Analysis and Implementation of a Novel four-step Commutation Method for Direct Matrix Converters based on FPGA and DSP

This paper presents a novel current-controlled four-step commutation method for robust and safe operation of direct matrix converters (DMC) by dynamically adjusting the most critical commutation time according to amplitude of the output load current, which is an optimization for the overall necessary commutation time. Meanwhile, this method also helps to ensure the desired switching sequence to be implemented correctly. The principle of proposed strategy is explained in detail and a formula of setting the most critical commutation time is given. Simulation results are used to verify this proposed strategy. A low voltage laboratory platform consisting of a DMC and a brushless motor (BLDC) is implemented and controlled using a hybrid hardware concept based on a field-programmable gate array (FPGA) and a digital signal processor (DSP). Experimental studies on the laboratory prototype confirm the feasibility and effectiveness of the proposed method.