Speed Compensation for Sensorless Induction Motor Based on AFO With Virtual Voltage Injection In Low Speed

Sensorless control of Induction Motor is popular because of its low cost, high reliability application areas. Especial in low speed area, induction Motor has its own advantage, however the unobservable problem is still existed when the synchronous speed is low or is equal to zero. To solve this problem, Dr Sun has proposed the method of virtual voltage injection. With the virtual voltage injected into the observer, the unobservable problem is solved and the Induction Motor is able to run stablely but the method brought speed estimated error at the same time. This paper will use the feedback gains matrix to reduce the speed estimated error and simultaneously not to destroy the stability of the motor system. Finally it's validity is verified by simulations and experiment.