Patent ID: 8342812

Claim:
A variable speed air compressing system, comprising: a compressor; a motor configured to actuate the compressor; a rectifier configured to receive alternating current from a first power source and to provide rectified direct current having a first voltage; an inverter configured to receive the rectified direct current and to receive direct current from a second power source having a second voltage, the inverter further configured to provide alternating current to the motor, wherein the alternating current provided to the motor is based on the rectified direct current if the first voltage is greater than the second voltage and wherein the alternating current provided to the motor is based on the direct current from the second power source if the second voltage is greater than the first voltage; and a controller configured to vary the first voltage to adjust an amount of allowable sag of the second voltage by raising the first voltage to decrease the amount of allowable sag or by lowering the first voltage to increase the amount of allowable sag.