Implementation of 1.7 kV silicon carbide metal oxide semiconductor field effect transistors in auxiliary power supplies for industrial applications

Xuning Zhang,Gin Sheh

doi:10.23919/cjee.2020.000018

Abstract

An auxiliary power supply (Aux-PS) has become an essential component of electronic equipment for many industrial applications, such as in motor drives, photovoltaic (PV) inverters, uninterruptible power supply (UPS) systems and modular multilevel converters. The introduction of 1 700 V silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) is useful for such applications, providing benefits with respect to a low on-state resistance, smaller package, low switching loss and single-switching implementation. A single end flyback Aux-PS is designed for industrial applications with a wide input voltage range using 1.7 kV SiC MOSFETs. The special design tradeoffs involved in the usage of SiC MOSFETs are discussed in detail, such as those with regard to gate driving voltage selection, isolation transformer design considerations, and clamping circuit design details. A 60 W demonstration hardware is developed and tested under different working conditions. The results verify the higher efficiency and better thermal performance of the proposed hardware relative to those of traditional Si solutions.

Highlights

An auxiliary power supply (Aux-PS) has become an essential component of electronic equipment for many industrial applications, such as in motor drives, photovoltaic (PV) inverters, uninterruptible power supply (UPS) systems and modular multilevel converters
This study presents the design of a single end flyback Aux-PS for industrial applications with a wide input voltage range, using 1.7 kV silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs)
The results indicate that the efficiency difference is negligible at a 50% load and above, and the performances are all improved over high-voltage Si MOSFET solutions

Summary

Introduction1

Silicon carbide (SiC) power metal oxide semiconductor field effect transistors (MOSFETs) have emerged as ideal candidates for helping to meet increasing demands for efficiency, power density, reliability, and lower cost in power electronics systems[1]. Transistors in Auxiliary Power Supplies for Industrial Applications switching device Another drawback is that the leakage inductance of the transformer will induce a high voltage spike during device turn-off; a clamping circuit is required to limit the voltage spike. 2 000 V and above-rated Si MOSFETs can provide a sufficient margin, but the specific “on” state resistance is much higher than that of lower-voltage MOSFETs, which reduces the converter efficiency and compromises heat management. This may require larger cooling solutions with forced air cooling even for low power conversion applications, compromising the cost, size, and reliability. The results verify the higher efficiency and better thermal performance of the proposed hardware as compared with traditional Si solutions

Converter design summary

Driving voltage selection

Transformer and clamping circuit design considerations

Performance comparison

Findings

Conclusions