Research On Reliability Evaluation Method Of IGBT Based On Temperature Sensitive Parameters

China is the country with the largest scale and fastest growth rate of wind power.The proportion of wind energy in the energy structure has increased year by year.The IGBT(Insulated Gate Bipolar Transistor)is the core component of the wind power converter and is responsible for the regulation of the wind turbine and grid side output power.Due to the large randomness of wind energy distribution in time and space,the output power of the fan fluctuates frequently,which causes the IGBT's junction temperature to fluctuate drastically,which aggravates the aging failure of the device and brings great challenge to the reliable operation of the power electronic conversion system,therefore carrying out research on the reliability evaluation method of IGBT is of great significance.The junction temperature is closely related to the IGBT operating characteristics and is one of the important parameters reflecting the aging state of the device.Therefore,accurately and effectively acquire the junction temperature of the IGBT can take protective measures to minimize the loss before the device aging failure.In order to accelerate the heat loss,the IGBT needs to rely on the heat sink with good assembly quality.The quality of the assembly between the IGBT and the heat sink directly affects the heat dissipation effect of the entire heat dissipation component,so it has important practical significance for the performance evaluation of the heat dissipation component.Based on the above considerations,this paper establishes the research topic of IGBT reliability evaluation method based on temperature-sensitive parameters.The main contents include:This thesis designs an equipment and method for IGBT junction temperature calibration and heat dissipation component performance evaluation keeping bias current dynamically constant and explained in detail the experimental device and method steps for calibration and measurement of two working modes.In the calibration mode,and saturation conduction voltage drop of the device under test is measured at different gate voltage and junction temperature,and relationship between junction temperature,gate voltage,and saturation conduction voltage drop is fitted;In the measurement mode,controling the heating power of the device under test in a specific range,and saturation conduction voltage drop and the gate voltage of the device under test is measured,and the junction temperature of the device under test is calculated according to the relationship between junction temperature,saturation conduction voltage drop and gate voltage of the calibration mode,and The junction temperature characteristics of the device under test at different heating powers is drawn,and finally the heat dissipation performance of the heat dissipation component is evaluated according to the characteristic curve.This thesis designs a set of IGBT accelerated aging test program which taking aging control strategy of constant junction temperature fluctuation and controls the IGBT turn-on and turn-off time by monitoring the saturation conduction voltage drop in the heating phase and the cooling phase.The test process and method steps of the aging test plan are given in detail.The relationship between the saturation conduction voltage drop and the junction temperature of the IGBT module before and after aging was measured.The experimental results show that under the same collector current and gate voltage,the saturation conduction voltage drop of IGBT increases with the progress of aging process.Finally,a method for measuring the change trend of the relationship between the saturation conduction voltage drop and the junction temperature to evaluate the aging state of the IGBT is proposed.