Current compensation method for sensorless controlled induction motors operated in low switching frequency

Sensorless controls need accurate fundamental components of the inverter voltage and the detected motor current. However, In a certain type of inverter systems the switching frequency is limited. In that case, the harmonic component degrades the current regulator and speed estimator. Also, when the number of pulses is limited, the fundamental component of inventer voltage should be confirmed its preciseness. In this research, authors propose compensating current with predicted average current.