A Non-Linear Control Strategy for Instantaneous Power Factor Correction in 3-ø 4-Wire Electrical Systems under Asymmetrical and Non-Linear Loads

A non-linear control strategy in a rotating frame for an active filter based on a voltage source converter shunt topology in a three-phase four-wire electrical system is proposed. The converter in combination with the proposed control strategy guarantees balanced overall currents, unity displacement power factor, and reduced current harmonics in the common coupling point. These features are achieved regardless of the linear/non-linear and/or balanced/unbalanced nature of the load. The proposed control strategy is based on the input-output linearization method which is implemented on a dq0 rotating current reference generation method. Various experimental tests demonstrate the high performance of the proposed scheme