Passivity-Based Design of a Resistive Active Power Filter through Virtual Impedance

To enhance the stability of resistive active power filter (RAPF), a new control scheme along with its passivity-based design for resistive active power filter is proposed in this paper. By introducing an additional capacitor voltage feedforward path, the output admittance of the converter at resonant frequency is not zero anymore. Further, with properly designed resonant controllers, the output admittance of the RAPF seen from the point of common coupling can appear as a pure resistor at resonant frequencies. By solving a series of nonlinear equations, the compensation angles of resonant controllers are obtained which guarantees the dissipativity around resonant frequencies. The passivity-based design makes the output admittance of RAPF dissipative below Nyquist frequency. Relevant simulations and experiments verify the effectiveness of the proposed control scheme.