Fault-Tolerant and Self-Reliant Characteristic in Series Resonant Converter for Semiconductor Open/Short-Circuit Faults

Abstract

With the increased popularity of series resonant converter (SRC) in grids and microgrids, a robust converter with fault-tolerant (FT) feature becomes supremely important. A single-switch primary-side failure results in half of the pre-fault voltage and lesser power at the output. While a secondary-side short-circuit (SC) fault results in negligible voltage and power, leading to discontinuous converter operation. For more than one switch fault on any side, the SRC behavior in the post-fault condition is different. This article analyses the self-reliant characteristic in SRC for single/two-switch open-circuit (OC) and SC fault. A post-fault correction is proposed, which maintains the continuity of operation and the rated output voltage at the load for different fault conditions. An FT capacitor is used along with the control parameter variation in the post-fault correction for a single-switch and different combinations of two-switch faults. The proposed method is also applicable for single-diode SC or OC fault. The analysis of the self-reliant feature and the post-fault correction is discussed and tested on a 1 kW, 250 V SRC prototype for different fault conditions.