Thermal smooth control based on orthogonal circulating current for multi-MW parallel wind power converter

Multi-MW wind power converters are widely applied in wind power field. Converters are paralleled to expand converter´s capacity. Due to the wind power fluctuation, IGBT´s power handling ability together with its drive power is fluctuating largely and rapidly, which will cause a large temperature variation, affecting the reliability and lifetime of power semiconductors. In this paper, the thermal smooth control for DC-BUS connected parallel wind power converter is proposed to improve the converter´s reliability. In the proposed thermal smooth control, orthogonal circulating current is introduced to smooth the thermal stresses of IGBTs. Therefore, a balanced thermal can improve IGBT´s reliability, which can improve the wind power converter´s reliability. Finally, MATLAB/PLECS simulation is carried out to validate the proposed thermal control. The simulation results indicate the feasibility and advantage of the proposed thermal smooth control.