METHOD AND APPARATUS FOR TRANSDUCERLESS FLUX, POSITION AND VELOCITY ESTIMATION IN DRIVES FOR AC MACHINES

摘要

Power is provided to the stator windings of an AC motor (31) from inverter drive system (38). The inverter (38) receives commandsignals for the fundamental frequency d and q axis currents (40, 41) and higher frequency voltage command signals (42) from a positionand velocity observer (43). The position and velocity observer (43) uses information from the signals (44, 45) to provide estimates for therotor position and speed provided as output signals (47, 48). The direct field oriented controller (50) includes a flux regulator (58), a torquecalculator (60) and a rotor flux observer (61) and provide the inverter (38) with the fundamental frequency current command signals (4041). Conventional induction motors can be provided with sufficient spatial variations in the stator winding impedance as a function of rotorposition by varying the depth and/or width of the slots over the rotor conductive bars or by varying the cross-section of the bars, or byfilling or partially filling some of the slots.