A Digital-Controlled SiC-Based Solid State Circuit Breaker with Soft Switch-Off Method for DC Power System

Abstract

Due to the lower on-state resistance, direct current (DC) solid state circuit breakers (SSCBs) based on silicon-carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) can reduce on-state losses and the investment of the cooling system when compared to breakers based on silicon (Si) MOSFETs. However, SiC MOSFETs, with smaller die area and higher current density, lead to weaker short-circuit ability, shorter short-circuit withstand time and higher protection requirements. To improve the reliability and short-circuit capability of SiC-based DC solid state circuit breakers, the short-circuit fault mechanisms of Si MOSFETs and SiC MOSFETs are revealed. Combined with the desaturation detection (DESAT), a “soft turn-off” short-circuit protection method based on source parasitic inductor is proposed. When the DESAT protection is activated, the “soft turn-off” method can protect the MOSFET against short-circuit and overcurrent. The proposed SSCB, combined with the flexibility of the DSP, has the μs-scale ultrafast response time to overcurrent detection. Finally, the effectiveness of the proposed method is validated by the experimental platform. The method can reduce the voltage stress of the power device, and it can also suppress the short-circuit current.

Gate Current and Snapback of 4H-SiC Thyristors on N+ Substrate for Power-Switching Applications

“…15keV, 3X10 13 cm -2 50keV, 6X10 13 cm -2 100keV, 8X10 13 cm -2 170keV, 9X10 13 The distance between the P+ anode and N+ gate, l space , was optimized at 10 µm, as a built-in potential cannot be established between the P+ anode (emitter) and N base of a PNP BJT if l space is short. The parameters t drift and N drift represent the thickness and doping concentration of the P-drift region, respectively.…”

“…The thermal conductivity of 4H-SiC is 3.3-4.9 W cm −1 K −1 , which is also greater than that of Si, which is 1.4-1.5 W cm −1 K −1 . Therefore, 4H-SiC is well-suited for use in power switches [8][9][10][11][12][13][14]. Recently, various research results related to the SiC power devices have been published.…”

“…Recently, various research results related to the SiC power devices have been published. The 10 kV SiC pin diode [11], 11 kV SiC merged pin-Schottky diode [12], SiC-based solid state circuit breaker [13], and intelligent control using SiC metal-oxide-semiconductor field-effect transistor for reduced electromagnetic interference generation [14] were reported.…”

Photovoltaic-Driven SiC MOSFET Circuit Breaker with Latching and Current Limiting Capability

“…D FW partly alleviates the overvoltage when inductive loads are switched off. In [25] a new "soft turn-off" technique is proposed in order to reduce the voltage overshoot and short circuit peak current. In this work, the use of Digital Signal Processor to control the operation of the SSCB also allows other enhanced protection functions.…”