A robust current control strategy for single-phase shunt active power filters

This paper proposes a robust current control strategy for single-phase shunt active power filters (APFs) based on the dynamic model of a single-phase voltage source inverter (VSI) with four controllable switches. The idea in this strategy is to generate a switching function in terms of the filter current reference and then apply it to VSI so that the actual filter current follows its reference. The load current is measured and subtracted fro the source current reference to form the filter current (compensating current) reference. The amplitude of the input current reference can be adjusted by using a PI controller that regulates the dc capacitor voltage. It is shown that the proposed method has a good robustness to parameter changes. In addition to this, the method has another advantage of using only one current sensor for the load current. Computer simulation and experimental results are compared and good agreement is reported verifying the correct operation of the proposed control method.