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.