TWI296457B - High-performance power conditioner for solar photovoltaic system - Google Patents

Description

1296457 IX. INSTRUCTIONS OF THE INVENTION: TECHNICAL FIELD The technical field of the present invention includes automatic control, power electric DC/DC conversion technology, DC/AC current conversion technology, and energy division, although the present invention relates to The technology field is extensive, but it mainly lies in the use of solar photovoltaics in the city and the system to improve the current solar photovoltaic application ^ power parallel power supply system. ' φ

[Prior Art] Although the advancement of science and technology has brought many conveniences to human life, the same problem has also been derived from the reduction of petrochemical stocks, the awareness of energy crisis, the rise of environmental awareness, and the Kyoto Protocol. Regulations and soaring energy prices... In addition to reducing the waste of existing energy use, the development of new energy sources is an urgent task. Generally, new energy has little impact on the environment, and the pollution caused by air, water or waste is less significant. More importantly, such energy development is more reusable, with sustainable development characteristics, and renewable energy ( Renewable Energy) is a new energy source that includes energy such as solar energy, wind power, biomass energy, geothermal energy, ocean energy, and non-pumping water. [1, 2] Contaminated and easily accessible features have become one of the hot research areas in recent years and have developed many different architectures. The mains parallel solar photovoltaic energy conversion system mainly generates photoelectric power through the photoelectric conversion of the 1% energy board, and then converts the DC power to the AC output through the power regulator and feeds the busbar of the mains in parallel with the commercial power [3, 4], generally including DC input power, Power Conditioner (Power Conditioner), distribution box, transformer, battery, etc., power adjustment 7 1296457 section is mainly by DC / DC converter (Converter), DC / AC converter (Inverter ) and the system controller, and depending on the application and user needs. Due to the low output voltage of the solar panel, the required DC bus voltage is conventionally formed in series [5, 6]. However, the bus voltage is easily affected by the load, which makes the design of the rear converter difficult. In the case of DC load supply, the problem of poor power quality is generated; in addition, if the power generation function of any module in the series module is degraded or malfunctions, the overall power generation system performance is greatly reduced. Therefore, the AC power output is generally completed by a two-stage power conversion method. The input voltage is stably boosted by a DC/DC converter, and then converted to an AC voltage output by a DC/AC converter. The conventional DC/DC boost circuit usually adopts a boost converter circuit composed of a single inductor. The power semiconductor switch in the circuit is subjected to high voltage, large current and reverse recovery surge current of the output diode. The power conversion efficiency is not good, and the boost limit is up to about seven times. Secondly, with the transformer boost, the boost range is limited by the turns ratio. If the leakage inductance energy cannot be effectively processed, the conversion efficiency is difficult to increase. In order to improve the problem, the present invention uses the high-boost ratio conversion circuit of the coupled inductor bidirectional magnetic circuit energy transfer of reference [7] to replace the conventional circuit, which has the advantages of high step-up ratio and better conversion efficiency, and can provide system continuous flow. High-efficiency DC/DC power conversion with voltage boost ratios over thirty times higher. In order to enable the stable power supply of the solar photovoltaic energy conversion system, the present invention controls the converter with a microprocessor. Generally, when the control problem is solved, the parameter variation and various uncertainties are often encountered. In the control field, 1296457 has various Various control theories, such as Proportional-Integral-Derivative (PID) control [8], or modern control theory using complex equations such as Computed Torque Control, Sliding Mode Control (Sliding_Mode Control) [9, 10], etc. are all designed to make the behavior of the system conform to the design requirements of system parameters and various external disturbances. Proportional, integral, and derivative controllers have been widely used in the industry because of their simple structure, ease of design, and low cost, but for systems with uncertain dynamics, proportional-integral-derivative controllers do not provide perfect performance. Computational torque control uses a nonlinear term that eliminates some or all of the nonlinear equations to obtain its linearization equation, and then designs a linear feedback controller to achieve the designed closed loop control characteristics. However, since the computational torque control is based on the idealized theory of eliminating nonlinear dynamics, its shortcoming is the lack of understanding of the system uncertainty in the time domain, including system parameter changes and external disturbances. Therefore, larger control is usually selected. Gain to achieve system robustness and to ensure system stability. Variable Structure Control or Sliding Mode Control is one of the effective methods for nonlinear robust control [9-18], because the controlled system dynamics are not affected by system uncertainties and disturbances in /monthly mode. The impact of the item. The design of the sliding mode control system can be divided into two major steps. First, the sliding plane in the state change space is selected according to the required closed loop control. The design control law moves the system state toward the sliding plane and remains on the sliding plane. The situation before the system state trajectory touches the sliding plane is called the Reaching Phase. Once the system state trajectory reaches the (7) moving plane, the system state remains on the plane and faces the target 1296457. This condition is called the sliding phase. (Sliding Phase). However, when the t is in the near phase, it will still be subject to system parameter changes and the external pile = ring 2. Therefore, many scholars have proposed the approach phase design or the Total Sliding_Mode Control to reduce the system uncertainty. Impact [12-15]. Gao and Hung [12] jointly studied the design of the two imminent laws to specify the kinetic energy of the system state in the near phase, but in this case, the uncertainty of the system will still affect the system control performance. In = sliding mode control [13-15] means that there is no imminent phase in the control process = all states are in the sliding plane, and the whole control process is not affected by the system uncertainty, but it may still cause the control to tremble. Phenomenon and the instability of the system. Many research scholars have cited the boundary layer in the past few years (B〇undary

Layer) concept [16,17] to eliminate the control tremor phenomenon, unfortunately, if the inappropriate boundary layer width is selected, it is easy to cause unstable control response of the system, which means that the stability in the boundary layer cannot be guaranteed. Therefore, some scholars have introduced an adaptive algorithm that can handle uncertainty estimation [18] in order to reduce the control tremor phenomenon. This invention is applied to the control of a full-bridge converter. The output power of solar panels is subject to large variations with different sunshine intensity. In Taiwan, for example, the maximum average illuminance for the year is positive south and the tilt angle is 23.5. Therefore, most domestic manufacturers adopt this position for fixed installation of solar panels. However, this fixed installation mode is not easy to extract the maximum solar energy, so that the performance of the solar photovoltaic energy conversion system cannot be improved. Therefore, in recent years, many scholars have devoted themselves to the study of the Japanese system [19-21], the traditional passive chasing system on the solar panel. The two ends of the frame are erected by the light-sensing element 1296457' 7 and the light-sensing device is used. When the light-sensing device at both ends of the frame is fed back, the same day: ', which means that the solar panel is forward light source and has the maximum amount of sunlight, but The adjustment of the meter sensation is not easy and the light-sensitive element is susceptible to the change of the s. In view of this, this kind of logistics is self-sufficient. ^ ^ ^ The earth-cutting system uses the solar panel's open circuit voltage to compare with the characteristics of the sun's illumination to track the solar azimuth and improve the shortcomings of the traditional passive pursuit. The voltage and current and power of the board are too nonlinear. The output power of the solar panel will be affected by different factors such as day 2, intensity, temperature, or due to component aging and optoelectronic materials. Due to different conditions, they all have unique working curves. Each of the I working lines has only one maximum power point, which is the best working point of the solar panel. Therefore, in order to fully utilize solar photovoltaic energy, it is necessary to design appropriate control rules to enable maximum power extraction from solar panels in various = same working environments. This control method is called the maximum power tracking method [22-25], which is mainly in the general literature. Can be summarized as Voltage Feedback Method, Power ® Feedback Method, Incremental Conductance

Method), Linear Approximation Method, Practical Measurement Method, and Perturbation and Observation Method, where the perturbation observation method is used more often because it does not require system parameters and the control structure is simple. However, the magnitude of the disturbance is not easy to balance between the response speed and the energy loss, and the energy loss is easily caused. Therefore, the present invention proposes that the adaptive step disturbance method improves the shortcomings of the conventional disturbance observation method, accelerates the tracking of the maximum power point, and reduces the energy. Loss. 11 1296457 Remarks: References [1] S. R. Bull, "Renewable energy today and tomorrow/5 Proc. IEEE, vol. 89, no. 8, pp· 1216-1226, 2001.

[2] S. Rahman, “Green power: what is it and where can we find it?,”’ IEEE Power Energy Mag., vol. 1? no. 1? pp. 30 — 37, 2003.

[3] C. Yang and K. M. Smedley, “A cost-effective single-stage inverter with maximum power point tracking/5 IEEE Trans. Energy Conversion, vol. 195 no. 5, pp. 1289-1294, 2004.

[4] Β· Μ· Τ· Ho and SH Chung, “An integrated inverter with maximum power tracking for grid-connected PV systems/5 IEEE Trans, Energy Conversion, vol. 20? no. 45 pp. 953 — 962, 2005 .

[5] T. F· Wu, CH Chang, and Υ·H· Chen, “A fuzzy-logic-controlled single-stage converter for PV-powered lighting system applications^ IEEE Trans, Ind. Electron., vol. 47? Φ no. 2? pp. 287 — 296, 2000.

[6] T. J. Liang, Y. C. Kuo, and J. F Chen, “Single-stage photovoltaic energy conversion system/9 IEE Proa Electr. Power Appl^ vol. 148, no· 4, pp· 339- 344, 2001.

[7] R. J. Wai and R. Y. Duan, "High step-up converter with coupled-inductor^ IEEE Trans. Power Electron., vol. 209 no. 5, pp. 1025 — 1035, 2005.

[8] KJ Astrom and T. Hagglund, PID Controller: Theory, Design, 12 1296457 Λ and Tuning. Research Triangle Park, NC: ISA, 1995. ^ [9] KK Shyu, Y· W. Tsai, and CK Lai, "Sliding mode control for mismatched uncertain systems/9 Electronic Letters, vol. 34? no. 24, pp. 2359-2360, 1998.

[10] K. K. Shyu, Y. W. Tsai, and C. K. Lai, “Stability regions estimation for mismatched uncertain variable structure systems with bounded controllers^ Electronic Letters, vol. 35? no. 165 pp. • 1388-1390, 1999.

[11] V. I. Utkin, “Sliding mode control design principles and applications to electric drives/5 IEEE Trans. Ind Electron., vol. 40, no· 1, pp· 23 — 36, 1993.

[12] W. Gao and J. C. Hung, "Variable structure control for nonlinear systems: a new approach/5 IEEE Tran. Ind. Electron., vol. 405 no. 1, ρρ·2 - 22, 1993.

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

[14] KK Shyu and J. C. Hung, “Totally invariant variable structure control systems/9 IEEE Conf Ind. Electron. Contr. Instrument, vol· 3, pp· 1119—1123, 1997· 13 1296457 [15] K. Shyu? J. Υ. Hung, and JC Hung, 'Total sliding mode trajectory control of robotic manipulators/9 IEEE Conf Ind. Electron, Contr. Instrument., vol. 3? pp. 1062-1066, 1999.

[16] J. J. E. Slotine and W. Li? Applied Nonlinear Control. Englewood Cliffs, NJ: Prentice_Hall, 1991.

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

[18] R. J. Wai and KM Lin, “Robust decoupled control of direct field-oriented induction motor drive/5 IEEE Trans. Ιηά Electron., νο1·52, no· 3, pp. 837—854, 2005· [ 19] B. Koyuncu and K. Balasubramanian, “A microprocessor controlled automatic sun tracker/5 IEEE Trans. Consumer Electron., vol. 31, no. 4? pp. 913 — 917, 1991.

[20] A. Ferriere and B. Rivoire, “An instrument for measuring focused solar-radiation: a photo-sensor interfaced with an integrating sphere/v^o/. Energy, vol. 72? no. 3, pp. 187— 193, 2002. pi] J. D. Garrison, “A program for calculation of solar energy collection by fixed and tracking collectors/9 Sol Energy, vol. 12, no· 4, pp· 241-255, 2002· [22] C. Hua, J. Lin, and C. Shen, "Implementation of a 14 1296457 λ DSP_controlled photovoltaic system with peak power tracking,'' • IEEE Trans. Ιηά Electron., vol. 45? no. 1? pp. 99— 107, 1998.

[23] Υ·H. Lim and D. C. Hamill, “Simple maximum power point tracker for photovoltaic arrays/5 Electronics Letters, vol. 36? no. ll, pp· 997 — 999, 2000.

[24] E. Koutroulis, K. Kalaitzakis, and N. C. Voulgaris, "Development of a microcontroller-based, photovoltaic _ maximum power point tracking control system/5 IEEE Trans,

Power Electron., vol. 16, no. 1? pp. 46 — 54, 2001.

[25] M. A. S. Masoum, H. Dehbonei, and E. F. Fuchs, "Theoretical and experimental analyses of photovoltaic systems with voltage-and current-based maximum power-point tracking/5 IEEE Trans, Energy Conversion, Vol. 17? n〇· 4? pp. 514 — 522, 2002. SUMMARY OF THE INVENTION The overall architecture of the high performance solar photovoltaic energy conversion system disclosed in the present invention is shown in FIG. 1 , and the solar panel 10 is used to absorb sunlight. After the photoelectric conversion, the DC power source Fp is output and connected with the high step-up ratio DC/DC conversion circuit 20 to provide a DC/DC voltage conversion with high boost ratio and high conversion efficiency, and a high step-up ratio DC/DC conversion circuit architecture such as 2, the DC voltage of the DC input circuit 201, when the power semiconductor switch 2 of the primary side circuit 202 is turned on, the current is stored in the coupled inductor 7; the primary side winding A; and the secondary side circuit 204 is coupled to the inductor 7 The second 15 1296457 side winding z2 head with two-way electric material Wei Road, the money point is positive) 'series-regeneration passive cushioning circuit 2〇3 system= voltage, through the work The semiconductor switch 2 and the discharge diode z>2 circuit, the pair 1 = the circuit 204 is high and the red 2 is charged (the charging current ^ the semiconductor switch (4) is instantaneous, the secondary circuit is carrying the current away from the power ^ the conductor switch 2, via regeneration The clamped two-pole 被动 of the passive cushioning circuit 203: melon into the sea, the circuit of the capacitor q, and the secondary side of the circuit current & must use the clamp tj - polar body A and discharge diode & Flow to release the energy stored in the second-side winding of the turn-in inductor. The energy stored by the leakage inductance is absorbed by the high-voltage capacitor C2. The second-side winding is released. The first-side winding & leakage inductance energy is determined according to the magnetic flux. The excitation current will steer the secondary side current h, and the rectifying diode of the filter circuit 〇5 is turned on and injected into the filter capacitor of the circuit to obtain a DC voltage that is constant and difficult to change, thereby improving the conventional single-stage solar photovoltaic energy source. The converted DC busbar voltage is susceptible to load fluctuations and is connected to the full-bridge converter 3G. The DC voltage can be regarded as a fixed value and dynamically decoupled from the downstream converter. The design of the converter control system. Derivation] k Let the coupled inductor 7; the primary side winding A and the secondary side winding & the turns ratio of the heart / force, the coupling coefficient A is defined as L · where A « is the magnetizing inductance (also known as mutual inductance), 4 For the sense of the primary winding, the circuit voltage analysis can be used to derive the voltage gain of the conversion circuit and (2) the voltage to which 1296457 is 2, as shown in equations (2) and (3).

Vd _2 + nk D(\~k)(n-1) vi

1-D (3)

Vpv D(l-k)(n-l) l — D "2(1 - D)pv where Z) is the duty cycle of the switch, so that the coupling coefficient A: is equal to 1, the formula (2) and equation (3) can be rewritten as follows:

G

1 a Z) (4) vDS=Vpv/(l-D) (5) Substituting equation (5) into equation (4) can obtain the voltage value of the switch as follows: vDS=Vd/(n + 2) (6)

Observing equation (6), the output voltage 匕 and the turns ratio π are fixed, and the voltage with which the power semiconductor switch 2 is subjected is independent of the input voltage and duty cycle ,), so that the maximum voltage tolerated by the power semiconductor switching element can be ensured. As long as the input voltage is not higher than the withstand voltage of switch 2, the conversion circuit designed according to equation (6), in combination with the original high voltage gain ratio, will accept input voltages with high and low voltage variations. The full-bridge converter 30 is connected to the high-boost DC/DC converter circuit 20 for DC/AC conversion. The control unit 50 includes a microprocessor 60 and a drive circuit 70. The present invention utilizes the feedback of the system state. The microprocessor 60 controls and outputs a driving signal by a unipolar (unipolar) pulse switching method in a sinusoidal pulse width modulation (Sinusoidal 17 1296457 * Pulse-Width-Modulation, SPWM) technique, and a driving circuit of the converter 70 pairs of four power crystal switches of the full bridge type converter 30 are controlled, and the output thereof is connected with the choke inductor 40, thereby filtering out the high frequency component of the AC output voltage of the converter and simultaneously converting the AC output of the converter. The voltage is an AC current output and is supplied in parallel with the mains. The decoupled system equivalent circuit is shown in Figure 3. In order to make the description simple and easy to understand, the proper nouns are not too long, and the circuit attribution figure number (such as ... circuit • 10) is omitted, directly referring to the description of the schema. It is clear. In the figure, the DC busbar voltage of the output of the high-boost ratio DC/DC converter circuit is the AC voltage of the high-frequency harmonic component after the DC busbar voltage is modulated by the full-bridge converter, and the high-frequency harmonic component thereof It can be filtered by a properly designed choke inductor Zy to further obtain the AC output current, rZ/ is the equivalent internal resistance of the choke inductor, and the voltage source % represents the interference voltage caused by the load change. In order to facilitate the analysis and simplify the derivation of the state space equation, this paper assumes that (1) the equivalent internal resistance of the choke inductor I/ is small, so it is neglected; (2) 10 assuming that the power switch is an ideal component, the conduction loss of the switch And the switching loss is 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 and the modulation frequency of the system, so the control signal and input can be controlled during a switching cycle. The output voltage is considered to be a fixed value. According to the above assumptions, the power switch switching mode of unipolar sinusoidal pulse width modulation is divided into positive and negative half cycles. Since the voltage polarity of the negative half cycle is opposite to that of the positive half cycle, the operation principle is similar to that of the positive half cycle. Therefore, the following detailed analysis is performed. The positive half cycle is an introduction. There are two different states for the first half-cycle switching. The equivalent circuit is shown in Figure 4. Therefore, the present invention is directed to the dynamic space equation of the entire positive half-cycle after the positive half-cycle is deduced by the state space averaging method and the linearization technique. It can be expressed as 匕 is the AC output current, and 13⁄4 is the duty cycle of the switch and the heart conduction during each switching cycle. Define the duty cycle a = with the bridge

Power level gain = 6/1, where is the sinusoidal control signal, / is the peak value of the triangular wave signal, then the system dynamic model can be rewritten as shown in the equation 'and the Laplace Transform can further transform the system equivalent model This is shown in Figure 5. ’,

WM chooses exchange h

V con -V a --- hU ^ , Vd (δ) equation; with the ==^ system state ^ as the control variable,

> can be rearranged as follows: ^ (0 ^ dpu(t) + epf{t) + g(t) Then ^ (^pn + ^pn)U^f) + {^ρη+ ^epn)f{t) + ^ dpnU(0 + epnf(t) + h{t) K, — vcon, dp = KPWM !Lf, ep 2~]Ji^, = /Zy ; and respectively represent the normal case 4 and indeed κ玲『P «And « represents the parameter perturbation of the system; /? (〇 represents the total set (0 svj ^ (9) system parameters; μ and is defined as j. , ^ ^dpnu{t) + Aepnf(t) + g(t) % + Total A > /, the boundary value of the uncertainty is given by the system (10) of Equation (u), where 1296457 k pg is a positive constant. , l^wl < pg (ίο In the case of a full-bridge converter with uncertainties and external interference, the output current can still effectively follow the current command and be in phase with the same frequency and the same phase to achieve the best parallel efficiency of the unit power, the present invention The output current of the converter is controlled by Adaptive Total Sliding-Mode Control (ATSMC), as shown in Fig. 6, defining a control error gas -X%, where is the output current command > Design the sliding plane & (7) for & = gas (〇一气 (9) + (7) (12) α where α is a positive constant and \(〇) is the initial value of & (1). The adaptive global sliding mode control system can be mainly divided into three parts: The first part is system performance planning, this method is mainly Clearly plan the system performance expected under normal conditions, and assign it to the basic model design > (Baseline Model Design) %; the second part is the construction of the constraint controller (Curbing Controller) Wc, that is, the elimination from the system The parameter variation, the interference voltage caused by the load change, and the unpredictable disturbance effect of the unpatterned system dynamics make it possible to fully satisfy the system performance of the basic (4) design; in addition, the third part is the development of the adaptive algorithm (Adaptive). Obse cut design...) Estimate 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 constrained controller. The overall control design of the adaptive global sliding converter control system is as follows. Theorem-show, in addition, if the system's post-level DC/AC conversion mechanism 1296457 • changes, it can be deduced in the same way. Complete the converter control - system design. [Theorem 1] Assume that the full-bridge converter shown in equation (9) adopts adaptive global sliding mode control, and the various parts of the controller are designed as equations (13) to (15). As shown, and the development of the adaptive algorithm is as shown in equation (16), the stability of the system will be guaranteed. u = ugb + Ugc (13) ugb= - d~pln(epnf + aeg^xgd) (14) ugb= - Pg(〇dplnsgn(sg(t)) (15) From) Gentry (16) where sgn (·) is a symbolic function, · is an absolute value function, and \ is a positive constant. [Proof] According to the analysis of Lyapunov stability theory [16,17], the stability of the converter control system can be guaranteed, because the proof of Theorem 1 is roughly the same as the reference [18], so Omitted. Although the solar tracking control can make solar panels gain greater sunlight intensity and improve system power generation efficiency, there are still difficulties in implementation, such as sensor technology, external interference elimination, reliability and cost issues. The common method for sun tracking is to erect a light quantity sensing device composed of light sensing elements at both ends of the solar panel frame, and change the angle of the board surface by rotating the actuating device, when the light amount sensing device at both ends of the solar panel frame is returned When the amount is equal, it means that the solar panel is forward source and has the maximum amount of sunlight. However, the adjustment of the 21 1296457 light quantity sensing device is not easy and the photosensitive element is susceptible to the age of the device, which causes the component characteristics to change. In view of the above, the present invention proposes an active solar tracking system, which utilizes the solar panel open circuit voltage proportional to the characteristics of the sunshine intensity, and rotates the surface of the solar panel through the actuating device to change the incident angle of the sunlight, thereby performing the open circuit voltage of the solar panel. Disturbance, by feedback of the open circuit voltage of the solar panel, the microprocessor will be able to determine the correct direction of rotation and send a drive signal to drive the actuator. This method only needs to feedback the open circuit voltage of the solar panel to track the sun's azimuth. At the same time, because the position of the sun moves slowly and monotonously, the single-month climbing angle does not change and the variation range is ±10 in one year. Therefore, the tracking system does not need to adjust its tilt angle, and the maximum illumination can be achieved by controlling the azimuth angle with a single axis position. It is not necessary to change the original structure of the system, improve the shortcomings of the traditional passive sun chasing system and have the advantages of convenient construction. The program control flow is shown in Figure 7, where -1] is the current and previous open circuit voltage; the open circuit voltage change; because the sun only moves from east to west in one direction in one day, the program Start clockwise (from east to west) by rotating L seconds per unit angle to change the angle of the solar panel, thereby disturbing the open circuit voltage of the solar panel, and thus judging whether it should continue to rotate in the same direction to obtain greater sunshine. If the open circuit voltage drops due to excessive rotation angle or external environment influence (shading), the system will rotate counterclockwise to return to the previous board position, and wait for a while (seconds) to track again. In the traditional maximum power tracking rule, the disturbance observation method is often used because of its simple structure and lack of system parameters. However, the selection of the disturbance amount is not easy to be a disadvantage. Although the large disturbance amount can effectively improve the response speed, when the sun 22 1296457 When the output of the energy board reaches the maximum power point, its disturbance behavior will not stop, but the energy loss will be disturbed near the maximum power point. Although the step of each disturbance can be reduced to improve this disadvantage, but when the temperature Or when the illuminance changes greatly, the characteristic curve changes, and the maximum power point moves, causing the time response to track to the new maximum power point to slow down. At this time, there will be energy loss, so the amount of perturbation needs to be in response speed and energy. Weigh the tradeoffs. Therefore, the present invention proposes an Adaptive Step-Perturbation Method, which can calculate the output voltage and output power of the solar panel by the microprocessor through the feedback of the output voltage and the output current of the solar panel. The relationship of the person appropriately adjusts the disturbance step according to the system condition, which can effectively improve the shortcomings of the traditional disturbance observation method, accelerate the tracking of the maximum power point and reduce the energy loss. The control flow of the adaptive step disturbance method is shown in Figure 8, where & νΜ, and corpse; respectively, the current output current, voltage and power; /pV [/7 -1] ' [« -1] and [«-1] is the previous output current, voltage and power; and Δ^ν is the output voltage and output power variation; and Af^/ is the output voltage command and the disturbance step; ^ is a positive gain. At the beginning of the program, the current input voltage and input current will be obtained, and then the output power and the input voltage variation will be obtained. According to the design of the adaptive disturbance step AF^/^V/AF^, the disturbance step can be found to be proportional to the solar energy. The slope of the output voltage vs. output power (ΔΡρν/Δ1^ν) means that the disturbance step will have the ability to adjust to the system conditions, which can speed up the tracking of the maximum power point and reduce the energy loss. After obtaining the solar panel voltage command, the voltage error-factor can be used to generate the current amplitude command of the current transformer 23 1296457 to indirectly control the solar panel voltage, as shown in Figure 9, where % is a positive constant. Converter current command change amount, % = 2 type is especially the mains frequency; maximum current tracking produces the current amplitude command of the converter 'multiplied by the unit sinusoidal signal sin(wj) in phase with the mains to form a complete current The command is passed to the adaptive global sliding mode control system designed by the present invention to complete the maximum power tracking and the power of the unit power supply parallel supply. [Embodiment] The high-performance solar photovoltaic energy conversion system disclosed by the present invention adopts six F-MSN-75W_R-〇2 models of solar panels produced by Motech Company in parallel as a low-voltage DC power supply for high-boost DC. / DC conversion circuit used, the solar panel under the standard test conditions (IkW / m2, 〗 〖). The electrical specifications of the board is rated output power is 76.78W, rated output voltage is 17.228¥, rated output current is 4.4567 In, the open circuit voltage is 21.61, the short-circuit current is 4·9649Α, and the photoelectric conversion efficiency is 11.92%. Since the high-boost ratio DC/DC conversion circuit has a duty cycle D of about 0·5, the circuit components are turned on. The current has a small chopping component, especially the component with the conduction relationship is complementary, the influence is more significant, and since the input voltage of the solar panel is close to the maximum power point at about 17V, the enthalpy efficiency is better, so the equation can be utilized ( 4), and set the rated output voltage to 200V, the design of the invention turns ratio "equal to 4, through the equation (6) can get the switch maximum clamping voltage of 34V. Even if the input minimum voltage is ιον and the output voltage is 200V, the duty cycle can be calculated by equation (4). The duty cycle is 0·7, which is a practical value of 24 1296457 V. The invention sets a high-boost ratio DC/DC conversion circuit switching frequency of 100 kHz, which is a high-frequency switching frequency commonly used in the industry, and the detailed circuit specifications are as follows:

Vd : DC 200V

Tr : =9μΗ ; I2 =143μΗ ; Nx : N2=3 : 12 ; k=0.91 ; core : EE-55

Q : IRFP048N : 55V/64A ; C1N : 3300μΡ/5〇ν*2 Cx : 6.8μΡ/10〇ν ; C2 : 1μΡ/25〇ν*2 ; C〇: 47μΡ/45〇ν*2 • A : SB2060 , 60V/20A (Schottky), TO-220AC D2, D0: SB20200CT, 200V/20A (Schottky), TO-220AB In order to understand the contents of the high step-up ratio DC/DC conversion circuit extended by the present invention, the experiment of the following examples Waveform, the code for the voltage and current of the circuit components, please refer to Figure 2. The actual response of the step-up ratio DC/DC converter circuit at 4 〇w (light load) and 320 W (heavy load) is shown in Figure 1 and Figure n. The voltage across the switch can be found in the figure. Being clamped around the sigma, the switching current k is approximately square wave, and the display switch has better utilization and can reduce the conduction loss. View all the diode voltage and current waveforms, the reverse recovery current is lower than the conduction current, and without the cushion circuit, there is no surge voltage at both ends of the diode and lower than the output voltage 200v, indicating The diode has achieved the voltage box system and flexible switching effect. It is worth mentioning that the light current is discontinuous, light and close, and the leakage inductance of the primary and secondary windings will be generated with the parasitic capacitance inside other components. The vibration phenomenon, as shown in Figure 10, is caused by the leakage inductance of the primary winding and the resonance of the internal parasitic capacitance of the switch. 25 1296457 Figure 12 shows the response waveform of the 咼 boost ratio DC/DC converter circuit in the load from 8〇w gradually to 320Wk 'rectifier diode % current, voltage ~ and switch 2 voltage vm It can be found that under different load conditions, the voltage of one pole is below 200V, and the voltage of switch g still has good clamping effect. Figure 13 shows the conversion efficiency under different loads. The highest conversion efficiency of the circuit exceeds 96.5%. The load-time conversion efficiency is above 95%, thereby verifying the effectiveness of the high step-up ratio DC/DC conversion circuit used in the present invention. The invention adopts the digital signal processor TMS320LF2407A produced by Texas Instruments Co., Ltd. to realize the adaptive global sliding mode control in the full-bridge converter's selection control variable, \=3·3, the switching frequency is 20 kHz, and the converter details The circuit specifications are organized as follows:

Ta+Ja-Jb+Jb- : IRFP264:250V/38A Zy: 7.5mH is a current command that generates the same frequency and same phase as the mains to make the output current of the converter be able to work with the mains voltage after control. The invention generates a sine function value in a form of table construction, saves the operation time, and uses the digital ja 7 tiger to deal with the e-day observing interrupt function to timely accumulate the sine function index value cut, which will make the current command and the mains voltage frequency the same. The interruption time is set to 166ps' The mains frequency is 60HZ. In addition, the interruption time can be adjusted depending on the application, increasing system flexibility. The invention adopts the commercial zero-crossing point detection circuit shown in FIG. 14 to obtain the mains phase signal 比较 by the comparator circuit composed of the IC LM311 after the mains voltage 乂 is separated by the transformer isolation stepped signal 々, due to the external interruption of the digital signal processor The upper limit of the pin input is 3 3ν, 26 1296457, so the voltage is divided by the voltage divider circuit, and the voltage is processed with the voltage of (4) and used as the trigger signal of the external interrupt function of the digital signal processor. The index value of the sine function table is reset, thereby correcting the phase difference between the sine wave current command and the mains voltage. The control flow is as shown in FIG. 15, where W is the current amplitude command, which can be determined by the maximum power tracking method. Figure 16 shows the waveforms of the mains voltage and output current for the system at light and heavy loads. 'The figure shows that the system has a good control response at steady state, and the power factor (Ρ_心(10), PF) is higher than normal. Commercial product specifications • PF = 95% or more. The actual response of the system when the load changes is shown in Figure 17, which is the mains waste and output current waveforms from light load to heavy load, heavy load to light load, no load to full load and full load to unloaded sundial. It can be seen from the figure that when the load changes, the output current of the system can still be effectively controlled. The output current and the mains voltage are almost the same frequency and in phase, with high power factor, and the display system has good transient and steady state. Control response. In order to make the surface of the solar panel change the incident angle of sunlight 1 into an active tracking system to obtain a large contrast intensity, the present invention uses the synchronization of GL Yun No. 35 produced by Tongling Company. The motor acts as an actuating device. When the motor inputs the AC voltage n〇v, the power consumption is only 15W'. The angle of change of the rotating platform when energized is 3 per second. The maximum load of the motor is 38kg, so the solar panel can be mounted on the rotating platform to control the angle of the solar panel. In the middle of the day, the initial position of the solar panel in the early morning hours is facing the east. The chasing day (four) turns (four) the shirt is too large to get a larger amount of sunshine; and the noon is the traditional fixed sun. Optoelectronics 27 1296457 The source conversion system is facing the sun, so in order to clearly see the effectiveness of the active chase system, the selected time is more appropriate. The invention was made at 3 pm on October 5, 1994. Left and right, the illuminance is 67mW/cm2 and the nuclear plate temperature is 50. At C, the system is continuously measured, and the timing interruption time is set to lms ’. The motor rotation angle is 3 per unit time. Read and select the control parameter L = 30. Fig. 18 is the actual response of the active sun-tracking system under the conditions of no shading and occlusion, and in Fig. 18(a), after the start of the tracking process, the surface of the solar panel is rotated by the synchronous motor. Open circuit voltage is also

The change in the angle of the board is increased from the original 18.5V to 2〇v. In order to test the impact of external interference on the system, the shading conditions were added to the measured conditions. From Fig. 18(b), it can be found that when the system starts to track the sunshine for a period of time, the board surface is shaded at 34 seconds. At this time, the open circuit voltage drops, and the program returns to the previous board position after judging that the voltage drops, and waits for a soldier (about 30 seconds) to wait for the elimination of external interference, and removes the board at 62 seconds. Secret 'open circuit voltage rises to steady state, the board will be ^

The rotation is performed when the second opening is performed, and the tracking control is completed. According to the radio and television and the template temperature conditions in Figure 18, the solar panel characteristics of the mosquito-mounted and active 曰^ are improved, which can improve the traditional fixation: 2:: Power can be improved 'When active tracking system: power: two rate. It is worthwhile to synchronize the horse with the required/moving chasing money: According to the numerical simulation results, the practicality of the active day chasing system developed by the invention 7 28 1296457 can be verified. Figure 20 to Figure 23 show the system illumination at 88 mW/cm2 and template temperature 53 after November 06, 1994. (: When the solar panel is used as the system input, the system control parameter is selected & =〇.〇〇1, /? = 〇.〇2. It can be observed from Fig. 20 when the system is in small step (0.15V) When the disturbance is performed, in addition to the slow tracking speed, the maximum power tracking can be effectively performed along the power curve, but it takes a long time. If you want to speed up the tracking, you must increase the disturbance step ( 0.3V), in fact, as shown in Figure 21, it is found that the system takes less time to track to the maximum power point, but because the traditional disturbance observation method uses a fixed disturbance step, it will still be large at the maximum power point. The phenomenon of system jitter caused by step disturbance causes power loss. When the system is operated on the left half of the power curve due to unstable operation point, it will easily collapse due to jitter and cause harm to the system. Figure 22. Figure 23 shows the practical response of the adaptive step-distance perturbation method. It can be found that the system can reach the maximum power point in less time and there is no jitter. Therefore, it can be seen whether it is transient tracking or stable. State operation The adaptive step-distance perturbation method has good maximum power tracking performance. [Simplified illustration] Figure 1 The overall architecture of the high-performance solar photovoltaic energy conversion system of the present invention. Figure 2 The high-performance solar photovoltaic energy conversion system of the present invention High boost ratio DC/DC converter circuit architecture. Figure 3. Equivalent circuit of the high performance solar photovoltaic energy conversion system of the present invention. Figure 4 Full-bridge converter of the high performance solar photovoltaic energy conversion system of the present invention 29 1296457 r in the positive half cycle Two states during switching: (a) h+ and conduction; (b) 7^+ and Γβ+ conduction or coincidence-and-heart-conduction. Figure 5 Converter equivalent of the high performance solar photovoltaic energy conversion system of the present invention Figure 6. The adaptive global sliding mode converter control system of the high performance solar photovoltaic energy conversion system of the present invention. Figure 7 The control flow of the active tracking system of the high performance solar photovoltaic energy conversion system of the present invention. The adaptive step-disturbance method control flow of the high-performance solar photovoltaic energy conversion system. Figure 9 The converter of the high-performance solar photovoltaic energy conversion system of the present invention Figure 10 is one of the embodiments of the high-boost ratio DC/DC conversion circuit of the high-performance solar photovoltaic energy conversion system of the present invention, which is applied to the voltage and current waveforms of various components when the solar panel is boosted to 200V and the output power is 40W. 11 The high-boost ratio direct current/DC conversion circuit embodiment of the high-performance solar photovoltaic energy conversion system of the present invention is applied to the voltage and current waveforms of various components when the solar panel is boosted to 200V and the output power is 320W. One of the embodiments of the high-boost DC/DC conversion circuit of the high-performance solar photovoltaic energy conversion system is applied to the solar panel to boost to 200V, and the output power is changed from 80W to 320W, V% and waveforms. One of the high-boost DC/DC conversion circuit examples of the high-performance solar photovoltaic energy conversion system is applied to the solar panel boosting 30 1296457 to 200V, and the output power is changed from 40W to 320W. Fig. 14 shows a commercial zero-crossing point detection circuit of the high performance solar photovoltaic energy conversion system of the present invention. Figure 15 shows the control flow of the high performance solar photovoltaic energy conversion system of the present invention. Figure 16 is a diagram of an embodiment of the adaptive global sliding mode converter control system of the high performance solar photovoltaic energy conversion system of the present invention. The system responds to light load and heavy load: (a) light load; (b) heavy load . 17 is an embodiment of an adaptive global sliding mode converter control system of the high performance solar photovoltaic energy conversion system of the present invention, the system responds to changes in load: (a) light load to heavy load; (b) heavy Loaded to light load; (c) no load to full load; (d) full load to no load. Figure 18 is a diagram showing an embodiment of the active solar tracking system of the high performance solar photovoltaic energy conversion system of the present invention, the system reacting in the presence or absence of shading: (a) no shading conditions; (b) shading conditions. Figure 19 is one embodiment of the active tracking system of the high performance solar photovoltaic energy conversion system of the present invention. The comparison between the fixed installation and the active tracking system is: (a) output voltage versus output power curve; (b) output voltage pair Output current curve. Figure 20 is one of the maximum power tracking embodiments of the high performance solar photovoltaic energy conversion system of the present invention. The system responds to the disturbance step of 0.15V: (a) output power, input voltage and input current relationship; (b) transient state Tracking trajectory; (c) steady state trajectory. Figure 21 is a schematic diagram of one of the maximum power chasing 31 1296457 traces of the high performance solar photovoltaic energy conversion system of the present invention, the system responds to the disturbance step of 0.3V (shake production) (8) output power, input voltage and input Current relationship; (b) transient tracking trajectory; (c) steady state trajectory. Figure 22 is one of the maximum power tracking embodiments of the high performance solar photovoltaic energy conversion system of the present invention, the system responds (crash) in the disturbance step of 0.3V (8) output power, input voltage and input current relationship; (8) transient state Tracking the execution; (c) Steady-state execution. Figure 23 is one of the maximum power tracking embodiments of the high performance solar photovoltaic energy conversion system of the present invention, and the system responds in response to the adaptive step disturbance method: (4) output power, input voltage and input current relationship; (8) transient state Tracking the execution; (c) Steady-state execution. [Main component symbol description] 10: Solar panel 20: High step-up ratio DC/DC converter circuit 201: DC input circuit 202: - Secondary circuit * 203: Regenerative passive cushion circuit 204: Secondary side circuit 205: Filter circuit 30 : Full-bridge converter 40: choke inductor 50: system control unit 60: microprocessor 70: drive circuit 32 1296457, 80: actuating device - Fpv: solar panel output voltage / pv: solar panel output current 匕: High boost ratio DC/DC converter circuit output voltage vw: mains voltage full bridge converter output current 7; transformer with high excitation current (referred to as coupling inductor) β: power semiconductor switch with high step-up ratio DC/DC converter circuit # A: Coupled inductor primary winding: coupled inductor secondary winding ': coupled inductor primary side magnetizing inductance 4: shank combined inductor primary winding leakage inductance · · DC input circuit input capacitor C\ : regenerative passive cushioning circuit Clamping capacitor c2: high-voltage capacitor of secondary circuit c^: filter capacitor of filter circuit • Μ: clamped diode of regenerative passive cushion circuit: regenerative passive cushion circuit Discharging diode: rectifier smoothing circuit of diode 33

Claims (1)

1296457 X. Patent application scope: 1. A high-performance solar photovoltaic energy conversion system, which comprises a solar panel: for absorbing solar energy and photoelectric conversion to generate electric energy; a high step-up ratio DC/DC conversion circuit: The conversion low-voltage DC power source is a high-voltage DC power source and is outputted to a high-voltage DC bus bar; a system control unit: which includes a microprocessor and a driving circuit for system control; a full-bridge converter: It consists of four power transistor switches connected to the high-voltage DC bus, controlled by the system control unit for DC/parent voltage conversion, and a choke inductor: connected to the output of the full-bridge converter and the mains. Between the high frequency components of the AC output voltage of the converter, and the AC output voltage is converted into an AC current output; the constant action device is a low power motor for supporting and actuating the solar panel, controlled by the system Unit manipulation and thus changing the panel angle of the solar panel; it is characterized by when the output voltage of the solar panel array is low As a system input, it provides DC/DC voltage conversion with high step-up ratio and high conversion efficiency, allowing system input parallel operation to avoid the overall failure caused by series boost and improving system performance. In addition, the DC bus voltage is difficult to change due to stability. It can be regarded as fixed value and dynamically decoupled from the downstream converter, which effectively simplifies the design of the converter control system. At the same time, the system implements the converter control strategy with the microprocessor. In addition to effectively planning the system performance, it has 34 1296457 The ability to compensate for uncertainties and external disturbances makes the system stable in parallel with the mains and has a high power factor; on the other hand, to improve system efficiency, the system adds a low-power actuator to change The angle of the solar panel is controlled by the microprocessor to obtain the maximum solar energy by changing the angle of the panel of the solar panel; in addition, the microprocessor can indirectly control the solar panel by controlling the output current of the converter. The operating point allows the solar panel to operate at an optimum point and output maximum power. 2. The high performance solar photovoltaic energy conversion system according to claim 1, wherein the high step-up ratio DC/DC conversion circuit comprises: a secondary circuit comprising: a power semiconductor switch, a primary winding of a coupled inductor, The polarity point is defined at the positive connection of the DC input circuit; a regenerative passive cushion circuit: a clamped diode, a discharge diode and a clamp capacitor; a secondary circuit: comprising a high voltage capacitor and a coupling Inductor secondary winding, the polarity point is defined at the junction with the high voltage capacitor; a filter circuit: a filter capacitor and a rectifying diode; when the power semiconductor switch of the primary circuit is turned on, the current stores energy in the coupled inductor The primary side winding, while the polarity point voltage of the secondary winding of the coupled inductor is positive, the winding voltage regenerates the passive cushioning circuit to clamp the capacitor voltage in series, and the regenerative passive cushioning circuit discharges the diode, applying a high voltage and a low current to the second High-voltage capacitor charging of the side circuit; when the power semiconductor switch is turned off, regeneration The clamped capacitor of the passive cushioning circuit, through which the diode is clamped, first absorbs the leakage inductance of the primary winding of the coupled inductor 35 1296457 - the current of the secondary winding of the coupled inductor, and the non-polar-point voltage of the winding is Positive, series coupled inductor primary side winding excitation current generated at non-polar point positive voltage, DC input voltage and secondary side circuit high voltage capacitor voltage four voltage, through the rectifier circuit of the filter circuit, charge the filter capacitor, stabilize DC output voltage; characterized by high boost ratio and high conversion efficiency, all switches and diodes can achieve voltage clamping function, no short-circuit current when the switch is turned on, and reverse high recovery current of the diode, and current Low ripple, optional respectively • Use low-cost high-efficiency components suitable for voltage range; this device proves that the conversion efficiency is not directly related to the boost ratio, and it is related to the duty cycle and whether the switch-on current is square wave. The higher the voltage ratio, the lower the efficiency of the technical bottleneck of the conventional circuit; the voltage of the power semiconductor switch is only related to The coupled inductors turns ratio and the voltage related to this characteristic is more suitable for application of DC power converter input voltage variation of a large range. 3. A high performance solar photovoltaic energy conversion system as described in claim 1 wherein the microprocessor performs an adaptive global sliding mode control strategy, a chasing time control strategy, and an adaptive step disturbance method, and is built in a pulse width modulation output module, the pulse width modulation output module outputs a pulse width modulation signal, and drives a power transistor switch of the full bridge converter through a converter driving circuit for controlling The output current of the converter. 4. A high performance solar photovoltaic energy conversion system as described in claim 3, wherein the adaptive global sliding mode control strategy performed by the microprocessor comprises a system performance plan: a system that is expected to be obtained under the normal conditions of the planning 36 1296457 • Performance; • A constrained controller: eliminates unpredictable disturbance effects from disturbances caused by system parameter changes, load changes, and unpatterned system dynamics; an adaptive algorithm: above the total set uncertainty The boundary is estimated to avoid the control force tremor caused by improper selection of the upper bound of the constraint controller; it is characterized in that the control process does not have an impending phase mode and all states are 10 on the sliding plane, and the whole control process is not affected by the system. Uncertainty influence, and can effectively reduce the control tremor phenomenon. At the same time, the full-bridge converter can effectively follow the current command and the same frequency as the mains in the case of uncertainties and external interference. Phase to achieve the best parallel efficiency of unit work. 5. The high-performance solar photovoltaic energy conversion system according to the third aspect of the patent application, wherein the microprocessor performs a sun-tracking control strategy by judging the open circuit voltage of the solar panel to determine the direction of rotation of the solar panel surface, and • The microprocessor outputs a drive signal to drive the actuator to obtain maximum solar energy; it is characterized by a simple architecture and easy implementation, and only needs to return the open circuit voltage of the solar energy; and because the sun moves slowly and monotonously, with low power The actuating device adopts a fixed interval time method to obtain the maximum solar energy energy and complete the chasing after the solar panel open circuit voltage is oscillated in one direction. 6. The high-performance solar photovoltaic energy conversion system as described in claim 3, wherein the adaptive step-disturbing method performed by the microprocessor transmits the output voltage and the output current of the solar panel back to 37 1296457, and calculates the round-out The power and the output voltage are less than i $the whole voltage perturbation step, and the output voltage of the solar panel is indirectly controlled by the current output of the converter to operate at the maximum power point; /... It has the advantage of the conventional disturbance observation method, but the disturbance step is adjusted with the system=condition. The response speed is fast and the operation can be stably operated. The maximum power is improved. The disturbance disturbance observation method has the disadvantage that the disturbance step and the response speed are difficult to be balanced, thereby reducing the power loss. Improve system performance. 38