System-level lifetime-oriented power sharing control of paralleled DC/DC converters

Thermal cycling is a critical stressor on semiconductor elements as they are the main functional components of power electronic converters. Load variation of a converter causes temperature swing, which intensively affects the lifetime of semiconductor switches. In this paper, an active thermal controlling method is proposed in order to enhance the overall system reliability. The proposed strategy applies power sharing among the converters by taking into account the lifetime of the power switches in the paralleled converters under different loading conditions. Hence, the lifetime of the converters is equally consumed in terms of load variations, and the overall system reliability is improved. Simulations and experimental case studies on two parallel-connected power converters have demonstrated that the power sharing control is an effective solution in terms of enhancing the overall power system reliability.