JPH0797882B2 - Braking control device for electric vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle control device that performs regenerative braking using, for example, a chopper, and particularly, at the time of the regenerative braking, a resistor is inserted in series with a motor for regenerative braking. The present invention relates to improvement of a short-circuit control system for the resistor when the area is expanded.

[Conventional technology]

FIG. 3 is a circuit diagram showing a conventional electric vehicle control device of this type disclosed in, for example, Japanese Patent Laid-Open No. 61-37842. In the figure, (1) is a power supply line, (2) is a current collector such as a pantograph, (3) is a filter reactor, (4) is a filter capacitor, (5) is a freewheel diode, and (6).
Is a chopper that conducts and cuts off the main circuit current and controls the lead time to control the motor current. (7) is a main smoothing reactor for smoothing the motor current. (8) and (9) are motors. Field and armature, (10) for expanding the regenerative area motor field (8) and armature (9)
A resistor for enlarging the regeneration area, which is inserted in series with (11), is a switch that short-circuits the resistor (10) to remove it from the circuit when the vehicle speed falls below a predetermined speed. Then, the resistor device (12) is composed of the resistor (10) and the switch (11).
Make up. (13) is a voltage detection device that detects the voltage of the filter capacitor (4), (14) is a voltage detection device that detects the voltage of the series body of the motor armature (9) and the resistor (10), (15) ) Is a current detection device for detecting the motor current, (16) is a brake command value, (17) is a load detection device,
(18) inputs the brake command value (16), the signal from the load detection device (17), and each voltage / current value to perform necessary calculations, and outputs a predetermined gate pulse to the chopper (6),
The control device outputs an open / close signal to the switch (11).

Next, the operation, particularly the operation after the regenerative braking operation is started with the switch (11) open based on the brake command issued in the high speed range, will be mainly described. When the switch (11) is open and the resistor (10) is inserted in the circuit, if the resistance value of this resistor (10) is R, then IM · R (where IM is the motor current value) ), The motor voltage is apparently lowered by IM · R. Therefore,
The electromotive force of the motor can be controlled substantially higher by that amount, the initial speed of the brake is increased, and the area of the regenerative brake is expanded.

Thus, in the high speed range, the resistor (10) is inserted, but when the vehicle speed decreases, conversely the voltage drop IM · R due to the resistor (10) causes the effective action of the regenerative brake. The lower limit speed increases, and the regenerative area decreases by this amount.
Therefore, it is necessary to short-circuit the resistor (10) by the switch (11) when the speed drops to a predetermined value. However, when the resistor (10) is short-circuited, a voltage fluctuation corresponding to IM · R apparently occurs in the circuit, the current of the motor (9) and the voltage of the filter capacitor (4) jump up, and the transient current, Due to the transient voltage, the overcurrent detection and the overvoltage detection may be activated to stop the brake control.

Therefore, the control device (18) detects the condition of short-circuiting the resistor (10) from the voltage and current value of each part, and outputs the closing signal to the switch (11) by the output and forcibly narrows down the motor current. Gate pulse for switch (1
Output to the chopper (6) after a set time delay from the operation time of 1). By controlling as above,
It prevents the current from splashing due to the short circuit of the resistor (10).

[Problems to be Solved by the Invention]

Since the conventional electric vehicle control device is configured as described above, the operating time of the switch (11) may vary,
Further, if there is a change in the ON time of the main contact due to wear of the main contact, a difference occurs between the timing when the switch (11) is actually closed and the timing when the current is narrowed down by the chopper (6). As a result, for example, when the former timing is early, the motor current becomes excessive and the overcurrent detection operates, and in order to avoid this, the amount of narrowing down the motor current is increased in consideration of the variation in the operation time, and When the narrowing time is extended, there is a problem that the brake torque is affected and the riding comfort during braking is impaired.

The present invention has been made to solve the above problems and does not require forcible motor current narrowing,
Therefore, it is an object of the present invention to provide a simple and stable electric vehicle control device that does not require synchronization with a switch closing operation.

[Means for Solving the Problems]

In the electric vehicle control device according to the present invention, the resistance device is constituted by a plurality of section resistors and a plurality of unit switches for appropriately short-circuiting the section resistors to sequentially reduce the resistance value of the resistors stepwise. , The resistance value of the segmented resistor is set so that the transient current due to the short circuit is less than the set value for overcurrent detection of the circuit, and the unit switches are closed sequentially at a time interval longer than the settling time of the transient current. It is the one.

[Action]

First, the regenerative braking operation from the high speed range is started in the state where all the segment resistors are inserted. When the vehicle speed gradually decreases due to the braking force and reaches a predetermined set speed,
The plurality of unit switches are sequentially closed at a predetermined set time interval, and accordingly, the resistance value of the resistor decreases stepwise and reaches zero.

Although the motor current increases when each segmented resistor is short-circuited, its resistance value is regulated and the insertion interval is also regulated.Therefore, a series of short-circuits of these segmented resistors does not activate overcurrent detection. A stable control characteristic can be obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. What is different from the conventional case is the resistance device (19) and its resistor (2
0) is two segmented resistors (20a) connected in series with each other
The switch (21) is composed of a thyristor switch (21a) as a unit switch capable of short-circuiting the segment resistor (20a) during regeneration and both segment resistors (20a) (20a).
It consists of a thyristor switch (21b) that can short circuit b). Then, these thyristor switches (21a) (21
The gate pulse to b) is output from the controller (22).

Here, for example, the rated voltage value of the power supply line (1) is 750V,
The maximum brake control current is 500A, and the total resistance of the resistor (20) requires 0.3Ω for the regenerative brake performance. The voltage fluctuation when the segmented resistor is short-circuited is the power supply line (1).
The resistor (20) is composed of two-stage segmented resistors (20a) (20b) each having a resistance value of 0.15Ω so that the voltage is approximately 10% of the rated voltage value of 750V, that is, 75V. The above 10% is set because the set value for overcurrent detection in this type of device is usually about 1.3 to 1.4 times the maximum control current.

In addition, the operating time interval between both thyristor switches (21a) and (21b) is such that the transient component of the transient current due to the short circuit of the segmented resistor (20a) by the previous thyristor switch (21a) is attenuated, and It is set to 0.3 seconds, which is longer than the time until the current value is reached, that is, the transient current settling time (usually about 0.1 to 0.2 seconds).

Next, the operation will be described. As in the conventional case, when the vehicle enters the regenerative braking operation with the resistor (20) inserted from the high speed range and the vehicle speed gradually decreases and the resistance short circuit condition is satisfied, the control device (22) sends a firing signal to the thyristor switch (21a). Is output, and first, the sectional resistor (20a) is short-circuited. This causes the motor current to transiently increase, but in this case the voltage fluctuation is set to about 10% of the rated value, so
In particular, overcurrent detection does not operate even if the chopper (6) is not narrowed down. The control device (22) outputs an ignition signal to the thyristor switch (21b) 0.3 seconds after the thyristor switch (21a) is closed to close the thyristor switch (21b) and short-circuit both the segment resistors (20a) (20b). In this case, since the settling time or more has elapsed since the previous short circuit, there is no residual current transient at the time of the previous short circuit, so the transient current due to the closed circuit of the thyristor switch (21b) also detects overcurrent. It does not work.

Since the time required for firing the thyristor switch is about a few microseconds after the firing signal is given, variations in the time interval between both thyristor switches (21a) (21b) do not pose any problem.

Next, in the regenerative operation, the motor current is changed by the action of the motor voltage limiter and the power supply line voltage limiter determined from the characteristic curve of the motor so that the motor current changes to the brake command value (16) and the load detection device (17).
Consider the characteristics when the control is performed by narrowing down the value of the required brake pattern determined by the signal from and.
In this case, in the conventional control device, if the current is narrowed down by the chopper (6) synchronized with the short circuit of the resistor by the same amount as the amount required at the maximum braking current, the current will be narrowed down too much. Therefore, regardless of the above current pattern, it is necessary to narrow down the amount proportional to the current that is actually flowing, and the control becomes complicated accordingly. On the other hand, in the present invention, as described above, when the current is narrowed down by the limiter and controlled, the voltage fluctuation component IM · R at the time of short circuit becomes smaller accordingly, and as a result,
Since the increase in motor current decreases and the settling time also shortens,
The control characteristics tend to be more stable and there are no problems.

In addition, considering the current capacity of the thyristor switch (21), the thyristor switch (21b) in the latter stage must have sufficient current capacity to flow the motor current after the resistor short circuit, but Since the energization time of (21a) is a short time of about 0.3 seconds, a small capacity can be adopted accordingly.

FIG. 2 shows a resistance device (19) according to another embodiment of the present invention.
Indicates. Here, the thyristor switch (21a) short-circuits only the segmented resistor (20a) and the thyristor switch (21a)
b) has a circuit configuration in which only the segmented resistor (20b) is short-circuited. In this case, the thyristor switch (21a) (21b)
Both have a large current capacity, but the voltage may be low,
In addition, both have the same rating.

Although the resistor (20) is divided into two stages in each of the above-described embodiments, three stages may be used depending on the voltage rating value of the power supply line (1) and the total resistance value required for the resistor (20). It may be divided into the above. Further, although the voltage fluctuation IM · R due to the short circuit of each classification resistor is set to 10% of the rated value, it can be set arbitrarily within the operation level of overcurrent detection. Regarding the operation time interval of the thyristor switch, the value in the above embodiment may be changed as long as it is the settling time or more.

Further, in each of the above-mentioned embodiments, the thyristor switch is used as the unit switch and the chopper is used for controlling the main circuit, but the present invention is not limited to these and can be applied.

〔The invention's effect〕

As described above, according to the present invention, a plurality of segmented resistors and unit switches are used, and the circuit overcurrent detection is prevented from operating by a short circuit of each segmented resistor. It is not necessary to control the current narrowing, which is simple and always provides stable control characteristics.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an electric vehicle control device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a resistance device according to another embodiment of the present invention, and FIG. 3 is a conventional electric vehicle control device. It is a circuit diagram. In the figure, (8) and (9) are motor fields and armatures, (19) is a resistance device, (20) is a resistor, and (20a) (20).
b) is a segmented resistor, (21) is a switch, (21a) (21b)
Is a thyristor switch as a unit switch, and (22) is a control device. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a regenerative braking control for a main circuit of an electric vehicle, the main circuit comprises a motor (9), a resistor (20) and a switch (21), and the motor (9) and the resistor are connected. The switch (21) is connected in series with the resistor (20) and is connected between the overhead wire and the ground, and the switch (21) is configured to short-circuit the resistor (20) when the vehicle speed falls below a predetermined set speed. The resistor (20) includes a plurality of segmented resistors (20a, 20b), the plurality of segmented resistors (20a, 20b) are connected in series with each other, and the switch (21) includes a plurality of segmented resistors (20a, 20b). Unit switch (21a, 21
b), the plurality of unit switches (21a, 21b) are configured so that the resistance value of the resistor (20) can be sequentially reduced in a stepwise manner by sequentially shorting the segmented resistors (20a, 20b). , The resistance value of each of the above segmented resistors (20a, 20b) is determined by the unit switch (21a, 21b) of each of the segmented resistors (20a, 20b)
Is set to a value at which the transient current of the main circuit that flows when the main circuit is short-circuited is less than the set value for overcurrent detection of the main circuit, and the interval for closing operation of each unit switch (21a, 21b) is
A braking control device for an electric vehicle, wherein a transient current settling time based on a short circuit of the above-mentioned segmented resistor due to a closing operation performed previously is set to be equal to or longer than a settling time.