Patent ID: 7667418

Claim:
A motor drive system comprising: an electrical motor having i) a stator with a core; ii) a rotor supported for movement relative to the stator, and iii) polyphase windings wound on the core, each polyphase winding being spatially separated by 360 electrical degrees; a polyphase power supply for each of the polyphase stator windings, each polyphase power supply comprising a pole pair; an inner loop controller configured for controlling the polyphase power supply for each of the polyphase windings, the inner loop controller having a pole pair configured for controlling a rotor reference frame q-axis current and a rotor reference frame d-axis current; and an outer loop controller configured for: i) determining torque and force requirements necessary for motoring and levitation; and ii) converting the torque and force requirements to appropriate commands for the rotor reference frame q-axis currents and the rotor reference frame d-axis currents for each of the polyphase systems, whereby the rotor reference frame d-axis current commands and the rotor reference frame q-axis currents commands are sent to the inner loop control.