Improved sliding-mode control method of V/v tractive power supply system

Abstract

The present invention discloses an improved sliding-mode control method of a V / v tractive power supply system. The method comprises the steps of: controlling load voltages of two supply arms by a railway power regulator connected between the two supply arms through adoption of an improved sliding-mode control strategy; employing wavelet transform and a single-phase phase-locked loop to obtain phases of load currents of the two supply arms according to the instantaneous values of the load currents of the two supply arms, and obtaining the effective values of the load currents of the two supplyarms based on the instantaneous reaction power theory; obtaining the effective values of the reference instruction active currents and the effective values of the reference instruction reactive currents of the two supply arms according to the phases and the effective values of the load currents of the two supply arms to obtain the reference instruction currents of two converters; and obtaining theoutput voltages of the converters by employing the improved sliding-mode control strategy to allow the output current of the railway power regulator to be tracked and controlled. The method providedby the invention achieves accurate tracking for the compensation current of the railway power regulator, reduces the influences of harmonic waves and a negative-sequence current and obviously improvethe electric energy quality of the V / v tractive power supply system.

Description

Technical field [0001] The invention belongs to the technical field of electrified railways, and more specifically, relates to an improved sliding mode control method for power quality of a V / v traction power supply system. Background technique [0002] With the rapid development of electrified railways, a large number of AC-DC electric locomotives have been invested in railway operations in my country. Electric locomotives are high-power, non-linear single-phase loads. During operation, due to their own characteristics, large amounts of negative sequence and harmonic currents will be generated, and the power factor is low, which greatly reduces the power quality and safety and stability of the power system. It may even cause misoperation of nearby power system devices, seriously affecting the reliable operation of the power system. Therefore, effective measures must be taken to manage the power quality of the traction power supply system. [0003] Japanese scholars first propose...

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Problems solved by technology

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides an improved sliding mode control method for the power quality of the V / V traction power supply system, aiming at solving the problem that the harmonics and negative sequence components in the prior art cannot maintain system stability run problem

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