Bidirectional Supercascode High-Voltage DC Solid-State Circuit Breaker With Sensorless CurrentCTime Configuration

This article presents a bidirectional normally-on SiC junction field-effect transistor (JFET) based supercascode high-voltage dc solid-state circuit breaker (BSC-SSCB) with sensorless current-time configuration. A sensorless detection-driving circuit (DDC) is proposed to detect the current and drive the main switch by directly utilizing the forward voltage of the BSC-SSCB. The DDC only contains a few passive components and a low-voltage MOSFET, whereas no high-voltage input or high-isolation auxiliary power supply is used. In addition, the current-time tripping response can be configured by only setting two resistors and two capacitors of the DDC without additional controllers. The configurable current-time tripping response enables the BSC-SSCB to avoid unnecessary breaking-off caused by impulse current. A design procedure for the DDC and the main circuit is carried out. A 4-kV/15-A BSC-SSCB prototype is designed and tested. Simulation and experimental results show that the proposed BSC-SSCB can quickly break off the fault current and achieve balanced voltages of all power JFETs. The current-time tripping curve can be fine-configured, which agrees with theoretical analysis. The results indicate that the proposed BSC-SSCB can be applied to medium-voltage dc for fast circuit breaking.