Leakage Current Reduction with 240CPWM in Silicon Carbide based Transformerless Grid-connected PV Converter

High leakage current is one of the major reliability concerns in transformerless grid-connected (TLGC) PV converters due to lack of galvanic isolation. Large leakage capacitance of PV modules in TLGC PV systems makes the resonant frequency of the leakage path very low. It forces high leakage current if switching frequency of inverter is close to the resonant frequency as in traditional inverters. Switching frequency can be kept higher than the resonant frequency of the leakage path to achieve lower leakage currents. A relatively new PWM method called
$240^{\circ}$
clamped PWM (240CPWM) encourages the use of higher switching frequency because of its lowest switching loss. This work deploys 240CPWM in silicon carbide based inverter at switching frequency of 100 kHz that gives 70% saving in leakage current and 4.7 times reduction in AC filter inductor volume as compared to silicon based inverter switching at 10 kHz without compromising the inverter efficiency.