Solid-state AC breaker with parallel switched capacitor circuits for microgrid system

ABSTRACT

In this paper, a novel solid-state AC breaker, based on double-paralleled switched capacitors controlled with complementary pulse width modulation technique, is proposed for transition of microgrid due to its advantages of low di/dt stress to power devices and controllable resistance features. The circuit topology of the breaker is based on parallel switched capacitors, its operating and control theory are analyzed in detail to show its advantage in theory. The equivalent impedance of proposed parallel switched capacitor circuits is up to the switching frequencies, and the proposed switch is suitable for seamless transition between the island mode and grid-connected mode to reduce the current shock by changing the switching frequencies. Simulation and experimental results verify the effectiveness and feasibility of the new AC breaker.