A method of commutation of current by bi-directional switches of matrix converters

摘要

A method of commutation of current by separately controlled in each direction bi-directional switches of a matrix converter (MC) with at least three input phases, which allows to provide a safe step-by-step commutation of the current by MC switches without using information of the load current polarity and of the exact relation of mains voltages at the moment of step-by-step commutations beginning.It is suggested variants of implementing the proposed invention in the three phase-to-three phase MC with a space vector modulation (SVM) which provides the synthesis of space vectors of the output voltage and input current of zero and non-zero stationary vectors during each SVM cycle, with dividing the mains voltage period into six intervals with boundaries being determined by moments of input phase voltage polarity changing. Due to special method of zero vector forming and its alternating with non-zero vectors it is possible to provide a safe commutation of current even under very significant distortions of the mains voltage waveform. All the commutations of the MC switches are expedient and do not create the additional dynamical losses.