A Novel Self-Powered Supply for GCT Gate Drivers

The commercial power supply for the gate driver of integrated Gate Commutated Thyristors (GCT) is an expensive device since the supply´s output must withstand the high voltage potential of the GCT switch against all other relevant potentials in the converter. This voltage potential varies from a few thousand volts to several ten thousands of volts over the GCT application range. In this paper, a novel self-powered supply (SPS) is proposed for the GCT gate driver, where the supply obtains energy from the snubber circuit of the GCT switch and then provides a regulated dc voltage for the gate driver. Since the snubber circuit is at the same potential as the GCT, the insulation level of the supply is reduced from thousands of volts to a couple of hundred volts, leading to a significant reduction in cost and size. The supply configuration is introduced and its operating principle is discussed. The design guidelines and experimental results are also provided.