JPS62221805A - Control method of motor for electric automobile - Google Patents

Abstract

PURPOSE:To allow the torque control with high precision, by finding the indicating speed by the target speed and the car speed changing rate from the operation of travelling speed command, the opening of accelerator/car speed data and the travelling condition. CONSTITUTION:A target car speed arithmetic circuit 14 operates target car speed signals based on travelling commands given from an accelerator, a brake sensor, etc. and a predetermined opening extent of accelerator/car speed data. A target acceleration arithmetic circuit 18 operates the car speed changing rate DELTAN from the target car speed signals, running commands and the present travelling condition. An adder 16 subtracts the target car speed signals and the car speed changing rate DELTAN to supply an indicating car speed N0* to a motor control circuit. Thus independently of the size of load the drivability to meet the operation of accelerator can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for controlling a motor for an electric vehicle, and in particular to an electric vehicle in which the number of rotations of the motor is controlled by accelerator operation to improve drivability when the vehicle is running. related to the control method of motors for

[Prior Art] Electric vehicles are being researched as pollution-free vehicles that do not produce harmful exhaust gases, and some are already at the stage of practical use.

DC motors, which are easy to control, were used as the drive source in early electric vehicles, but these DC motors require maintenance such as brushes, etc., and in recent years, easy-to-maintain induction motors have been used as the drive source for electric vehicles. Motors were coming into use.

Motors used in electric vehicles, unlike ordinary industrial motors, are controlled by 1 to 111 torque, as shown in the frequency λ1. It is controlled by ff1l control or slip frequency control.

As mentioned above, the output torque of the motor is proportional to the sum of the motor magnetic flux and the torque current, and in order to obtain the required torque, either the motor magnetic flux or the torque current must be changed to give the necessary primary current to the motor. Good.

In conventional electric vehicles, the output of the motor is controlled by 1 to 1 lux in response to accelerator operation. This is because it is based on the concept of using a motor as a substitute for a conventional internal combustion engine, and the content of the 1 to 1 torque control itself is designed to approximate the characteristics of an internal combustion engine as much as possible.

[Problems to be solved by the invention] Conventional problems In conventional electric vehicles, the motor was controlled by torque, so for example, even if the number of revolutions was 0. Therefore, a latch mechanism like that found in internal combustion engines was not installed.

However, in order to achieve smooth acceleration when starting a vehicle or climbing a hill, precise torque control is required.

Purpose of the Invention The present invention has been made to solve the above problems, and in addition to controlling the motor by controlling the rotation speed, the rate of change in vehicle speed from the current vehicle speed to the target vehicle speed is calculated and drivability is taken into account. The present invention relates to a control method for an electric vehicle motor that can perform optimal control.

1. Means and operation for solving the problem] This invention has the following features:
A control method for an electric vehicle motor that calculates a target vehicle speed based on a driving command including an accelerator operation and current driving conditions, and controls the motor to achieve the target vehicle speed. A target vehicle speed is calculated based on the opening degree/vehicle speed data, then a vehicle speed change rate is calculated from the target vehicle speed, the travel command, and the current travel condition, and an instructed vehicle speed is determined from the target vehicle speed and the vehicle speed change rate. The present invention is characterized in that a control command corresponding to the commanded vehicle speed is given to the motor control circuit.

In the present invention, the target vehicle speed is determined by a predetermined calculation formula based on the accelerator opening given by the accelerator operation and predetermined accelerator opening/vehicle speed data. In addition, the vehicle speed change rate is J: from the current vehicle speed to the target vehicle speed.
This serves as a standard for determining how much time it takes to drive a car, and at the same time, the rate of change in vehicle speed is one of the factors that has a significant impact on driver comfort.

However, the vehicle speed change rate (ΔN) is ΔN-/(NO-N
As shown in the formula o), it is obtained as a function of the difference between the target vehicle speed (NO) and the current vehicle speed (NO),
When the difference between the target vehicle speed (NO) and the current vehicle speed (NO) is large, the vehicle speed change rate (ΔN) is set small.

Further, the motor control circuit is supplied with an instruction vehicle speed signal (NO) corresponding to the difference between the target vehicle speed (NO> and the vehicle speed change rate (ΔN)), and the rotation speed of the motor is controlled via an inverter or a stopper.

As a result of the above-1, the speed of the vehicle is controlled by, for example, accelerator operation alone, regardless of the magnitude of the load, even when the vehicle is climbing or dismounting, and drivability corresponding to the accelerator operation can be ensured.

[Example] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the flowchart V-1 when the control method according to the present invention is used for actual electric vehicle motor control.
Furthermore, a control circuit for executing the flowchart of FIG. 1 is shown in FIG.

In FIG. 2, a motor 10 which is a drive source of an electric vehicle
An induction motor is used, and current for this motor 10 is supplied from a battery 22 via an inverter circuit 12. Further, the target vehicle speed calculation circuit 14 calculates the target vehicle speed N based on a driving command given from an accelerator sensor, a brake sensor, etc., and predetermined accelerator opening/vehicle speed data.
The target vehicle speed signal 0 thus calculated is sent to an adder 16 and a target acceleration calculation circuit 18.

The target acceleration calculation circuit 18 uses the target vehicle speed signal po, the given driving command and current driving conditions, as well as the motor rotation speed from the pulse generator 20 and the battery 22.
The vehicle speed change rate ΔN is calculated from the voltage, etc. based on a predetermined calculation formula. This medium speed change rate ΔN is sent to the tightening device 16, where the target vehicle daily O and the vehicle speed change rate ΔN are sent to the tightening device 16.
The indicated vehicle speed NO* is calculated from the difference between the indicated vehicle speed and the indicated vehicle speed NO*.
Q* is supplied to the motor 11 control circuit 24.

The rotation speed of the motor is controlled by the motor control circuit 24, and a primary current is supplied to the induction motor 10 via the inverter circuit 12. The current of the inductive converter 10 is supplied from the battery 22 via the inverter circuit 12 as described above.

In general, the voltage of the battery 22 is detected by a voltage detection circuit (not shown), the rotation speed of the induction motor 10 is detected by a pulse generator 20, and these detection signals are sent to desired arithmetic circuits 14, 18 and control circuit 2, respectively.
4 is supplied.

In this embodiment, the motor is described as being an induction motor, but the present invention is not limited to this, and a direct current motor may be used.

Next, the control method of the present invention will be explained according to the flowchart of FIG.

First, in step 101, various types of data are read, and the read data at this time is the accelerator sensor.
, accelerator switch, brake sensor.

Driving commands from the brake switch, forward/reverse switch, manual switch to switch between sporty and mechanical, and the motor rotation speed (NO) that indicates the current vehicle speed.
) and running conditions consisting of varying voltages.

The target vehicle speed calculation circuit 14 includes an accelerator sensor, an accelerator switch, and a brake sensor.

The accelerator opening degree (θ. ), that is, the accelerator opening speed (θACC) and the brake depression speed m (θBRK) are calculated.

In this case, if the reading in step 101 is performed at regular intervals, the accelerator change speed Δθ can be calculated without performing differential calculation of the accelerator opening degree and brake depression amount. . . and brake pedal speed as θBRK as Δθ (n)-θ ('1)-θ (n-1)8CCACCACC to 80 (n)-θ (n>-〇 (n-1)B
RK B RK B R
K may also be used.

Next, in step 103, the accelerator opening degree (θA
CC>, target vehicle speed mouth 0 is calculated, but at this time, the third
As shown in the accelerator opening/vehicle speed data in the figure, the relationship between the accelerator opening (θACC) and the target vehicle speed &O is predetermined, and for example, the accelerator opening (θ.C
), the target vehicle speed NO does not necessarily have to have a linear relationship, and can be determined along a characteristic curve that gives the driver a feeling of good drivability.

Also, the output signal from the accelerator opening speed (θACC> is O
If the target vehicle speed NO changes near position A, stable control can be obtained by uniformly setting the target vehicle speed NO to O by switching the accelerator switch on and off, or by setting it to a predetermined small value. I can do it.

Next, in step 1 (E), the accelerator opening degree (θ...

), the accelerator opening speed (θ...), or the amount of brake depression (0) and the brake depression speed (θBRK), etc., the following formula calculates the speed from the current vehicle speed to the target vehicle 0 every day. A vehicle speed change rate ΔN is determined.

ΔN=to/(agony 0−NO) In the above, 100 is the target vehicle speed, NO is the current vehicle speed, and K is a constant, and by changing the value of K, the vehicle speed change rate ΔN is determined.

That is, if the constant K is large, the vehicle speed change rate ΔN becomes small, and if the constant K is small, the vehicle speed change rate ΔN is set too large. As shown in Fig. 4, the values of the constants at this time are the accelerator opening degree (θACC>) and the accelerator opening speed (θACC>).
. . . ), and this K is further determined by the relationship between the brake depression amount (θBRK > and the brake depression speed (θ
It is similarly determined by the relationship with BRK>.

Also, θ. . . When set to -θBRK-0, it is also possible to provide an engine braking effect like in a normal internal combustion engine vehicle.

In step 105, the instructed vehicle speed NO* to the motor is calculated, and this instructed vehicle 3! N □ * is No =
It is given by NO-ΔN...■.

Further, in step 106, the commanded vehicle speed No.* is inputted to the motor control circuit 24, and the rotation speed of the motor 10 is controlled regardless of the magnitude of the load on the vehicle.

In the above, for example, the vehicle speed change rate ΔN=c in equation 0
Onst is the commanded vehicle speed No. according to the target vehicle speed No.
is applied to the motor control circuit 24, or N is set as ΔN=O.
Operation can be made extremely simple by controlling O=NO.

As explained above, according to this embodiment, even when the load applied to the vehicle changes, such as when climbing up or down the vehicle, the rotation speed of the motor is controlled, making it easy to operate the accelerator. It is possible to ensure drivability according to the

Furthermore, by controlling the motor at O speed, starting on a boarding road becomes extremely easy. Furthermore, it is possible to arbitrarily adjust the vehicle speed change rate ΔN and driving performance according to the current vehicle speed and battery voltage. For example, when the battery charging resistance decreases, the vehicle's speed is suppressed to extend the running distance. You can also do

[Effects of the Invention] As explained above, the present invention calculates a target medium speed based on a given driving command and predetermined accelerator distance/vehicle speed data, and then calculates the target medium speed based on the given driving command and predetermined accelerator distance/vehicle speed data, and then calculates the target medium speed, the driving command, and the current driving speed. The vehicle speed change rate is calculated from the conditions, the commanded vehicle speed is determined from the target vehicle speed and the vehicle speed change rate, and a control command corresponding to the commanded vehicle speed is given to the motor control circuit, thereby reducing the load applied to the vehicle. Regardless of the size, the drivability can be increased by 1q depending on the accelerator operation.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing a preferred embodiment of the control method according to the present invention, Fig. 2 is a circuit diagram for executing the flowchart of Fig. 1, and Fig. 3 is a diagram showing the acceleration/vehicle speed ratio. - An explanatory diagram based on the data, Fig. 4 is the accelerator operation (θACC) used in the present invention.
FIG. 3 is a data map diagram showing the relationship between the speed and the speed between the accelerators (θ...). 10 ... Motor 12 ... Inverter circuit 14 ... Target vehicle speed calculation circuit 16 ... Gratitude accelerator 18 ... Target acceleration calculation circuit 20 ... Pulse generator 22 ... Battery 24 ... Motor control circuit.

Claims (1)

[Claims] A control method for an electric vehicle motor that calculates a target vehicle speed based on a driving command including an accelerator operation and current driving conditions, and controls the motor to achieve the target vehicle speed. A target vehicle speed is calculated based on the opening degree/vehicle speed data, then a vehicle speed change rate is calculated from the target vehicle speed, the travel command, and the current travel condition, and an instructed vehicle speed is determined from the target vehicle speed and the vehicle speed change rate. 1. A method for controlling an electric vehicle motor, characterized in that a control command corresponding to a commanded vehicle speed is given to a motor control circuit.