TWI309694B - Grid-connected wind generation system and its maximum-power-extraction control method - Google Patents

Description

1309694 IX. Description of the Invention: [Technical Field] The present invention relates to the field of automatic control, power electronics, DC/AC converter technology, and energy technology, although the technical field involved is extensive, but the present invention It is mainly applied to wind power generation in parallel with the mains, and to improve the technology of the current maximum power capture control. • [Prior Art] Although the advancement of technology has brought many conveniences to human life, many problems have arisen from f, with the reduction of fossil fuel stocks, the ambiguity of energy, the awareness of energy crisis, and environmental protection. In addition to reducing the waste of existing energy use, the development of new energy sources is even more urgent. The new energy has little impact on the environment, and the air, water or waste pollution is in the air. The behavior is less significant, and the more important β# energy development is more reusable and has the characteristics of sustainable development. Then: «(R_ableEnergy) is more important in new energy, including solar energy, wind power, biomass energy, The mantle, the scorpion...the sea year and the non-pigmenting water power, etc. can be used forever, ', and the energy used by the shell. In addition, it is estimated that to the west 2 ^ is. V 0 years, the world's wind power will provide 100% In the case of Taiwan, the power generation capacity of the Republic of China was 92,400 watts [2]. It can be seen that wind power systems are booming today. wind power The reasons for the emphasis - 1309694 mainly include (1) mature technology development, (2) reduced pollution emissions, (3) financial incentives provided by the government, and (4) short construction time; but wind power also has initial investment costs. High and unstable wind supply. Using the wind power system, the Maximum-Power-Extraction Algorithm (MPEA) is an indispensable core technology. At present, many domestic and foreign experts and scholars invest in the maximum power of wind power. The research can be divided into the following three control modes: • The first is the Tip-Speed Ratio control, which uses the actual wind speed to calculate the optimal speed required for the wind turbine to operate. The speed is used to achieve the optimal wing speed ratio and maximum power, but the main disadvantage is that the cost is high, and the anemometer and the generator tachometer are required. The second is the power signal feedback control, which needs to be established in advance. The power curve is to provide the maximum power to follow the target. This method belongs to the offline measurement mode, and there is uncertainty in the actual operation; The three are incremental search for maximum power control, and the Lilu series judges that the operating point is incremented to the maximum power. This method takes time to search and cannot grasp the maximum power point [3]. In terms of the latest research report, the variable speed is used. Control::: Provides a way to control the voltage compared to the traditional fixed voltage, 9:11% of the wind power generation [4], but its maximum power curve must first be obtained through the appropriate:: However, this practice is applied in practice. The difficulty is doubled. 1^ The processor records the maximum power curve of the wind power system as 8 1309694. One of the solutions is m, the maximum power operation point is set and the stored data is updated, and the maximum power curve can be made. Gong (4) follows the goal, however, it is applied to the actual wind power energy conversion system. Under the condition that the wind speed changes very quickly, the time required for the maximum power operation point of the E set is too long, and the time is saved to the transient state. Negative material, not the maximum power point, can't get better performance in the real % * brother. The maximum power capture control method of the present invention is based on the third control method described above—incrementally searching for the maximum power control, and cutting into the Maximum-Power Differential Speed (MPDS) control to save power to the maximum. The search time of the power point is the purpose of instantaneously achieving the maximum power extraction under the rapidly changing wind conditions such as the rising or falling wind speed, and the maximum power extraction control method of the present invention belongs to the method of variable speed control, which is comparable to the conventional constant voltage. The control method increases the power drawn. In summary, the advantages of the control method proposed by the present invention are mainly as follows: first point, reduce φ, use anemometer and generator tachometer to reduce system cost; second point, above maximum starting wind speed, lower than maximum cutoff wind speed Between the wind speed changes, the maximum power draw of wind power can be instantly realized, and the maximum output power can be adjusted instantly to change the wind speed; combining the above two points to solve the shortcomings of the current wind power energy extraction system can be applied In the actual wind power conversion system, this is the innovation prospect of the control method of the invention. In order to make the wind power system stable power supply and unit power factor 1309694 • The sub-controller has been widely used in the industry because of its simple structure, easy design and low cost, but for systems with uncertain dynamics, proportional integral derivative control But it does not provide perfect performance. Computational torque control is beneficial: shoulders, except for some or all of the nonlinear terms in the linear equation to obtain the unity power factor, the present invention uses a microprocessor to control the output current of the variable flow, generally solving When controlling problems, they often encounter parameter changes and various uncertainties. There are various control theories in the control field, such as Proportional-Integral-Derivative (PID) control [5] ' or Modern control theory using complex equations, such as calculated torque control (c〇mputed Torque Control), is designed to make the behavior of the system conform to the design requirements of system parameters and various external disturbances. Proportion, points and micro

Sexualized equations Loop control characteristics. Non-line! The theory developed by the development of life, the shortcoming is the lack of m in the time

1309694 Adaptive algorithm [11] in order to reduce the control tremor phenomenon, the invention is applied to the current control of the full-bridge converter, in order to achieve the effect of grid connection of unit power. Remarks: References [1] P. Fairley, ^Steady as she blows; 5 IEEE Spectrum, vol. 40, no. 8, pp. 35-39, 2003.

[2] Chen Wenshu, Renewable Energy, Energy Bureau of the Ministry of Economics, Energy Report, July 2004 issue. [3] K. Tan and S. Islam, ^Optimum control strategies in energy conversion of PMSG wind turbine system without mechanical sensors, ^ IEEE Trans. Energy Conversion, vol. 19, pp. 392-399, 2004.

[4] Q. Wang and L. Chang, wAn intelligent maximum power extraction algorithm for inverter-based variable speed wind turbine systems, IEEE Trans. Energy Conversion,, vol. 19, pp. 1242-1249, 2004.

[5] K. J. Astrom and T. Hagglund, PID Controller: Theory, Design, and Tuning. Research Triangle Park, NC: ISA, 1995.

[6] J. C. Hung, “Total invariant VSC for linear and nonlinear systems/5 A seminar given at Harbin Institute of Technology, Harbin, China, Dec. 1996; Hunan University Changsha, China,

Dec. 1996. 11 1309694 [7] Κ. Κ. Shyu and J. C. Hung, 'Totally invariant variable structure control systems, IEEE Conf. Ind. Electron. Contr. Instrument., vol. 3, pp. 1119-1123, 1997.

[8] Κ. K. Shyu, JY Hung, and JC Hung, 'Total sliding mode trajectory control of robotic manipulators, M IEEE Conf. Ind. Electron. Contr. Instrument.,\o\. 3, pp. 1062-1066 , 1999.

[9] J. J. E. Slotine and W. Li, Applied Nonlinear Control. Englewood

Cliffs, NJ: Prentice-Hall, 1991.

[10] K. J. Astrom and B. Wittenmark, Adaptive Control. New York: Addison-Wesley, 1995.

[11] R. J. Wai and Κ. M. Lin, “Robust decoupled control of direct field-driven induction motor drive, IEEE Trans. Ind. Electron., vol. 52, no. 3, pp. 837-854, 2005.

[12] S. Morimoto, H. Nakayama, M. Sanada, and Y. Takeda, uSensorless output maximization control for variable-speed wind generation system using IPMSG, 55 IEEE Trans. Industry Applications, vol. 41, pp. 60-67 , 2005.

[13] A. M. Knight and G. E. Peters, “Simple wind energy controller for an expanded operating range/5 IEEE Trans. Energy Conversion, vol. 20, pp. 459-466, 2005.

[14] B. K. Bose, Power Electronics and AC Drives. New Jersey: 12 1309694

Prentice Hall, 1986.

[15] R. J. Wai, C. M. Lin, and G. F. Hsu, ''Adaptive fuzzy sliding-mode control for electrical servo Fuzzy Sets and

Systems, vol. 143, pp. 295-310, 2004. [Invention] The overall architecture of the grid-connected wind power generation system and its maximum power capture control method disclosed in the present invention is as shown in FIG. The blade 101, the permanent magnet synchronous generator 102, the rectifier 1〇3, the filter 1〇4, the full bridge converter 1〇5, the transformer 106, the mains 107, and the system control unit 108, wherein the system control unit 1〇8 is The frequency detector 1〇9, the maximum power capture controller 110, the phase detector 111, the current controller U2 of the converter, and the drive circuit 113 are composed. The maximum power extraction control method proposed by the invention utilizes the grid-connected current peak command calculated by the maximum power capture controller 11〇 to adjust the output power, indirectly controls the generator speed, and makes the wind speed change The system remains operating at the maximum power point. For wind power generation systems, the wind energy extraction mechanism is the fan blade 101. First, the wing end speed ratio γ of the fan blade is defined as follows: γ V (1) where r(m), %(rad/s), and v(m/ s) respectively indicates the radius of the fan blade, the rotational speed of the generator shaft, and the wind speed. In addition, the power factor of wind power generation is a function of the wing end speed ratio cy=/g(r), and different wind turbines have different work 13 1309694 rate coefficient and wing end speed ratio correspondence, and the wind power generation system used in the present invention The power coefficient is shown in Figure 2. When the wing end speed ratio is /=5.09, the maximum power factor occurrence is (^=0.42, according to the method of numerical fitting (Curve Fitting), the correspondence between the two It is represented by the following approximate function [12]: J(1.12/-2.8)exp(-0.38^), />2.5 C,1 0 ,γ<1.5 (2)

Where exp(·) represents an exponential function. The mechanical power generated by the generator; „(w) is proportional to the air density p(kg/m3), the blade rotation area j(m2), the power factor and the cube of the wind speed. The mechanical power can be expressed as:

Pm=Q.5PAC〆(3) The maximum power extraction control method proposed by the present invention belongs to variable voltage control/changeable wind turbine speed, so that the wing end speed ratio is maintained at about 5.09, and the maximum is generated at this time. Power extraction, efficient use of wind resources. Next, the dynamic characteristics of the permanent magnet synchronous generator are analyzed. The mechanical torque rw(Nm) and the electrical torque re(Nm) of the wind turbine can be expressed as follows: T — Pm Lm - (4) Te=^ (5 Where _Pe(w) is the electrical power output by the wind power system, <ye(rad/s) is the electrical angular frequency, and the electrical angular frequency can be expressed as: 弋二(尸/2)1 (6) 14 1309694 where p is the number of poles of the stator winding of the generator. Since the electrical angle frequency of the generator and the rotational speed of the generator shaft are linear (6), the frequency detector 109 shown in FIG. 1 is used to measure the output voltage of the first end of the permanent magnet synchronous generator & The relative voltage signal of the output voltage A of the second end of the magnetic synchronous generator, due to the relationship between the rotational speed of the permanent magnet synchronous generator 102 and its power generation voltage, can be easily obtained by the mechanical tachometer without the need of a mechanical tachometer. The maximum power draws the input signal of the controller and adjusts the output power of the full-bridge converter to achieve the advantages of sensorless control. In addition, consider that the stator winding is a multi-pole permanent magnet synchronous generator, and its mechanical equation can be expressed as:

Tm~iTe —Βω„ or

(7)

Where /(Nm/Oad/s2) is the generator rotor inertia and 5 (Nm/(rad/s)) is the generator friction coefficient. The torque generated by the permanent magnet synchronous generator 102 minus the difference between the electric torque and the friction torque of the generator, and the torque required to increase or decrease the speed of the wind turbine, and the characteristics of the equation are used to adjust the full bridge converter. The output power of the device, indirectly controlling the electrical torque to control the speed to achieve the wing end speed ratio is maintained at 5.09, achieving maximum power operation. The AC power generated by the permanent magnet synchronous generator 102 is rectified by the rectifier 1〇3, and then the DC power source is taken out, and after passing through the filter 104, the post-stage full-bridge converter 105 is used, and the rectifier 103 includes a power semiconductor component. The rectifier device and the rectifier capacitor having the AC/DC power conversion function are generally referred to as an active rectifier composed of a power semiconductor switch or a passive rectifier formed by a diode bridge.

1309694, the rectifier capacitor cr is used to filter the rectified low-frequency voltage chopping, and the filter 104 is composed of a filter inductor Zy and a filter capacitor for filtering the rear-stage full-bridge converter 105, the power semiconductor switch The high-frequency current chopping caused by the switching and the voltage chopping twice the frequency of the mains voltage, since the electric energy is the serial type 'and the functions of the rectifier 103 and the filter 104, the electric power outputted by the wind power generation system can be expressed as a direct current voltage. The product of the DC current is as follows: 弋(8) where vr(V) and ((A) represent the rectifier output voltage and the rectifier output current respectively. The post-stage full-bridge converter 105 is four power semiconductor switches and full bridge The converter inductor is composed of a unipolar (unipolar) voltage switching method in the Sinusoidal Pulse-Width-Modulation (SPWM) technology to control the grid-connected current ^(Arms), by variable current The drive circuit 113 of the full-bridge converter 105 modulates the four power semiconductor switches of the full-bridge converter 105. To facilitate analysis and simplify the derivation of the state space equation, this paper assumes (1) full-bridge converter The equivalent internal resistance of sense 4 is small, so it is neglected; (2) assuming that the power switch is an ideal component, the conduction loss and switching loss of the switch are zero; (3) ignoring the reaction delay time of the switch on and off; 4) The switching frequency of the switch is much larger than the natural frequency of the system. Therefore, the control signal and the input/output voltage can be regarded as fixed values during a switching cycle. Therefore, the full-bridge converter model can be simplified as follows. :

~l<d<\ (9)

(12) 1309694 where V; is the filter output voltage, V. For grid-connected voltage, vw is the interference when the analog load changes, and ί/ is the duty cycle of the full-bridge converter. For the current controller 112 of the converter, this paper uses Adaptive Total Sliding-Mode Control (ATSMC) to achieve the purpose of integrating the unit power into the network and reducing the impact of load changes and external interference. First, define the output grid-connected current error (e) as follows: e = i〇~l〇 (10) where i·. For the grid-connected current command', it can be further expressed as: h = \peak Sin(6i/) (u) where ω:2;τ/ is the electrical frequency of the commercial power 107 is the electrical frequency of the mains 1〇7. Figure! The phase anger detector m is used to detect the mains phase (4) and (4) (10) to facilitate the goal of grid integration of the unit. Then define the sliding flat as follows: t , (t) = e(t) - e(0) + a ^β{τ)άτ where e(〇) is the initial 妗σ value of the grid-connected current error e(7), or is one Positive constant. The adaptive global sliding mode control can be divided into two parts: the first part is the performance planning of the system. This method is mainly based on the system performance obtained in the Ming Dynasty and is attributed to it. Brother expects u, η . , j 丞 丞 core design (Baseline

Model Design) 4; the second part is

The construction of the Controller) element, that is, the generation of the controller (the interference voltage caused by the change of the Curbmg load and the disturbance effect of the system parameter change and prediction, so that it can completely be fully dynamic); The third part is development: the system w-performance algorithm of the basic model design (Adaptive 17 1309694)

Observation Design)^, estimates the upper bound of the total uncertainty of the set to avoid the control tremor caused by improper selection of the upper bound of the constraint controller. Assume that the full-bridge converter shown in equation (9) adopts adaptive global sliding mode control. The various parts of the controller are designed as shown in equations (13) to (15), and the adaptive algorithm is developed as equation (16). ) shown 'the stability of the system will be guaranteed. d ~ db+dc (13) ~ββ)ννι,η (Η) dc ~ - ~Lo nu(t)sgn(sg(t))/vi n (15) u{t) =Μ/λ (16) Where sgn(.) is a symbolic function, |.| is an absolute value function, and \ and eve are positive values, and % and /^ respectively represent the inductance of a full-bridge converter. And the normal value of the filter output voltage v,. According to the analysis of Lyapunov stability theory [9,10], the duty cycle of the full-bridge converter outputted by the current controller 112 of the converter is designed as equation (13), and the grid current error e will converge to zero and the stability of the full bridge converter 105 will be guaranteed. The maximum power capture controller 110 is configured to generate a grid-connected current peak command to control the electrical power outputted by the wind power generation system, and indirectly control the electrical torque to control the rotational speed to achieve a wing end speed ratio of 5.09 to achieve maximum power capture. The flow of the maximum power capture controller 110 is shown in Figure 3, which includes two control rules, namely Maximum-Power Error Driven (MPED) control and Maximum-Power Differential Speed (Maximum-Power Differential Speed, MPDS) control, the sampling time of this control flow is △ & 18 1309694 First consider the maximum power error drive control, the output of this controller is the maximum power error drive control index; the electrical power change of the grid-connected wind power system is defined as: ep(n) = Pe(n)-Pe(n- \) (17) where "the number of controls for the maximum power capture controller 110. According to formula (17), the positive and negative sign of electric power change can be calculated, and the positive and negative signs of the previous maximum power error drive control index Fm^O-Ι) can be used to calculate the maximum power error drive control index provided. ) is as follows: VMPED(n) = KPsignVsign (18) where A: is the length used to adjust the indicator. When the output power increases, the symbol calculated by the last maximum power error drive control is maintained; when the output power is decreased, the sign calculated by the last maximum power error drive control is reversed, that is, the direction of the grid-connected current peak command is changed, The maximum power point is incremented. When the wind condition is continuously increasing or fixed, Equation (18) ensures that the electrical power is increased to the maximum power output; but when the wind speed is reduced, the output electrical power is bound to continue to decrease, and the grid-connected current threshold command needs to be greatly reduced. The control method is to reduce the grid-connected current peak command at a fixed step distance. The result of the reaction speed being too slow will cause the speed to decrease rapidly, and finally the wind power generation system fails. Therefore, the present invention introduces another additional control law to assist the lack of this control method. Solve the problem of wind power system failure that may occur when the wind speed is lowered from high to low. Considering the maximum power speed change control, according to the mechanical equation of the generator, the maximum power conversion change control index provided by the controller is a function of the wind turbine speed change, which is expressed as follows: 19 1309694 . 'MPDS, n, - f匕1m) ^εχρ(Δ^-Δ^), >Αω. iyub K2 exp[ - (Δ^ - Aam;b)], <Αω^ (19) A〇)m, lb ^ ^ ^m, Ub

Where && is a positive constant ' and Α%, /6 are the default positive value and the negative dead zone, respectively. When the speed change is between this area, the maximum power speed change control provides zero index, which means that when the wind power system operates near the maximum power point, the maximum power speed change control does not operate under the condition that the speed change amplitude is small. Avoid output power fluctuations. When the wind speed increases, the generator speed changes positively, so increase to increase the output electrical power, indirectly increase the electric torque' to make the system reach the maximum power balance point; when the wind speed decreases, the mechanical turn Under the condition of moment reduction, the generator speed change is negative, (both provide negative indicators, so that the grid-connected current peak command is greatly reduced. When the electric torque is reduced, the direction of increasing output power is gradually increased, and finally maintained at The balance point of the maximum power, through the adjustment of the maximum power speed change controller, ensures that the system will not fail due to the sudden decrease of the wind speed, and will quickly reach the maximum power extraction operation point under the condition of drastic changes in wind speed. In the practice of the maximum power speed change control proposed by the present invention, the 匕 ( (") needs to be expressed in the form of an integer, in addition to the pre-machine edge FA / / W, lim, to avoid the actual system The noise and the slamming of the glitch, the problem of the system failure, and the resulting "fwmO" re-transformation (2〇) function Logical judgment. 1309694 Ο) = r〇undds W) z/ ^MPDS (n) I - ^MPDSM 5 (20) then VMPDS — sgn( FM/)£)5. («)) FMi, D5. lim where round(·) Is an integer operator. In the wind power maximum power capture controller 110, the possible output power range is first divided by the same power step, and the relationship between the maximum power current index and the grid-connected current peak command is made, that is, an index corresponds to a peak command #, and The adjustment amount of the maximum power current indicator _ Δ / & is calculated by the above two maximum power draw control rules of the plant M /> £ D (8) and the factory (8) summed to calculate the maximum power current index After &, substitute the grid-connected current peak command correspondence table /_&[·] to find the current peak command. The maximum power extraction control method proposed by the invention does not need to use a mechanical sensor, such as an anemometer and a tachometer, and only needs to return the electrical signal and the terminal voltage of the permanent magnet synchronous generator to achieve maximum power capture. The purpose and proposed control method are simple, which helps to reduce the wind power generation system and its application in practical systems. [Embodiment] Since the external wind speed change is not artificially controlled, the grid-connected wind power generation system of the present invention and its maximum power extraction control method employ a wind power simulation system to verify the effectiveness of the present invention. In the embodiment, a 300W three-phase permanent magnet synchronous generator is used as the wind power generator, and its rated speed is 3000 rpm, and the power range of possible output is first 0.1 to 300 W.

1309694 0.1W is divided into 3000 indicators, namely 1S/&S3000. As far as the power supply in Taiwan is concerned, the power supply is ll〇Vrms/60Hz, and the transformer turns ratio #=5.5 is appropriately selected, and the grid-connected voltage % is 20Vrms/60Hz. Therefore, the grid-connected current peak command correspondence table /#%[ The current range of the wind power generation emulation system of the embodiment of the present invention is as shown in FIG. 4, and the system parameters of the embodiment of the present invention are as follows: Wind emulation system full bridge type converter maximum Power Carrying Controller P 1.2 (kg/m3) f 60 (Hz) 0.006 (rad/s) Y 0.458 (10) fs 20 (kHz) -0.009 (rad/s) B 3.04χ10'3 (Nm/(rad/s )) L〇1.5 (mH) κ 10 J 6.24x10'4 (Nm/(rad/s2)) a 0.166 尺1 150 P 4 (poles) β 4000 κ2 120 Kt 0.4851 (Nm/A) λ 3.2 ^MPDSJim 50 △'α·2 1 (ms) 10 (ms) Rectifier and filter cr 600 (μΡ) h 4.85 (mH) c, 600 (μΡ) This example uses different wind speed data to verify the test with 100 seconds of experimental time. The effectiveness of the invention's maximum power capture control method, first tested for wind speed conditions [13].

8sin(X) (21) Another wind speed condition is the wind speed data detected by a small weather station installed on the top floor of the third building of Yuanzhi University (about 30 meters above the ground). The measuring condition is every 12 1309694 10 minutes. Record an average wind speed 'record 144 wind speed data per day. This article uses the average wind speed recorded every 10 minutes to compress to an average wind speed of 1 second. When the wind season of November 22, 2004 and May 25, 2005 are selected, The wind speed data in the wind season is 1 〇〇 pen' I wind power simulation system under the maximum power extraction control method disclosed in the present invention 100 seconds dynamic response, the maximum power extraction control method proposed by the present invention is further Testing and verification. After collecting the wind speed data, the wind emulation system pushes the 800W induction motor coaxially connected with the permanent magnet synchronous generator through the wind emulation controller and the induction motor drive device, emulating the real wind blowing through the fan blade ι〇1 to drive the permanent magnet synchronous transmission. In the case of the motor 102, the AC power connection rectifier 103 and the filter 104 from the permanent magnet synchronous generator supply a DC voltage to the rear-stage full-bridge converter 1〇5, wherein the operating frequency of the four power semiconductor switches is 20=20 kHz. 'The power supply is connected in parallel with the mains through the transformer. The flow of the wind emulation controller is shown in Figure 5. The sampling time is ΔGMms, and the induction motor needs to generate a controllable mechanical torque through the method of Field-Oriented Control [14, 15]. Express this mechanical torque as

Tm = iqs (22) where the ruler is the torque coefficient of the induction motor and the torque current command is used; the wind simulation controller is based on the formula (丨^^) and (22) to produce a simulated real wind. Drive the mechanical torque of the permanent magnet synchronous generator. In the embodiment of the grid-connected wind power generation system and the maximum power extraction control method disclosed by the present invention, the rectifier 103 includes a power semiconductor element 23 1309694 composed of a rectifying device with an AC/DC power conversion function and a rectifier capacitor ' The rectifying device generally refers to an active rectifier composed of a power semiconductor switch or a passive rectifier formed by a diode bridge. In this embodiment, a three-phase bridge rectifier composed of a conventional six rectifying diode FR307 is used. And the rectifier capacitor C is used to filter out the rectified low frequency voltage chopping; in the system control unit 108, the maximum power extraction control flow and the current control method of the full bridge converter use a digital signal processor (Digital-Signal_Processor , DSP) is implemented, and the frequency detector 109, phase detection circuit ill and drive circuit 113 are realized by analog circuit; the digital signal processor adopts the digital signal processor module TMS320LF2407EVM produced by Texas Instruments, frequency detection 109 uses the IC LM2907 to detect electrical angular frequencies ranging from 5 to 100 Hz, phase detection The circuit in uses the IC LM311 to detect the zero-voltage crossover point of the mains, and uses the external interrupt of the digital signal processor to reset the phase of the current command // to zero, and the driver circuit 113 uses the IC TLP250. 6 is a diagram showing one embodiment of a grid-connected wind power generation system according to the present invention, a voltage-current waveform of a full-bridge converter and a commercial power supply in parallel, and FIG. 6(a) shows a grid-connected voltage vc (20 Vrms) and a grid-connected current t. (2.5Arms) In the experimental wave of output power 50W, the power factor is 0.987. Verify that the current controller 110 of the converter adopts adaptive global sliding mode control to achieve near-unit power. The effectiveness of the grid connection; Figure 6 (a) is the experimental waveform of the output power of 15 〇 w, the power factor of the grid is 〇 981, also achieve the near-unit power factor for the purpose of grid connection to provide good power quality. Figure 7 shows one of the embodiments of the grid-connected wind power generation system of the present invention. The wind 24 1309694 simulates the wind speed and speed test waveform of the system, and the test wind speed condition is the formula (^) and the wind season 2〇 (Μ/;Π/22 and In the non-wind season, the actual wind speed data of (4) 25, the average wind speed of artificial wind speed is 8.2m/s, the average wind speed of wind season is 7Μ, and the average wind speed of non-wind season is 4.4m/s. The result of this experiment shows the wind emulation system. The speed of the generator follows the change of wind speed, as the actual wind speed drives the generator, verifies the effectiveness of the wind emulation system, and can be used to test the effectiveness of the grid-connected wind power generation system of the present invention and its maximum power control method. 8 shows the embodiment of the grid-connected wind power generation system of the present invention, the wind speed, mechanical power and power coefficient experimental waveform of the wind power simulation system, and FIG. 8(a) shows the system response of the wind speed condition as the equation (21), and the wind power generation. The average power is H) 9.8W 'and the power coefficient reacts to the optimum value 〇42 in 1 '2', that is, the maximum power draw is achieved. Under the maximum power operation control method disclosed by the present invention, the wind speed is obtained. Under high conditions, the fan will increase, the change of the speed is positive, and the maximum power speed change control is used to increase the grid current peak command ('_to increase the electric torque, the time required to increase to the maximum power point can be reduced') In response to the instantaneous change of wind speed, the adjustment is close to the optimal value; the rotation is reduced under the condition of decreasing wind speed, and the peak value of the grid-connected current is reduced to reduce the electric torque 'so that the system will not be drastically reduced due to the wind speed' The rapid decrease of the rotational speed causes the system to be deactivated. Since the maximum power capture control method of the present invention belongs to the variable voltage control mode, 'the second is more efficient, the wind energy is taken out' and the transient reaction time is less than 1 〇 y, ^ The maximum power draw is achieved under the condition of wind speed change. Figure 8(b) and Figure 8(c) show the system change when the wind speed condition is wind season and non-wind season respectively, and the average of 25 1309694 wind power generation The power is 80.3W in the wind season and 14.5W in the non-wind season. The good response results are also shown in the figure. The power coefficient is reacted to the optimal value C/=0.42 in 10 seconds and the maximum power is drawn. The experimental results of the embodiment can verify the effectiveness of the grid-connected wind power generation system and the maximum power extraction control disclosed in the present invention, and achieve the purpose of maximum power extraction. Figure 9 shows the grid-connected wind power generation system of the present invention and A block diagram of another preferred embodiment of the maximum power capture control method. The main difference from FIG. 1 is to add the DC/DC converter 901 and reduce the filter 104 and the transformer 107. The DC/DC converter 901 is an operation. In a continuous current mode (CCM) converter, a power supply that converts the output of the rectifier 103 to a fixed voltage provides a full bridge converter 105 as an input voltage, and the fixed voltage is higher than the mains voltage, First, the low frequency transformer 106 for boosting or stepping down can be omitted to reduce the system volume without considering electrical isolation, and the DC/DC converter 901 can be replaced by a converter operating in a continuous current mode. The power of the device 103 can be obtained by the output of the rectifier 103 at the output of the rectifier 103. The control unit 108 performs one of the signals required for maximum power capture control. [Simple diagram of the diagram] Figure 1 The overall architecture of the grid-connected wind power generation system and its maximum power capture control method. Figure 2 shows the characteristics of the wind power coefficient corresponding to the wing end speed ratio. 26 1309694 Figure 3. Flow of the maximum power capture controller. Figure 4 is a block diagram of the wind power simulation system. Figure 5 shows the flow of the wind emulation controller. Fig. 6 One of the embodiments of the grid-connected wind power generation system. The voltage and current waveforms of the full-bridge converter and the mains are connected in parallel: (a) output power 50W; (b) output power 150W. Figure 7 shows one of the embodiments of the grid-connected wind power generation system. The wind speed and speed test waveforms of the wind-effect system: (a) artificial wind speed; (b) 2004/11/22 actual wind season wind speed; (c) 2005/05/ 25 actual non-wind season wind speed. Figure 8 is one of the embodiments of the grid-connected wind power generation system. The wind speed, mechanical power and power coefficient of the wind power simulation system are: (a) artificial wind speed '(b) πο4/;^/22 actual wind season wind speed; (c • Actual non-wind season wind speed. Fig. 9 is a block diagram of another preferred embodiment of the grid-connected wind power generation system and the charging method of the electric power system. [Main component symbol description] * 101: Fan blade 102: Permanent magnet synchronous generator 103: Rectifier 104: Filter 105: Full-bridge converter 106: Transformer 107: Mains 108: System control unit 27 1309694 109: Frequency detection Detector 110: maximum power capture controller 111: phase detector 112: current controller 113 of the converter: drive circuit 901: DC/DC converter: first-end output voltage v of permanent magnet synchronous generator, Permanent magnet synchronous generator second terminal output voltage • Called: generator electrical angular frequency: rectifier capacitor ι: rectifier output voltage t: rectifier output current Zy: filter inductance | ς: filter capacitor V,.: filter output voltage A: Full-bridge converter inductance • %: grid-connected voltage: grid-connected current #: transformer turns ratio <9: mains phase C: grid-connected current command #: grid-connected current peak command J: full-bridge type Responsibility cycle of the flow device: power factor · 28 1309694 r : wing end speed ratio ^M> £D(W): maximum power error drive control index 匕: maximum power speed change control index /i (&: maximum power current indicator Δ/& : maximum power current indicator Whole amount: grid current peak value command correspondence table

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Claims (1)

1309694 X. Patent application scope: 1. A grid-connected wind power generation system, which comprises a fan blade: mechanical energy for converting wind power into a rotating form; a permanent magnet synchronous generator: means that one can rotate a permanent magnet synchronous generator in which the mechanical energy of the form is converted into alternating current energy; a rectifier comprising: a rectifying device comprising a power semiconductor component having an alternating current/direct current electrical energy conversion function and a rectifying capacitor; a filter: the system includes An inductor and a capacitor for filtering the voltage and current chopping of the AC component; a full bridge converter comprising a converter comprising a DC/AC power conversion function comprising four power semiconductor switches And an inductor controlled by the system control unit for DC/AC power conversion; a transformer: refers to a low-frequency transformer with a fixed turns ratio to achieve the effect of electrical isolation and voltage regulation; Power supply AC bus; a system control unit: which includes a frequency detector, a phase a detector, a maximum power capture controller, a current controller of a converter, and a drive circuit for controlling the grid-connected wind power generation system; characterized by being connected to the grid under conditions of changes in external wind speed The wind power generation system extracts the maximum electric energy that can be produced by the fan blade and the permanent magnet synchronous generator in the form of current and is connected to the grid, and the grid-connected current has a good power quality with high power factor. 2. For the grid-connected wind power generation system described in the first paragraph of the patent application, the frequency detector of the system control unit in 30 1309694 can know the electrical angular frequency of the generator output voltage, and then obtain the generator speed. For maximum power capture controller use. 3. For the grid-connected wind power generation system described in claim 1, wherein the phase detector of the system control unit can know the phase of the mains, and provide the current controller of the converter as the phase command of the grid-connected current. 4. For the grid-connected wind power generation system described in claim 1, wherein the current controller of the converter of the system control unit adopts an adaptive global sliding mode control strategy to generate an appropriate duty cycle to control the grid-connected current. Following the grid-connected current command, the adaptive global sliding mode control strategy includes: a system performance planning: clearly defining the expected system performance under normal conditions, a constraint controller: eliminating the occurrence of changes from system parameters and load changes Interference voltage and unpredictable disturbance effects of unpatterned system dynamics; an adaptive algorithm: estimate the upper bound of the total set uncertainty to avoid control tremor caused by improper selection of the upper bound of the constraint controller It is characterized in that there is no impending phase mode in the control process and all states are on the sliding plane. The whole control process is not affected by the system uncertainty, and the control force chattering phenomenon can be effectively reduced. At the same time, the full bridge converter is in existence. In the case of uncertainties and external interference, the grid-connected current can still be effective Follow the grid-connected current command and the same parallel frequency efficiency as the mains and the same frequency to reach 31 1309694 to unit power. 5. The grid-connected wind power generation system according to claim 1, wherein the driving circuit of the system control unit is configured to convert the duty cycle generated by the current controller of the converter into a pulse width modulation Signal, a power semiconductor switch that drives a full-bridge converter. 6. The grid-connected wind power generation system according to claim 1, wherein the maximum power draw controller of the system control unit includes maximum power error drive control and maximum power speed change control, and the two control mechanisms respectively generate maximum The power error drive control index and the maximum power speed change control index are added to obtain the maximum power current index adjustment. The maximum power current indicator is the sum of the last maximum power current indicator and the maximum power current indicator. The maximum power current indicator is substituted into the grid-connected current peak command correspondence table to obtain a grid-connected current peak command; wherein the grid-connected current peak command corresponds to the possible output power range and the grid-connected voltage, and is segmented by the same power step. Cheng, that is, a maximum power current indicator corresponds to a grid-connected current peak command. 7. In the grid-connected wind power generation system described in claim 6, wherein the maximum power error controller of the system control unit drives the DC voltage and the DC current at the output of the rectifier, The multiplier is obtained to obtain the electrical output power of the generator. When the output electrical power increases, the positive and negative signs of the maximum power error driving control index generated by the last maximum power error driving control are maintained, that is, the direction of the peak value of the grid-connected current command is maintained, so that the wind power generation is performed. The system operates in the direction of the maximum power point; when the output electrical power decreases, the maximum power error is changed to drive the control 32 1309694 to the positive and negative signs of the heartbeat, that is, to change the direction of the grid current peak command change' to operate the wind power system to the maximum power point direction. . 8. In the grid-connected wind power generation system described in claim 6, wherein the maximum power speed change control of the system control unit, the maximum power speed change control transmits the electrical angular frequency of the generator through the frequency detector. The generator speed is obtained. When the wind speed increases, the generator torque changes positively under the increase of the mechanical torque. Therefore, the maximum power speed change control is increased to increase the output grid-connected current peak command, which indirectly increases the electrical turn. The moment 'makes the system to reach the equilibrium point of maximum power; when the wind speed decreases, the machine torque changes to negative, the maximum power speed change control indicator provides a negative indicator, and the grid current peak command is greatly reduced. Small, it also allows the wind power system to operate in the direction of the maximum power point. 9. A maximum power extraction control method for a grid-connected wind power generation system, comprising maximum power error drive control and maximum power speed change control, and two control mechanisms respectively generate a maximum power error drive control index and a maximum power speed change control index, The sum of the two can obtain the adjustment of the maximum power current index. The maximum power current indicator is the sum of the last maximum power current index and the maximum power current indicator adjustment amount, and the maximum power current indicator is substituted into the grid-connected current peak. The command correspondence table obtains a grid-connected current peak command; wherein the grid-connected current peak command correspondence table depends on the output power range of the grid and the grid-connected power is divided by the same power step, that is, a maximum power current index corresponds to the same Net current peak command. 10. The maximum power extraction control method for the grid-connected wind power generation system described in claim 9 wherein the maximum power error drive control returns 33 1309694 generator output electrical power, and maintains when the output electrical power increases The maximum power error generated by the last maximum power error drive control drives the positive and negative signs of the control index, that is, maintains the direction of the grid-connected current peak command change, and causes the wind power generation system to operate toward the maximum power point; when the output electrical power decreases, the maximum power is changed. The error-driven control index has positive and negative signs, that is, changes the direction of the grid-connected current peak command change, so that the wind power generation system operates toward the maximum power point. 11. The maximum power capture control method for a grid-connected wind power generation system according to claim 9, wherein the maximum power speed change controls the feedback of the generator speed, and when the wind speed increases, the mechanical torque increases. , the generator speed change is positive, so increase the maximum power speed change control index to increase the output grid-connected current peak command, indirectly increase the electrical torque, so that the system reaches the maximum power balance point; when the wind speed decreases, the mechanical torque decreases Under the circumstance, the generator speed change is negative, the maximum power speed change control index provides a negative indicator, and the grid-connected current peak command is greatly reduced, and the wind power generation system is also operated to the maximum power point. 12. A grid-connected wind power generation system comprising a fan blade: mechanical energy for converting wind into a rotating form; and a permanent magnet synchronous generator: converting a mechanical energy of a rotating form into an alternating current A permanent magnet synchronous generator; a rectifier comprising: a rectifying device comprising a power semiconductor component having an AC/DC power conversion function and a rectifying capacitor; and a DC/DC converter: operating in a continuous current The input current source type DC/DC converter in the mode can convert the DC voltage to 34 1309694 and another fixed and higher DC voltage than the mains voltage; a full bridge converter: which contains one of four powers The semiconductor switch comprises a converter device with a DC/AC power conversion function and an inductor, which is controlled by the system control unit for DC/AC power conversion; a utility power: an AC busbar that is generally referred to as a power supply; Unit: The system includes a frequency detector, a phase detector, a maximum power capture controller, and a change The current controller and a driving circuit of the current device are responsible for the control of the grid-connected wind power generation system; and the utility model is characterized in that the wind turbine blade and the permanent magnet synchronous hair are taken out through the grid-connected wind power generation system under the condition that the external wind speed changes. The maximum electrical energy that the motor can produce is connected to the grid in the form of current, and the grid-connected current has a good power quality with high power factor. 13. The grid-connected wind power generation system according to claim 12, wherein the frequency detector of the system control unit can know the electrical angular frequency of the generator output voltage, and further obtain the generator speed for maximum power. Use the controller. 14. The grid-connected wind power generation system according to claim 12, wherein the phase detector of the system control unit can know the phase of the mains, and the current controller of the converter is provided as the phase command of the grid-connected current. 15. The grid-connected wind power generation system according to claim 12, wherein the current controller of the converter of the system control unit adopts an adaptive global sliding mode control strategy to generate an appropriate duty cycle to control the grid-connected current. Following the grid-connected current command, the adaptive global sliding mode control strategy 35 1309694 contains: a system performance planning: clear system performance expected under normal conditions; a constraint controller: eliminates the generation of changes from system parameters, load changes The induced interference voltage and the unpredictable disturbance effect of the unpatterned system dynamics; an adaptive algorithm: estimate the upper bound of the total set uncertainty to avoid the control force caused by improper selection of the upper bound of the constraint controller Trembling phenomenon; characterized in that there is no impending phase mode in the control process and all states are on the sliding plane, which is not affected by the system uncertainty during the whole control process, and can effectively reduce the control force tremor phenomenon, and the full bridge converter In the case of uncertainties and external interference, its grid-connected electricity The flow can still follow the grid-connected current command effectively and with the same frequency and phase in the same phase as the mains to achieve the best parallel efficiency of the unit. 16. The grid-connected wind power generation system according to claim 12, wherein the driving circuit of the system control unit is configured to convert the duty cycle generated by the current controller of the converter into a pulse width modulation Signal, a power semiconductor switch that drives a full-bridge converter. 17. The grid-connected wind power generation system according to claim 12, wherein the maximum power capture controller of the system control unit includes maximum power error drive control and maximum power speed change control, and the two control mechanisms respectively generate maximum The power error drive control index and the maximum power speed change control index, the two can be added to obtain the maximum power current index adjustment 36 1309694 quantity, the maximum power current indicator is the last maximum power current indicator and the maximum power current indicator adjustment And, the maximum power current indicator is substituted into the grid-connected current peak command correspondence table, and a grid-connected current peak command is obtained; wherein the grid-connected current peak command corresponds to the possible output power range and the grid-connected voltage, with the same power step Split, that is, a maximum power current indicator corresponds to a grid-connected current peak command. 18. The grid-connected wind power generation system according to claim 17, wherein the maximum power error controller of the system control unit drives the DC voltage and the DC current at the output of the rectifier, The multiplier is obtained to obtain the electrical output power of the generator. When the electrical output power increases, the positive and negative signs of the maximum power error driving control index generated by the last maximum power error driving control are maintained, that is, the direction of the peak value of the grid-connected current command is maintained, so that the wind power generation is performed. The system operates in the direction of the maximum power point; when the output electrical power decreases, the positive and negative signs of the maximum power error drive control index are changed, that is, the direction of the grid-connected current peak command change is changed, so that the wind power generation system operates toward the maximum power point. 19. The grid-connected wind power generation system according to claim 17, wherein the maximum power speed change controller of the system control unit controls the electrical angular frequency of the generator through the frequency detector. The generator speed is obtained. When the wind speed increases, the generator torque changes positively under the increase of the mechanical torque. Therefore, the maximum power speed change control index is increased to increase the output grid-connected current peak command, and the electrical torque is indirectly increased. The system reaches the equilibrium point of maximum power; when the wind speed decreases, the generator torque changes negatively under the condition of mechanical torque reduction, and the most 37 1309694 high-power speed change control index provides a negative indicator, and the grid-connected current peak command is greatly reduced. Small, it also allows the wind power system to operate in the direction of the maximum power point. 20. The grid-connected wind power generation system according to claim 12, wherein the DC/DC converter converts the DC power of the rectifier output into a DC power source that is fixed and higher than the commercial voltage, and provides a full bridge converter. As an input voltage, the low-frequency transformer that provides boost or step-down can be omitted and the system volume is reduced, and the input current source type DC/DC converter operates in continuous current mode, and the DC voltage required for the electrical signal of the generator is required. And the DC current product can be obtained at the output of the rectifier to provide the signal required for maximum power capture control. 38