Research On Junction Temperature Detection Of IGBT Module In Wind Power Converters

The wind power converter is the key control channel for the wind turbine and the power grid,and the IGBT power module is the core power conversion component of the wind power converter,its reliability is crucial for wind power converters and even the entire wind turbine.In wind power working condition,because of the fluctuation and randomness of wind speed,the IGBT module carries intermittent power stress,which causes the junction temperature to fluctuate in a reciprocating fashion,leading to the thermal cycle of the chip,the bonding wire and each package layer.The thermal expansion coefficient of each layer is different,which leads to the cyclic expansion and contraction of each layer material and the shear cycle of adjacent layer material,the thermal conductivity of the package is degraded due to the change of the thermal resistance of the package,the saturation voltage drop is increased due to the warpage of the bonding wire,and the chip junction temperature is increased under the same power stress.Therefore,the junction temperature and its fluctuation of IGBT chip are the key factors that affect the lifetime of power semiconductor devices,the research of junction temperature detection of IGBT module under wind power working condition is important for the condition monitoring and operational reliability of the component itself and the wind power converter.In order to study the method of junction temperature detection of IGBT module in wind power working condition,the main work is as follows:（1）From the view of turn-on state of IGBT,the relationship between collector-emitter saturation voltage drop V_CEsatEsat which is the static parameters of temperature sensitive parameters and the junction temperature T_j of IGBT module is studied.The volt-ampere characteristics and temperature sensitive characteristics of saturation voltage drop are analyzed from the view of physical mechanism.The experiment is designed to measure the saturation voltage drop at different junction temperature and collector current.The experimental results are studied by using mathematical model,physical model and neural network model,and the junction temperature detection model based on collector-emitter saturation voltage drop is established.（2）From the view of switch status of IGBT,the relationship between turn-on and-off delay time t_donon and t_doffoff which is the dynamic parameters of temperature sensitive parameters and the junction temperature T_j of IGBT module is studied.The temperature sensitive characteristics of turn-on and-off delay time are analyzed from the view of physical mechanism.The experiment is designed to measure the turn-on and-off delay time at different junction temperature,bus voltage and collector current.The turn-on and turn-off delay time are compared and analyzed,then the linear and stable temperature sensitive parameters is selected,and the junction temperature detection model based on turn-off delay time considering the influence of voltage and current is established.（3）From the view of working condition of IGBT,the application method of electro-thermal coupling model of IGBT module to detect junction temperature in wind power condition is studied.Junction temperature detection model in wind power condition is established,including the wind turbine model considering the wind speed and electro-thermal coupling model considering the ambient temperature.The wind speed and ambient temperature data in winter and summer for each nine days from a wind farm is entered,then the junction temperature in winter and summer is obtained.The thermal safety of IGBT module in wind power converters is evaluated by extracting three characteristic parameters from junction temperature sequence,then the main factors that affect the thermal safety of IGBT module are studied.The lifetime consumption of IGBT module in wind power converters is studied by extracting accumulated damage in winter and summer,then the main factors that affect the lifetime consumption of IGBT module are studied.