Frequency-hybrid vector control and its performance for sensorless induction motor drive

This paper newly identifies usefulness of the frequency-hybrid (FH) vector control scheme for speed/position sensorless induction motor drive, which we have recently developed, through actual-machine-based performance evaluation tests. The FH scheme utilizes a new indirect and a new stable-filter-embedded direct orientation methods and well exploits their advantages. It is confirmed through the extensive tests by small to big standard motors of 0.3, 3.7, 30 (kW) and special low-voltage motors of 2.0, 5.5 (kW) dedicated to electric scooters and cars that the sensorless vector control scheme has such usefulness supported by the following potential performance: (1) it can make machines to produce more than 200% rated torque at standstill; (2) in both motoring and regenerating modes, rated torque on be produced even in very slow speed range including zero-speed and zero-frequency; (3) for constant speed good linear characteristics of torque response is attained; (4) it has ability to make machines to track variable speed command of acceleration up to ±5,000 (rad/s²) in mechanical sense; (5) it can accept zero-speed command and settles the machines at a stable standstill with no vibration; and (6) it accepts instant injection of rated load even for zero-speed control The performance confined by the tests shows a high degree of usefulness of the proposed up vector control scheme