Simplified Design of Phase Compensated Multi-Resonant Controllers for Grid-Connected Inverters

This paper concern with the design of phase compensation multi-resonant current controllers for AC converters based on system stability analysis for precise tracking and disturbance rejection. Phase compensation method is used to enhance the system stability in order to compensate the system total sampling and transport delay, since it can improve the phase response of resonant controller and consequently system phase margin. However, the phase compensation open loop system results in large anti-peaks around resonant frequencies, which may cause tracking error and system instability. This paper proposes a simpler design of phase compensated multi-resonant controller based on compensation of the phase lag of only the last resonant term of the multi-resonant controller in order to eliminate the anti-peaks effect and improve the system robustness and disturbance attenuation. Simulation results validate the proposed design methodology.