JP3441109B2 - Drive control device for electric vehicle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for an electric vehicle, and more particularly, to a motor control device according to a throttle operation amount and a rotation speed of the motor or a speed of the vehicle. The present invention relates to a drive control device for an electric vehicle, which controls a vehicle by switching between a driving state and a braking state. 2. Description of the Related Art A conventional vehicle using an internal combustion engine is operated to perform throttle operation to perform acceleration / deceleration control of the vehicle based on a driver's intention. It is desired that an electric vehicle such as an automobile having the same as a driving source has a similar operation feeling. The inventor of the present invention previously obtained the target rotation speed of the electric motor corresponding to the throttle operation amount by performing various actual measurements and simulations, and determined that the target rotation speed corresponding to the throttle operation amount was higher than the actual rotation speed. It has been found that the throttle operation amount and the actual rotation speed are made to match by setting the electric motor to the braking state when the rotation speed is larger and the driving state when the rotation speed is smaller than the actual rotation speed. [0004] Here, in order to perform the above-described control, the drive is performed with a threshold given by a function of a throttle operation amount and a target rotation speed corresponding to the operation amount as a boundary. Since the electric motor is switched from the state to the braking state or from the braking state to the driving state, if the motor rotation speed fluctuates near the above-described threshold value for some reason, the motor may be hunted. [0005] In view of such findings of the inventor, a main object of the present invention is to provide a drive control device for an electric vehicle that can improve the operation feeling without impairing the stability of motor rotation. According to the present invention, there is provided a drive control apparatus for an electric vehicle, comprising: throttle means for controlling a drive state of a motor; The motor is switched between a driving state and a braking state based on a speed sensor for detecting a rotation speed or a vehicle speed and a threshold value of an output value of the speed sensor given as a function of a displacement amount of the throttle means. and control means for said threshold value, the driving state for switching between the braking state when the speed is decreasing
And a first threshold if the speed is increasing .
Offset to the speed increase side with respect to the threshold
On purpose or a second threshold value for switching between the braking state
Between the first threshold value and the second threshold value.
The speed while maintaining the driving state or the braking state.
The threshold value corresponding to either the increase or decrease of
This is attained by providing a drive control device for an electric vehicle, which is characterized in that: With this configuration, the driving state and the braking state are switched according to the state of the output value based on the threshold value of the output value of the speed sensor given as a function of the displacement amount of the throttle means. Since the motor is controlled at the time, for example, when the actual rotation speed is higher than the rotation speed corresponding to the displacement amount of the throttle means, the braking state can be set,
Conversely, when the actual rotation speed is low, the driving state is set, so that the driving control can be performed according to the driver's operation request. Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a schematic configuration of a driving device for an electric vehicle to which the present invention is applied. A motor 1 is composed of, for example, a brushless motor, and is driven by a control means 2 composed of an IC, a transistor, or the like. Controlled. The control means 2 is mainly composed of a microcomputer 3 and a drive circuit 4. For example, by turning on / off a switching means (not shown) constituting the drive circuit 4 in accordance with a drive command from the microcomputer 3, a battery (not shown) is provided. Is supplied to the motor 1. The control means 2 is connected to a throttle means 5 for outputting a throttle signal according to the throttle operation amount of the driver, and detects the rotation speed of the motor 1 as a reciprocal of the rotation period. A speed sensor 6 for outputting a rotation cycle signal is connected. The driving of the motor 1 is controlled by the driving device constructed as described above. In order to bring the motor 1 into the driving state, the motor 1 in the driving circuit 4 is supplied so as to supply electric power to the motor 1. For example, PW
M control may be performed, and the motor 1 can be brought into a braking state by performing, for example, regenerative braking control of the drive circuit 4 so as to cut off the supply of the electric power. Here, the microcomputer 3 determines whether the motor 1 is in the driving state or the braking state. Each target rotation period of the motor 1 corresponding to each displacement amount of the throttle means 5 is determined. Is converted into a function in advance by simulation or the like, and the threshold given by the function is stored in a memory (not shown) in the microcomputer 3 as a data map. Then, in the microcomputer 3,
Throttle signal from throttle means 5 and speed sensor 6
, And determines whether or not the actual rotation cycle exceeds the threshold value, and determines the rotation state of the motor 1 based on the result. That is, as shown in FIG. 2, the horizontal axis represents the displacement amount of the throttle means 5 and the vertical axis represents the rotation period of the motor 1 which is the reciprocal of the rotation speed of the motor 1, and the function of the throttle signal and the target rotation period. Prepare a data map in which the threshold given by is stored. By comparing the target rotation period of the motor 1 according to the throttle signal with the actual rotation period, the motor 1
The control means 2 performs control to switch the state so that the state is set to the driving state or the braking state. Further, a data map storing a threshold value different from the data map described above is prepared, and stored in the memory as first and second data maps, respectively. These first
And the second data map, the first threshold value with respect to (indicated by A in FIG. 2), a second threshold value that is offset at a certain predetermined distance (Figure 2 B stored in the first data map Are stored in the second data map. Then, one of the data maps is selected according to the driving state of the motor in accordance with an algorithm described later. Next, the algorithm of the present invention will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. First, step 1 is a process of converting the displacement of the throttle means into data represented by a hexadecimal number (referred to as THRM data) by inputting a throttle signal from the throttle means 5. The next step 2 is to input the rotation speed signal from the speed sensor 6 to reduce the actual rotation cycle of the motor 1 by one.
This is a process of converting into data represented by a hexadecimal number (referred to as rotation period T data). Step 3 is a process of comprehending increase / decrease of the rotation cycle of the motor 1 by comparing the previously input rotation cycle T data with the currently input rotation cycle T data. Then, the process proceeds to step 4, and if it has decreased, the process proceeds to step 8. Step 4 is a process of searching the first data map for target rotation cycle data of the motor 1 corresponding to the THRM data converted in step 1. The next step 5 is a process of comparing the rotation cycle T data converted in step 2 with the rotation cycle data retrieved in the previous step 4. If the rotation cycle T data is smaller than the rotation cycle data, step 6 is performed. Then, control is performed to bring the motor 1 into the braking state, and the process returns to the main routine. If it is equal to or longer than the rotation cycle data, the process proceeds to step 7 to perform control to bring the motor 1 into the driving state, and Return to the main routine. Step 8 is a process of searching the second data map for target rotation period data of the motor 1 corresponding to the THRM data converted in step 1. Then, the next step 9 is a process of comparing the rotation cycle TL data converted in step 2 with the rotation cycle data searched in the previous step 8, and if the rotation cycle T data is less than the rotation cycle data. If so, the control proceeds to step 6 to control the motor 1 to be in the braking state and returns to the main routine. If the rotation cycle data is equal to or more than the rotation cycle data, the control proceeds to step 7 to perform control to bring the motor 1 into the driving state. Return to the main routine in the same manner as. In the above flow, the rotational state of the motor 1 is grasped in step 3 to determine whether the driving state or the braking state when the actual rotation period is increasing is determined in the third step. The determination is performed based on the threshold value stored in the first data map, and when the rotation cycle is decreasing, the determination is performed based on the threshold value stored in the second data map. That is, the threshold for switching the state can be provided with hysteresis. Therefore, even if the rotation cycle slightly fluctuates near each threshold value, the driving state is not switched from the driving state to the braking state or from the braking state to the driving state, so that stable driving control can be performed without causing hunting of the motor. In this embodiment, the rotation cycle of the motor 1 is detected by the rotation sensor 6 to correspond to the rotation speed of the motor 1. However, the present invention is not limited to this.
The drive control device of the present invention can be realized by directly detecting the rotation speed of the motor 1 or detecting the speed of the vehicle. Further, providing the threshold value with hysteresis is not affected by fluctuations such as camera shake and vibration generated when the throttle means 5 is operated, as a matter of course. As described above, according to the drive control apparatus for an electric vehicle of the present invention, the drive state and the braking state are determined based on the threshold value of the output value of the speed sensor given as a function of the displacement amount of the throttle means. By changing the driving speed, the operation feeling of the throttle is improved, and the threshold value is provided with hysteresis. Therefore, even if the rotation speed is not stable near the threshold value, the motor drive will not fluctuate within a predetermined hysteresis range. Alternatively, since stable rotation is guaranteed without switching the braking state, it is possible to provide the driver with an operation feeling that is no different from a vehicle using an internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram schematically illustrating a drive device for an electric vehicle to which the present invention is applied. FIG. 2 is a graph showing a data map stored in a microcomputer in the driving device of FIG. FIG. 3 is a flowchart for explaining the operation of the driving device of FIG. 1; [Description of Signs] 1 Motor 2 Control means 3 Microcomputer 4 Drive circuit 5 Throttle means 6 Speed sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60L 15/20 H02P 5/00

Claims (1)

(57) [Claim 1] A drive control device for an electric vehicle, comprising: throttle means for controlling a drive state of a motor; and detecting a rotation speed of the motor or a speed of the vehicle. A speed sensor, and control means for switching the motor between a driving state and a braking state based on a threshold value of an output value of the speed sensor given as a function of a displacement amount of the throttle means, When the threshold is reduced , the drive
A first threshold for switching between a braking state and the braking state ;
Increasing the first threshold value when the speed is increasing
Speed side and the driving state and the braking state
Consists of a second threshold value for switching bets, the drive shape between said first threshold and the second threshold value
State or the braking state while maintaining the braking state.
The drive control device for an electric vehicle, wherein the threshold value corresponding to either one of the decrease and the decrease is selected .