A novel safe shutdown strategy for matrix converter even under fault condition

The reliability of power electronic devices is of paramount importance in practical application. This paper firstly presents detailed fault condition of the matrix converter-induction motor drive system. Then a novel protection strategy is proposed. The key of the proposed protection strategy is to provide a controlled free-wheeling path for the motor currents when a fault happens. By using the new protection strategy, the motor currents can be reduced to zero as soon as possible, while the safety of the semiconductors is assured. In order to avoid unexpected overvoltage fault, a clamp circuit is still needed. But in cooperation with the proposed protection strategy, the capacitance requirement of the capacitor in the protection circuit is small. And the use of an electrolytic type can be avoided. In the end, the simulation and experimental results validate the proposed strategy.