A Snubber Circuit With Clamped Energy Feedback for SiC MOSFETs in Hybrid ANPC Converter

In active neutral-point clamped (ANPC) converters using wide bandgap devices, high switching speeds and inevitable loop parasitics cause voltage overshoot and oscillations during commutation, reducing reliability. Conventional mitigation strategies such as short-loop commutation mode, RC snubbers across switch terminals, or decoupling in long-loop commutation mode either introduce extra losses or exacerbate device heating. This paper proposes a commutation snubber circuit based on intentionally increasing loop inductance, comprising an RL damping network and a capacitor–diode (CD) absorption circuit (RL-CD). The design reduces current slew rate, enables quasi-zero-voltage switching (QZVS), suppresses turn-off voltage oscillations of SiC MOSFETs, and enables omission of external RC snubbers across the switch terminals, reducing auxiliary dissipation and mitigating device heating. Energy stored in the absorption network can be recovered to the DC side via energy conversion. The method provides a novel solution for overvoltage and oscillation in WBG-based ANPC converters, with potential applicability to other multilevel converter architectures.