An instantaneous compensation technique for supply disturbances in direct frequency converters

Voltage sags and swells are a common occurrence in industrial power distribution system. Even though the matrix converter has more vulnerable structure than the conventional rectifier-inverter drives, it has the inherent ability to compensate three-phase voltage sags and swells. In this paper, a simple instantaneous compensation technique for voltage disturbances is presented. Two methods are provided based on both the Venturini´s method and the SVM method. The algorithms are based on the modification of controllability such as the voltage transfer ratio in the Venturini´s method, and the modulation index of the rectifier stage in the SVM in the event of the supply disturbances. For compensations of supply disturbances, the utility input voltages are sensed and then converted to the value reflecting the instantaneous supply voltage amplitude. Then, the controllability inside the matrix converter is corrected to compensate the supply disturbances if voltage sags and swells do occur. Analysis and simulation are presented for the feasibility of the proposed technique.