Control of an active power filter based on input-output linearization

In this paper the input-output linearization technique is used to synthesize a control system for a shunt active power filter. This control system is composed of two control loops connected in cascade. The inner loop, the current control loop, is realized in a synchronous reference frame where it is easier to get the reference compensating currents. The outer control loop maintains the DC voltage in a required level. This second loop is required to be more slow. As there are only two input control functions and three output state variables to be controlled, the d component of the AC reference current is added with the required current to control the DC voltage. As the first synthesized current control loop is very dependent on parameters, a second current control loop was developed based on the PI controllers