METHOD FOR SEAMLESS SWITCHING BETWEEN OFF-GRID AND GRID-CONNECTED AND HOUSEHOLD ENERGY STORAGE SYSTEM

The present application relates to a method for seamless switching between off-grid and grid-connected including: in a grid-connected state, when a host determines that utility power is abnormal, a grid-connected working mode is closed, a phase-locked source of the host is switched from the utility power to a self-oscillation state, the phase-locked source of the slave is switched to the self-oscillation state of the host, and phase-locking is performed, and an off-grid working mode is started after an input switch is turned off; in an off-grid state, when the host determines that the utility power is normal, the phase-locked source of the host is switched from the self-oscillation state to the utility power, and, the phase-locked source of the slave is switched to the utility power, and phase-locking is performed, and the grid-connected working mode is started after the input switch is turned on.