Efficiency Evaluation Of Single-Phase SiC PV Inverter

SiC power devices have superior characteristics and get well concerned, and the field of PV distributed generator systems is a focus of current.The structure of residential PV inverter and several single-phase inverters are introduced. The inverter stage is the core of the PV generator systems. To improve the working performance of the inverter, SiC MOSFET is applied, and the influence on the efficiency is focused on.The characteristics of SiC MOSFET are different from traditional Si MOSFET. In the high frequency applications where SiC MOSFET is applied, the false turn-on phenomenon is faced. According to the characteristics and application of SiC MOSFET, a driver is designed with the consideration of circuit structure, drive resistor, drive voltage and safety drive. The test experiment of the designed driver is carried out on a boost.SiC MOSFET has a better body diode, and is easy to be used in full-bridge inverter. To improve the power density of the inverter, the switching frequency is raised to100kHz. The parameters of the inverter are designed. The power devices in full-bridge inverter are hard switched, and layout of the circuit is optimized to reduce the stray inductor. The efficiency of100kHz SiC full-bridge inverter is analyzed according to the working process. The Si H6inverter and SiC full-bridge inverter at the switching frequency of20kHz are also analyzed and the efficiencies are compared with the100kHz full-bridge inverter. A1.6kW SiC full-bridge inverter prototype is constructed and the related experiment efficiency curves are tested.To improve the efficiency SiC inverter, a ZVS technique is proposed. Firstly, the working stages of the ZVS inverter are analyzed and the component parameters are designed. Then, the efficiency of the inverter is analyzed and compared with that of the hard-switching inverter. At last, the ZVS inverter prototype is constructed, and related experiments are carried out. The waveforms of the inverter are observed to verify the realization of ZVS turn-on. The ZVS parameters are optimized to achieve high efficiency, and the efficiency curve is also tested.