EFOSMO

EFOSMO is an abbreviation of encoderless full order sliding mode observer. It is used to estimate the unmeasured variables in electrical drives to implement the encoderless control method. In model based observer methods, mostly the estimated speed is a necessary feedback for the observer, such as Model Reference Adaptive System (MRAS) (1) and Full order Sliding mode observer (FOSMO) (2). The speed calculation is normally the last step of the estimation, which means the cumulative estimation error will be injected to the observer. To reduce the influence of the estimated speed, an EFOSMO is proposed in (3). By considering the observer in a 'dq' frame, the observer does not need the feedback of the calculated speed any more, which means the error injected by the calculated speed is removed from the observation system.