Cascaded and parallel multi-converter systems: a review of modeling, nonlinear phenomena analysis and control
Xiongjian Li, Fan Xie, Bo Zhang, Kibok Lee, Huayu Ji, Wenkai DongPurpose
This paper aims to review the stability of cascaded and parallel multi-converter systems (CPMCS) in power-electronics-dominated applications and clarify why their stability should be interpreted as a system-level nonlinear problem shaped by source-load coupling, common-bus interaction, switching dynamics and coordinated control, rather than as a simple aggregation of individually stable converters.
Design/methodology/approach
The review follows a problem-oriented route from observed nonlinear phenomena to modeling, analysis and stabilization. Representative phenomena are interpreted through their governing stability objects, after which modeling methods, analysis criteria and control strategies are compared according to the dynamic information they retain and the stability problem they address.
Findings
The reviewed literature shows that CPMCS stability is governed by the dynamic information retained in modeling, rather than by a universal criterion. Continuous-time reductions capture equilibrium interaction and weak modal coupling, whereas sampled-data and hybrid models are required when switching-period or boundary effects dominate. Impedance formulations offer modular insight into port interaction, but finite-disturbance recovery still requires attraction-domain or energy-region information. A persistent gap remains in linking local margins, orbit degradation and recoverable regions across multi-module, multi-timescale converter networks.
Originality/value
This review synthesizes CPMCS stability studies around how converter coupling leads to nonlinear stability loss. It defines the structural scope of CPMCS, interprets nonlinear phenomena through stability objects, compares models by retained dynamics rather than mathematical form, and relates analysis boundaries to stabilization targets, thereby supporting model, criterion, and control-strategy selection for cascaded and parallel converter architectures.