A New AC Bidirectional Switch with Regenerative Snubber to Realize a Simple Series Connection for High Power AC/AC Direct Converters

This paper proposes a new bidirectional switch and snubber circuit for high power AC to AC converter. The proposed switch can be constructed with a 2-in-l IGBT module and 2-in-l diode module and can reduce the voltage stress of the switching device by series connection. The proposed snubber configuration is very easy and it can regenerate absorbed energy. On the other hand, a timing error of switching between the series- connected switches causes the voltage unbalance in the snubber circuit. This paper also proposes a simple voltage unbalance reduction method with one voltage sensor for each switch circuit. The proposed method controls snubber voltages by adjusting switching timings. Furthermore, this paper mentions that the proposed switch circuit can be applied to the matrix converter. These new proposals are confirmed by experimental results.