14. Distributed Control Strategy for Hybrid Series–Parallel Microgrid

Hybrid series–parallel microgrid is becoming a new emerging structure to integrate multiple low-voltage power sources. This chapter briefly compares and analyzes the decentralized power control strategy of parallel microgrid and series microgrid, and try to explore a unified decentralized synchronous control for hybrid series–parallel microgrid. A globally distributed control strategy is presented to implement power sharing control in hybrid series–parallel microgrid under both resistive-inductive (RL) and resistive-capacitive (RC) load, where a sign function is introduced to automatically match load characteristic. Active power and reactive power regulators without frequency drop are developed, and low-bandwidth communication network is employed to support power management and improve system redundancy. Furthermore, small-signal model of hybrid series–parallel microgrid with RL load and RC load is established. Also, small-signal stability and dynamic performance of the proposed distributed control strategy is investigated. Simulation results show that the globally distributed control strategy is able to implement desirable power sharing under different load types with superior control performance. Also, the proposed control strategy is able to improve system redundancy and support plug-and-play operation of microgrid.