兼具有源阻尼器功能的并网逆变器改进虚拟阻抗控制方法OA

To enhance the resonance suppression effect of the grid-connected inverters with active damper function under variations in grid impedance,an improved virtual impedance control method applied in the active damper function is proposed.Existing virtual impedance control method utilizes adaptive regulator to generate virtual impedance for damping wide-band harmonics,and no targeted enhancement of the damping effect on harmonics at the resonance frequency has been achieved.Based on the existing virtual impedance control methods,an improved module is added in the proposed approach.The sliding discrete Fourier transform(SDFT)is employed to identify the resonance frequency.The resonant suppression effect is enhanced by reducing the magnitude of the virtual impedance at the resonant frequency.Finally,the feasibility and effectiveness of the proposed improved virtual impedance control method for grid-connected inverter with active damper function are verified by simulation.