345 / 2021-11-10 11:50:18

Cluster Resonance Suppression Strategy of Grid-Connected Inverter System based on Hybrid Impedance Shaping

Grid-connected inverter; Impedance shaping ;Weak grid

Power electronics technology and application > Modeling, simulation and control in power electronics

The harmonic stability of the multi-paralleled inverter system is essential under weak grid conditions. The grid side impedance may trigger the resonance phenomenon of the commonly used LCL filter. However, previous active damping strategies based on capacitor current feedback require extra sensors, resulting in higher economic costs. This paper proposes a scheme of hybrid impedance shaping for cluster resonance suppression of the paralleled grid-connected inverter system. From the perspective of the single inverter, the proposed method adopts sensorless active damping achieved by capacitor current estimation. From the standpoint of the paralleled inverter, the proposed scheme utilized the passive resistor with the switch to enhance the passivity of the system. Both of them reshape the impedances and improve the stability of the whole system. Theoretical analyses and experimental results confirm the effectiveness of the proposed cluster resonance suppression strategy based on hybrid impedance shaping.