Visualization of PWM Strategy for a Direct Matrix Converter During Input and Output Voltage Periods

This paper presents a visualization of the PWM strategy of a matrix converter during input and output voltage periods. General relations for the duty cycles based on the input current references and the output voltage references are derived. Because the input current references and the output voltage references are treated as continuous values in the time domain, the PWM strategy can be extended to the input and output voltage periods from the control period treated as constant values. At a low carrier frequency compared with the actual frequency, the PWM patterns that reduce the number of commutations for switching loss reduction can be visualized. The PWM strategy can be directly evaluated by using the waveforms of the input current and the output voltage. In the transient state with change of the output voltage reference, the output voltage and input current can be visualized. The effectiveness of the visualization of the PWM strategy has been verified by comparison with the experimental waveforms.