ELECTRIC POWER SYSTEM FOR INTERNAL PUMP

PROBLEM TO BE SOLVED: To allow an internal pump to be operated continuously even when abnormality occurs in a control system. SOLUTION: This power system 1 for an internal pump provided with an alternating power source facility 2, a rectifier 4 for converting an alternating current of an output from the power source facility 2 into a direct current, a smoothing circuit 5 for smoothing the direct current of an output from the rectifier 4, and an inverter 6 of a voltage type pulse width modulation system for converting a direct current of an output from the smoothing circuit 5 into an optional voltage/frequency is provided, at least in one side of the rectifier 4 and the inverter 6, with a double system control means having rectifier control circuits 11, 12 and inverter control circuits 13, 14 provided as double systems, and a switching means such as a central operation controller 25 for conducting switching between the control circuits to switch one side operation to the other side operation when abnormality occurs in one out of the control circuits under operation thereof.