Loss Analysis And Efficiency Comparison Based On Si MOSFET And SiC MOSFET Full-Bridge Inverters

The actual performance of power electronic devices in the device is related not only to the actual circuit topology,control mode,external environment and so on,but also to the material of the device itself.Taking the traditional inverter technology as an example,in the case of high power application,the Si MOSFET’s conduction impedance and gate charge are large,which leads to its conduction loss and drive loss.In the practical work of the circuit,due to the influence of inductance in the circuit,the current does not change abruptly,so the body diode of the MOSFET itself needs to carry on freewheeling.The characteristics of the body diode affect the switching frequency of the device and the overall stability of the circuit.Under the same conditions,compared with the traditional Si MOSFET,the new SiC MOSFET has lower conduction impedance,less gate charge,and better simultaneous body diode properties.Moreover,the new SiC MOSFET also has the characteristics of high band gap width,high breakdown critical field strength,high saturated electron drift rate and high thermal conductivity.Its appearance makes power electronic technology continue to move forward.In this paper,the device characteristics of Si MOSFET and SiC MOSFET are compared comprehensively,and the advantages of SiC MOSFET in high-power application are highlighted.The double-pulse circuit was built,and the experiment of Si and SiC MOSFET was carried out at 25℃ and 75℃,respectively.The current waveform of the reverse recovery of Si and SiC MOSFET was collected and analyzed,which proved that the reverse recovery characteristic of Si SiC MOSFET was better than that of Si MOSFET.Secondly,it describes in detail the working principle and modulation method based on Si MOSFET and SiC MOSFET full-bridge inverter,and analyzes the loss.Finally,design each part of the main circuit of the full-bridge inverter,build an experimental platform based on Si MOSFET and SiC MOSFET full-bridge inverter,compare the working conditions of Si MOSFET and SiC MOSFET,and analyze the output voltage and current waveform THD.And the types of two switching devices of the same bridge arm are divided into four cases to conduct experiments to compare the efficiency.By drawing efficiency curves,it is found that the same-leg switch devices are all SiC MOSFET with the highest efficiency,which confirms the superiority of SiC MOSFET devices.