Patent ID: 7049786

Claim:
A unipolar drive, comprising: a booster comprising a first transistor, a first capacitor coupled to a first transistor terminal of the first transistor, and a first inductor coupled to the first capacitor and the first transistor terminal of the first transistor; an energy storage module coupled to the booster, the energy storage module comprising a second inductor coupled to the first capacitor, a second capacitor connected coupled to the second inductor at a first capacitor terminal of the second capacitor, and a first diode coupled to a second transistor terminal of the first transistor and a second capacitor terminal of the second capacitor, wherein the energy storage module is operable to transfer energy from the second capacitor to the booster using the first diode; a unipolar inverter, comprising: a plurality of windings for a motor; a plurality of second transistors, each second transistor connected in series to one of the windings, and each second transistor operable to cause the respective winding to be energized; and a plurality of second diodes, each second diode coupled to one of the windings between the respective winding and the transistor in series with the winding, and each second diode operable to return energy from the respective winding to the energy storage module and the booster when the respective winding is not being energized; a voltage comparator operable to control the first transistor based on a comparison between an output voltage of the booster and a reference voltage; and a hysteresis comparator operable to control the second transistors based on a comparison between a reference frequency and a measured frequency of a motor driven by the unipolar drive.