Energy-feedback tractive power supply system with high power factor and high cost performance

Abstract

The invention discloses an energy-feedback tractive power supply system with high power factor and high cost performance, relating to an energy-feedback tractive power supply system. The system comprises a main substation, a medium-voltage ring network, a first to an Nth energy-feedback tractive substations, a direct-current contact network and a steel rail. In the energy-feedback tractive substations, a set of 12-pulse-wave rectifier unit and a set of PWM (Pulse Width Modulation) unit are connected in parallel; by sufficiently utilizing respective advantages of the rectifier unit and the PWM unit, bidirectional flow of energy is realized on the one hand, braking energy of a train is fed back to an alternating-current grid, and electric energy is saved; on the other hand, the energy-feedback tractive power supply system integrates the advantages of simpleness and reliability, low cost and strong overload capability of a diode rectifier unit; beside, certain sensitive and capacitive reactive power is injected into the medium-voltage ring network by utilizing the PWM rectifier unit, and the power factor at the alternating-current incoming line of the main substation can be greatly increased. The whole tractive power supply system has higher cost performance.

Description

technical field [0001] The invention relates to an energy-feedback traction power supply system, in particular to an energy-feedback traction power supply system with high power factor and high cost performance for powering urban rail transit vehicles. Background technique [0002] Urban rail transit traction power supply system is mainly composed of traction substation and DC catenary system, among which the traction substation is the core of the entire traction power supply system, and shoulders the task of converting AC power into DC power. [0003] The AC power introduction method of each traction substation mainly adopts the centralized power supply mode, that is, each traction substation obtains electric energy from the main substation uniformly through the medium-voltage ring network. Since the medium-voltage ring network is laid along the subway line, the reactive power generated by the parasitic capacitance of a large number of medium-voltage grid cables makes the p...

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Problems solved by technology

It is characterized by simple system structure, high power density, and low equipment cost, but the DC voltage is uncontrollable and has a large fluctuation range; at the same time, the energy can only be transmitted in one direction, and the excess energy of the regenerative braking of the train cannot be fed back to the AC grid. The dynamic resistance is consumed, resulting in a waste of energy

The energy-feedback traction power supply device based on high-power PWM rectifier is used to completely replace the diode rectifier unit, which can not only ensure the stability of the DC grid, improve the quality of power supply, but also realize the feedback of the train braking energy to the AC grid, and avoid the consumption of braking energy on the resistor. , to save energy, but the high price of PWM rectifiers, large volume, poor overload capacity and other constraints make it difficult to popularize and apply PWM rectifiers to completely replace diode rectifiers.

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