JPS5952602B2 - Electric car chip protection system - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electric vehicle chopper protection system.

Electric cars using choppers are becoming popular, especially in subway trains, due to their reduced power costs, maintenance costs, and high performance.For example, an electric car chopper device as shown in Figure 1 is being used. .

Figure 1 shows the main circuit of a typical electric vehicle chopper device, where 1 is the current collector, 2 is the first unit switch, and 3 is the main circuit of the electric car chopper device.
is a high speed current reducer 1. 4 is a current reduction resistor, 5 is a second unit switch, 6 is a charging resistor for the filter capacitor, 7 is a filter reactor, 8 is a filter capacitor, 9 is the traction motor armature winding 10 is a main motor field winding, 11 is a main smoothing reactor, 12 is a freewheeling diode,
13 is a chopper, and 14 is a main motor current detector.

The configuration shown in FIG. 1 operates as follows during power running.

When the high-speed flow reducer 9 is turned on by the reset I command at the time of leaving the warehouse, it is always turned on unless an accident occurs.

When the power running notch is commanded, first the first unit switch 2 is turned on, and the filter capacitor 8 is charged through the current collector 1, the unit switch 2, the high-speed current reducer 3, the charging resistor 6, and the filter reactor 7. .

Here, the charging resistor 6 is preselected to have a resistance value such that the filter capacitor voltage does not oscillate due to the filter reactor 7 and filter capacitor 8 during charging.

At this time, since the chopper 13 is not yet in operation, no current flows through the armature winding 9 and field winding 10 of the main motor.

When charging of the filter capacitor 8 is completed, the second unit switch 5 is turned on and the charging resistor 6 is short-circuited.

The chopper 13 starts its on/off operation under the condition that the unit switch 5 is turned on.

When the chopper 13 is turned on, the main motor current flows through the current collector 1
One unit switch 2 - High speed flow reducer 3 One unit switch 5 -
The flow increases through the filter reactor 7, armature 9, field 10, main flat sliding axle 11, and chopper 13 in series.

On the other hand, when the chopper 13 is turned off, the main motor current circulates through the armature 9, the field 10, the main flat sliding axle 11, and the freewheeling diode 12, and is attenuated.

The chopper 13 thus controls the main motor current to a constant current while repeating on and off operations.

In such an electric vehicle, the main circuit during regenerative braking is as shown in FIG.

That is, in FIG. 1, an armature 9, a field 10, a main flat sliding axle 11. The series circuit of the current detector 14 is connected to the chopper 1.
The connection configuration will be the same as if it were reconnected in parallel to 3.

In FIG. 2, when the chopper 13 is turned on, the main motor current flows through the armature 9 - field 10 - main flat sliding axle 11 - chopper 13 and increases.

On the other hand, when the chopper 13 is turned off, the main motor current flows through the armature 9 - field 10 - main flat sliding axle 11 - free boiling diode 12 - filter reactor 7 - unit switch 5 - high speed current reducer 3 - unit It is regenerated to the overhead wire through the switch 2 and current collector 1.

In this manner, the chopper 13 repeatedly turns on and off in the same way as when traveling, controlling the main motor current to a constant current.

However, if there is no regenerative load such as another power vehicle during regenerative braking, there is no place for the regenerative current to go, the voltage value of the filter capacitor 8 increases, and when the overvoltage limit occurs, the main circuit is opened and the regenerative braking is performed. It no longer takes.

In this case, braking force must be secured using an air brake.

As a countermeasure against this problem, conventionally a shunt resistor 15 and a thyristor 16 are connected in parallel with the chopper 13 as shown in FIG.
A method has been proposed in which the bypass is performed by igniting the ignition.

In this way, when the chopper 13 is off, the current flows through the thyristor 1.
6 and the bypass resistor 15, constant current control becomes possible and stable electric brake action can be continued.

In this way, connect the bypass resistor in parallel with the chopper 13,
This system, which enables stable electric braking even when the regenerative load disappears, helps prevent accidents caused by wear and overheating of the brake shoes and wheels due to continuous use of the air brake when performing slow braking on long-distance slope sections. This is an effective method.

On the other hand, conventional chopper devices as shown in Figures 1 and 2 are equipped with various protection functions such as overvoltage detection, overcurrent detection, and low voltage detection. When a series circuit of the bypass resistor 15 and the thyristor 16 is provided in the circuit, detection and protection in the event of a failure must also be taken into consideration.

First, considering the thyristor 16, if it has an open failure, no current will flow through the resistor 15 even if a gate signal is applied to the thyristor 16 when the regenerative load disappears in FIG. 3, so the voltage across the filter capacitor 8 will decrease. The voltage continues to rise until the overvoltage is detected, the main circuit is opened, and the air brake is activated.

Therefore, even if the thyristor 16 has an open failure, there is no particular harm, and since the overvoltage detection operates every time the regenerative load disappears, the failure can be detected.

However, if the thyristor 16 has a short-circuit failure, it cannot be directly recognized as a phenomenon, and when the main circuit is configured, the current flows through the newly installed resistor 15 whether the thyristor 16 is running or braking. will continue to flow, and this resistor 1
There is a risk that a current exceeding the capacity of the resistor 15 will flow, resulting in burnout of the resistor 15 and, in turn, a fire accident in the vehicle.

Therefore, a short-circuit failure of the thyristor 16 must be detected.

As this method, a current detector is provided in the series circuit of the resistor 15 and the thyristor 16, and when there is a regenerative load during power running or regenerative braking and the gate I signal is not applied to the gate of the thyristor 16, When current flows through resistor 15 when it should not, thyristor 1
6 methods of detecting short-circuit failures can be considered.

However, this method requires a new current detector, which inevitably makes the overall structure complicated and large.

In consideration of the above points, the present invention can detect a short-circuit failure of the thyristor 16 and protect the shunt resistor 15 using the conventional system shown in FIG. 1 without providing a new current detector. This is what we are trying to do.

An example of the present invention will be described below in detail with reference to the drawings. In the present invention, a failure of the thyristor 16 connected in parallel to the chopper 13 is detected prior to operation of the chopper.

In other words, at the start of the 4-way operation, the parallel circuit of the chopper 13 and the series circuit of the thyristor 16 and the bypass resistor 15 is shown in FIG. As shown in FIG. 2, the armature 9 of the main motor, the field 10, the main smoothing reactor 11 and the current detector 14 are connected in series.

In the connection state shown in FIG. 4, when a power running notch command is given, the unit switch 2 is turned on at time t1 as shown by the interlock signal S1 in FIG. 5A, and the voltage S2 across the filter capacitor 8 increases as shown in FIG. The battery is charged as shown in C.

When charging of the filter capacitor 8 is completed at time t2, the switch 5 is turned on as shown by the interlock signal S3 in FIG. 5B, and the chopper 13 starts to turn on and off in response to this interlock signal S3.

In this way, the period until the chopper 13 starts operating is
The AND condition output S4 (FIG. 5D) of the interlock signal S1 and the negative output of 83 is obtained.

On the other hand, the traction motor current is detected by the traction motor current detector 14, and a failure detection signal S6 is formed by ANDing the detected output S5 (FIG. 5E) and the conditional output S4.

Therefore, if a short-circuit failure has not occurred in the thyristor 16, as shown in FIG. In this state, the detection output S5 is not obtained from the main motor current detector 14 as shown in FIG. Therefore, the failure detection signal S6 also does not become "1".

On the other hand, if a short circuit failure occurs in the thyristor 16,
As shown in FIGS. 6A-F corresponding to FIGS. 5A-F, between time points t1 and t2, the traction motor current flows through the thyristor 16, so the traction motor detection output S5 is obtained (
(E) in FIG. 6, therefore, the failure detection signal S6, which is the AND condition of the conditional output S4 and the detection output S5, becomes "1".

As described above, according to the present invention, in a chopper system in which a series circuit of a thyristor and a shunting resistor is connected in parallel with the chopper to shunt the regenerative current, a short-circuit failure of the thyristor can be reliably detected. By doing so, it is possible to prevent burnout of the resistor and the occurrence of a fire accident in the vehicle, and this can be easily realized without adding any equipment to the conventional device.

[Brief explanation of drawings]

1 to 3 are connection diagrams showing an electric vehicle chopper device to which the present invention can be applied, and FIGS. 4 to 6 are connection diagrams and signal waveform diagrams showing an example of an electric vehicle chopper protection system according to the present invention. It is. 1: Current collector, 2: First unit switch, 3: High speed current reducer, 4: Current reducing resistor, 5: Second unit switch, 6:
Charging resistor, 7: filter reactor, 8: filter capacitor, 9: traction motor armature winding, 10: traction motor field winding, 11: main smooth axle, 12: freewheeling diode, 13: chopper, 14: Main motor current detector, 15: Shunt resistor, 16: Thyristor.

Claims (1)

[Claims] 1 Connect the first unit switch, a parallel circuit of a charging resistor and a second unit switch, and a filter capacitor in series with the power supply, and connect the traction electric machine in parallel with the series circuit of the thyristor and shunt resistor. In the electric vehicle chopper device that performs power or regenerative braking using a chopper that is
Turn on the unit switch to start charging the filter capacitor through the charging resistor, and then turn on the second unit switch to start charging the filter capacitor through the charging resistor.
the thyristor connected in parallel with the chopper, on the condition that current flows through the main motor until the charging resistor is short-circuited by turning on the unit switch and the chopper starts operating. An electric vehicle chopper protection system, which protects the braking resistor by detecting a short-circuit failure of the electric vehicle chopper.