A simple predictive voltage control method with unity displacement power factor for four-leg indirect matrix converters

While the known modulation and control techniques for four-leg matrix converters are based on pulse width modulation or three-dimensional space vector modulation, this paper presents a finite control set model predictive control strategy with a prediction horizon of one sample time to control the four-leg indirect matrix converter. An LC output filter is connected between the converter and the load. The four-leg indirect matrix converter is developed to deliver power to the unbalanced/nonlinear three-phase loads and it can produce three output voltages independently with one additional leg. The proposed voltage control strategy is based on prediction calculation to select the switching states of the converter. By using a predictive cost function, the optimal switching state to be applied to the next sampling time is selected. This is done in order to obtain unity displacement power factor in the input side and a positive dc-link voltage at any time, while maintaining a good tracking of the load voltages to their respective references. The feasibility of the proposed strategy is verified by simulation results.