A Family of Asymmetrical SVPWM Schemes with Normal and Open-Circuit Fault-Tolerant Operation Capability for a Three-Phase Isolated AC-DC Matrix Converter

Abstract

The three-phase isolated ac–dc matrix converter (3P-IMC) inherits all the merits of the conventional matrix converter. But it also suffers from a large number of bidirectional switches and cannot operate safely in an open-circuit fault condition. Hence, with a general space vector PWM (SVPWM) model presented in this article, three types of asymmetrical SVPWM (ASVPWM) schemes are first proposed for normal and open-circuit fault-tolerant operation. The ASVPWM schemes have more kinds of synthetic vectors with asymmetrical distribution, however, also feature a higher freedom and flexibility to further improve the system performance. Then by sectional combining the above ASVPWM schemes with the conventional one, the 3P-IMC could be continued to operate with a tight dc output voltage regulation under single-switch open-circuit fault condition, which has an inherent open-circuit fault-tolerant capability. Compared with the conventional two-phase fault-tolerant operation, the proposed strategy has a smaller output voltage ripple, lower current stress, lower current harmonic, higher maximum output power, etc. The safety and reliability of the converter are greatly improved. Finally, a 3P-IMC experimental prototype is built up to verify the performance of the proposed ASVPWM schemes.