JP4062072B2 - Electric vehicle control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electric vehicle, and more particularly to a control device that performs traveling control during climbing.
[0002]
[Prior art]
[Patent Document 1]
JP, 11-215687, A In an electric vehicle, there is a possibility that the electric motor may be locked due to an insufficient amount of depression of an accelerator pedal during climbing. When the electric motor is locked, the current concentrates on a specific switching element of the inverter that drives the electric motor, and a sudden temperature rise may occur, which may cause thermal destruction of the switching element.
Conventionally, in order to prevent thermal destruction of the switching element of the inverter in such a locked state of the motor, the locked state of the motor is detected from the temperature rise of the switching element and the rotation speed of the motor, or the output current is limited, or It has been considered to shift the rotation angle of the rotor of the electric motor by stopping the output and causing the vehicle to move down (see Patent Document 1).
[0003]
[Problems to be solved by the invention]
According to this prior art, when it is detected that the electric motor is in a locked state, the torque of the electric motor is reduced, the rotation angle of the rotor is shifted, the phase is changed, and the heated state is obtained due to the locked state. By shifting energization from the switching element to another switching element that is not in a heated state, a large torque can be generated and the locked state can be released.
However, even if the electric motor is started to rotate using a switching element that is not in a heating state, torque is generated by the switching element that is in a heating state again, and there is a problem that the overheating state continues.
[0004]
In order to solve the above-described problems, an object of the present invention is to provide an electric vehicle control apparatus that can prevent a motor from being locked and avoid a continuation of an overheated state of a switching element.
[0005]
[Means for Solving the Problems]
Therefore, the present invention provides an electric motor that is a driving force source of a vehicle, torque calculating means that calculates a required torque for the electric motor based on an accelerator operation amount of a driver, and generation of the electric motor based on the required torque. In a control apparatus for an electric vehicle provided with torque control means for controlling torque, an inclination angle detecting means for detecting an inclination angle of a road surface, and an uphill that is a torque necessary for the uphill based on at least the road surface inclination angle and the vehicle weight Climbing torque calculating means for calculating torque, and the torque control means prohibits generation of torque of the motor when the required torque is equal to or lower than the climbing torque.
[0006]
【The invention's effect】
According to the present invention, the climbing torque calculating means calculates the climbing torque necessary for climbing the slope, the torque calculating means calculates the required torque to the motor, the torque control means compares both, and the required torque is equal to or lower than the climbing torque. Since the torque generation of the electric motor is prohibited, the electric motor can be prevented from being locked.
As a result, current can be prevented from concentrating on a specific switching element of the electric motor power source.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 is a block diagram of a control device for an electric vehicle.
An accelerator opening sensor 6, an inclination angle sensor 7, a vehicle speed sensor 11, and a reverse switch (reverse SW) 12 are connected as inputs to the control determination unit 1 that controls driving of the electric motor 5.
A control signal is output from the control determination unit 1 to the brake control device 14, and the brake 15 is operated and released.
[0008]
In addition, a control signal is output from the control determination unit 1 to the inverter 4, and the inverter 4 controls the power supplied to the motor 5 based on the control signal from the control determination unit 1, thereby controlling the drive of the motor 5.
Further, an ignition switch (ignition SW) 16 is connected to the control determination unit 1 as a main switch. The ignition switch 16 is turned on when a key cylinder switch (not shown) is in the ignition position.
[0009]
The configuration of the control determination unit 1 and its input / output relationship will be described in more detail.
The control determination unit 1 includes a torque command value calculation unit 2, an electric motor output control unit 3, a vehicle specification storage unit 8, an uphill torque calculation unit 9, and an uphill control determination unit 13.
The accelerator opening sensor 6 is connected to the torque command value calculation unit 2 of the control determination unit 1 and inputs an accelerator opening signal.
The inclination angle sensor 7 detects the inclination angle of the uphill road in the longitudinal direction of the vehicle body and inputs it to the uphill torque calculation unit 9.
[0010]
The vehicle speed sensor 11 calculates the vehicle speed from the number of rotations of the tire, and inputs a vehicle speed signal, which is positive when traveling forward and negative when traveling backward, to the uphill control determination unit 13.
The reverse switch 12 is a switch that is turned on when the shift lever operated by the passenger is in the reverse position (reverse position). The state signal of the reverse switch 12 is input to the uphill control determination unit 13.
[0011]
The torque command value calculation unit 2 calculates a command value of a required torque when the inverter 4 drives the motor 5 from the accelerator opening, and sends it to the motor output control unit 3.
The uphill control determination unit 13 detects the actual traveling state of the vehicle such as stop, forward, reverse, etc. of the vehicle based on the vehicle speed signal from the vehicle speed sensor 11, and the traveling direction intended by the driver based on the switch signal from the reverse switch 12. Is detected, whether or not the driving state is not intended by the driver, that is, whether or not the climbing control is to be performed, and the climbing control permission signal is sent to the climbing torque calculation unit 9 and the motor output control unit 3.
[0012]
Specifically, when the reverse switch 12 is off (forward position) and the vehicle speed sensor 11 indicates the reverse or stop state of the vehicle, the uphill control determination unit 13 determines that the driving state is not intended by the driver. Similarly, when the reverse switch 12 is on (reverse position) and the vehicle speed sensor 11 indicates the forward or stop state of the vehicle, the uphill control determination unit 13 determines that the traveling state is not intended by the driver.
[0013]
When the climbing control determining unit 13 determines that the driving state is not intended by the driver, the climbing control determining unit 13 issues a climbing control permission signal to the climbing torque calculating unit 9 and the motor output control unit 3.
If it is determined that the driving state is intended by the driver, the climbing control permission signal is not issued to both.
[0014]
The vehicle specification storage unit 8 stores vehicle specification data of vehicle weight, reduction ratio, and tire diameter in advance.
When the climbing torque calculation unit 9 receives the climbing control permission signal, the climbing torque calculation unit 9 reads the vehicle specification data stored in advance from the vehicle specification storage unit 8, and the tilt angle and the vehicle specification data detected by the tilt angle sensor 7. The torque required for climbing, that is, the climbing torque is calculated based on the above and output to the motor output control unit 3.
[0015]
As shown in FIG. 2, when the inclination angle of the slope is θ, the climbing torque is expressed by the following expression when expressed by the output torque Tm of the shaft of the motor.
Tm = (Mc × g × sin θ × r) / Gr (1)
Here, the vehicle weight is Mc, the gravitational acceleration is g, the total reduction ratio is Gr, and the tire radius is r.
[0016]
The motor output control unit 3 receives the climbing control permission signal from the climbing control determination unit 13 and compares the climbing torque from the climbing torque calculation unit 9 with the command value of the requested torque from the torque command value calculation unit 2.
As a result of the comparison, if the climbing torque is equal to or greater than the required torque command value, the brake control device 14 is commanded to operate the brake, and the motor drive output target value is output to the inverter 4 as zero.
On the contrary, when the hill-climbing torque is less than the required torque command value, the brake control device 14 is instructed to release the brake, and the inverter 4 is output with the motor drive output target value corresponding to the required torque command value.
[0017]
When the motor output control unit 3 has not received the climbing control permission signal from the climbing control determination unit 13, the motor output control unit 3 commands the brake control device 14 to release the brake, and the inverter 4 drives the motor corresponding to the command value of the required torque. Output target value.
In addition, the motor output control unit 3 determines the rotation direction (forward / reverse rotation) of the motor 5 based on the ON / OFF signal of the reverse switch 12 and outputs a rotation direction signal together with the motor output target value.
[0018]
The inverter 4 includes a switching element, and the current and voltage from a power source battery (not shown) are energized and controlled by the switching element based on the electric motor drive output target value signal and the rotation direction signal from the electric motor output control unit 3 to control the electric motor 5. Control drive is performed so that the output corresponds to the reverse rotation / forward rotation control and the input motor drive output target value.
The control determination unit 1 is composed of a microcomputer.
[0019]
The operation of this embodiment will be described below. FIG. 3 is a flowchart showing the operation of the control determination unit 1.
When the ignition switch 16 is turned on to start the main control and the driver performs an accelerator operation, the torque command value calculation unit 2 and the motor output control unit 3 start driving the motor 5 via the inverter 4.
In step 101, the torque command value calculation unit 2 calculates a command value for the required torque corresponding to the signal from the accelerator opening sensor 6.
In step 102, the uphill control determination unit 13 reads the state of the reverse switch 12, and detects whether the driver's intention is forward or reverse.
In step 103, the uphill control determination unit 13 reads the vehicle speed from the vehicle speed sensor 11.
[0020]
In step 104, the uphill control determination unit 13 determines whether the vehicle is in a traveling state intended by the driver from the detection results in steps 102 and 103.
In other words, when the reverse switch 12 is off (that is, in a state where the vehicle is intended to move forward) and the vehicle speed signal from the vehicle speed sensor 11 is 0 or negative (the vehicle traveling state is stopped or reverse), the vehicle travels unintended by the driver. Judged as a state.
The same applies to the case where the reverse speed switch 12 is turned on (that is, in a state where reverse travel is intended) and the vehicle speed signal from the vehicle speed sensor 11 is 0 or positive (the vehicle travel state is stopped or advanced).
[0021]
When it is determined that the travel state is intended (when the reverse switch 12 is OFF and the vehicle is in a forward state, or when the reverse switch 12 is ON and the vehicle is in a reverse state), the process proceeds to step 114. .
In step 105, the uphill control determination unit 13 outputs an uphill control permission signal to the uphill torque calculation unit 9 and the motor output control unit 3.
[0022]
In step 106, the climbing torque calculation unit 9 receives the climbing control permission signal and reads the tilt angle from the tilt angle sensor 7.
In step 107, the climbing torque calculation unit 9 calculates the climbing torque from the data in the vehicle specification storage unit 8 and the inclination angle θ according to the equation (1), and outputs it to the motor output control unit 3.
After step 107, the process proceeds to step 108.
[0023]
In step 108, the motor output control unit 3 checks whether the command value of the required torque exceeds the climbing torque. If it is above, go to step 112; if it is equal or below, go to step 109.
In step 109, the motor output control unit 3 outputs a brake operation signal to the brake control device 14 and causes the brake 15 to brake the vehicle.
[0024]
In step 110, the motor output control unit 3 outputs the motor drive output target value as zero (motor output not permitted). In other words, the drive of the electric motor is prohibited.
In step 111, the torque command value calculation unit 2 calculates a command value for the required torque corresponding to the signal from the accelerator opening sensor 6.
After step 111, the process returns to step 108.
That is, the driver further depresses the accelerator pedal, inputs the command value of the increased required torque to the motor output control unit 3, and repeats the loop from step 108 to step 111 until the climbing torque is exceeded.
[0025]
In step 112, the motor output control unit 3 outputs a brake release signal to the brake control device 14 to release the brake 15.
In step 113, the motor output control unit 3 outputs a motor drive output target value corresponding to the command value of the required torque to the inverter 4 (motor output permission).
After step 113, the process proceeds to step 115.
Thus, in the next step 115, the inverter 4 follows the electric motor drive output target value and drives the electric motor 5.
[0026]
On the other hand, when it is determined in the check in step 104 that the driving state is intended by the driver, in step 114, the motor output control unit 3 outputs the motor drive output target value corresponding to the required torque command value to the inverter 4 (motor). Output permission). After step 114, the process proceeds to step 115.
As a result, a series of control flow ends and the process returns to the beginning.
[0027]
The torque command value calculation part 2 of this Embodiment comprises the torque calculation means of this invention. Step 102 in the above flow is a selected traveling direction detecting means, step 103 is a traveling state detecting means, steps 104 and 105 are traveling determining means, step 106 is an inclination angle detecting means, and step 107 is an uphill torque calculating means. Steps 108 and 110 and Steps 113, 114 and 115 constitute torque control means, and Steps 109 and 112 constitute braking means.
[0028]
As described above, according to the present embodiment, the uphill control determination unit 13 determines that the actual vehicle traveling state is based on the signal from the reverse switch 12 indicating the traveling direction selected by the driver and the signal from the vehicle speed sensor 11. It is determined whether the vehicle is traveling in the direction intended by the person. If it is determined that the vehicle is not traveling, the motor output control unit 3 determines the command value of the required torque corresponding to the accelerator opening and the inclination angle of the slope. And the climbing torque calculated based on the vehicle weight, and if the command value of the required torque is equal to or lower than the climbing torque, the brake is operated and the drive output to the electric motor 5 is set to zero.
[0029]
As a result, the locked state of the electric motor does not continue, and damage due to overheating of the switching element of the inverter can be prevented.
Further, when the accelerator is further depressed and the command value of the required torque exceeds the climbing torque, the motor output control unit 3 releases the brake and outputs it to the motor, so that it is possible to prevent the vehicle from sliding down when starting on a slope.
[0030]
In the present embodiment, the inclination angle of the uphill road is detected by the inclination angle sensor 7, but the inclination angle of the uphill road is detected from the map information of the car navigation instead of the inclination angle sensor 7. Also good.
Further, when the command value of the required torque is equal to or lower than the climbing torque, the automatic transmission may be switched to the “parking position (parking position)” instead of the brake and the vehicle may be stopped.
[0031]
The climbing torque is calculated based on the vehicle weight stored in advance in the vehicle specification storage unit 8. For example, the vehicle weight detecting means detects the vehicle weight from the stroke amount of the suspension when the ignition switch is turned on. You may use the value detected by.
In such a vehicle weight detection method, the weight of the occupant and the loaded luggage is appropriately reflected in the vehicle weight, so that the accuracy of climbing torque calculation is improved.
[0032]
In the present embodiment, the reverse switch 12 signal is input to the control determination unit 1 to switch between forward / reverse, but the reverse switch 12 is turned on by detecting the reverse position of the transmission (not shown) The reverse operation may be performed on the side, and the control determination unit 1 may not perform forward / reverse control.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a diagram showing a method for obtaining a climbing torque.
FIG. 3 is a flowchart illustrating the operation of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control judgment part 2 Torque command value calculation part 3 Electric motor output control part 4 Inverter 5 Electric motor 6 Accelerator opening degree sensor 7 Inclination angle sensor 8 Vehicle specification memory | storage part 9 Uphill torque calculation part 11 Vehicle speed sensor 12 Reverse switch 13 Uphill control judgment part 14 Brake control device 15 Brake 16 Ignition switch

Claims (4)

An electric motor as a driving force source of the vehicle; torque calculating means for calculating a required torque for the electric motor based on a driver's accelerator operation amount; and torque control means for controlling a generated torque of the electric motor based on the required torque In an electric vehicle control device comprising:
An inclination angle detecting means for detecting an inclination angle of the road surface;
A climbing torque calculating means for calculating a climbing torque that is a torque required for climbing based on at least the inclination angle of the road surface and the vehicle weight,
The control device for an electric vehicle, wherein the torque control means prohibits the generation of torque of the electric motor when the required torque is equal to or less than the climbing torque. 2. The control apparatus for an electric vehicle according to claim 1, further comprising braking means for braking the vehicle when torque generation of the electric motor is prohibited by the torque control means. A selected travel direction detection means for detecting a selection state of forward and reverse of the vehicle;
Traveling state detecting means for detecting the traveling state of the vehicle;
A travel determination unit that determines that the driver does not intend the travel state when the travel direction detected by the selected travel direction detection unit is different from the actual travel state of the vehicle detected by the travel state detection unit;
The electric vehicle control device according to claim 2, wherein the braking means performs the braking when the driving state is not intended by the driver. The climbing torque calculation means has an inclination torque of (Mc × g × sin θ × r) / Gr, where the inclination angle θ of the road surface in the longitudinal direction of the vehicle, the vehicle weight Mc, the reduction ratio Gr, the tire radius r, and the gravitational acceleration g. The electric vehicle control device according to claim 1, wherein the electric vehicle control device is calculated according to an expression represented.

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