Realization of High Efficiency AC link Converter System based on AC/AC Direct Conversion Techniques with RB-IGBT

This paper proposes how to realize high efficiency of 95% for the high frequency AC link converter of three-phase input and output. The proposed control method is based on virtual converter system control method without resonant. Two novel approaches are proposed in this paper. First, reducing method of a switching loss is proposed. The proposed method realizes zero voltage switching for generator side converter without auxiliary circuit. Second, this experimental converter uses a reverse blocking IGBT (RB-IGBT) instead of a series connection diode to realize the AC switches. The effects of the RB-IGBT is mentioned by the loss analysis using PSIM and experimental results. At last, the benefit of adopting the RB-IGBT to the AC/AC direct converter is verified through experiments. The efficient of the proposed approach are confirmed through 1.5 kW experimental system with the RB-IGBT. The clean sinusoidal waveforms for power line side current and generator side voltage, and the maximum efficiency of 94.7% are obtained. The RB-IGBT improves the efficiency of 1.9 point. The efficiency of around 95 % is very high in case of AC/AC converter with transformer system at 1 kW class. In addition, the motor drive characteristics with 1.5 kW induction motor are also shown in this paper