Research On Temperature Estimation Model Of IGBT For Electric Heat Pump Compressor Controller

Electric vehicles have no heat source for cooling in winter,and PTC heating is used for cooling in winter,which greatly reduces the cruising range.The heat pump compressor replaces the PTC heating of traditional new energy vehicles,greatly reducing the loss of battery pack power during heating in winter.As the brain of the heat pump compressor,the safety of the controller directly affects the safety of the driver.As the main power device,the safety of IGBT is directly related to the safety of the controller.In this paper,the IGBT junction temperature estimation model is designed for the IGBT junction temperature in the electric heat pump compressor controller.First,select different driving parameters to conduct a double-pulse experiment on the controller,and analyze and study the loss and driving waveforms under different parameters.Then,in view of the problem that the IGBT loss cannot be dynamically calculated in the double pulse experiment,the loss generated by the IGBT module was analyzed and calculated,and the loss calculation model was built,and the accuracy of the model was verified by simulation with PLESC software.Research the common equivalent thermal network model,and build an RC model through the definition of thermal resistance and thermal capacity to connect electrical parameters with thermal parameters.Through the junction temperature calculation method,the IGBT junction temperature estimation model is built in the Matlab/Simulink module,and the model parameters are identified based on the nonlinear least square method.Perform real machine calibration on the identified parameters to obtain the optimal value.Then use the optimal value as the initial value to identify again,and compare the two sets of parameters.Aiming at the junction temperature estimation model,the current and voltage signals are simulated for simulation verification.The simulation results confirmed the reliability of the junction temperature estimation model.Set up an experimental environment for the whole machine,and perform multi-condition verification on a certain type of compressor.The experimental data shows that within a certain error range,we can accurately estimate the internal junction temperature of the IGBT.Aiming at the problem of slowing down the temperature rise: research on the adjustment of the controller software.Through the study of two-phase modulation and threephase modulation control methods in SVPWM control,the difference in IGBT module loss between three-phase modulation and two-phase modulation control methods is analyzed and calculated,and based on the ideal motor model,the two modulations are verified under the same operating conditions.In the mode,the conduction loss remains unchanged,and only the switching loss changes.Through real machine verification,it is proved that under the same working conditions,two-phase modulation can effectively reduce the internal junction temperature of the IGBT module.