Research On Three-Level Converter Technology Of Permanent Magnet Direct Drive Wind Power System

Energy and the environment are the pressing issues,facing the survival and developmentof humanity today, while wind power as a clean, non-polluting energy, and gradually getpeople’s attention.The wind power industry is conducive to the people’s livelihood andsocial harmony and stability to the development of the industry.Permanent magnetdirect-drive synchronous generator(PMSG)which eliminates the gearbox and reduces themaintenace has become an important research subject besides the Double-fed inductorgenerator.The full scale power converter is a key part of the wind power system.In thetraditional wind power system the two-level converter is mostly adopted.With theincreasing of unit capacity,the full power three-level converter with switch voltage stressreducing is suitable to a direct drive wind power system.In this paper, a new topology using diode rectifier, three-level boost (TLB) and NPC fullpower converter has been proposed.It also analyzes the dynamic and operatingcharacteristics of the wind turbine and studies the control strategy which takes the methodto track maximum power point(MPPT) under the rated wind speed.This paper analyzes PMSG mathematical model and dc-link three level boost(TLB)converter has been studied with which the MPPT and netural point voltage balance havebeen achieved.This paper also analyzes the grid side of the three-level invertermathematical model and the three-level SVPWM modulation principle.Through the gridvoltage-oriented vector control, controling the reactive power current,realizing reactivepower regulated independently.Finally, based on Matlab/Simulink to build permanent magnet direct-drive wind powersystem simulation experiment to test the three-level boost converter and the network sideconverter control strategy, providing further research and foundation.