Design of Isolated Gate Driver Power Supply in Medium Voltage Converters using High Frequency and Compact Wireless Power Transfer

Abstract

Emerging Medium Voltage (MV) Silicon Carbide (SiC) 10kV/15kV MOSFETs are capable of high switching speed, which makes them highly desirable for many existing and emerging high power MV power conversion applications. One of the significant technical challenges of using these devices is extremely high dV/dt during switching transitions, imposing a stringent requirement on capacitive coupling in gate driver circuit to reduce Electromagnetic Interference (EMI). This paper presents the design of an isolated gate-driver power supply (GDPS) using a high-frequency inductive power transfer (IPT) to achieve a low coupling capacitance. The clearance and creepage requirements are met in compact form factor by encapsulating the IPT system in a potting compound. This paper provides a systematic approach for the design of the IPT system used for the isolated power supply, including coil optimization, analysis of matching network and hardware implementation. LMG5200 GaNs are utilized in the conversion circuit of the proposed IPT system which works at 4 MHz. Experiments show that the proposed IPT system is suitable to drive MV devices.