Safe commutation strategies for matrix converter

Commutation problem is one of the reasons why matrix converter has not been used in high-power conditions. To avoid zero crossing problem of the current-controlled commutation, four-step safe commutation strategy in transition intervals was proposed based on traditional voltage-controlled commutation. Three free wheeling states were used between two adjacent input voltages to realize safe commutation. The voltage-controlled commutation was consummated and the short-circuit phenomenon during changing intervals was solved. The strategy has many advantages such as little influence on input and output waveform, easy to realize and low additive switching loss. Experimental results of 380 V voltage input and 5 kW power output verified that the new method is valid and feasible. The commutation scheme can find broad applications in high-power AC-AC matrix converters.