A novel self-powered supply for GCT gate drivers

This thesis is devoted to the development of a novel self-powered supply (SPS) for the gate driver of integrated Gate Commutated Thyristors (GCT). In commercial GCT power supplies, a high-voltage isolation transformer is an indispensable device. Since the GCT devices are normally for high-power converters operating at a voltage level of 2.3KV to 13.8KV, the high-voltage isolation transformer is expensive in cost and bulky in size. The SPS proposed in this thesis transfers energy from GCT snubber circuits and generates a regulated dc supply for the GCT gate driver. Since the snubber circuit is at the same potential as the GCT device, the insulation level of the self-powered supply is reduced from a few thousand volts to a couple of hundred volts, leading to a significant reduction in cost and size. In this thesis, the configuration of the proposed SPS is presented, and its operating principle is elaborated. The strategy for maximizing the SPS output power is analyzed. It is demonstrated that SPS can provide a regulated output up to 60W for most commercial GCT gate drivers. The performance of the SPS is verified by experiments on a 60W laboratory prototype.