Test bench test for electric brake stoppage of electric locomotives

The use of electric brakes has many advantages, such as reducing the quality of the brake system, reducing the cost of replacing the brake shoes, and the train running deceleration is higher.

The algorithm for stopping the train completely by electric braking and the new ramp estimation feedforward torque characteristic control algorithm are derived by derivation and verified on the rolling test bench of the vehicle.

The verification results show that even on the simulated ramp of the taxi, only the electric brake can be used to completely stop the wheel and maintain above in the stop state.

Key words electric brake electric locomotive motor vehicle inverter control vector control stop brake test bench test foreword In order to alleviate the congestion of railway transportation in large cities, it is necessary to improve the transportation capacity. One of the measures is to shorten the running time interval.

To shorten the running interval, it is necessary to reduce the braking time.

Therefore, it is important to increase the deceleration.

In the electric brake of electric locomotives, regenerative braking is widely used. In the current situation, it is necessary to supplement the mechanical brake or switch not only when the regenerative load is insufficient or the electric braking force is insufficient, and if it is controlled by the inverter, It was originally estimated that the electric brake could only be used to stop the parking, but it was still necessary to switch to the mechanical brake at low speed to zero speed.

If the electric brake can make the speed to zero, not only can the electric brake control be quickly responded to the stop, but also the effect can be achieved. The deceleration is high. The mechanical brake device is light, the brake shoe is lightly replaced, and the maintenance work is reduced. .

There have been reports on parking with electric brakes, but reports that can only be stopped on the ramp with electric brakes and that can maintain the parking state have not been seen.

The ramp prediction feedforward torque characteristic control of this design was tested on the vehicle test bench as a control system using only electric brakes, and the results showed that not only in the flat section but also on the simulated ramp of the taxi The locomotive can be completely stopped, and the above time can be maintained in the stopped state.

This paper introduces this newly developed control method and reports the test results, pointing out the practical value of this control system.

In addition, the control system proposed below differs only by the control of the electric brake stop and the control of maintaining the stop state after the stop state is controlled to stop.

When the motor is electrically braked, the motor's induction potential is low due to the low speed zone. Therefore, the effective range of the electric brake has a lower speed limit. In particular, during the period of parking, the electric braking force is gradually weakened and the air braking force is increased. That is, the electric air is switched and finally replaced by air brake.

Since the inverter control, the braking mode of the electric air switching has been followed, but the response to the electric braking force and the air braking force command is different when the electric power is switched, and the wheel and the brake shoe are made during air braking. The deviation of the friction coefficient between the moving plate and the brake piece causes the braking force of the whole train to change and generates a longitudinal impact. Before the parking is approached, the braking force is too large to affect the riding comfort.

If the train can be stopped by only electric braking, not only the above problems can be solved, but also the basic braking devices such as hundreds of kilograms of brake cylinders carried by each of the bogies can be simplified.

Since frictionless brake shoes or brake pads are not used as much as possible, noise and abrasion dust during braking can be reduced, thereby reducing environmental pollution.

In addition, in the maintenance site such as the vehicle workshop or the depot, the number of brake shoe replacements and the maintenance work of the mechanical brake components can be greatly reduced.

2 The effect of using electric brake system stop The regenerative braking is widely used in electric locomotives. When the electric braking force is insufficient due to insufficient power regeneration load, the air brake is used to supplement the braking force, or the electric brake is switched to the mechanical brake. brake.

In the past, the electric braking energy in the high-speed zone using the DC-carrying technology problem is large, and there is a fear of regenerative failure when there is no regenerative load. Therefore, if the braking resistor installed in the vehicle consumes energy, the problem can be solved.

As for the braking energy consumption in the low-speed zone, although there is no vehicle in the same feeding zone for its load, since the braking energy itself in the low-speed zone is small, it can be controlled by the internal circuit of the vehicle or the traction motor circuit such as the control circuit or the lighting air conditioner. Loss and the like are consumed, and the electric brake does not fail.

In addition, during the control of the parking period, the inverter can be used to maximize the quadrant operation, the forward traction, the forward braking, and the rearward traction. If the above advantages are effectively utilized, the main brakes are used. The technology focuses on how to control to make the speed to zero. This test of the electric brake system of the electric locomotive is controlled by the test bench and the electric traction.

One of the control problems of electric brake system stop is that when the asynchronous electric control mode of slip frequency control is adopted, the inverter control can not instantaneously control the torque, and the phase sequence switching during stop and speed is negative. Torque tuning is difficult, so complicated algorithms have to be used, which is a disadvantage.

If vector control is used for this, the phase sequence switching problem can be ignored, and the braking force can be controlled only according to the detected speed.

Another issue of electric locomotive brake control is how to solve the problem of low resolution of the speed sensor.

Generally, on the railway rolling stock, a speed sensor called a sensor is used, which is characterized in that the motor outputs about 60 pulses per revolution, which is higher than that of a rotary encoder such as an elevator used in a general industrial variable speed control motor. /A lot less per revolution.

For this, it can be improved by the pulse algorithm, and has been put into practical use in the inverter control of railway vehicles.

However, the lower the speed, the longer the detection pulse is. Even in the latest vehicle, the lowest detected speed is only one. Because the speed detection at low speed is difficult, it is expected that it is difficult to implement the stop control in the low speed feedback control.

On the premise of using the existing speed sensor, one way to solve this problem is to use the output signal of the speed sensor together with the speed estimation mechanism when the vehicle is about to stop, and perform torque feedforward control based on the estimated speed.

In order to solve the problem of torque control before parking, the following control methods are now adopted to realize the electric brake system stop at low speed. The speed estimation mechanism is used. The stop control algorithm uses the torque control of the tracking torque characteristic and promotes it to the ramp. The ramp on the line speculated that the feedforward torque characteristic control was tested on the test bench, demonstrating that the electrical brake can be used to speed up to zero.

The main equipment used is an asynchronous traction motor that is used on a running vehicle and that can individually control the traction motor. The asynchronous traction motor is controlled by a slip frequency vector and the speed sensor generally used on a railway rolling stock.