Harmonic resonance assessment of multiple paralleled grid-connected inverters system

This paper presents an eigenvalue-based impedance stability analytical method of multiple paralleled grid-connected inverter system. Different from the conventional impedance-based stability criterion, this work first built the state-space model of paralleled grid-connected inverters. On the basis of this, a bridge between the state-space-based modelling and impedance-based stability criterion is presented. The proposed method is able to perform stability assessment locally at the connection points of the component. Meanwhile, the eigenvalue-based sensitivity analysis is adopted to identify the root causes of harmonic resonance, which thus combines the advanced merits of the two worlds, and enhances the analytical ability to perform a harmonic resonance assessment. Simulations and experimental results are provided to demonstrate the effectiveness of the proposed method.