For matrix converter (MC), real-time correction of duty cycles is a good solution to eliminating the effects of input voltage disturbances on output performance. However, MC adopting this solution suffers from stability deterioration. The typical active stabilization method is based on modifying output voltage reference with the filtered input voltage. In this paper, its performance is evaluated under input voltage disturbances. It is found that this method will introduce extra low-frequency harmonics into output reference voltage, degrading the output quality.
The reason lies in the inability of the adopted digital highpass filter to block the disturbances. To maintain good output performance, the improved active stabilization method is proposed, which utilizes resonant controllers to eliminate the extra low-frequency harmonics. The principle and theoretical equations of the improved method are presented.
The consideration of input frequency variation and the influence on input power quality are also discussed. Experimental results have verified the correctness of the performance evaluation and effectiveness of the proposed improvement.