Controller of energy feedback device, traction power supply system for rail transit and control method of traction power supply system for rail transit

Abstract

The invention discloses a controller of an energy feedback device. The controller of the energy feedback device is used for controlling the magnitude and direction of transmission power of a regenerative electric energy feedback device; the controller of the energy feedback device comprises an analog input unit and a reactive power calculation unit; the analog input unit is used for obtaining alternating current bus voltage of a traction station, incoming line current of the traction station, alternating current bus voltage of a main station and incoming line current of the main station; the reactive power calculation unit outputs the corresponding reactive power according to a target value of a power factor of the traction station and compensates the power factor of the traction station;or, in order to improve a power factor of the main station, the regenerative electric energy feedback device is controlled to output given reactive power. The invention further provides a traction power supply system for rail transit and a circulating current suppression method thereof, the reactive power is output by adjusting the regenerative electric energy feedback device, the alternating current output voltage of the regenerative energy feedback device is stabilized, and the circulating current between the regenerative energy feedback device and a traction rectifier is avoided.

Description

technical field [0001] The invention belongs to the field of urban rail transit, and in particular relates to an energy feed device controller, a rail transit traction power supply system and a circulation suppression control method. Background technique [0002] In order to solve the increasingly prominent traffic problems in big cities, urban rail transit has entered a period of large-scale and high-speed development due to its high punctuality, speed, comfort and large transportation capacity in recent years. At present, there is a demand for the utilization of regenerative energy in the domestic urban rail transit field. When the locomotive enters the station during operation, the braking energy will be fed back to the traction network, which will raise the DC traction network voltage. When the energy feedback set in the substation is reached When the start-up threshold of the device is set, the device is switched on and starts to feed back regenerative electric energy. ...

AI Technical Summary

Problems solved by technology

However, in actual engineering, the DC traction grid voltage is not only related to the regenerative energy, but also to the AC bus voltage of the main station. The increase of the AC side voltage will also lead to the increase of the DC grid voltage. At this time, if the regenerative power feedback enters the feedback state, The DC traction network voltage has a downward trend, causing the AC voltage of the traction rectifier to be higher than the DC traction network voltage, and the energy is returned from the AC side to the DC side again, forming a circulating current

The circulating current affects the normal energy feedback of the regenerative power feedback device to the grid, reducing the utilization efficiency of regenerative energy; and the long-term existence of the circulating current will greatly increase the loss of the traction rectifier and the regenerative power feedback device, affecting the life of the equipment

[0003] In the prior art, there is a method of using a floating threshold to avoid circulating currents. The main principle of this method is to adjust the start-up threshold of the regenerative power feedback device according to the change of the AC voltage. When the AC voltage has harmonics or negative sequence, the threshold value setting will be inaccurate, which will affect the efficiency of energy feedback

(2) When the AC voltage changes frequently, the threshold value changes frequently, making the working state of the device unstable

(3) When the grid voltage rises, the threshold value rises. If the regenerative energy increases slightly at this time and does not reach the threshold value, the energy feedback device will refuse to operate, which will affect the feedback efficiency

(4) Although this method can solve the circulating current in the station, the AC voltage of the energy-feeding device of each traction station is different, and the threshold value is also different. Improper control will lead to circulating current between stations, which requires coordinated control between stations, which increases the complexity of the system

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