Design And Condition Monitoring Of Maglev Train Suspension Chopper Based On SiC MOSFET

In this paper,the maglev train suspension chopper is taken as the research object,and the SiC-based suspension chopper is designed and analyzed.The switching characteristics of the power device and the bus capacitance in the chopper are monitored.The main research contents are as follows:1.Based on the comparison of the losses of the Si IGBT module and the SiC MOSFET module,the heatsink of suspension chopper is optimized according to the application conditions of the suspension chopper,and the weight of new heatsink is reduced by 79%.The prototype of SiC MOSFET suspension chopper was designed and built and tested experimentally.2.In order to test the switching characteristics of SiC MOSFET suspension chopper power devices,the switching state test method is studied.A dual pulse signal test board was designed.The switching state monitoring experiment of the chopper power transistor was carried out,and the switching transient waveform of the power device was obtained.3.The mathematical model of the bus capacitance voltage is analyzed to provide a theoretical basis for the prediction of the bus capacitance parameters.The simulation model of the floating chopper is established to obtain the ripple voltage value and load current value of the bus capacitance under different aging conditions.The ripple voltage value and load current value are used as the input data of the neural network,the capacitance value and the equivalent series resistance value are used as the output data of the neural network.These data are trained in neural networks.4.A state monitoring experimental platform for busbar capacitance is built,and the measured busbar capacitor ripple voltage and electromagnet current data are used as training inputs of the neural network,and the measured capacitance value and ESR value are used as outputs for neural network training.The accuracy of the parameter prediction of the neural network is tested to verify the feasibility of the scheme.In summary,this paper studies the suspension chopper from three aspects: SiC suspension chopper design,power device switching characteristics and bus capacitance state monitoring,which improves the reliability of the suspension chopper.