A sensorless stator flux oriented vector controlled induction motor drive with neuro-fuzzy based performance enhancement

A high-performance stator flux oriented speed sensorless direct vector-controlled induction motor drive is described in the paper. The drive can start from stand-still, operate at any speed in all the quadrants including the field-weakening region, and then stop at zero speed. The drive incorporated the following novel features: (1) software-programmable cascaded low-pass filter units permit machine terminal voltage integration to synthesize the precision stator flux vector at any frequency; (2) zero-speed stand-still start-up of the drive using machine current model equations without speed sensor, and then transitioning to direct vector control (and vice versa); (3) light load steady state efficiency improvement by on-line search of flux that is based on neuro-fuzzy control; and (4) stator resistance estimation during operating condition by quasi-fuzzy technique for compensation. The drive with the proposed control and estimation techniques has been extensively analyzed, investigated by simulation study, and then finally implemented by distributed DSP system on an experimental laboratory drive. The drive is primarily intended for an electric vehicle type drive, but can be extended for an industrial drive