltage mode is executed when the absolute value is equal to or less than the first threshold value.
Vehicle control unit. As a control mode of the motor generator, a batteryless mode for stopping power transfer between the motor generator and the high-voltage side battery can be executed.
The batteryless mode is executed when the absolute value is equal to or less than the second threshold value smaller than the first threshold value.
The vehicle control device according to claim 1.

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