An Adaptive-Switching-Frequency-Based Active Thermal Control Method for the IGBTs in Virtual Synchronous Generators

Typically, in power electronics, power devices such as IGBTs are often the most vulnerable to failure, and their reliability often depends on peak junction temperature and maximum fluctuation. To delay the aging of the device and prolong its lifetime, adaptive switching frequency control is adopted. The control methods employed in some of the existing literature are effective in preventing excessive cooling down of the semiconductors during power cycling. However, they ignore the increase in the average temperature and also fail to decrease the periodic temperature fluctuation. Therefore, this work presents an adaptive-switching-frequency-based method for the IGBT in the generators. The method can reduce the peak temperature and the maximum thermal swing by adaptively adjusting the switching frequency while satisfying the minimum power factor. Also, the method changes the input given reactive power, which further improves the voltage support ability of the inverter to the grid. Finally, the validity of the method proposed in this paper is confirmed by building a suitable simulation model.