Impact of Virtual Inertia Frequency Regulation Control on Junction Temperature of Machine‐Side Converter in Doubly‐Fed Induction Generator

ABSTRACT

In this letter, we investigate the influence of virtual inertia frequency regulation control on the junction temperature of a machine‐side converter for a 2 MW doubly‐fed induction generator (DFIG), utilising the electro‐thermal co‐simulation method. Virtual inertia control affects the junction temperature not as a root cause, but indirectly through the following mechanism chain: control parameters alter the rotor speed dynamics, which changes the rotor current amplitude and frequency, subsequently affecting the power device losses and ultimately causing junction temperature fluctuations. The findings indicate that when the unit operates at wind speed near synchronous speed, the rotor speed easily crosses the synchronous speed during frequency regulation, resulting in severe junction temperature fluctuation of the converter. Conversely, when the unit operates at high or low wind speed, the rotor speed is far from the synchronous speed, and the junction temperature fluctuation is relatively moderate. The droop coefficient has a significantly greater impact on junction temperature fluctuation than the virtual inertia coefficient.