A Fully Self-Synchronized Control for Hybrid Series-Parallel Electronized Power Networks
Zexiong Wei, Yao Sun, Xiaochao Hou, Mei Su
TL;DR
The paper addresses the challenge of self-synchronization in islanded hybrid series-parallel power networks, where traditional parallel and series methods do not directly apply. It proposes a fully decentralized control that combines $P-ω$ droop and φ-ω droop, enabling each inverter module to synchronize using only local information and to balance active and reactive power across the hybrid topology. Through steady-state analysis, it shows that the modules reach a common power-angle equilibrium δ across all modules, with a consistent distribution of $P_{ij}$ and φ_{ij} satisfying the droop conditions. A small-signal stability analysis yields explicit eigenvalue-based conditions for stability and provides design ranges for the droop parameters, supporting robust, scalable operation of hybrid microgrids with distributed inverters.
Abstract
The hybrid series-parallel system is the final form of the power electronics-enabled power system, which combines the advantages of both series and parallel connections. Although self-synchronization of parallel-type and series-type systems is well known, self-synchronization of hybrid systems remains unrevealed. To fill in this gap, a fully self-synchronized control for hybrid series-parallel system is proposed in this paper. Based on the self-synchronization mechanism of power angle in parallel-type system and power factor angle in series-type system, a decentralized control strategy by integration of power droop and power factor angle droop can realize self-synchronization and power balancing of each module in the hybrid system.