Power supply source switching apparatus for hybrid engine generator

Usability is improved and noise and fuel consumption are lowered by preventing stopping of a generator output. A hybrid power generator (1) includes a battery (4) an alternator (3), a rectifier unit (51), a DC-DC converter (9) stepping up an output of the battery (4), and an inverter unit (53) converting outputs of the rectifier unit (51) and the DC-DC converter (9) to AC and outputting the AC as a generator output. At a time when a load output reaches an upper limit of an allowable power range of the DC-DC converter (9), the engine (2) is started and power supplying from the battery (4) is switched to power generation by the alternator (3). A generated power restricting unit (27) suppresses the output of the inverter unit (53) during the starting of the engine so that the generator outputs allowable power range of the DC-DC converter (9).