摘要
本论文主要针对大功率双馈风力发电机的控制策略进行研究,使风电机组达到变速恒频发电的效果。同时介绍了双馈风力发电机系统在低压穿越时的运行模式,并对其运行效果进行仿真分析。
文中通过与其它风力发电机系统的比较,介绍了双馈风力发电机系统的结构特点。并采用双馈发电机的T型等效电路对其运行控制原理进行了分析。双馈发电机可通过控制转子侧转差功率的方式实现定子侧输出功率的有效控制。文中还对双馈发电机变速恒频发电的原理及双馈风力发电机系统的其它部分进行了介绍。
文中通过双馈发电机系统的数学模型对其控制策略进行了设计研究。这是一种基于定子电压定向的转子电流矢量控制的控制方式,可实现双馈发电机输出有功功率、无功功率的独立控制。与定子磁链定向的方式相比,这种方式省略了磁链测量部分。并根据此控制方法,使用Matlab/Simulink软件构建了一个用于1.5MW双馈风力发电机的控制系统,仿真验证了当输出有功功率、无功功率改变时,该控制策略的有效性。
当电网电压出现骤降时,风力发电机需保持并网实现低压穿越,这是对风电机组的新要求。对双馈风力发电机系统而言,低压穿越时会遇到许多问题,目前常用的解决方式是采用主动式Crowbar电路,其作用是在发电机并网的状态下保护转子侧的变流器。文中对不同类型的Crowbar电路进行比较分析,并对其在双馈风力发电机系统中的运行效果进行了仿真研究,仿真中仍采用上述的功率控制策略。
This thesis deals with the control scheme of doubly-fed induction generator (DFIG) in wind power conversion system, which can make power generation in Variable Speed Constant Frequency (VSCF) mode. Furthermore, the operation mode of DFIG system in low voltage ride through (LVRT) condition is investigated and simulated in detail.
The structure characteristic of DFIG system is described by comparing with other kinds of wind generators. The power characteristic of DFIG is analyzed by using the T- type equivalent circuit, which means the stator-side output power of DFIG can be controlled by adjusting the rotor-side slid power. Also the principle of VSCF mode on DFIG is described, and the other parts of DFIG system is introduced briefly.
The control scheme of DFIG system is designed based on its mathematical model, which is a kind of rotor current vector control in stator-voltage-oriented frame, and can control active and reactive output power of DFIG independently. Compared to the stator-flux-oriented frame, this control method doesn't need stator-flux measurement. The control system is simulated by Matlab/Simulink for 1.5MW DFIG. The simulation results show the effectiveness of the control scheme during variations of active power and reactive power.
LVRT is a new and necessary request to wind turbines, which means the generator should keep connecting to the grid when grid voltage sag happens. There are many problems to DFIG system in LVRT operation, and the general answer to these problems is active crowbar circuit, which can protect rotor-side converter and keep generator connecting to the grid during LVRT. The different types of active crowbar circuit are investigated in this thesis, and the operation effect is simulated based on the control scheme mentioned above.
引文
[1]李俊峰,高虎.2008中国风电发展报告[M].北京:中国环境科学出版社,2008.
[2]全国风力机械标准化技术委员会.JB/T 7878-1995风力机术语[S].北京:中国标准出版社,1995.
[3]叶杭冶.风力发电机组的控制技术[M].北京:机械工业出版社,2002.
[4]张崇巍,张兴.PWM整流器及其控制[M].北京:机械工业出版社,2003.
[5]R Pena,J C Clare,and G M Asher.Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation[J].IEEProc Elect Power Appl,1996,143(3):231-241.
[6]Shuhui Li,Sitanshu Sinha.A simulation Analysis of Double-Fed Induction Generator for Wind Energy Conversion Using PSipce[C]//Power Engineering Society General Meeting,Canada,2006:8 pp.
[7]Shuhui Li,Timothy A Haskew.Transient and Steady-State Simulation Study of Decoupled d-q Vector Control in PWM Converter of Variable Speed Wind Turbines[C]//The 33rd Annual Conference of the IEEE Industrial Electronics Society,Taiwan,2007:2079-2086.
[8]S Li,T A Haskew,L Xu.DFIG characteristic and control integration study under decoupled d-q vector control in stator flux oriented frame[C]//The 4th IET Conference on Power Electronics,Machines and Drives.York,UK,2008:391-395.
[9]Texas Instruments Incorporated.Field Orientated Control of 3-Phase AC-Motors[R/OL].http://focus.ti.com.cn/cn/lit/an/bpra073/bpra073.pdf
[10]Andreas Petersson,Lennart Harnefors,Torbjorn Thiringer.Comparison Between Stator-Flux and Grid-Flux-Oriented Rotor Current Control of Doubly-Fed Induction Generators[C]//35th Annual IEEE Power Electronics Specialists Conference,Aachen,Germany,2004:482-486.
[11]L Xu,P Cartwright.Direct active and reactive power control of DFIG for wind energy generation[J].IEEE Trans on Energy Conversion,2006,21(3):750-758.
[12]Noel A Janssens,Guillaume Lambin,Nicolas Bragard.Active Power Control Strategies of DFIG Wind Turbines[C]//IEEE Power Tech 2007,Lausanne,Switzerland,2007:516-521.
[13]Dawei Zhi,Lie Xu.Direct Power Control of DFIG With Constant Switching Frequency and Improved Transient Performance[J].IEEE Trans on Energy Conversion,2007,22(1):110-118.
[14]Dawei Zhi,Lie Xu,John Morrow.Improved Direct Power Control of Doubly-Fed Induction Generator Based Wind Energy System[C]//The IEEE International Electric Machines and Drives Conference,Antalya,Turkey,May,2007:436-441.
[15]F Poitiers,M Machmoum,R Le Doeuff,et al.Control of a Doubly-Fed Induction Generator for Wind Energy Conversion Systems[J].International Journal of Renewable Energy Engineering vol.3,No.2,Aug.2001.
[16]Osama S Ebrahim,Praveen K Jain,Goel Nishith.New Direct Power Control for the Wind-Driven DFIG with Improved Performance[C]// 29th International Telecommunications Energy Conference,Rome,Italy,2007:550-556.
[17]A Petersson.Analysis,Modeling and Control of Doubly-Fed Induction Generators for Wind Turbines[D].Sweden:Chalmers University of Technology,2005.
[18]郭晓明,贺益康,何奔腾.双馈异步风力发电机开关频率恒定的直接功率控制[J].电力系统自动化,2008,32(1):61-65.
[19]邹旭东,赵阳,康勇等.并网型双馈发电机功率控制模式研究[J].大电机技术,2007,(02):71-76.
[20]黄守道,谭健,许(王争),高剑.双馈风力发电机有功、无功的解耦控制[J].电气传动,2008,38(9):7-10.
[21]S Muller,M Deicke,De Doncker,et al.Doubly fed induction generator systems for wind turbines[J].IEEE Industry Applications Magazine,2002,8(3):26-33.
[22]中国电力科学研究院.国家电网风电场接入电网技术规定(试行)[S/OL].http://www.fenglifadian.com/zhengce/339CCJJ1.html
[23]Florin Iov,Anca Daniela Hansen,Poul Sφrensen,et al.Mapping of grid faults and grid codes[R].Denmark:Technical University of Denmark,2007.
[24]I Erlich,M Wilch,C Feltes.Reactive power generation by DFIG based wind farms with AC grid connection[C]// The 12th European Conference on Power Electronics and Applications.Aalborg,Denmark,2007:1-10.
[25]Anca D Hansena,Gabriele Michalke.Fault ride-through capability of DFIG wind turbines[J].Renewable Energy,2007,32(9):1594-1610.
[26]C Abbey,G Joos.Effect of Low Voltage Ride Through(LVRT)Characteristic on Voltage Stability[C]// IEEE Power Engineering Society General Meeting,California,USA,2005:1901- 1907.
[27]Johan Morren,Sjoerd W H de Haan.Ridethrough of Wind Turbines with Doubly-Fed Induction Generator During a Voltage Dip[J].IEEE Transactions on Energy Conversion,2005,20(2):435-441.
[28]Oriol Gomis-Bellmunt,Adri'a Junyent-Ferr'e,Andreas Sumper,et al.Ride-Through Control of a Doubly Fed Induction Generator Under Unbalanced Voltage Sags[J].IEEE Transactions on Energy Conversion,2008,23(4):1036-1045.
[29]G.Joos.Wind Turbine Generator Low Voltage Ride through Requirements and Solutions[C]//2008 IEEE Power and Energy Society General Meeting-Conversion and Delivery of Electrical Energy in the 21st Century,Pennsylvania,USA,2008:1-7.
[30]Chad Abbey,Wei Li,Loic Owatta,Geza Joos.Power Electronic Converter Control Techniques for Improved Low Voltage Ride Through Performance in WTGs[C]// PESC '06.37th IEEE,Power Electronics Specialists Conference,Jeju,South Korea,18-22 June,2006:1-6.
[31]Akhmatov V.Analysis of dynamic behavior of electric power systems with large amount of wind power[D].Denmark:DTU,2003.
[32]耿华,杨耕,崔扬等.并网型风力发电系统的现状与发展[J].东方电气评论,2006,20(2):1-7.
[33]Jean Momeau,Chad Abbey,Geza Joos.Effect of Low Voltage Ride Through Technologies on Wind Farm[C]// 2007 IEEE Canada Electrical Power Conference,Montreal,Canada,25-26 Oct.2007:56-61.
[34]B Palle,M G Simoes,F A Farret.Dynamic Interaction of an Integrated Doubly-Fed Induction Generator and a Fuel Cell Connected to Grid[C]\\Power Electronics Specialists Conference,2005:185-190.
[35]B Palle,M G Simoes.Dynamic Integration of a Grid Connected DFIG Wind Turbine with a Fuel Cell[C]\\ Industry Applications Conference,2007.42nd IAS Annual Meeting.Conference Record of the 2007 IEEE,2007:650-655.
[36]K Ghedamsi,D Aouzellag,E M Berkouk.Control of wind generator associated to a flywheel energy storage system[J].Renewable Energy,2008,33(9):2145-2156.
[37]D Aouzellag,K Ghedamsi,E M Berkouk.Network power flux control of a wind generator[J].Renewable Energy,2009,34(3):615-622.
[38]Marta Molinas,Jon Are Suul,Tore Undeland.A Simple Method for Analytical Evaluation of LVRT in Wind Energy for Induction Generators with STATCOM or SVC[C]// 2007 European Conference on Power Electronics and Applications,Aalborg,Denmark,September 2-5,2007:1-10.
[39]Ion Etxeberria-Otadui,Unai Viscarret,Izaskun Zamakona,et al.Improved STATCOM operation under transient disturbances for wind power applications[C]\\ 2007 European Conference on Power Electronics and Applications,Aalborg,Denmark,September 2-5,2007:1-10.
[40]Jouko Niiranen.Second Generation Active Crowbar for Doubly Fed Generators[C]\\ Nordic Wind Power Conference,Espoo,Finland,2006:1-4.
[41]Andreas Dittrich,Alexander Stoev.Comparison of Fault Ride Through Strategies for Wind Turbines with DFIM Generators[C]//2005 European Conference on Power Electronics and Applications,Dresden,Germany,2006:P.1-P.8.
[42]姚骏,廖勇.基于Crowbar保护控制的交流励磁风电系统运行分析[J].电力系统自动化,2007,31(23):79-83.
[43]梁亮,李建林,许洪华.双馈感应式风力发电系统低电压穿越研究[J].电力电子技术,2008,42(3):19-21.
[44]王伟,孙明冬,朱晓东.双馈式风力发电机低电压穿越技术分析[J].电力系统自动化,2007,31(23):84-89.
[45]蒋雪冬,赵舫.应对电网电压骤降的双馈感应风力发电机Crowbar控制策略[J].电网技术,2008,32(12):84-89.
[46]Lennart Harnefors,Hans-Peter Nee.A General Algorithm for Speed and Position Estimation of AC Motors[J].IEEE Transactions on Industrial Electronics,2000,47(1):77-83.
[47]Karl Johan Astrom,Bjorn Wittenmark.Computer-controlled systems,theory and design[M].Prentice Hall International Editions,3rd Edition,1997.
[48]卞松江.变速恒频风力发电关键技术研究,浙江大学博士学位论文,2003.6.
[49]杨淑英.双馈型风力发电变流器及其控制,合肥工业大学博士论文,2007.10.
[50]李建林,许洪华等.风力发电中的电力电子变流技术[M].北京:机械工业出版社,2008.
