Research On Losses Calculation For Three-phase Converter Based On SiC MOSFET

The continuous development of industry promotes the progress of power electronics industry.As the core of power electronic converters,the performance of power electronic power switches has a direct impact on the efficiency of the system.The new generation of wide-band-gap semiconductor devices represented by silicon carbide devices broke through the performance limitations of previous silicon devices,and provided the possibility for the development of power electronics towards high frequency,high performance and high power density.Among them,the losses of power switching devices is one of the important issues in the study of converters.Firstly,according to the working characteristics of MOSFET and IGBT,this paper analyzes the power losses calculation method of three-phase converter based on different types of semiconductor devices and deduces the power losses calculation process of three phase converter in SVPWM modulation.Secondly,simulate the power losses of three-phase converter under different types of semiconductor devices in order to verify the advantages of SiC devices.Simulate the power losses of three-phase converter with different switching frequency and heat-sink resistance and design the the cooling system in terms of the simulation experiment result.Finally,in order to achieve the purpose of applying power losses algorithm to embedded real-time simulation platform,this paper presents a sampling algorithm for calculating the losses of semiconductor devices.The algorithm takes the actual circuit recoverable signal as the basis and calculate the power losses by sampling averaging method.According to the influence of different sampling frequencies on the accuracy and speed of the algorithm,the sampling algorithm is optimized and propose a variable sampling frequency algorithm.This method can achieve the double optimization of the speed and accuracy of the power losses calculation.