Heat Dissipation Structure Design And Multi-Objective Optimization Of Inverter Based On Optimal Control Strategy

In recent years,due to the increasingly serious environmental problems,the automotive industry is also facing huge chan ges and new energy vehicles are developing rapidly.The motor controller directly affects the pe rformance of the electric vehicle.The working environment of electric vehicles is relatively harsh.The main heat source in the controller is a high-power switch module,namely IGBT module.Therefore,the thermal reliability requirements of the IGBT module are higher and the operating temperature is a key factor affecting the thermal reliability of the IGBT module in the inverter.In order to improve the thermal reliability of the IGBT module,the thermal reliability of the inverter from the perspective of heat generation and heat dissipation is studied.Firstly,we introduce the working principle of IGBT module and deduces the method of loss calculation.Then,an inverter matching the permanent magnet synchronous motor is selected for research.There are two kinds of torque control strategies commonly used in its constant torque area: i_d=0 and maximum torque current ratio(MTPA).Under the same operating conditions,it is found that the current utilization rate is higher under the MTPA control strategy.Then,by calculating the losses of the IGBT module under the two control strategies,it is found that the heat loss generated by the IGBT module is lower under the MTPA torque control strategy.Secondly,a heat dissipation structure combining heat pipe and air cooling is designed.Based on the MTPA control strategy,thermal simulation analysis is performed in Fluent and the performance of the two radiators is compared.It is found that the heat dissipation capacity of the combined heat pipe and air cooling radiator is further improved compared with the original air cooling structure.Finally,multi-objective optimization is performed on the heat dissipation structure.The optimal Latin hypercube test design is used to extract the sample points.The response surface,radial basis and kriging proxy model are constructed.The accuracy of three proxy models are compared and selects a high-precision proxy model to optimize the designed radiator.Taking the volume of the heat sink,the maximum temperature and the minimum temperature of the IGBT module chips as optimization targets,the NSGA-Ⅱ optimization algorithm is used to optimize the proxy model.After optimization,the volume of the heat sink,the maximum temperature and the minimum temperature of the IGBT module can be reduced,which further improves the reliability of the IGBT module and the economy of the heat sink.