Drexel University

Lehigh University

Reza Kheirollahi

Hua Zhang

Fei Lu

Yao Wang

Shuyan Zhao

There may be two active snubbers for direct current (dc) solid-state circuit breakers (SSCBs): metal-oxide-varistor with resistor-capacitor-switch (MOV-RCS) and active-MOV with resistor-capacitor-diode (AMOV-RCD). In the snubber branch, either half- or full-controlled switch can be used, leading to four topologies. The improved snubbers offer several improvements: 1) MOV is disconnected from the power line during SSCB OFF-state, which enhances reliability as neither voltage nor power appears on MOV; 2) voltage utilization rate ηv of the main switch is remarkably increased, which improves efficiency and power density, and reduces design cost shows experiments of five prototypes are conducted including four proposed snubbers and a comparison with conventional MOV-RCD snubber.

Active snubbers for solid state circuit breakers to improve switch voltage utilization rate

With the fasting growth of renewable energy resources and DC supplied loads, DC electrical systems have been increasingly received attentions all over the world. DC breaker systems play a key role in protection systems for disconnecting sources and loads, and they are also used mainly for removing faulted sections from the system accurately and reliably. Solid state DC breakers benefit from fast response time and compactness features; however, due to the lack of zero current realization and high-power losses, the reliability and efficiency of these devices is low. The system proposes a solid-state DC breaker for medium voltage DC (MVDC) systems. The presented structure have two main parts: 1) a main conduction branch including stacked MV Silicon-Carbide (SiC) devices to improve the efficiency and provide a fast response time, 2) a breaker branch including a wireless capacitive coupling to avoid metal-to-metal contact and increase the overall reliability, and also a modular current pulse power supply to realize zero-current switching.

Growing community of inventors

Philadelphia, PA, United States of America

Reza Kheirollahi