Abstract
This paper proposes a simple and high efficiency control method for a high-frequency link three-phase AC/AC direct converter. There are three topics in this paper. First, the control strategy of the AC/AC converter is proposed based on a conventional rectifier and inverter system. Thus, the proposed method realizes wide control range and the high performance as same as the conventional PWM rectifier and inverter system. Second, the proposed method is that a switching loss can be reduced by the proposed commutation method using a voltage polarity. The commutation timing of the secondary converter synchronizes with generating zero voltage vector of secondary converter. Therefore the zero voltage period of secondary converter is made by short circuit of the transformer during the zero voltage vector of secondary converter. Thus, the proposed method prevents commutation failure and reduces switching loss for ZVS. In this result, the proposed method can achieve unity power factor and THD of the input and output current are less than 6%. The total efficiency is 94.7%. Those results provided that the proposed method realizes high efficiency for the high-frequency link converter.
