Robust perfect compensation of load harmonics in shunt active filters

In this paper an advanced control strategy is proposed for shunt active filter (SAF) used in three-phases three-wires current harmonic compensation. The SAF considered are based on AC/DC three-phase boost converter topology. The robust solution presented by the authors previously is used as a starting point to develop the stabilizing controller of the DC-MA voltage dynamics. SAF resistive power losses cause the instability of this voltage dynamics when perfect harmonics compensation is achieved. An integrator with a suitably designed deadzone is placed in the voltage controller to guarantee DC-link voltage dynamics stabilization without perturbing the current harmonics compensation. Two time-scale behavior of the SAF is exploited to apply the averaging technique and input to state stability arguments in the control design.