Stability Analysis of Power Converter-Based Constant Power Load With Reduced-Order Model

Abstract

The negative incremental resistive feature is one characteristic of power electronics-based constant power load, which may cause system instability. However, the stability assessment of such a system is not easy and the computation burden is usually heavy due to the complexity of the models. With this consideration, a simplified model using Jordan continued-fraction expansion is proposed to reduce the model complexity while the accuracy can be maintained entire the whole frequency range. Moreover, this paper thoroughly analyzes the impact of different control elements and their parameters of three-phase converter-based constant power load on system stability based on the analysis of the reduced-order impedance model. The parameter sensitivity analysis is carried out to reveal the influence of different parameters on the system stability. Simulation and experimental results are provided to verify the effectiveness of the reduced-order model and the theocratical analysis.