A 50kW high power density paralleled-five-level PV converter based on SiC T-type MOSFET modules

SiC T-type LCL inverter can achieve smaller device loss than two-level topology, however its improvement on power density is limited by current ripple loss on magnetic components as switching frequency increases. This paper presents a paralleled-five-level (P5L) PV inverter which achieves better utilization of SiC devices than traditional T-type three-level (3L) LCL topology at higher switching frequency. Comparison of the SiC P5L PV inverter with SiC T-type 3L LCL PV inverter has been presented. The design challenges and methods to solve magnetic balancing, short circuit protection, and digital controller computation time issues are analyzed. A 50kW PV converter including boost stage and inverter stage has been built in the laboratory, which achieves a power density of 22.7 W/in
³
and 2.5 kW/kg, and measured peak efficiency of 99.2%.