Patent ID: 8779709

Claim:
An apparatus for controlling an electric motor through use of a motor drive apparatus, the electric motor operatively coupled to line power and rotating in a normal direction, the apparatus comprising: a rectifier section having electrical inputs for receiving an input alternating current line signal from a line source and plus and minus bus outputs for providing a direct current bus signal; an inverter section having inputs connected to the plus and minus bus outputs of the rectifier section and providing an alternating current motor drive signal at inverter outputs adapted for connection to the electric motor; a first power storage arrangement connected across the plus and minus bus outputs and having a first capacitor arrangement having a first capacitance; and a second power storage arrangement connected across the plus and minus bus outputs and having a second capacitor arrangement having a second capacitance and a rate limiting arrangement in a series relationship with the second capacitor arrangement, with the second capacitance larger than the first capacitance and configured to provide sufficient power for maintaining the electric motor rotation, in the normal direction, throughout an interruption of power.