Research On Coordinated Control Method For Microsources In Microgrid

Microgrid provides an effective technical way for scale application of new energy grid connection generation. And the use of Microgrid technology improve the complementarities of different types of distributed generation and reduce the impact of distributed power on the safe operation of power grid, which is helpful to achieve the convenient connection and maximize the use of renewable energy, in line with China’s new energy generation and sustainable development strategy requirements. With the development of Microgrid technology, it is urgently needed to solve many problems including coordinating control of microsources, Microgrid operation mode switching and so on. Therefore, this paper will study based on the perspective of Microgrid control system to achieve the large-scale applications of Microgrid technology.First, this paper expounds the major overall control strategy of Microgrid and the control method of microsource inverter interface side, and analyzes the corresponding application scopes, advantages and disadvantages of various control strategy; Then, this paper proposes a power optimal decentralized coordination control method of microgrid based on P-f/Q-V droop control. Aiming at the unreasonable Microgrid power distribution problem, this paper analyzes the shortcomings of traditional droop control P-f/Q-U, proposes the p-f/Q-v droop control and establishes the mathematical model for Microgrid. Under partially decentralized coordinated control, voltage and frequency are within the normal range based on reasonable power distribution of Microsources. The simulation results show that the distribution of reactive power has been significantly optimized by the premise of active power being unaffected and the Microgrid is always in steady state. Finally, the integrated control strategy combining equal control and master-slave control is designed. Aiming at the problems of Microgrid operation mode conversion, this paper gives the Microgrid operation mode conversion conditions in line with China’s national conditions. The smooth and controllable switch is achieved and the surge impact to Microgrid is reduced by adopting the integrated control strategy combining equal control and master-slave control and the smooth switching control with controller state following. Simulations verify the feasibility of the control strategy.