VVVF on-line control of matrix converters

A matrix converter does not have any energy storage components, so it is smaller than a converter-inverter system with same KVA. Although a matrix converter requires 18 switching devices instead of 12, each device capacity is 0.383 times with a total capacity of 0.575 times that of the converter-inverter system. For the matrix converter, we proposed a firing sequence which eliminated voltage and current spikes in switching operations and a control method I which generated the output voltage of 0.866 times the supply voltage. Moreover, we proposed control method II which improved the waveform distortion of the input current and realized unity input power factor. In this paper, we propose a new VVVF gate circuit based on control method II for matrix converter, which can on-line control input current waveform and output voltage waveform to sinusoidal even if there is fluctuation, asymmetry, and/or harmonics in the supply voltage. We also confirm by experiments that the waveform distortion of the input current and the input power factor were greatly improved.