The Research Of Wind Power System Based On Permanent Magnet Direct Drive

The energy crisis and environmental issues have become a serious challengeencountered in the process of economic development of many countries in the world.Manycountries have to find new green renewable energy as theirs energy strategy. China is in acritical period of urbanization and building a well-off society. Dealing with the relationshipbetween environmental protection and economic development, building a harmonious andbeautiful China are the major historic task of the current period.Wind power is generated by the sun and renewable resource. Global energy supplytension, environment pollution is serious. And wind energy can reduce global energy crisisalso contribute to human environmental protection. Compared with traditional coal-firedpower, hydro-power, wind power industry is advantage, and get the favour of broadmanufacturers and researchers. At first, the wind power system consists of wind turbine,gear box, generator, etc.Due to the gear box has insurmountable large noise, mechanicalstress big shortcoming, permanent magnet direct drive wind power system slowly came tobe the attention of researchers and lead the direction of the wind power technologydevelopment. This article select2MW Z72type permanent magnet direct drivesynchronous wind turbine as the research content, the paper main content are:First, this paper first analyzes the converter’s three kinds of topology structure,and onthe basis of comparing their advantages and disadvantages to choose the dual PWMconverter topology structure as the research emphasis in this paper. Then tells the internalstructure and working principle of D-PMSG.Sets up many mathematical model ofD-PMSG system, such as PMSG,wind turbine shafting, dual PWM converter, the DC link,etc.Second, the space vector modulation (SVPWM) technology and the maximum windenergy capture theory in-depth analysis, and focus on the study of motor side and grid sidedual PWM converter control strategy. Implementation method is: machine side convertercurrent d axis component of0is used to realize the maximum wind energy capture.Network side converter uses a voltage double closed loop control strategy of the inner ring,outer ring current implements the net side current unit power factor control, and be able tokeep the dc side voltage stability.Again, this paper chose the2MW Z72type wind power system as the research focus,first to the main circuit parameters are calculated, and then set in Matlab7.0platform,machine side converter, the net side current transformer simulation model simulation, etc.Finally, based on low voltage through the ability to wind power generation system,carried on the thorough analysis, and put forward the reasonable implementation schemeusing method is: Crowbar circuit in DC side, so that the consumption of overvoltage of extra energy, so as to ensure the normal order of the motor online.