DC link fuzzy control for an active power filter, sensing the line current only

A different approach for controlling a shunt active power filter is presented. The DC link is controlled with fuzzy logic, and the current generated for the filter to compensate harmonics and power factor is not sensed. The sensors acts directly on the mains line currents, forcing them to be sinusoidal, and in phase with the mains voltage supply. The amplitude of the current is controlled by the fuzzy system, which operates through the error between the DC link voltage of the PWM modulator (active power filter), and a pre-established reference voltage, Vref. The main advantages of this approach are the following: (a) the control block becomes simpler because there is no need to evaluate the current template for the filter currents; (b) the DC link fuzzy control has better dynamic behavior than conventional PI control; and (c) the filter can operate simultaneously as a power factor compensator, and as a four quadrant rectifier-inverter system