Patent ID: 8058746

Claim:
A converter for electrical power recovery comprising a power input terminal which receives power from a commercial power supply system, an in-house power generation device which supplies power to a load by setting up cooperation between input terminal power at the power input terminal and in-house generated power which is generated in-house, a power accumulation device which accumulates power, and a control unit which, when the in-house generated power has exceeded the power consumed by the load, controls the input power to the power accumulation device so that the surplus power, which is the amount of the excess, is accumulated in the power accumulation device, comprising: a switching unit which is provided at the power input side of the power accumulation device, and which switches the input power and inputs it to the power accumulation device; and a sensor unit, which is provided to the power input terminal, and which detects the magnitude of the current flowing in the power input terminal; and wherein the control unit comprises: a switching control means which, when the in-house generated power is larger than the power consumed by the load, performs a first type of control in which it controls the switching unit so that the output of the sensor unit becomes approximately zero, and which, when the output of the sensor unit is approximately zero, performs a second type of control in which it controls the switching unit for an extremely short time to the extent that no influence is exerted upon the first type of control so that the output of the sensor unit becomes a value which corresponds to a predetermined target received power which is larger than zero and the input power corresponding to the target received power is accumulated in the power accumulation device in an operating state where the in-house power generation device supplies power to the load by setting up cooperation between the input terminal power at the power input terminal and the in-house generated power generated in-house; and a sensor unit decision means which decides that the sensor unit is anomalous if, during the second type of control by the switching control means, the output of the sensor unit is not elevated and is approximately zero.