Bidirectional Supercascode High-Voltage DC Solid-State Circuit Breaker With Sensorless Current–Time Configuration

This article presents a bidirectional normally-<sc>on</sc> 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.