Steady State Over-Modulation of Matrix Converter Using Simplified Carrier Based Control

Abstract

In this paper, the simplified carrier-based control of matrix converter is modified to operate the converter in the over- modulation region. Both the input-side and output-side over- modulation modes have been studied and their limits of operation are derived. With output-side over-modulation, the maximum output to input voltage transfer-ratio with 6-step square wave output voltage is found to be 0.95 which is higher than the 0.866 intrinsic limit of the matrix converter. With input-side over- modulation the maximum voltage transfer-ratio is found to be 0.908 while still being able to control the power factor of the input currents. With simultaneous input and output-side over- modulation, a unity voltage transfer-ratio is achieved. This improvement in the voltage transfer-ratio in the above three cases is achieved at the cost of low frequency distortion in the output voltages and input currents. With simultaneous input and output- side over-modulation, a voltage transfer-ratio of 0.958 is achieved without significantly increasing the harmonics in the input currents and output voltages. Theoretical calculations are supported by experimental results on a laboratory prototype.