A Self-Charging Assisted Commutated DC Solid State Circuit Breaker

Power electronic devices has low inrush current tolerance, the device itself is limited in its interrupting capacity, usually with additional auxiliary current switching measures to enhance the interrupting capacity, but the common auxiliary current commutation methods are more complex, requiring additional control loops, etc. This paper proposes a DC solid-state circuit breaker topology based on passive triggering of thyristor-assisted current commutation by a Zener breakdown diode, which, based on the nonlinear characteristics of breakdown diodes, automatically triggers a pre-charged capacitor discharge thyristor after the occurrence of a short circuit or fault. Fault occurs automatically triggers the pre-charged capacitor discharge thyristor. The operating principle of this topology is analyzed. The proposed topology is characterized by high reliability since it does not require active control of current switching and does not need a controller to judge the triggering moment. The triggered current-switching approach can reduce the opening current of the power electronic device, significantly increase the short-circuit opening capability of the device, and reduce the opening loss of the device itself. The use of current-switching capacitors to inject reverse current into the semiconductor switch reduces the size of the shutdown current of the semiconductor switch, and significantly improves the shutdown capability of the power electronic device. Moreover, this topology adopts passive triggering structure, which is simple and reliable, and has greater application potential.