A study on different modulation techniques in presence of resonant controllers applied to active power filters

Resonant current controllers applied to active power filters have shown a good performance in terms of reference tracking. A resonant controller behaves like an integrator for specific frequencies being capable of completely eliminating the steady-state error to sinusoidal inputs. Hence, the possibility of eliminating the coordinate transformation of standard PI controllers and of lowering the computational effort related to the control algorithm implementation. To fully take advantage of the characteristics of this controller, a suitable modulation technique must be used. Indeed, in such applications as active power filters is very important to consider modulation techniques capable of reproducing the controller output not only at the grid frequency but also at higher harmonic orders. In this paper the performance of different modulation techniques applied to the resonant current control of an active power filter has been evaluated. The presented results show how the space vector modulation allows the best reference tracking