JPH09135504A - Hill holding device for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make is possible to park a vehicle on a sloping road even if the vehicle will otherwise move back by itself. SOLUTION: It is judged at a shift position judgment unit 13 whether a shift lever 23 is positioned in the D or R range or not, and vehicle speed and the direction of drive are detected at a speed detect unit 11. If tires are rotated backward, a hill holding torque command unit 19 generates a hill holding torque command according to the proper direction of rotation and an accumulative value of infinitesimal rotational speed. If it is detected as the result of comparison at a comparator 21 that the hill holding torque command value is larger than an accelerator torque command value, it is judged whether the speed of the tires detected at the speed detect unit 11 is zero or not. If the speed is not zero, the infinitesimal rotational speed is increased to increase the hill holding torque command value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hill hold device for an electric vehicle, and more particularly, to a hill hold device for an electric vehicle that can stop the vehicle even when the vehicle moves backward on a slope.

[0002]

2. Description of the Related Art Conventionally, as an electric vehicle hill hold device, one shown in FIG. 5 is known.

In this system, the accelerator opening of the accelerator 113 detected by the accelerator amount detector 115 is in a zero output state, and the brake 109 is braked by the brake operation determiner 111.
When the vehicle is not stepped on and the shift lever 121 is set to the traveling range by the shift position determination unit 123, the vehicle speed due to the rotation of the wheels 117 detected by the vehicle speed detection unit 119 is predetermined. When it is smaller than the creep speed, the torque command unit 107 outputs a low torque signal to the inverter 103 to cause the motor 105 to generate a low torque.

In this way, when the vehicle speed is lower than the creep speed when the vehicle is set to the running range without the accelerator or brake being operated, a low torque signal is output to generate a low torque in the motor. This prevents the vehicle from moving backward even when the vehicle is stationary on a slope.

[0005]

However, in the conventional hill hold device for an electric vehicle, if the slope of the slope is large and the output torque of the motor is insufficient, the vehicle may move backward. .

Further, when the creep speed is generated on a slope, the creep torque becomes zero after the brake or accelerator pedal is lightly stepped on. Therefore, when the braking force or the torque command by the accelerator is insufficient, There is a problem that the vehicle may be jerky because the vehicle moves backward.

[0007] The present invention has been made in view of the above,
An object of the invention is to provide a hill hold device for an electric vehicle that can stop the vehicle even when the vehicle moves backward on a slope.

[0008]

According to the first aspect of the present invention,
In order to solve the above problems, a device for supplying power to an inverter that controls a motor for driving a vehicle from a battery mounted on an electric vehicle and driving the vehicle by applying a torque command to the inverter, Drive direction determination means for determining forward or backward as the drive direction of the vehicle, reverse direction movement detection means for detecting that the vehicle has moved in the direction opposite to the drive direction, and when the reverse movement is detected, And a torque command generating means for generating a forward torque command to the motor so that the moving speed of the vehicle becomes zero.

According to the first aspect of the present invention, forward or backward is determined as the driving direction of the vehicle, and when it is detected that the vehicle has moved in the direction opposite to the driving direction, the moving speed of the vehicle. Even if the vehicle retreats on a slope, by generating a forward torque command to the motor so that the speed becomes zero, the motor tries to generate torque and keep the speed at zero. It has the effect that it can be stopped.

In order to solve the above-mentioned problems, a second aspect of the present invention is characterized in that the torque command generating means limits the generated torque command to a maximum torque limit value or less.

According to the second aspect of the present invention, the generated torque command is limited to be equal to or less than the maximum torque limit value, so that the power consumption of the battery is limited.

In order to solve the above-mentioned problems, the invention according to claim 3 has an accelerator / torque generating means for generating an accelerator / torque command in accordance with an access opening representing an operation amount of the accelerator. When the torque command generated in step 2 becomes larger than the accelerator / torque command, the gist is to switch to the accelerator / torque command to control the inverter.

According to the third aspect of the present invention, when the accelerator / torque command is generated according to the access opening representing the operation amount of the accelerator, and the generated torque command becomes larger than the accelerator / torque command. Has an effect of driving and controlling the vehicle according to the accelerator operation of the driver by switching to the accelerator / torque command and controlling the inverter.

In order to solve the above-mentioned problems, the invention according to claim 4 is provided with a battery voltage detecting means for detecting an output voltage of a battery for supplying a current to the inverter, and an output voltage from the battery. In the case of being equal to or less than the reference value, it is a gist to have a torque command stopping means for stopping the output from the torque command generating means.

According to the fourth aspect of the invention, the output voltage of the battery for supplying the current to the inverter is detected, and if the output voltage from the battery is equal to or lower than the preset reference value, the output is changed. Stopping has the effect of preventing over-discharge of the battery and protecting the battery.

In order to solve the above-mentioned problems, the invention according to claim 5 is characterized in that the torque command stopping means has a notification means for notifying that the torque command is stopped.

According to the invention of claim 5, by notifying that the torque command is stopped, there is an effect that a warning sound can be generated for the driver.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a hill hold device for an electric vehicle according to a first embodiment of the present invention. A hill hold device 1 for an electric vehicle shown in the figure has a battery 3 for supplying a direct current to an inverter 7, a main switch 5 for intermittently connecting the supply of a direct current from the battery 3, and a plurality of switching elements inside. Then, the inverter 7 configured to convert the direct current from the battery 3 into the alternating current by controlling ON / OFF of this switching element according to the PWM signal and the induction motor, rotate the three-phase alternating current from the inverter 7. A motor 9 for driving the vehicle by converting it into a vehicle speed, a vehicle speed detection unit 11 for detecting a rotation direction and a rotation speed of the motor, a shift position determination unit 13 for detecting a D range and an R range, and a generation according to an accelerator opening degree. Accelerator / torque command unit 15 for outputting a torque signal
And a determination unit 17 that outputs the rotation direction and the rotation speed only when the motor is reversely rotated in the D range and the motor is normally rotated in the R range.
A hill hold / torque command unit 19 that calculates and outputs a generated torque (positive / negative) signal required from the information of the rotation direction and the rotation speed during reverse rotation of the motor in the range or forward rotation of the motor in the R range. Comparing the magnitudes and giving priority to the larger one, and outputting the larger one, the comparator 21 that limits the maximum torque, the gear shift lever 23 that sets the rotation speed of the motor 9 according to the shift position, and the heat generation temperature of the motor 9 are detected. Temperature sensor 25, an accelerator 27 that detects the accelerator operation by the driver and outputs the accelerator opening, a voltage detector 29 that detects the output voltage of the battery 3, and a temperature sensor 31 that detects the heat generation temperature of the inverter 7. Composed of and. The motor 9 may be a DC motor or a synchronous motor, and in this case, the inverter 7 has a configuration of D
The configuration is such that the C motor and the synchronous motor can be driven.

Next, the configuration and operation of the accelerator / torque command unit 15 will be described with reference to FIG. The accelerator / torque command unit 15 shown in the figure includes a maximum torque map 41, a calculation accelerator opening map 43, and a limiting coefficient calculation processing unit 45.
And an arithmetic processing unit 47. Here, the input information necessary for calculating the accelerator / torque command is the motor rotation speed as the information for determining the torque command, the accelerator opening as the information for determining the torque command, and the shift as the information for selecting the map. The information is roughly classified into six types such as a position, a battery state quantity as information for limiting the torque command, a motor temperature as information for limiting the torque command, and an inverter temperature as information for limiting the torque command. .

Next, a method of calculating the accelerator / torque command based on these input information will be described. The accelerator / torque command unit 15 uses the maximum torque map 4 based on the D range or the R range as the shift position.
1 and the map used in the accelerator opening map 43 for calculation are selected. The maximum torque that can be output at the rotation speed is calculated from the selected map based on the motor rotation speed. The ratio (%) of the torque calculation accelerator opening to be output is calculated from the selected map based on the motor rotation speed and the accelerator opening.

The torque command is determined by multiplying the ratio calculated by the maximum torque calculated in step 1. In order to protect the battery 3, the motor 9, and the inverter 7, the limiting coefficient calculation processing unit 45 calculates the limiting coefficient based on the battery state quantity, the motor temperature, and the inverter temperature. The torque command determined by the arithmetic processing unit 47 is multiplied by the limiting coefficient calculated in to output the accelerator / torque command in which the torque is limited as necessary. As described above, the accelerator / torque command unit 15 calculates and outputs the accelerator / torque command required for normal operation.

Next, the operation of the hill hold device 1 for an electric vehicle will be described with reference to the flowchart shown in FIG. First, in step S10, the shift position of the shift lever 23 operated by the driver is determined by the shift position determination unit 13, and it is determined whether the shift position is the D range indicating forward movement or the R range indicating backward movement. Here, in the case of the D range or the R range, the process proceeds to step S20, and otherwise, the process returns to step S10 to repeat the process.

Next, in step S20, the vehicle speed and the traveling direction are detected by the vehicle speed detecting portion 11 having a rotary encoder attached to the rotating shaft of the motor 9 or the rotating shaft of the tire, and the traveling direction is in the D range. It is judged whether the vehicle is retreating to the front, or forward in the case of the R range. That is,
Determine if the tire is rotating in reverse. here. If the tire is rotating in the reverse direction, the process proceeds to step S30. If not, the process returns to step S10 to repeat the process.

When the tire is rotating in the reverse direction, in step S30, the hill hold / torque command unit 19 generates a hill hold / torque command in accordance with the normal rotation direction and the cumulative value of the minute rotation speed amount. Next, step S4
At 0, the comparator 21 compares the accelerator / torque command from the accelerator / torque command unit 15 with the hillhold / torque command from the hillhold / torque command unit 19 to determine whether or not the accelerator / torque command is larger. Here, if the accelerator / torque command is greater, the process proceeds to step S50, while if not, the process proceeds to step S50.
Proceed to 60.

Next, when the accelerator / torque command is larger, in step S50, the accelerator / torque command generated by the accelerator / torque command unit 15 is output to the inverter 7 via the comparator 21. Then, in step S10
And repeat the process. That is, even if the accelerator 27 is operated, the accelerator / torque command is not used until the accelerator / torque command exceeds the hillhold / torque command, and the accelerator / torque command is exceeded when the accelerator / torque command exceeds the hillhold / torque command. Since the command is prioritized, it is possible to prevent the vehicle behavior from being jerky when starting.

On the other hand, when the hill hold / torque command from the hill hold / torque command unit 19 is larger,
In step S60, it is determined whether the tire speed detected by the vehicle speed detector 11 is "0". Here, if the speed is "0", the vehicle is stopped, so step S
Returning to step 10, the process is repeated. On the other hand, when the speed is not “0”, the tire of the vehicle is rotating in the reverse direction, so the process returns to step S30, and the torque command output from the hill hold / torque command unit 19 is increased by increasing the minute rotation speed amount. Increase the amount.

Thus, for example, when the tire of the vehicle rotates in the direction opposite to the traveling direction due to the shift position of the speed change lever 23 on a slope, the processing in steps S30 to S60 is executed to execute the hill in the normal direction. The hold torque command can be generated while being increased by the hill hold torque command unit 19, and as a result, step S3
A servo function can be configured to hold the speed of the vehicle at "0" in 0 to S60, and the vehicle can be stopped even when the vehicle moves backward on a slope. That is, the speed servo is applied to generate the hill hold / torque command, so that the torque command can be generated even when the vehicle moves backward on a slope, and the speed is kept at zero. Therefore, stop the vehicle on the slope. As a result, it is possible to prevent the vehicle behavior such as the conventional backward movement on a slope or the amount of brake depression.

(Second Embodiment) FIG. 4 is a diagram showing a hill hold device for an electric vehicle according to a second embodiment of the present invention. The hill hold device 1 for an electric vehicle shown in the figure is characterized in that the battery state quantity of the battery 3 detected by the voltage detector 29 is input, and when the battery voltage included in the battery state quantity is equal to or less than a reference value, It consists of a hill hold / torque command section 19 for stopping the hold / torque command and an alarm device 51 for warning the driver of stopping the output of the hill hold / torque command.

Next, the operation of the hill hold device 1 for an electric vehicle shown in FIG. 4 will be described. The output voltage of the battery 3 for supplying the current to the inverter 7 is detected by the voltage detector 29, and when the output voltage from the battery 3 is less than or equal to a preset reference value, the hill hold / torque command unit 19 By stopping the hill hold / torque command output, the battery 3 can be prevented from being over-discharged and the battery 3 can be protected.

When the hill hold / torque command unit 19 stops the hill hold / torque command output, the alarm device 51 gives a warning in advance that the hill hold / torque command output will be stopped. The brake (not shown) can be stepped on when the sound is noticed, and the driver can be kept comfortable.

[0031]

As described above, according to the present invention as set forth in claim 1, forward or backward is determined as the driving direction of the vehicle, and it is detected that the vehicle has moved in the direction opposite to the driving direction. In this case, by generating a forward torque command to the motor so that the moving speed of the vehicle becomes zero, torque is generated in the motor and the speed becomes zero even when the vehicle moves backward on a slope. Since the vehicle tries to hold the vehicle, the vehicle can be stopped on the slope, and even if the slope of the slope is large, it is possible to prevent the vehicle from moving backward because the output torque of the motor can be sufficiently produced. It is possible to prevent the vehicle behavior and the like due to the backward movement on the slope and the increase / decrease of the brake pedal.

According to the second aspect of the present invention, the power consumption of the battery can be limited by limiting the generated torque command to the maximum torque limit value or less.

Further, according to the present invention as set forth in claim 3, the accelerator / opening is calculated in accordance with the access opening indicating the operation amount of the accelerator.
If a torque command is generated and the generated torque command is larger than the accelerator torque command, the accelerator
By switching to the torque command and controlling the inverter, the drive of the vehicle can be controlled according to the accelerator operation by the driver, and the vehicle can quickly shift from the stationary state to the accelerated state.

According to the present invention as set forth in claim 4, the output voltage of the battery for supplying the current to the inverter is detected, and when the output voltage from the battery is less than or equal to a preset reference value, By stopping the torque command output, the battery can be prevented from being over-discharged and the battery can be protected.

According to the fifth aspect of the present invention, it is possible to generate a warning sound to the driver by notifying that the torque command is stopped.

[Brief description of the drawings]

FIG. 1 is a diagram showing a hill hold device for an electric vehicle according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an accelerator / torque command unit 15.

FIG. 3 is a flowchart for explaining the operation of the hill hold device 1 for an electric vehicle.

FIG. 4 is a diagram showing a hill hold device for an electric vehicle according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a system configuration of a conventional hill hold device for an electric vehicle.

[Explanation of symbols]

 3 Battery 7 Inverter 9 Motor 11 Vehicle Speed Detecting Section 13 Shift Position Determining Section 15 Accelerator / Torque Commanding Section 17 Evaluator 19 Hill Hold / Torque Commanding Section 21 Comparator 23 Shift Lever 25 Temperature Sensor 27 Accelerator 29 Voltage Detector 31 Temperature Sensor

Claims (5)

[Claims] 1. A device for driving a vehicle by supplying a power source to an inverter for controlling a motor for driving the vehicle from a battery mounted on an electric vehicle and applying a torque command to the inverter to drive the vehicle. Driving direction determining means for determining forward or backward as a direction, reverse movement detecting means for detecting that the vehicle has moved in a direction opposite to the driving direction, and vehicle movement in the case where reverse movement is detected. Command generating means for generating a forward torque command to the motor so that the moving speed of the motor becomes zero, the hill hold device for an electric vehicle. 2. The hill hold device for an electric vehicle according to claim 1, wherein the torque command generating means limits the generated torque command to a maximum torque limit value or less. 3. An accelerator / torque generating means for generating an accelerator / torque command according to an access opening representing an accelerator operation amount, wherein the torque command generated by the torque command means is more than the accelerator / torque command. 2. The hill hold device for an electric vehicle according to claim 1, wherein when it becomes larger, the accelerator / torque command is switched to control the inverter. 4. A battery voltage detecting means for detecting an output voltage of a battery for supplying a current to the inverter, and the torque command generating means when the output voltage from the battery is equal to or less than a preset reference value. 2. A hill hold device for an electric vehicle according to claim 1, further comprising a torque command stop means for stopping output from the vehicle. 5. The hill hold device for an electric vehicle according to claim 4, wherein the torque command stop means has a notification means for notifying that the torque command is stopped.