JPH0477524B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is designed to ensure stable electric braking force even when the regenerative load is reduced or eliminated, mainly in electric railway vehicles. This invention relates to a braking control device for electric vehicles.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional control device for a chopper for a dynamic brake disclosed in, for example, Japanese Patent Publication No. 47-2698. In the figure, 1 is an overhead power source, 2 is a collector, and 3 and 8 are main 4 is a filter reactor; 5 is a filter capacitor that constitutes a filter circuit together with the filter reactor 4; 6 is a resistor for dynamic braking; 7 is a resistor for dynamic braking 6; 9 is a main motor circuit, 10 is an overhead line current detector that detects the current flowing into the main motor circuit 9 from the overhead line power supply 1 or the current flowing out from the main motor circuit 9; 11 is an overhead line current detector for controlling the flowing current; a voltage detector for detecting the voltage across the filter capacitor 5; reference numeral 12 is a current flow rate calculation circuit that calculates the current flow rate of the dynamic brake chopper 7 so that the voltage across the filter capacitor 5 becomes a predetermined value; 13 is a phase shifter circuit that converts the output of the duty ratio calculation circuit 12 into a pulse signal for turning on and off the chopper 7 for dynamic braking, and 14 is composed of the duty ratio calculation circuit 12 and the phase shifter circuit 13. It is a current limiter.

Next, the operation will be explained. However, since the method of controlling the conduction rate of the dynamic brake chopper 7 according to the change in the voltage across the filter capacitor 5 is well known, detailed explanation thereof will be omitted.

In the case of calculation in the duty ratio calculation circuit 12, a fixed value is determined in advance by considering the substation voltage or the amount of regenerated electric power, and this is used as the voltage pattern, for example. Now, if the voltage across the filter capacitor 5 obtained by the voltage detector 11 exceeds the above voltage pattern, the conductivity calculation circuit 1
2 increases, the phase angle of the phase shifter circuit 13 also widens, and the conduction rate of the dynamic brake chopper 7 increases, so that the voltage across the filter capacitor 5 decreases.

In this way, the dynamic brake chopper 7 is connected to the other regenerative load (not shown) connected to the overhead line power source 1.
It functions to keep the voltage across the filter capacitor 5 constant against changes in the current regenerated from the main motor circuit 9 or changes in the current regenerated from the main motor circuit 9. Here, in the case of an electric railway vehicle, the power generating brake needs to operate when the regenerative load of other vehicles is insufficient or absent. Therefore, the voltage pattern is set to be larger than the rated overhead line voltage so that the shortage of regenerative load can be detected from the rise in voltage across the filter capacitor 5.

Note that when there is a sufficient regenerative load, the voltage across the filter capacitor 5 is reduced by another control circuit (not shown), so that the operation of the dynamic brake chopper 7 is stopped.

[Problem that the invention seeks to solve]

Conventional braking control devices for electric vehicles are configured as described above, and the voltage pattern is a fixed value, so if the overhead line voltage rises beyond the voltage pattern due to the influence of other regenerative vehicles, etc. Even though it is a brake circuit, a current on the power running side flows from the overhead line power source into the main circuit, and this current is superimposed on the current regenerated from the main motor circuit 9 and flows through the dynamic brake resistor 6. The capacity of the dynamic brake resistor 6 is normally set to be efficient so as to consume only the power regenerated from the main motor circuit 9, so if the current from the overhead line power source 1 continues to flow, However, there was a problem in that the resistor for dynamic braking exceeded its capacity, resulting in overheating and burnout.

This invention was made to solve the above-mentioned problems.In the unlikely event that an external factor such as an increase in overhead line voltage due to another regenerative vehicle or an internal factor such as an error in the set value of the voltage pattern , even if the overhead wire current on the powering side tries to flow into the main circuit, the current flowing to the dynamic braking resistor is restricted, preventing it from heating up, and maintaining stable dynamic braking function. The purpose is to obtain a braking control device.

[Means for solving problems]

The braking control device for an electric vehicle according to the present invention inputs a current detection signal from an overhead line current detector to the current limiter, thereby increasing or decreasing the conduction rate of a chopper for dynamic braking.

[Effect]

The overhead line current detector in this invention detects the powering side current flowing from the overhead line power supply, and inputs a current detection signal to the current limiter. Since the current limiter throttles the current flow rate of the dynamic brake chopper based on this input, the current flowing through the dynamic brake resistor is limited. This means that the voltage across the filter capacitor is increased from the value of the voltage pattern described above to be equal to the overhead line voltage, and functions in the same way as when preventing the inflow of powering side current.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, numerals 1 to 14 indicate the same or corresponding components as those in FIG. 3. The difference between the one in FIG. 1 and the one in FIG. 3 is that the current detection signal from the overhead wire current detector 10
The point is that it is now being inputted into .

Next, the operation will be explained. Now, overhead power supply 1
If the powering side current flows into the main circuit from
The overhead line current detector 10 detects this current and outputs a current detection signal to the conductivity calculation circuit 12. The conductivity calculation circuit 12 thereby sends an output signal of an appropriate calculated value to the phase shifter circuit 13, and the dynamic brake chopper 7 is controlled on/off by the pulse signal from the phase shifter circuit 13, and the conductivity is controlled. narrowed down. Therefore, the current flowing through the dynamic brake resistor 6 is limited, and overheating and burnout thereof are prevented.

Limiting the current in this way has the same effect as when the voltage across the filter capacitor 5 is raised above the value of the voltage pattern described above to be equal to the overhead line voltage, thereby preventing the inflow of powering side current. It is something. In other words, like the conventional device,
Even if the device controls the voltage across the filter capacitor 5 to a constant value, it is possible to change the apparent constant voltage pattern, thereby limiting the current of the dynamic brake resistor 6. .

If the overvoltage increases abnormally, an overvoltage detector (not shown) is activated to protect the main circuit equipment shown in FIG. 1.

Next, another embodiment of the invention will be described with reference to FIG. In this figure, 15 is a comparison circuit that detects that the current detection signal value outputted by the overhead wire current detector 10 has exceeded a predetermined value, and 16 is a counter circuit that counts time upon receiving the output of the comparison circuit 15. . That is, when the comparator circuit 15 detects that the current detection signal value from the overhead line current detector 10 has exceeded a predetermined value, and this state continues for a preset period of time, the output of the counter circuit 16 causes the main circuit to Switches 3 and 8 are designed to open.

With the above configuration, in the unlikely event that the current limiter 14 does not operate for some reason, or a switching element such as a transistor or thyristor used in the dynamic brake chopper 7 breaks down, or Even if the control system of the dynamic brake chopper 7 becomes abnormal, overheating and burnout of the dynamic brake resistor 6 can be reliably prevented.

〔Effect of the invention〕

As described above, according to the present invention, the current detection signal from the overhead line current detector is inputted to the current limiter, and the conduction rate of the dynamic brake chopper is controlled according to the magnitude of the overhead line current. This has the effect that it is possible to prevent excessive current from flowing into the dynamic brake resistor, and to maintain a stable dynamic brake function.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a brake control device for an electric vehicle according to an embodiment of the present invention, FIG. 2 is a block diagram showing a brake control device for an electric vehicle according to another embodiment of the invention, and FIG. 3 is a conventional brake control device. FIG. 2 is a block diagram showing a control device for a chopper for a power generation brake. 1 is an overhead line power supply, 5 is a filter capacitor, 6 is a resistor for dynamic braking, 7 is a chopper for dynamic braking, 9 is a main motor circuit, 10 is an overhead line current detector, 11 is a voltage detector, 12 is a conduction rate calculation circuit,
13 is a phase shifter circuit, and 14 is a current limiter.
In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A braking control device for an electric vehicle having a current detector 10, a voltage detector 11, and a current limiter 14, wherein the electric vehicle has a reactor 4 connected to a current collector 2.
A main motor circuit 9 is connected after the capacitor 5 of a chopper input filter consisting of a capacitor 5 and a resistor 6 connected in series and a chopper circuit 7 connected in parallel to the capacitor 5 to perform power running and regenerative braking. The current detector 10 is connected to the main motor circuit 9 to detect its current, and the voltage detector 11 is used to detect the voltage across the capacitor 5. Yes, the current limiter 14 inputs the detection signals from the current detector 10 and the voltage detector 11, keeps the voltage across the capacitor 5 constant, and turns off the current when the detection signal from the current detector 10 indicates an increase. A braking control device for an electric vehicle that outputs a duty ratio control signal to a chopper circuit 7 to reduce the duty ratio.