A Self-Regulating Gate Driver for High-Power IGBTs

Abstract

To gain accurate control of the whole switching transients, this article proposes a self-regulating voltage-source gate drive (SRVSD) method for high-power insulated gate bipolar transistors (IGBTs) working under hard switching conditions. The SRVSD has a high-speed circuit capable of adjusting drive levels. With high-speed feedbacks, the on-board field programmable gate array (FPGA) identifies each switching stage and accordingly varies drive voltages. In this way, switching delay, diC/dt and dvCE/dt are regulated individually. The SRVSD allows accelerated delays and dvCE/dt stages without increasing diC/dt. Based on their principles, SRVSD is compared with existing active drivers comprehensively to verify its delay and loss reductions performance. By experiments, compared to conventional gate drive (CGD), SRVSD achieves at most 80%, 72% reductions in turn-on and turn-off delays, and 58%, 31% reductions in turn-on and turn-off losses at identical current/voltage overshoots. Moreover, the proposed adaptive control concept is verified in this article. Within several cycles, this concept automatically regulates durations of all delay, diC/dt and dvCE/dt stages to reach individual target values, largely independent of switching conditions. A practical piecewise linear switching-based loss model is proposed. Combined with SRVSD, this practical loss model can offer convenient sensing and control of switching losses in an accurate and online manner.