Reference Generation for Harmonics Cancellation

This paper presents two recursive schemes for current reference generation for shunt active filters under unknown fundamental frequency. The schemes are based on the liner Kalman filter that needs the knowledge of the fundamental frequency. In practice, the fundamental frequency of the power system grid can vary. If it differs from the fundamental frequency considered in the mathematical model used in the Kalman filter the estimates provided by the filter will not be accurate. This paper proposes the use of on-line identification of the fundamental frequency of the power system. The identified frequency is used to update de Kalman filter model. Key-Words: Reference generation, active filters, harmonics, Kalman filter, identification.