MULTIPLE PR CONTROLLER-BASED METHOD FOR SUPPRESSING THE RESONANCE OSCILLATION OF TRACTION NETWORKS USING THE AUXILIARY CONVERTER OF AN ELECTRIC LOCOMOTIVE

Abstract

With the extensive application of AC drive technology, the content and times of harmonics injected into the traction network are increasingly diversified, leading to resonance accidents, especially for the harmonics of integer multiples with switching frequencies caused by AC drive technology. When the resonance occurs, the train terminal coupling over-voltage would lead to the breakdown of power supply equipment, which will affect the normal operation of the train. In order to restrain the traction network resonance, this paper analyses the resonance mechanism and proposes an improved method by using a locomotive auxiliary converter. The scheme introduces the active filter function into the fourquadrant converter control in the auxiliary power supply. Thus, in addition to the filter function, the auxiliary converter is designed to produce a compensation current by detecting the primary side current, extracting harmonic current using DFT analysis and tracking the reference current using zero-error multiple PR(M-PR) controller. Under this condition, the harmonic current value of primary side would be eliminated to almost zero and the resonance would be suppressed. The results are verified by Matlab/Simulink simulation and experiments on RT-LAB platform.