DC solid-state circuit breaker with a solid-state aided airgap that provides a fail-safe mechanism

A method for providing a fail-safe mechanism in a DC solid-state circuit breaker, the method comprising:

• providing a sensing and control circuit configured to realize designed functions,
• providing a power electronics section that includes a first solid-state switching component for normal operations,
• providing an air gap section disposed in series with the power electronics section, and is configured to perform fail-safe interruption and to provide isolation,
• wherein the air gap section includes an isolation switch which is connected in series to a fail-safe interruption combination of a current commutation switch and a second solid-state switching component, the current commutation switch and the second solid-state switching component being connected in parallel,
• providing a first overvoltage protection device;
• providing a second overvoltage protection device to protect the first solid-state switching component during an overvoltage after interruptions,
• wherein the first solid-state switching component is semiconductor based and selected from metal-oxide-semiconductor field-effect transistors (MOSFETs) and Thyristors;
• and
• providing a third overvoltage protection device, wherein both the isolation switch and the current commutation switch need to open for a successful fail-safe interruption, and
• wherein the first solid-state switching component is a single component or multiple components connected in parallel and the second overvoltage protection device is connected in parallel to the first solid-state switching component or is connected between a system voltage after the first solid-state switching component.