JPH06217406A - Driver for electric automobile - Google Patents

Abstract

PURPOSE:To prevent deterioration of comfortableness due to abrupt deceleration when the motor of an electric motor is subjected to regenerative braking. CONSTITUTION:A control circuit 8 drives a motor 5 through a switching circuit 4 based on a command while at the same time executes regenerative braking. A regenerative power means 12 delivers a received acceleration amount to the control circuit 8 and detects acceleration/deceleration of an electric automobile based on the r.p.m. of the motor 5 and then delivers a command for restricting the acceleration/deceleration within an upper limit to the control circuit 8. The control circuit 8 restrains the regenerating amount in such a manner thus preventing abrupt deceleration of the electric automobile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a control circuit for converting direct current power of a power storage device into alternating current power by an inverter based on an external command to control a motor at a variable speed and executing regenerative braking during deceleration. And a drive device for an electric vehicle.

[0002]

2. Description of the Related Art Inverters generally used in industrial and household electric motors are used to drive the electric motors at variable speeds, and are constructed, for example, as shown in FIG. That is, in FIG. 10, the AC from the commercial power supply 1 is converted into the rectifier 2
The DC voltage is converted into a direct current, and then rectified by the capacitor 3. The switching circuit 4 operates the motor 5 at a variable speed by converting direct current into alternating current having an arbitrary frequency.

The motor 5 is operated by the control circuit 8 on the basis of the voltage value of the DC voltage, the rotation speed detected by the rotation sensor 6, the current value by the current sensor 7 and the command value from the outside, and the control circuit 8 By controlling the switching circuit 4 by 8, the control circuit 8 is controlled to an appropriate state.

By the way, when the motor 5 is stopped,
Electric braking is performed using a regenerative braking function that operates the motor 5 as a generator. At this time, when the commercial power source 1 cannot regenerate electric power (for example, when the rectifier 2 is used as shown in FIG. 10), the direct current voltage, that is, the voltage of the capacitor 3 rises due to the regenerative operation, The rated voltage of 3 may be exceeded.

Therefore, generally, when the voltage of the capacitor 3 is detected and the detected voltage exceeds the rated voltage, the discharging resistor 9 and the discharging switching circuit 1 are detected.
When 0, the regenerative energy is consumed by resistance to prevent the rise of the DC voltage.

FIG. 11 shows a power storage device 11 instead of a commercial power source.
An example using (storage battery) is shown. In FIG. 11, when the power storage device 11 is used, when the motor 5 is used as an electric motor, the same operation as the above-described commercial power source drive is performed, but the motor 5 is operated as a generator to perform regeneration. When braking, the power storage device 11 is generally used.
Then, regenerative energy is applied to charge the power storage device 11. In this case, the voltage of the power storage device 11 and the current are detected by the current sensor 7 to monitor the state of charge of the power storage device 11. When the charging is completed, the voltage of the capacitor 3 rises, so the regenerative power is consumed by the discharging resistor 9 and the switching circuit 10.

[0007]

By the way, when the inverter having the above-mentioned configuration is adopted in an electric vehicle, the amount of regeneration during regenerative braking is always constant, so a large amount of braking acts during regenerative braking, which causes occupant discomfort. There is a drawback of giving. The present invention has been made in view of the above circumstances, and an object thereof is to provide a drive device for an electric vehicle that does not give an occupant an uncomfortable feeling when the electric motor is regeneratively braked.

[0008]

According to the present invention, a control circuit for converting a DC power of a power storage device into an AC power by an inverter based on an external command to control a motor at a variable speed and executing a regenerative braking during deceleration. In a drive device for an electric vehicle provided with, a regenerative power consumption means for consuming regenerative power provided from the electric motor to the power storage device is provided, the acceleration of the electric vehicle is detected, and a deceleration acceleration of the electric vehicle is detected during regenerative braking. A regenerative electric power unit is provided for instructing the control circuit so that the electric power storage device becomes a predetermined upper limit value or less and for driving the regenerative electric power consumption unit when the power storage device is in a fully charged state.

In this case, the acceleration of the electric vehicle is detected, and at the time of regenerative braking, the control circuit is instructed so that the deceleration acceleration of the electric vehicle becomes equal to or less than a predetermined upper limit value, and the power storage device is fully charged. At this time, regenerative power means for instructing the control circuit to suppress the regenerative power may be provided. Further, each of the regenerative electric power means may be configured to include instructing the control circuit to generate the regenerative electric power according to the operation amount of the brake pedal.

Further, each of the above-mentioned regenerative electric power means may be configured to include a command to the control circuit so that the electric vehicle stops operating at a predetermined speed or less. Further, each of the regenerative electric power means may be configured to instruct the control circuit to generate the regenerative electric power such that the sum of the mechanical braking force and the regenerative braking force matches the command value.

[0011]

According to the drive device of the electric vehicle of the first aspect, the control circuit executes the regenerative braking when the vehicle is decelerated. At this time, the regenerative power means detects the acceleration of the electric vehicle, and commands the control circuit so that the deceleration acceleration of the electric vehicle becomes equal to or less than the predetermined upper limit value. This allows
Since the control circuit suppresses the regenerated electric power, the electric vehicle slows down slowly. Then, when the power storage device is fully charged by the regenerative power, the regenerative power means drives the regenerative power consuming means, so that the regenerative power is consumed without being given to the power storage device.

According to another aspect of the invention, the regenerative electric power means instructs the control circuit so that the deceleration acceleration of the electric vehicle becomes equal to or less than the predetermined upper limit value during the regenerative braking. As a result, the control circuit suppresses the regenerative electric power, so that the electric vehicle slowly decelerates. When the power storage device is in the fully charged state, the regenerative power means instructs the control circuit to suppress the regenerated power, so that a large regenerative power is not given to the fully charged power storage device. .

According to the third aspect of the present invention, the regenerative electric power means instructs the control circuit to generate the regenerative electric power according to the operation amount of the brake pedal. As a result, regenerative braking is added to the electric vehicle in addition to mechanical braking, so the braking ability is improved.

According to the fourth aspect of the present invention, the regenerative electric power means instructs the control circuit to stop the operation of the electric vehicle at a predetermined speed or less. As a result, only the mechanical braking is executed when the electric vehicle has a speed equal to or lower than the predetermined speed, so that it is possible to prevent the braking ability from being suddenly lowered when the regenerative braking fails.

According to another aspect of the present invention, the regenerative electric power means causes the control circuit to generate the regenerative electric power so that the sum of the mechanical braking force and the regenerative braking force becomes the command value. Order. As a result, a stable braking ability can be obtained even when the magnitude of regenerative braking changes.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the entire configuration. The same parts as those in FIG. 11 are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described. 1 is different from FIG. 11 in that the power storage device 11 and the regenerative power means 12 are added as shown in FIG. 1 and the power source is replaced by the power storage device 11, so that the commercial power source 1 and the rectifier are provided. 2 is omitted.

The regenerative electric power means 12 inputs the accelerator amount, and outputs the input accelerator amount as a command value to the control circuit 8 in the power running region where the motor 5 operates as an electric motor. In this case, when the torque control is executed as the control of the electric vehicle, the accelerator amount becomes the torque command value,
The motor 5 rotates at a rotational speed that is in balance with the torque value of the motor 5.

Next, in the regenerative region in which the motor 5 operates as a generator, the regenerative energy is returned to the power storage device 11 to perform charging, and regenerative braking, which is electric braking, is executed.

FIG. 2 schematically shows the function of the regenerative power means 12. In FIG. 2, the regenerative electric power means 12 inputs a preset regenerative amount B when executing regenerative braking, and the value B1 obtained by an arbitrary function f1 (x) is a regenerative command. It becomes a value. Here, the regenerative power unit 12 detects the voltage of the power storage device 11 and compares the voltage with the upper limit voltage value. That is, when the power storage device 11 is a storage battery such as a battery as in the present embodiment, the battery may be damaged if it is charged at an upper limit voltage or higher. Therefore, the difference between the charging voltage of the power storage device 11 and the upper limit value is obtained, and the coefficient K is calculated by an arbitrary function f2.
V (0≤KV≤1) is multiplied by the regeneration amount B1 to obtain the regeneration amount BV.

Next, in the current detection, if the power storage device 11 is a battery, the battery may be damaged if the battery is charged at the upper limit current or more, as described above. In addition to finding the difference from the value, the regeneration amount BV is obtained by multiplying the regeneration amount BV by a coefficient KI (0≤KI≤1) using an arbitrary function f3.

In the final rotation speed detection, the detected rotation speed of the motor 5 is divided by the sample time t to obtain the acceleration during deceleration, and this acceleration and the upper limit value at which the ride comfort of the occupant is uncomfortable. Along with the difference being calculated, the coefficient Kr (0≤Kr≤1) is multiplied by the arbitrary function f4 and the regenerative quantity BVIr is calculated.

Then, the regenerative amount B obtained as described above
When VIr is input to the control circuit 8 as the torque command value,
The control circuit 8 executes regenerative braking according to the applied torque command value.

By the way, when regenerative braking is executed, regenerative power is applied to power storage device 11 to charge it. Then, when the power storage device 11 is fully charged, the voltage and current of the power storage device 11 become the upper limit values and the coefficients KV and KI become zero, and regeneration is not performed. In this case, however, the regenerative power means 12 consumes regenerative power. Discharge resistor 9 constituting the means 13
Also, the command value is changed so that regenerative braking is continued due to resistance consumption by the discharging switching element 10. As a result, the control circuit 8 controls the discharge switching element 10 to be turned on so that the regenerative electric power is consumed by resistance to maintain a constant regenerative braking force.

According to the above configuration, the regenerative electric power means 12 issues a command value to the control circuit 8 so that the electric vehicle will not suddenly decelerate during regenerative braking. Can be prevented. Therefore, unlike the conventional example in which a large amount of regenerative braking occurs during regenerative braking, the occupant does not feel uncomfortable.

FIGS. 3 to 5 show a second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described. That is,
Since the discharge resistor 9 and the discharge switching element 10 require a relatively large space and become a heat generation source during the regenerative operation, in the second embodiment, the discharge resistor 9 and the discharge switching element are used. It is configured by omitting 10.

FIG. 4 schematically shows the function of the regenerative power means 12. In this case, when the battery is fully charged, the regenerative electric power unit 12 changes the command value so as to reduce the regenerative amount and outputs the command value.

FIG. 5A shows a time chart when the command value of the regenerative amount is small. The battery voltage, current, rotation speed and rotation of the motor 5 from the start of regenerative braking to the stop of the motor. The output period of the ON signal that indicates that the acceleration limitation by the number (regeneration amount limitation) is being performed is T
Shown with 1. In this case, the values of the current and the rotation speed are shown as negative values for the sake of clarity.

In FIG. 5 (a), when regenerative braking is performed, the battery voltage rises and the current flows in the opposite direction to shift from the power running state to the regenerative state. Then, when T0 seconds elapse after the shift to the regenerative state, the regenerative electric power means 12 determines that the deceleration acceleration of the vehicle exceeds the upper limit value and continues to execute the acceleration limitation by the rotational speed for T1 seconds. After that, when the deceleration acceleration of the vehicle falls below the upper limit value due to the acceleration limitation, the acceleration limitation by the regenerative power means 12 is released. In this state, the vehicle stops while continuing the original regenerative braking.

Now, FIG. 5B shows a case where the command value of the regeneration amount is large, and regenerative braking acts largely as compared with the case of FIG. 5A. Therefore, in FIG. 5 (a) in which the command value of the regeneration amount is small, only the acceleration limitation based on the rotational speed operates, but in FIG. 5 (b), the acceleration limitation is T
During the period of operation for 3 seconds, the limitation of the regeneration amount due to full charge of the power storage device 11 also operates for T2 seconds.

According to the second embodiment, when the electricity storage device 11 is fully charged, the amount of regeneration is suppressed, so that the discharging resistor 9 and the discharging switching element 10 for consuming regenerative power are provided. Although omitted, the electric vehicle can be decelerated by the generation of regenerative electric power.

6 and 7 show a third embodiment of the present invention. The difference between the third embodiment and the second embodiment is that
In the second embodiment, the command value of the regenerative amount is set to a constant value, but in this third embodiment, the operation amount of the brake pedal is used as the command value of the regenerative amount, and the driver can change according to the state of the electric vehicle by regenerative braking. The point is that the regenerative braking force can be adjusted by the brake pedal.

FIG. 7 is a schematic diagram showing the function of the regenerative power means 12. In FIG. 7, the regenerative electric power means 12 inputs the brake amount as a command value of the regenerative amount and executes the same control as in the second embodiment.

According to the third embodiment, the larger the amount of operation of the brake pedal, the larger the amount of regeneration is instructed, so that the braking performance can be improved. In this case, since the regenerative braking force is suppressed when the electric vehicle reaches a predetermined deceleration acceleration, it is possible to prevent the riding comfort of the occupant from being deteriorated.

FIG. 8 is a schematic diagram of the regenerative electric power means 12 showing the fourth embodiment of the present invention. In FIG. 8, the regenerative electric power means 12 stops the regenerative braking in the low speed region and bears the mechanical control by the conventional hydraulic system or the like. This is because the amount of regenerative energy is small when the vehicle is at low speed, and in order to avoid danger in an emergency where regenerative braking is not executed due to an electrical defect, braking by regenerative braking is stopped at low speed.

FIG. 9 is a schematic diagram showing the regenerative electric power means 12 in the fifth embodiment of the present invention. That is, when the discharging resistor 9 and the discharging switching element 10 are not provided, the braking force due to regenerative braking varies depending on the state of charge of the battery. Therefore, control is performed by including a mechanical control command for keeping this constant. Configured. In this case, the regenerative power means 12
When a brake amount command value is given, control is performed so that the sum of the electric braking command and the mechanical braking command matches the command value. According to the fifth embodiment, the mechanical braking force is adjusted according to the magnitude of the regenerative braking force, so that the stable braking force can always be exerted.

[0036]

As is apparent from the above description, according to the driving apparatus for an electric vehicle of the present invention, the regenerative power means controls the deceleration of the electric vehicle to be equal to or less than the upper limit value during regenerative braking. Is configured to command
When the regenerative braking of the electric motor is performed, an excellent effect that no occupant feels uncomfortable is exhibited.

[Brief description of drawings]

FIG. 1 is an overall schematic view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a function of a regenerative power means.

FIG. 3 is an overall schematic diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a function of a regenerative electric power means.

FIG. 5 is a timing chart showing the state of charge during regenerative braking.

FIG. 6 is an overall schematic diagram showing a third embodiment of the present invention.

FIG. 7 is a diagram schematically showing the function of regenerative power means.

FIG. 8 is a diagram schematically showing the function of a regenerative electric power means in a fourth embodiment of the present invention.

FIG. 9 is a diagram schematically showing the function of a regenerative electric power means in a fifth embodiment of the present invention.

FIG. 10 is an overall schematic diagram of a conventional example using a commercial power source as a power source.

FIG. 11 is an overall schematic diagram of a conventional example using a power storage device as a power source.

[Explanation of symbols]

Reference numeral 4 is a switching circuit, 5 is a motor (power storage device), 6 is a rotation sensor, 7 is a current sensor, 8 is a control circuit, 11 is a power storage device, 12 is a regenerative power consumption means, and 13 is a regenerative power consumption means.

Claims (5)

[Claims] 1. A drive device for an electric vehicle equipped with a control circuit that converts direct-current power of a power storage device into alternating-current power by an inverter based on an external command to control an electric motor at a variable speed and executes regenerative braking during deceleration. In, the regenerative power consumption means for consuming regenerative power given to the power storage device from the electric motor, and provided to detect the acceleration of the electric vehicle, the deceleration acceleration of the electric vehicle is less than or equal to a predetermined upper limit during regenerative braking. And a regenerative electric power means for driving the regenerative electric power consuming means when the electric storage device is in a fully charged state. 2. A drive device for an electric vehicle equipped with a control circuit for converting direct-current power of a power storage device into alternating-current power by an inverter based on an external command to control an electric motor at a variable speed and performing regenerative braking during deceleration. In order to detect the acceleration of the electric vehicle, at the time of regenerative braking, the control circuit is instructed so that the deceleration acceleration of the electric vehicle is equal to or less than a predetermined upper limit value, and the power storage device is fully charged. At this time, a drive device for an electric vehicle is provided, which is provided with regenerative power means for instructing the control circuit to suppress regenerative power. 3. The regenerative electric power means is configured to include a command to the control circuit to generate the regenerative electric power according to the operation amount of the brake pedal. Drive system for electric vehicles. 4. The electric regenerator according to claim 1, wherein the regenerative electric power means includes a command to the control circuit to stop the operation of the electric vehicle at a predetermined speed or less. Vehicle drive. 5. The regenerative power means includes a command to the control circuit to generate the regenerative power such that the sum of the mechanical braking force and the regenerative braking force matches the command value. The drive device for an electric vehicle according to claim 1 or 2.