Comparative analysis of dual active bridge dc–dc converter employing Si, SiC and GaN MOSFETs for G2V and V2G operation

Abstract

Electric vehicles (EVs) are ideally suited for carbon footprint reduction and energy-efficient transportation. EV battery chargers comprise of cascade connection of ac–dc and dc–dc converters. With the bidirectional dc–dc converters, EV chargers can implement grid-to-vehicle (G2V) and vehicle-to-grid (V2G) functionality. Dual active bridge (DAB) converter is a bidirectional dc–dc converter that can support G2V and V2G operation. DAB converters are operated at high switching frequencies (fsw) leading to higher switching loss. This issue can be addressed by employing SiC and GaN-MOSFETs, which work with lesser switching losses and can operate at much higher fsw. This paper presents a detailed comparative analysis of DAB converter employing Si, SiC and GaN MOSFETs for G2V and V2G operation. The EV charging system with a DAB converter employing V2G and G2V operation is modeled in PSIM software. Single phase shift (SPS) modulation technique is employed for DAB converter. The system operation is analyzed for V2G and G2V operation with the fsw of 20 kHz, 50 kHz, 100 kHz and 200 kHz. The performance comparison reveals that DAB converter with GaN-MOSFETs has the highest operating efficiency. To validate the DAB operation with SPS modulation, experimental studies have been carried out with SPS modulation being implemented on TMS320F28335 DSP using SimCoder Module of PSIM. A step-by-step procedure to implement the modulation technique with SimCoder is also provided.