A simple snubber configuration for three-level GTO inverters

A simple snubber configuration for three-level gate turn-off thyristor (GTO) inverters is proposed. The proposed snubber has a single resistor per arm for stored energy dissipation, while the conventional RLD/RCD snubber contains six. This implies that the proposed snubber needs only one chopper circuit per arm for snubber energy recovery. This helps reduce the size, cost, and number of components. Besides the single resistor, the proposed snubber requires two less diodes per arm than the RLD/RCD snubber. Furthermore, the proposed snubber resolves the voltage imbalance problem between inner and outer GTOs without additional components. We have analyzed the proposed circuits and proven its performance through simulations and experiments.