Patent ID: 7863838

Claim:
An electric power supply system comprising: a plurality of drive motors; a bidirectional electric power converter for converting a DC voltage; and a plurality of electric power supplies with mutually different output voltages for supplying electric power to the plurality of drive motors, wherein each of the plurality of electric power supplies is connected to at least one of the plurality of drive motors by a path that does not include the bidirectional electric power converter, and also to at least one of the plurality of drive motors by a path that does include the bidirectional electric power converter; and when an abnormal output is obtained from at least one of the plurality of electric power supplies, the output from the electric power supply with the abnormal output and the power conversion of the bidirectional electric power converter are both suspended in order to supply electric power from an electric power supply other than the one with the abnormal output to at least one of the plurality of drive motors via a path that does not include the bidirectional electric power converter.