Solid-State Contactor for DC Electrical Systems

Electromechanical contactors are widely used in DC electrical systems. Solid-state contactors based on a semiconductor power switch (bipolar transistor, IGBT, MOSFET, etc.) are an alternative. Most solid-state DC contactors lack built-in voltage and current protection circuits, requiring designers to design external protection circuits, which complicates their use in electrical systems. Taking into account possible inductances in DC electrical system circuits, this paper proposes a calculation for the parameters of the built-in protective circuits of a solid-state DC contactor. A prototype contactor using a SIC MOSFET and built-in protective circuits is presented; the contactor is controlled via a CAN interface. Prototype tests confirmed the validity of the proposed calculation expressions for determining the parameters of the built-in protective circuits.