Analysis on the Characteristics of Dynamic Changes in Junction Temperature of Power Semiconductor Devices

As an important foundation of power electronic technology, power semiconductor devices are widely used in important fields such as new energy power generation, rail locomotive traction, electric vehicle driving, and aerospace. Whether power semiconductor devices can operate stably and reliably is a prerequisite to ensure the normal operation of these devices. In view of the fact that junction temperature fluctuation is an important factor affecting the reliability of power semiconductor devices, domestic and foreign scholars have proposed many junction temperature extraction methods based on thermally sensitive electrical parameters and thermal resistance network methods. However, these methods ignore the point at which the highest junction temperature of the device is generated. This paper takes boost circuit as an example to analyze the characteristics of power semiconductor device loss changing with time in PWM cycle, and further analyzes the junction temperature and loss during the turn-off period, and obtains the conclusion that the junction temperature is the highest at the end of the turn-off. Finally, simulation and experimental verification are carried out.