In view of the problem of icing for transmission lines in winter,this paper proposes a current source DC ice-melting device and its control method based on series connected IGCTs.The ice-melting device adopts current source rectifier topology and has the functions of both DC side ice-melting and AC side reactive power compensation.The proposed control method decomposes the instantaneous active and reactive power on the AC side using the instantaneous power theory,and performs dual-loop decoupling control of active and reactive power according to ice-melting power and AC side reactive power compensation demand,respectively.In order to save costs and reduce the use of sensors,the paper also proposes a control method that does not rely on voltage sensors of the filter capacitor.This method uses the grid-side voltage and current to do differential calculations and thus obtain the capacitance voltage in the LC filter.In addition,to suppress the influence of high-frequency harmonics on the control system,this paper introduces a virtual resistance control unit for feedforward suppression of high-frequency harmonics of the LC filter.Finally,a prototype ice-melting device with 10 kV AC voltage and the maximum ice-melting current of 1 000 A is designed for specific application scenarios.the effectiveness of the proposed technical solution and the control method is verified by numerical experiment.
维普
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