FREQUENCY STABILIZER

A frequency stabilizer includes a bidirectional AC/DC converter, a bidirectional DC/DC converter, a first energy storage system, a second energy storage system, and a building. The bidirectional AC/DC converter is connected between an AC power system and the first energy storage system. The bidirectional DC/DC converter is connected between the first energy storage system and the second energy storage system. Two or more of the first energy storage system, the second energy storage system, the bidirectional AC/DC converter, and the bidirectional DC/DC converter are disposed inside the building.