I. Introduction
In many industrial applications, the power supplies for the GCT gate drivers must be isolated from all other relevant potentials in the converter. This insulation requirement is fulfilled by an expensive and bulky highvoltage isolation transformer employed in IGCT gate unit power supplies, which operates at the utility supply frequency of 50Hz or 60Hz [1]. Fig. 1 displays the topology of GCT-based Current Source Rectifiers (CSR) commonly used in medium voltage drives as a front-end converter [2]. For example, in a system, the voltage of gate driver with respect to ground GND is (peak), and the voltage between gate driver and gate driver is (peak). To eliminate high-voltage isolation transformers, several methods were proposed in literature for SCR, GTO, and IGCT gate driver power supplies [3]. Due to the limitations of these methods and special gating requirements for GCT switches in CSI, none of the methods mentioned in [3] can be used for the GCT gate unit supply in CSI. A novel self-powered supply (SPS) was proposed for GCT gate units in [4],[5] to avoid the adoption of high-voltage isolation transformers. However, the proposed SPS developed for current source rectifiers (CSR) is unsuitable for current source inverters (CSI), since the voltage waveforms of the GCT voltage in CSR is different from that in CSI. PWM current source rectifier (CSR).