US Patent 6977446 Multiple inverter power system with regard to generator failure

The present invention is directed to a precise power system which utilizes two separate inverters fed by a rectifying power supply from a generator set. During normal operation, the first or critical inverter would feed the critical load(s) and the second or non-critical inverter would assist the electric utility in feeding the non-critical load(s). During utility grid failure, the second inverter is disconnected from the power supply so that the entire output of the generator set is available to the critical load. During generator set failure, the utility grid powers the second inverter to supply power to the first inverter for the critical load(s).