Full-Scale Physical Simulator of All SiC Traction Motor Drive With Onboard Supercapacitor ESS for Light-Rail Public Transportation

This article deals with the design and laboratory implementation of a full-scale physical simulator of an all-silicon carbide (SiC) traction motor drive for light-rail transit systems (LRTS) with onboard supercapacitor energy storage system (ESS). It consists of a pulsewidth modulation (PWM) rectifier representing the 750 V dc catenary line, a three-phase two-level PWM traction inverter to drive a three-phase squirrel-cage traction motor, a flywheel coupled to the motor shaft to represent the dynamic behavior of the transportation vehicle, a loading generator connected to the grid via a dc-link converter with active front-end, and a supercapacitor ESS containing a bidirectional dc-dc converter supplied from the common dc link. The PWM rectifier, a traction inverter, and a bidirectional dc-dc converter are all SiC power MOSFET-based converters for high efficiency and high power density. A physical simulator is a valuable tool in the design and testing of all SiC converters. It is equipped with software programs for a catenary model, rail track model, and vehicle model, and permits the performance verification of various control, modulation, and energy-saving strategies. The physical simulator system developed in this article also allows the performance verification of a vehicle formation on a prespecified real track and evaluation of benefits of the onboard supercapacitor ESS in real time.