Control device

Abstract

To provide a control device which suppresses the deterioration in vehicle performance by performing the appropriate switching of charging mode in accordance with the deterioration in battery charging rate.SOLUTION: A control device includes: a battery which can be charged and discharged between a rotary electric machine and the battery;, a load to which electric power is supplied from the battery; the rotary electric machine which converts the electric power supplied from the battery to torque and transfers the torque to a wheel, or generates electric power from a rotation force of the wheel and supplies the electric power to the battery; a converter which performs power conversion between the battery and the rotary electric machine; and a control part which outputs a control signal to the rotary electric machine. The control part switches over among a torque control mode which outputs the control signal based on wheel transmission torque to the converter, a charging priority mode which decreases power supply to the rotary electric machine and the load and precedes power supply to the battery, and a voltage control mode which outputs the control signal based on a voltage of the rotary electric machine to the converter when a difference between a present charging rate of the battery and a charging rate when the charging rate gets to the first predetermined value or less is a second predetermined value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device. [Background technology]

[0002] A vehicle that includes a motor as a power source is provided with a battery that can charge and discharge power between the motor. Patent Document 1 discloses a technology for charging the battery in an electric vehicle by using the motor that rotates in conjunction with the wheels of the vehicle as a generator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-125502 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the regenerative braking control method of the electric vehicle shown in Patent Document 1, the regenerative ECU of the battery may overestimate the decrease in the battery's charging rate due to delayed control response when restoring the battery's charging rate or increased use of in-vehicle equipment, and may switch the motor that powers the vehicle from torque control to voltage control. This may result in unnecessary functional restrictions on the various devices in the vehicle, and may result in a decrease in vehicle performance.

[0005] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a control device that suppresses deterioration of vehicle performance by appropriately switching charging modes in response to a decrease in the battery's charging rate. [Means for solving the problem]

[0006] A control device including a control unit that outputs a control signal to a converter to switch between a plurality of control modes for controlling a rotating electric machine that transmits torque for a vehicle to run, the control device including a storage battery that can be charged and discharged between the rotating electric machine, a load to which power is supplied from the storage battery, the rotating electric machine that converts the power supplied from the storage battery into torque and transmits it to wheels of the vehicle, or generates power from the rotational force of the wheels and supplies it to the storage battery, a converter that performs power conversion when charging and discharging between the storage battery and the rotating electric machine, converts the power from the storage battery and supplies it to the load, and is connected to the storage battery, the rotating electric machine, and the converter. and a control unit capable of outputting a control signal to the rotating electric machine, wherein the control unit performs control by switching between a torque control mode in which a control signal based on the torque to be transmitted to the wheels is output to the converter for control, a charge priority mode in which, when the charging rate of the storage battery falls below a first predetermined value in the torque control mode, power supply to the rotating electric machine and the load is reduced to prioritize power supply to the storage battery, and a voltage control mode in which, when the difference between the current charging rate of the storage battery and the charging rate when it fell below the first predetermined value falls below a second predetermined value, a control signal based on the voltage of the rotating electric machine is output to the converter for control. Effect of the Invention

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a control device that suppresses deterioration of vehicle performance by appropriately switching charging modes in response to a decrease in the battery's charging rate. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a vehicle equipped with a control device according to an embodiment. [Diagram 2] FIG. 4 is a diagram illustrating an example of an operation of the control device according to the embodiment. [Diagram 3] 5 is a timing chart showing a change in the charging rate when the control according to the embodiment is performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0010] FIG. 1 is a diagram showing an example of a vehicle equipped with a control device according to an embodiment. As shown in FIG. 1, the vehicle 1 includes a battery 2, a converter 3, a rotating electric machine 4, wheels 5a to 5d, an internal combustion engine 6, a load 7, and an ECU (Electronic Control Unit) 8. The vehicle 1 shown in FIG. 1 may be a hybrid vehicle equipped with two power sources, the rotating electric machine 4 and the internal combustion engine 6, and may adopt, for example, any of a series type, a parallel type, or a split type. Note that the vehicle 1 shown in FIG. 1 adopts a two-wheel drive type, but may adopt a four-wheel drive type. The control device CU includes the battery 2, the converter 3, the rotating electric machine 4, the load 7, and the ECU 8.

[0011] The battery 2 can be charged and discharged between the rotating electric machine 4 and supplies power to the load 7. While the vehicle 1 is traveling, charging and discharging of the battery 2 are performed simultaneously. In a charging operation of the battery 2, power is supplied to the battery 2 from the rotational force of the wheels 5a-5d, thereby charging the battery 2. In a discharging operation of the battery 2, power is supplied to transmit torque to the wheels 5a-5d, and power is also supplied to the load 7. The battery 2 may be, for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery.

[0012] The converter 3 performs power conversion when charging and discharging between the battery 2 and the rotating electric machine 4, converting the power from the battery 2 and supplying it to the load 7. The converter 3 includes an inverter, and for example, when discharging from the battery 2 to the rotating electric machine 4, converts DC power from the battery 2 into AC power and supplies it to the rotating electric machine 4. The converter 3 also includes a converter, and for example, when charging the battery 2 from the rotating electric machine 4, converts AC power generated from the rotational force of the wheels 5a-5d into DC power and supplies it to the battery 2, and also increases or decreases the voltage of the power from the battery 2 and supplies it to the load 7.

[0013] The rotating electric machine 4 converts the electric power supplied from the battery 2 into torque and transmits it to the wheels 5a-5d, or generates electric power from the rotational force of the wheels 5a-5d and supplies it to the battery 2. The rotating electric machine 4 may be, for example, a three-phase permanent magnet synchronous motor. The rotating electric machine 4 may include, for example, a sensor for detecting a rotation angle, such as a resolver for feedback control or an encoder.

[0014] The rotating electric machine 4 converts the electric power supplied from the battery 2 into torque and transmits it to the wheels 5a to 5d. Specifically, the electric power supplied from the battery 2 may be converted into torque via the converter 3 and transmitted to the wheels 5a to 5d.

[0015] Furthermore, the rotating electric machine 4 generates electric power from the rotational force of the wheels 5a-5d and supplies the electric power to the battery 2. Specifically, electric power may be generated from the rotational force of the wheels 5a-5d when regenerative braking is performed using a regenerative brake (not shown), or a part of the torque transmitted from the internal combustion engine 6 to the wheels 5a-5d may be converted into electric power and supplied to the battery 2 via the converter 3.

[0016] The wheels 5a to 5d drive the vehicle 1 based on torque transmitted from the rotary electric machine 4 and the internal combustion engine 6. The wheels 5a to 5d may be, for example, tires made of resin.

[0017] The internal combustion engine 6 burns fuel to generate torque and transmits it to the wheels 5a to 5d. A part of the torque generated by the internal combustion engine 6 may be converted into electric power by the rotating electric machine 4 and supplied to the battery 2. The fuel for the internal combustion engine 6 may be, for example, gasoline, hydrogen fuel, biomass fuel, etc.

[0018] The load 7 is supplied with power from the battery 2. The load 7 is each device in the vehicle 1 that consumes the power supplied from the battery 2. The load 7 may be, for example, a car navigation device, an audio device, an air conditioner, a headlight, a wiper, or the like, which requires a stable constant voltage.

[0019] The ECU 8 outputs a control signal to the converter 3 to control it. The ECU 8 detects the current flowing through the battery 2 when the battery 2 is charged or discharged, detects the voltage of the battery 2, and also detects the charging rate based on the voltage of the battery 2. The ECU 8 estimates the discharging tendency of the battery 2 based on the charging rate detected from the battery 2, and performs control by switching between a plurality of control modes, including a torque control mode, a charging induction mode, and a voltage control mode. The ECU 8 may be connected to, for example, a temperature sensor, an accelerator pedal, and various devices in the vehicle 1, which are not shown. Each control mode of the ECU 8 will be described below.

[0020] <Torque control mode> In the torque control mode, a control signal based on the torque to be transmitted to the wheels 5a-5d is output to the converter 3 for control. In the torque control mode, the ECU 8 determines a target value of the torque to be transmitted to the wheels 5a-5d in accordance with, for example, the depression amount of the accelerator pedal and the shift position, and adjusts the distribution of the torque from the rotating electric machine 4 and the internal combustion engine 6 so as to achieve the determined target value of torque, and transmits the torque to the wheels 5a-5d. At this time, the ECU 8 may calculate the torque from values ​​such as the rotation angle detected from the rotating electric machine 4, and perform feedback control on the inverter of the converter 3 based on the difference from the command torque, which is the target value.

[0021] <Charging priority mode> In the charge priority mode, when the charging rate of the battery 2 becomes equal to or lower than a first predetermined value in the torque control mode, the power supply to the rotating electric machine 4 and the load 7 is reduced to prioritize the supply of power to the battery 2. The charging rate of the battery 2 at the time of switching to the charge priority mode is set as a reference value. In the charge priority mode, for example, the power supply from the battery 2 to the rotating electric machine 4 is stopped, the power supplied to a part of the load 7 is stopped, and the power generated from the rotational force of the wheels 5a to 5d is continued to be supplied to the battery 2.

[0022] <Voltage control mode> In the voltage control mode, when the difference between the current charging rate of the battery 2 and the charging rate when the charging rate of the battery 2 becomes equal to or less than a first predetermined value becomes equal to or less than a second predetermined value, a control signal based on the voltage of the rotating electric machine 4 is output to the converter 3 for control. Switching to the voltage control mode is performed based on the difference between the current charging rate of the battery 2 and a reference value of the battery 2. In the voltage control mode, for example, the ECU 8 determines a target value of the current value supplied from the rotating electric machine 4 to the battery 2, and generates electric power from the rotational force of the wheels 5a to 5d so as to achieve the determined target value of the current value, thereby charging the battery 2. At this time, the ECU 8 may perform feedback control on the inverter of the converter 3 based on the difference between a command voltage based on the target value of the current value and the voltage detected from the rotating electric machine 4.

[0023] FIG. 2 is a diagram showing an example of the operation of the control device according to the embodiment. FIG. 3 is a timing chart showing a change in the charging rate when the control according to the embodiment is performed. In FIG. 2, the control performed in the control device CU proceeds along the control flow of steps S1 to S11. The timing chart shown in FIG. 3 shows a case where the control flow of steps S1 to S11 shown in FIG. 2 is executed twice. In addition, before time t1 in the timing chart shown in FIG. 3, the control device CU operates in the torque control mode. In addition, in the timing chart shown in FIG. 3, the first control flow proceeds in the order of steps S1, S2, S3, S4, S5, S6, and S8, and ends, and the second control flow proceeds in the order of steps S1, S9, and S11, and ends. Hereinafter, a description will be given with reference to FIG. 2 and FIG. 3.

[0024] In step S1, the ECU 8 compares the charging rate of the battery 2 with a first predetermined value th1. If the charging rate of the battery 2 is equal to or lower than the first predetermined value th1, the process proceeds to step S2. If the charging rate of the battery 2 is greater than the first predetermined value th1, the process proceeds to step S9.

[0025] In step S2, the control unit CU is switched to the charge priority mode. For example, as shown in Fig. 3, when the charging rate of the battery 2 becomes equal to or lower than a first predetermined value th1 at time t1, the charge priority mode switching signal is changed from low level L to high level H and output from the ECU 8 to the converter 3, so that the control unit CU continues the torque control mode and switches to the charge priority mode.

[0026] In step S3, a reference charging rate is set. The reference charging rate is the charging rate of the battery 2 detected by the ECU 8 when the control unit CU is switched to the charge priority mode in step S2. For example, in FIG. 3, the charging rate at time t1 is the reference charging rate.

[0027] In step S4, the ECU 8 compares the difference between the charging rate of the battery 2 and the reference charging rate with a second predetermined value th2. If the difference between the charging rate of the battery 2 and the reference charging rate is equal to or smaller than the second predetermined value th2, the process proceeds to step S5. If the difference between the charging rate of the battery 2 and the reference charging rate is greater than the second predetermined value th2, the process proceeds to step S10.

[0028] In step S5, the control unit CU is switched to the voltage control mode. For example, as shown in Fig. 3, when the difference between the charging rate of the battery 2 and the reference charging rate at time t2 is equal to or less than a second predetermined value th2, the voltage control mode switching signal is changed from low level L to high level H and output from the ECU 8 to the converter 3, whereby the control unit CU is switched from the torque control mode to the voltage control mode.

[0029] In step S6, the ECU 8 compares the current value supplied to the battery 2 with a target value. If the current value supplied to the battery 2 is equal to or greater than the target value, the process proceeds to step S7. If the current value supplied to the battery 2 is smaller than the target value, the process proceeds to step S8.

[0030] In step S7, the command voltage is lowered in the ECU 8. At this time, the ECU 8 lowers the current value higher than the target value, thereby lowering the command voltage based on this, and performs feedback control on the inverter of the converter 3 based on the difference between the lowered command voltage and the voltage detected from the rotating electric machine 4. By performing such feedback control, the tendency for the rotating electric machine 4 to charge the battery 2 is reduced.

[0031] In step S8, the ECU 8 increases the command voltage. At this time, the ECU 8 increases the current value lower than the target value, thereby increasing the command voltage based on this, and performs feedback control on the inverter of the converter 3 based on the difference between the increased command voltage and the voltage detected from the rotating electric machine 4. By performing such feedback control, the tendency for charging from the rotating electric machine 4 to the battery 2 increases. For example, as shown in FIG. 3, after time t2 when the control device CU switches from the torque control mode to the voltage control mode, the tendency for charging the battery 2 increases and the charging rate has an upward slope.

[0032] In step S9, the ECU 8 compares the charging rate of the battery 2 with a third predetermined value th3. If the charging rate of the battery 2 is equal to or lower than the third predetermined value th3, the process proceeds to step S10. If the charging rate of the battery 2 is greater than the third predetermined value th3, the process proceeds to step S11.

[0033] In step S10, the control unit CU is maintained in the torque control mode.

[0034] In step S11, the charge priority mode of the control unit CU is released. For example, as shown in Fig. 3, when the charging rate of the battery 2 is greater than a third predetermined value th3 at time t3, the charge priority mode switching signal and the voltage control mode switching signal are changed from high level H to low level L and output from the ECU 8 to the converter 3, thereby releasing the charge priority mode of the control unit CU.

[0035] As described above, by using the control device CU according to the present invention described with reference to FIGS. 1 to 3, a control device is provided that suppresses deterioration of vehicle performance by appropriately switching the charging mode in response to a decrease in the charging rate of the battery 2.

[0036] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs. [Explanation of symbols]

[0037] 1: Vehicle 2: Battery 3: Converter 4: Rotating electric machine 5a~5d: Wheels 6: Internal combustion engine 7: Load 8: ECU CU: Control unit t1~t3: Time th1~th3: 1st predetermined value, 2nd predetermined value, 3rd predetermined value

Claims

[Claim 1] A control device including a control unit that outputs a control signal to a converter to switch between a plurality of control modes for controlling a rotating electric machine that transmits torque for running a vehicle, a storage battery capable of being charged and discharged between the rotating electric machine and the storage battery; A load to which power is supplied from the storage battery; a rotating electric machine that converts electric power supplied from the storage battery into torque and transmits the torque to wheels of the vehicle, or generates electric power from a rotational force of the wheels and supplies the electric power to the storage battery; a converter that performs power conversion when charging and discharging between the storage battery and the rotating electric machine, converts the power from the storage battery, and supplies the converted power to the load; a control unit connected to the storage battery, the rotating electric machine, and the converter, the control unit being capable of outputting a control signal to the rotating electric machine; Equipped with The control unit is a torque control mode in which a control signal based on the torque transmitted to the wheel is output to the converter for control; a charge priority mode in which, when the charging rate of the storage battery becomes equal to or lower than a first predetermined value in the torque control mode, power supply to the rotating electric machine and the load is reduced and power supply to the storage battery is given priority; and a voltage control mode in which, when the difference between the current charging rate of the storage battery and the charging rate when it falls below the first predetermined value becomes equal to or less than a second predetermined value, a control signal based on the voltage of the rotating electric machine is output to the converter for control.

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