Performance comparison of Si IGBT and SiC MOSFET power devices based LCL three-phase inverter with double closed-loop control

Grid-connected inverters are essential equipment for DC-AC energy conversion between renewable energy generation and power grids, and their performance directly affects the stability of the operation of the power grid. Compared to the traditional L or LC filter, LCL filter is widely used in the grid-connected inverter due to its harmonic attenuation performance and system stability. Because of the requirements for higher switching frequency to increase the power density and reduce the cost of the inverter. Compared to the traditional silicon (Si) insulated gate bipolar transistor (IGBT) power device, the silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) has shown apparent advantages in high-power density inverters with a high switching frequency. This study first analyses and compares the suppression effects of passive damping methods on the resonance peak of the LCL filter; then, a double-current closed-loop control strategy as the active damping control is applied in the LCL filter three-phase grid-connected inverter; finally, the experimental platforms of IGBT inverter and SiC MOSFET inverter are built, and the filtering performances of the two inverters are compared. The experimental results show that the double-closed-loop control method significantly reduces the system harmonics and confirms the feasibility of the control strategy.