Circuit fault self-checking method and device and controller

The invention provides a circuit fault self-checking method and device and a controller, and the method mainly comprises the steps: carrying out the configuration of a first control unit and a second control unit after primary power-on; wherein the first control units and the second control units are in one-to-one correspondence and perform circuit abnormity monitoring mutually; after secondary power-on, the first control unit completes primary self-inspection, and selects to start a fault mechanism or a normal mechanism according to a primary self-inspection result; only in a normal mechanism, the second control unit completes secondary self-inspection, and controls normal output or disconnection of the power supply according to a secondary self-inspection result. The first control unit performs power management and power supply on the second control unit, and also performs mutual monitoring with the second control unit, so that the functional safety of the power supply system is ensured, and the stability a