風(fēng)力發(fā)電機(jī)外文文獻(xiàn)翻譯--小規(guī)模發(fā)電pmsg風(fēng)力渦輪轉(zhuǎn)換器矢量控制（英文）

1、 1Abstract--The purpose of this paper is to find an innovative, high efficiency, practical and low cost control system structure with an optimized control strategy for small-scale grid-connected wind turbine with dir

2、ect-driven permanent magnet synchronous generator (PMSG). This research adopts the sensorless vector control strategy based on phase-locked loop (PLL) for PMSG control, and the grid-side inverter control strategy is b

3、ased on the single-phase PLL. The simulation demonstrates that the sensorless control strategy and single-phase grid-side inverter control strategy are practical solutions for grid-connected PMSG wind turbines, and t

4、hey can provide both generator speed control for optimized wind power tracking and good power quality control for electricity delivered to the grid. The designed system offers many unique advantages, including simple

5、topology, optimized control strategy, cost-effective and fast respond to grid failures. Index Terms--Maximum power point tracking (MPPT), PMSG, pulse-width modulation (PWM) converter, speed control, variable-speed wi

6、nd turbine. I. INTRODUCTION n recent years, great attention has been paid on renewable energy sources, such as wind and solar energy. Wind energy is the most popular renewable energy source due to its relatively low

7、cost. The overall system cost can be further reduced by optimal control of high efficiency power electronic converters to extract maximum power in accordance with atmospheric conditions [11]. The wind energy conversi

8、on system based on permanent magnet synchronous generator (PMSG) is one of the most favorable and reliable methods of power generation. Reliability of variable-speed direct-driven PMSG wind turbines can be improved s

9、ignificantly comparing to doubly- fed induction generator (DFIG) wind turbines with gearboxes. Noise, power loss, additional cost, and potential mechanical failure are typical problems for a DFIG wind turbine because

10、of the existence of a gearbox. The use of direct-driven PMSG could solve these problems. Moreover, low voltage ride through (LVRT) is also a big issue for DFIG because the This work was supported in part by the specia

11、l funds from Beijing Municipal Education Commission. Chunxue Wen, Guojie Lu, Peng Wang and Zhengxi Li are with the Power Electronics and Motor Drivers Engineering Research Centre, North China University of Technology

12、,Beijing,China(e-mail: wenchx1980@yahoo.com.cn, lugod307@163.com, catdapeng2008@163.com, lzx@ncut.edu.cn). Xiongwei Liu and Zaiming Fan are with the School of Computing, Engineering and Physical Sciences, University o

13、f Central Lancashire, Preston, PR1 2HE, UK (e-mail: xliu9@uclan.ac.uk, zmfan@uclan.ac.uk) electromagnetic relationship between the stator and the rotor is more complex than PMSG. Therefore, it’s more difficult for DFI

14、G to solve LVRT problem safely and reliably. In a variable-speed PMSG system, vector control approach is often used to achieve nearly decoupled active and reactive power control on the grid-side inverter which is a cu

15、rrent regulated voltage source inverter. In this way, the power converter maintains the DC-link voltage and improves the power factor of the system [1], [7], [10]. Different control methods for maximum power point tr

16、acking (MPPT) in variable-speed wind turbine generators have been discussed in [2], [4], [7]. This research adopts the sensorless vector control strategy based on phase-locked loop (PLL) for PMSG control [2]. The me

17、thod requires only one active switching device, i.e. insulated-gate bipolar transistor (IGBT), which is used to control the generator torque and speed so as to extract maximum wind power. It is a simple topology and l

18、ow cost solution for a small-scale wind turbine because of the sensorless vector control strategy. The grid-side inverter control strategy is based on the single-phase PLL, which applies a control method in Direct-Qu

19、adrature (DQ) rotating frame to single-phase inverter and achieves superior steady state and dynamic performance [6]. For small-scale wind turbine, single-phase power supply to consumers is popular. There are many co

20、ntrol methods for single-phase inverter, such as PI controller, quasi-PR controller, etc. [5]. However, these methods can’t decouple the active power and reactive power so as to have good power control performance. S

21、ingle-phase PLL method based on DQ rotating frame can well solve this problem. On the other hand, encoders are vulnerable components for wind turbines, particularly for small wind turbines, because small wind turbine

22、s experience severer vibrations than their large counterparts. The sensorless vector control opts out the encoders, and therefore the reliability of wind turbines is much improved. For these reasons, the sensorless ve

23、ctor control and single-phase PLL method have their unique advantages for small-scale wind turbines. This paper is structured further in following three sections. In section II, the principle of the full power back-t

24、o-back PWM converter is introduced. Then the vector control of small-scale grid-connected wind power system including sensorless control, vector control of PMSG, single-phase PLL, vector control of grid-side inverter

25、 are described in section III. Finally, in section IV, the simulation results and conclusion are given. Vector control strategy for small-scale grid- connected PMSG wind turbine converter Chunxue Wen, Guojie Lu, Peng W

26、ang, Zhengxi Li Member IEEE, Xiongwei Liu Member IEEE, Zaiming Fan Student Member IEEE I3The actual rotor position of PMSG is indicated in the D-Q coordinate system. The estimated location for ∧ θ is the d q∧ ∧ ?coordi

27、nate system, αβ is the stationary coordinate system, as shown in Fig. 3. As the rotor position of PMSG is estimated rather than measured in the sensorless vector control system, there exists an error θ Δbetween the ac

28、tual rotor position θ and the estimated location ∧ θ . At the same time, the back- EMF (electromotive force) generated by the rotor permanent magnets generates two d-axis and q-axis components in the estimated rotor p

29、osition orientation coordinates, which are expressed as sd e∧and sq e∧ respectively. Conventional PI controller can achieve zero error control, i.e. sd e∧or θ Δcan be adjusted to zero value. The PLL sensorless vector

30、control schematic diagram is shown in Fig. 4, and the value of sd e∧and sq e∧can be obtained from (1). sdsd s sd d q sq sdsqsq s sq q d sd sqdi u R i L L i e dt di u R i L L i e dtωω∧ ∧ ∧∧ ∧ ∧? = + ? ? ? ? ? ? = + + +

31、? ?(1) θ θ ?θ Δαβdd ?q q ?Fig. 3. Presumed rotating coordinate system sK K i P + s1 θ Δ ω ? θ ? θFig. 4. Principle of PLL based sensorless vector control If we ignore the current differential items in (1), then we ha

32、ve sd s sd q sq sdsq sq s sq d sd? ? ? ? ? arctan( ) arctan( ) ? ? ? ? ?u R i L i ee u R i L iω θ ω? + Δ = ? = ? ? ?(2) where sd u , sq u , sd iand sq iare the d, q-axis components of the output voltage and current

33、of the generator stator; d L q L and s R are the inductance and resistance of the stator; ω is the generator electrical angular velocity of the generator; “ ∧ “ indicates estimated value. Block diagram of sensorless

34、 vector control based on digital PLL is shown in Fig. 5. The back-EMF (electromotive force) value of the estimated rotating coordinates can be obtained by calculating the three-phase voltages and currents of the PMSG

35、 stator. The calculated angle difference θ Δcan be used to estimate the angular velocity through the PI controller. Then the value of the estimated angle can be obtained by integral element. Generally, the speed has

36、considerable fluctuations using this method. Therefore it will achieve a better estimation by adding a low-pass filter (LPF), as shown in Fig. 5. filters us iEMF calculationd e∧q e∧ divider arctangentintegrator PI co

37、ntrollerθ ΔLPFθ∧ω∧Fig. 5. Block diagram of sensorless vector control based on digital PLL B. Vector control of PMSG In order to study the torque control of PMSG, it is necessary to establish a mathematical model. Beca

38、use q-axis leads d-axis 90° in the D-Q coordinate system, the generator voltage equation can be expressed as [8]: sd sd s sd d sq sqsqsq sq q d sddi u R i L L i dt di u Ri L L i dtωω ωψ? = + ? ? ? ? ? = + + + ? ?(

39、3) The significance of various physical quantities in (3) is the same as in (1). The generator electromagnetic torque equation can be expressed as: 3 3 ( ) 2 2 e sq d q sd sq T p i p L L i i ψ = + ?(4) where p is th

40、e number of generator pole pairs, and ψ is the magnetic flux. Based on the above mathematical model, the sensorless vector control program of PMSG is established, and its control block diagram is shown in Fig. 6. * ω

41、ω ? θ ?* sd i * sq isd ? i sq ? i* sd ? u * sq ? usa i sb iIpark IclarkPark ClarkFig. 6. Sensorless vector control block diagram of PMSG Generator rotor position and speed which are estimated by sensorless algorithm ca