Comprehensive treatment device and comprehensive treatment method for urban rail transit traction power supply system

Abstract

The invention discloses a comprehensive treatment device and a comprehensive treatment method for an urban rail transit traction power supply system. According to comprehensive treatment device, the alternating-current side of a PWM rectifying unit is connected with the alternating-current side of a diode rectifier and the low-voltage side of a rectifying transformer, and the direct-current side of the PWM rectifying unit is connected with the direct-current side of the diode rectifier and a direct-current traction network through a bidirectional DC / DC unit; under the vehicle traction condition, reactive power and harmonic current of the diode rectifier are compensated by the comprehensive treatment device, the output DC voltage of the diode rectifier is stabilized by providing capacitivereactive current for the rectifier transformer, and the comprehensive treatment device and the diode rectifier are used to provide power for the DC traction network together under the condition that the capacity of the diode rectifier is not enough; under a vehicle braking working condition, the comprehensive treatment device can transmit regenerated energy back to the alternating-current medium-voltage power grid. The device is further used for eliminating a circulation problem between the comprehensive treatment device and the diode rectifier by controlling the currents of the two energy storage inductors in the bidirectional DC / DC unit.

Description

technical field [0001] The invention belongs to the field of urban rail transit traction power supply control, and relates to a comprehensive treatment device and comprehensive treatment method applied to the urban rail transit traction power supply system. Background technique [0002] The traction network of urban rail transit traction power supply system adopts DC power supply, and the most commonly used voltage levels are DC750V and DC1500V. The traction substation first steps down AC10kV or AC35kV to 590V or 1180V AC, and then converts it to DC through diode rectification to supply the DC traction network. Such as figure 1 and figure 2 Shown is the common 12-pulse and 24-pulse rectification main circuit diagram, image 3 yes figure 1 and figure 2 The internal circuit diagram of the diode rectifier unit. This multi-pulse rectifier power supply system has the advantages of simple structure, high efficiency, good reliability, convenient maintenance, small current d...

AI Technical Summary

Problems solved by technology

[0012] Aiming at the problem that the direct parallel connection scheme of the PWM rectifier unit and the diode rectifier AC and DC side of the traction power supply system of urban rail transit has complicated control and difficult circulation control, which makes practical application impossible, the present invention proposes a comprehensive treatment device connected in parallel with the diode rectifier. A three-level bidirectional DC / DC unit with a symmetrical structure is added to the DC side of the rectifier unit and then connected to the DC side of the diode rectifier, and a circulation control unit is set to eliminate the circulation between the comprehensive treatment device and its parallel diode rectifier In addition, based on the device proposed by the present invention, a corresponding comprehensive treatment method is also proposed. When the vehicle is towed, the comprehensive treatment device can compensate the harmonics and reactive power generated by the diode rectifier, and can maintain the stability of the DC traction power grid, while using the work to reduce The bidirectional DC / DC unit in the voltage mode can also make the PWM rectifier unit and the diode rectifier work together to transmit energy from the AC traction network to the DC traction network; when the vehicle is braking, the bidirectional DC / DC unit working in the boost mode can Make the PWM rectifier unit feed back the regenerative braking energy of the vehicle to the AC traction grid, combined with the circulation control, the present invention can be realized in practical applications

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