A household energy storage system, comprising an energy management module, an energy gateway, an intelligent power distribution module, and at least one energy storage subsystem,
- wherein the energy management module comprises an energy management unit and a communication gateway, wherein the energy management unit is configured to control charging and discharging of the energy storage subsystem, and the communication gateway is configured to detect an operating state of the entire household energy storage system and communicate with an Internet of Things cloud platform;
- wherein the energy gateway is configured to cut off a connection between utility power and the household energy storage system when the utility power fails and is configured to resume the connection between the utility power and the household energy storage system when the utility power is restored;
- wherein the intelligent power distribution module is configured to control on-off of the energy storage subsystem and control an access of loads and an access of power supply equipment;
- wherein the energy storage subsystem comprises a battery management module, an energy storage battery module, and at least one power converter, wherein the battery management module is configured to manage charging and discharging of the energy storage battery module and acquire a signal of the energy storage battery module, the power converter is configured to convert an alternating current into a direct current rechargeable for the energy storage battery module, and when the energy storage battery module discharges, the power converter is configured to convert a direct current into an alternating current usable by grid-connected and home loads;
- wherein in a grid-connected state, when the energy management module determines that utility power is abnormal, a grid-connected working mode is closed;
- a phase-locked source of the energy management module is switched from the utility power to a self-oscillation state;
- the energy management module notifies the power converter to switch a phase-locked source and sends a phase-locked result to the power converter;
- the phase-locked source of the power converter is switched to the self-oscillation state of the energy management module, and phase-locking is performed;
- an input switch of the utility power is turned off when the phase-locking of the power converter ends;
- and an off-grid working mode is started after the input switch is turned off;
- and
- wherein in an off-grid state, when the energy management module determines that the utility power is normal, the phase-locked source of the energy management module is switched from the self-oscillation state to the utility power;
- the energy management module notifies the power converter to switch a phase-locked source and sends a phase-locked result to the power converter;
- the phase-locked source of the power converter is switched to the utility power, and phase-locking is performed;
- the input switch of the utility power is turned on after the phase-locking of the power converter ends;
- and the off-grid working mode is closed before the input switch is turned on, and the grid-connected working mode is started after the input switch is turned on.