Adaptive thermal control for power fluctuation to improve lifetime of IGBTs in multi-MW medium voltage wind power converter

Multi-MW wind power converter's reliability is a key issue for the whole wind power generation system. Due to wind power fluctuation, IGBT's handling power is fluctuating largely and rapidly, which will cause a large junction temperature variation of IGBT. Thermal stress is the main factor affecting IGBT's lifetime. In this paper, the adaptive thermal control is proposed to improve IGBT's lifetime during power fluctuation. In the adaptive thermal control, different vector sequences are adopted adaptively to power fluctuation levels. The IGBT's junction temperature variation can be reduced in comparison with normal vector sequence. According to power fluctuation level and IGBT's junction temperature, the relevant vector sequence is adopted. The adaptive thermal control can relieve IGBT's thermal stress and improve its lifetime during wind power fluctuation. The improvement of IGBT's lifetime can also improve wind power converter and system's reliability. Finally, the MATLAB/PLECS simulation is carried out. Simulation results indicate the feasibility and advantages of the proposed adaptive thermal control.