Comparative evaluation and analysis of GaN-based VSIs and CSIs

Abstract

In this paper, a SPICE-based assessment platform for fast-switching Gallium Nitride (GaN) devices-based voltage source inverters (VSIs) and current source inverters (CSIs) is presented. VSI has long been the dominant topology for motor drive systems. The previous research found enormous problems caused by the direct replacement of WBG switches in VSIs. As a viable alternative, the intrinsic properties of CSI topology make it suitable for WBG-based devices. The GaN device is selected in this paper as one of the most promising candidates among all WBG devices. Tailored double pulse test (DPT) is used to characterize the GaN switch in VSI and CSI topologies. VSI-DPT and CSI-DPT printed circuit boards (PCBs) are fabricated to experimentally evaluate the GaN switch, and to further modify the SPICE model. Moreover, the way to realize a dedicated SVPWM modulation scheme for three-phase CSI is introduced. The parasitic elements associated with the DPT-PCB layout are considered for the purpose of accuracy. VSI and CSI circuits are built in LTspice with a modified SPICE model of the GaN switch, enabling more precise analysis of GaN-based VSI and CSI under a wide range of operating conditions.