Research On Control Strategy Of The Direct-drive Permanent Magnet Wind Turbine Using Vanadium Redox Flow Battery Energy Storage System

As a kind of new renewable energy, wind energy is paid great attentions by windenergy research institutions in the world.because high conversion efficiency, and flexiblepower control, and high reliability, direct drive wind turbine composed an importantresearch direction following the double-fed wind turbine power technology. This paperresearch on modeling of the direct-drive permanent magnet unit, the maximum windenergy capture, control strategy issues of converter and energy storage system of vanadiumredox flow battery as the energy storage elements of the research, and theoretical researchverified by simulation is correctness and feasibility. The main content of this paper asfollows:This paper describes the mathematical model of the direct-drive permanent magnetgenerator system,including: wind speed model, wind turbine model, model of permanentmagnet motor, model of converter. Simulation models provide a theoretical basis fordesigning control strategy of direct-drive permanent magnet generator in the later chapters.chapter three describes basic principles of vanadium redox flow battery, and elaborateon its internal structure. Make a corresponding equivalent based on the electrochemicalcharacteristics and physical properties of the vanadium redox flow battery, establish anequivalent circuit model,and establish simulation model of the vanadium redox flowbattery. simulation test the charge and discharge characteristics of vanadium redox flowbattery，and lay the foundation for the energy storage system structure simulation.The fourth chapter of this thesis introduce control strategy of converter of direct-drivepermanent magnet generator system,the system by voltage feed forward compensation decoupling control, Build a direct-drive permanent magnet generator system simulationmodel in Matlab. simulation results show that the output power of the system is able toachieve the tracking control of the wind speed, but stabilize ineffective.The output power of direct-drive permanent magnet generator system is not ideal,it isnecessary to find a better way to solve the output power fluctuations. the vanadium redoxflow battery energy storage system connected to direct-drive permanent magnet generatorsystem in chapter five,and verify that the energy storage system can smooth the output ofactive power by studying control strategy and performance of energy storage system.Simulation results show that the energy storage system can smooth active power output.