A universal automatic and self‐powered gate driver power supply for normally‐ON SiC JFETs

Abstract

Abstract Normally‐ON silicon carbide junction‐field‐effect transistors have a simple design and exhibit advantageous performance in terms of losses, elevated junction temperatures and high switching frequencies. However, under a loss of power to their gate, normally‐ON junction‐field‐effect transistors are subject to a shoot‐through situation, which might be severe for their survivability. This paper presents a universal concept for an automatic and self‐powered gate driver power supply circuit for normally‐ON silicon carbide junction‐field‐effect transistors employed in high input‐impedance circuits. The power to the gate is supplied during start‐up and steady‐state operations through a mutually coupled inductor with the high input impedance inductor and by employing a typical low‐voltage, power supply circuit. The performance of the proposed automatic and self‐powered gate driver was evaluated on a DC/DC boost converter rated at 6 kW, as well as in a low‐voltage solid‐state DC circuit breaker. From experiments it is shown that using the proposed circuit, the start‐up process requires approximately 350 μs, while the steady‐state switching process of the junction‐field‐effect transistor during steady‐state is also shown. Using the proposed circuit in a low‐voltage solid‐state DC breaker, a fault current of 68 A is cleared within 155 μs.

Keywords

• Power electronics, supply and supervisory circuits
• Insulated gate field effect transistors
• Other field effect devices
• Relays and switches