An Advanced Commutation Method for Bidirectional Isolated Three-Phase AC/DC Dual-Active-Bridge Converter Based on Matrix Converter

This paper proposes a novel commutation method that improves efficiency of bidirectional isolated AC/DC Dual-Active-Bridge (DAB) converter based on matrix converter (MC). Although some modulation methods have been proposed, characteristics of the converter in low power region have not been discussed. In this region, efficiency of converter decreases because of commutation fault, which increases stress to devices and leads to shorten lifetime of the converter. In this paper, an advanced commutation method to reduce the commutation failure is proposed. The proposed method combines current commutation and voltage commutation implemented by a simple algorithm based on the waveform of modulation signal without information of the current direction. In addition, seamless and safe operation is inherently assured owing to no requirement of change in switching operation mode. The validity of the proposed method is verified by experiment employing a laboratory prototype.