Evaluation of the off-State Base-Emitter Voltage Requirement of the SiC BJT With a Regenerative Proportional Base Driver Circuit and Their Application in an Inverter

Neville Mcneill,Ian Laird,Bosen Jin,Xibo Yuan

doi:10.1109/tie.2019.2938492

Abstract

A strong candidate device for use in high-efficiency and high-density power converters is the SiC bipolar junction transistor, which requires a continuous gate (base) current to maintain its on -state. A base driver circuit with regenerative collector current feedback using a current transformer, and a negative off -state base-emitter voltage is presented in this article. The off -state base-emitter voltage required to prevent simultaneous conduction of a commercially available device when subjected to d v /d t’ s is assessed. The device is then utilized in a three-phase dc-to-ac power converter where the efficacy of using the proposed base driver is evaluated. The off -state base-emitter voltage used is informed by the d v /d t tests. The converter is supplied from a 600-V dc rail, switches at 50 kHz and supplies a 4.1-kW load at a modulation index of 0.9. An efficiency of 97.4% was measured.

Highlights

W IDE bandgap devices [1], [2], offer performance benefits when compared to their silicon counterparts, and candidate devices for use in high-efficiency power converters are SiC MOSFETs and bipolar junction transistors (BJTs)
Less data are available for the SiC BJT and the study in this article has been conducted
Whilst the high duty cycle operation needed for an inverter application is possible, the duty cycle is limited to less than 100% due to the need for current transformer (CT) reset

Summary

Introduction

W IDE bandgap devices [1], [2], offer performance benefits when compared to their silicon counterparts, and candidate devices for use in high-efficiency power converters are SiC MOSFETs and bipolar junction transistors (BJTs). Challenges include gate oxide reliability [5], and susceptibility to dv/dt-induced conduction (“crosstalk”) [6], [7], in voltage source converters (VSCs). It is difficult avoiding crosstalk whilst not exceeding the maximum allowed OFF-state. Manuscript received September 13, 2018; revised April 7, 2019 and July 4, 2019; accepted August 12, 2019. Date of publication September 26, 2019; date of current version April 30, 2020.

Results

Discussion

Conclusion