關于太陽能路燈的英文文獻

1、Design and Development of Energy-Free SolarStreet LED Light SystemMokhtar Ali1, Mohamed Orabi1, Emad Abdelkarim1, Jaber A. Abu Qahouq 2 and Abdelali El Aroudi31APEARC, South Valley University, Aswan 81542, Egypt2Electrical and Computer Eng. Dept., The University of Alabama, Tuscaloosa, Alabama 35487

2、, USA3Universitat Rovira i Virgili, Tarragona, SpainorabiAbstract- Today, all count words are about how to enhancethe electrical grid reliability during the peak instant. The directsolution for the grid is to cut off some loads to keep its stability.One of these loads is the street lighting especial

3、ly during thesummer period. This paper proposes an energy-free system forstreet lighting as there is no power demand from the grid. Astandalone solar street LED light system is proposed. Theproposed system consists of a PV panel, storage system, LEDlamp, power conditioning system (PCS) and the contr

4、oller whichcan manage the power direction and system operation. UsingLED in lighting applications has many advantages compared toother lamp. It is very efficient (very high efficiency lightingsource) lamps and cost effective (the life time is very longcompare to other lamps). In additions to, it nee

5、ds low dc voltagesource to be operated. The storage system will be charged duringthe day time using the available sunlight. On the other hand,during the night time the controller will give a signal to thesystem to connect the LED lamp to be ready for use. Since theLED needs a low dc voltage to be op

6、erated, a simple dc-dcconverter will be enough for this system resulting in decreasingthe cost of the overall system. Moreover, a low costmicrocontroller is proposed to handle the operation of the wholesystem. Applying this idea in the Egyptian streets enables thereduction of more than 50 % of the t

7、otal required energy by HIDlamps that enable the use for small PV system. By this proposedsystem, streets can be illuminated with lower power lamps, nooperating costs, no CO2 emissions, grid energy-free andenvironmentally friendly. Moreover, the proposed solution cansolve the Egyptian peak point cri

8、sis of load demand.Index Terms- energy-free system, LED, microcontroller, PVpanel, street lighting.I. INTRODUCTIONToday world is facing an energy shortage due to theincrease of the average consumption of energy per capita. Thisled to continuous decrease of the world storage of oil andnatural gaz. Al

9、so pollution problems have been highlighted asthe source of stresses on the ground life. Therefore,Renewable Energy Technologies have drawn tremendousinterest worldwide to find solutions for world energy crisis.Recently PV systems have found fairly wide applications fromlarge scale PV plants with cu

10、mulative power reachesapproximately a few tenths of GWp were connected toreaching the grid of a small scale PV reaching approximately afew tenths of Watts in applications such as Camera, watches,Mobiles, etc. One of these PV applications is the standalonestreet lighting system using the most efficie

11、nt and the costeffective Light Emitting Diode (LED) lamps. This systemconsists of PV panel, high quality battery, LED lamp, dc-dcconverter, and a controller.This system is not only an environmentally friendly option(requiring no power input plus free of pollution), but can alsobe located anywhere re

12、gardless of local grid availability. Thepower source is a solar power which is recognized as being anenvironmentally clean form an energy production point ofview. PV arrays utilize the sun radiation to produce electricity.These modules do not require fuel to operate.On the other hand, most current s

13、treet lighting uses highintensity discharge lamps. Recently, searching for new streetlighting modules has gained a lot of attention to reduce theamount of energy consumed by this type of lamp and also toreduce the amount of CO2 emissions. LEDs with their currentperformances have proved themselves to

14、 be the most suitablesolution for LED street lighting, 1 and 2. The LED lampoffers many advantages such as: extremely long life, 100,000hours, extreme robustness as there are no glass components orfilaments, no external reflector, a modular construction, noemissions like HID lamps and most important

15、ly their highefficiency. LEDs are good light source; their efficiency is 160Lm/W. So, using this type of lamps enables the reduction ofmore than 50 % of the total energy used by HID lamps; that byits order reduces the required PV arrays. Therefore, applyingthe proposed system, streets can be illumin

16、ated with lowerpower lamps, no operating costs, no CO2 emissions andenvironmentally friendly 3 - 4.Due to the importance of the issue, there are manycompanies around the world that are now involved indeveloping, building, and producing these products of streetlight. Also there is a variety of produc

17、ts with wide range ofpower and wide range of lamp type used. Figure 1 and 2 showexamples of the solar street LED light system produced byGEO-Technik 5.Fig. 1: LED Solar Pathway Light model LT-SOL10.Fig. 2: Solar Street Light LED model LT-SOLAR051-220L.(a)The Solar Illumination Project in Beijing Oly

18、mpic Wrestling Venue LampsLSL0733-7325LD30W/24 Pole height:7 meters Distance between two poles:15 meters Road width: 10 meters Solar energy system: 80W Quantity:10 PCS.(b)The Lingqiu County Solar Illumination Project in Datong of Shanxi ProvincePole height 7meters, Distance between two poles) 20m, R

19、oad width:15m,LSL0733-7325LD30W/24, quantity: 150pcsFig. 3: solar LED Street lighting (EverGEN 1500 Series).(c)This project is located in the Shipai Wetland Park. The park is located at theWest part of Dongguan with a planned area of 280,000 square meters. Basedon Kingsun Solar-Wind LED Street Light

20、 Project in Songshan Lake,Dongguan Government decides to use Kingsun Solar-Wind LED Street Lightin this project. The pole in this area is 10 meters height, we suggest our clientto using the KS-E108TX Solar-Wind LED Street Light system in this project.(d)This shows you BBE LU2 in Calama city of Chile

21、, solar LED street light is avery good choice for the clean energy with the sustainable development.Fig. 4: A few existence examples of solar light street applications.They are Sandstorm- and weatherproof PV street lightingfixture, equipped with high power LED Chip with powerrange of 100 W and 120 W

22、, respectively. By the use of LEDlamps and microcontroller system control, we think that itsapplication could be interesting as they have a longmaintenance-free life time. Figure 3 shows another model ofstreet light LED lamp, it is EverGEN 1500 Series producedby Solar Street Lights Company 6. Figure

23、 4 shows a fewexisting examples of solar street light applications thatconfirm that this proposed idea is a practical one. Looking intothe practicality of the idea and its suitability for Egypt, wethink that its application in this country could give interestingresults. The main reasons behind that:

24、 Egypt is one from themain counties where PV can be connected and have highpower generation at anywhere and the sunlight is available forlong day time. Egypt today has problems of CO2 emissionsand a lot of pollutions. Recently Egypt has a problem withpeak load demand that forces the companies to dis

25、connectsome regions from electricity to keep the stability of the grid.Also, Egypt has new long roads far away from the grid whoseconnection to the grid will be too costly. Moreover, the newpolicies in Egypt require using free and renewable energy. Allthese factors are pushing the direction of using

26、 the proposedsystem. However, it should be manufactured locally to reducethe system manufacturing cost. However, it should bemanufactured locally to reduce the system manufacturing costfrom one side and to create a locally expect and cheapmaintenance system from the other side. Therefore, its design

27、steps and modes should be understood and adopted based onevery country requirements and sources.Fig. 5: Energy consumed in Egypt by purpose in year 2008/2009.Fig. 6: Load demand before and after using the proposed system.II. EGYPT LOAD DEMAND AND EMERGED PROBLEMFigure 5 shows the consumed energy in

28、Egypt for2008/2009. The general lighting consumes 6.2 % of the totalGWhr in Egypt 7. By other word, the required energy forgeneral lighting in Egypt is 6982 GWhr in this year.Two simple proposed ideas can be discussed here. The firstis just simply using LED lighting only. This enables the 80WLED lam

29、p to replace the 150 W HPS lamp gaining the lowconsumption for the same lighting intensity, so an energyreduction by 46.67 % of the total power consumed by lightingsources. Using LED lamps requires only 3724 GWhr per year.Thus saving in power reaches approximately to 3258 GWhr.The amount of equivale

30、nt fuel consumption related to the6982 GWhr is 1519 thousand ton mazot. This charges 276.3million L.E. Moreover, by replacing this proposed system, thedaily load demand curve will change as shown in Fig. 6. Thelighting loads will work for approximately 10hours from about7:00 PM to 4:00 AM. The maxim

31、um load demand occursduring 8:00 PM to 11:00 PM 7. The maximum load demandwhich was found to be 21330 MW before using the proposedsystem will decrease to be 19391 MW. This is a very big stepin improving the load demand situation in Egypt.The second step is to use the remote PV-LED system whichwill c

32、ompensate for the general light energy totally and get therequired amount for LEDs through the PV system. This willsave for the load demand the total 6.2% as shown in Fig. 6.III. THE PROPOSED SYSTEM OPERATIONAL MODESFigure 7 shows the schematic circuit diagram of theproposed PCS which operates to ch

33、arge the battery at day timeand also to power the LED lamp at night time. The proposedcontrol loop has implemented using only one microcontrollerwhich will control the charge and discharge phases. It is worthnoting here that during charging period, the control shouldextract the Maximum Power Point (

34、MPPT) from the PVsystem. This is done by MPPT control algorithm implementedinside the microcontroller. The LED brightness is dependenton its current, so a LED current control algorithm is alsoemployed on the microcontroller. Figure 8 shows the proposedpower stage for driving the system of the standa

35、lone streetLED lamp light. The proposed system is 76 Watt street LEDlamp light. It consists of as mentioned before from the PVpanel with rating values of 85 Watt at 17 V and 5 A shortcircuit current ratings, storage battery system with voltage of24 V, PCS, and LED lamp. Figures 9 and 10 show the day

36、 andnight time operation modes of the system, respectively.During the day time, the lamp is disconnected and the derivedsystem is shown in Fig. 9 where the PV panel is connected tothe battery for charging it. So switches Q4 and Q5 are on theOFF state while switch Q1 is on the ON state. The twoswitch

37、es Q2 and Q3 are synchronously switched with PulseWidth Modulation (PWM) signal. Switch Q2 with the coil andthe switch Q3 are forming a simple boost converter system.This is because of the PV panel voltage supposes to be smallerthan the battery voltage. The switching signals of this modeare shown in

38、 Fig. 11. During the night time, the operation isreversed. Switch Q1 should be in the OFF state, since there isno sunlight and thus operation is unnecessary. But switch Q3 isturned on and switches Q4 and Q5 are operated synchronouslywith PWM. Switches Q2 and Q3 with the coil and the capacitorCo are

39、forming a simple boost converter system. This isbecause the load voltage (LED Lamp) is larger than thebattery voltage.Fig. 11: The switching signals of switches.Fig. 7: The schematic circuit diagram of the proposed system.Q1L2Q3PVArrayQ5Q2CbBatteryModelQ4Fig. 12: LED module array used in street ligh

40、tening.LEDCoStringIV. COMPONENT DESIGN AND SELECTIONTo study the feasibility of the proposed driver, a prototypeFig. 8: The power stage components of the proposed street LED light systemFig. 9: Mode 1day time OperationFig. 10: Mode 2 night time operationhas been designed for a LED street lighting la

41、mp of 80 W.Comparing to high pressure sodium lamp, the LED street lightcan save about 50% - 70% energy. Besides, the life span ofLED street lamp is 3 - 5 times to sodium lamps. For example,the 30 W, 60 W, 100 W and 180 W LED street lights are goodsolutions to replace the conventional 80 W, 150 W, 25

42、0 W and160 W high pressure sodium lamps 8. Because of low powerconsumption, it is the best candidate light source of solar streetlights. This can be assured by the LED lamp driver that waspresented for street lighting system in 9 and 10 foruniversal AC input. There are many LEDs that are forming the

43、lamp because of the illumination produced by a single LED isrelatively weak. Therefore, it is necessary to increase the fluxby incorporating strings of LEDs of series and parallelcombinations into a module array in order to use them forstreet illumination as shown in Fig. 12, 11. The LED lampthat wi

44、ll be used consists of 4 branches of 19 LEDs in series.The LEDs are of the type cool white Cree XM LED driven at400 mA. This type of LED lamp can give overall luminousefficacy of 132 lm/W 12.Batteries accumulate the energy created by the PV systemduring the day time and store it to be used at night.

45、 Batteriescan discharge rapidly and yield more current that the chargingsource can produce by itself. Battery capacity is listed in amphours at a given voltage. For our example of 76 Watt lamp a50 Amp.Hr Li-battery is used. This can withstand for anothercloudy day where there is weak sunlight for ch

46、arging. Theproposed system was simulated using PSIM software. TheBP485 85 W PV module is proposed to be used with thissystem 13. The electrical characteristics of the used PVmodule are shown in Table 1.Table 1: Electrical characteristics of BP 485 Solar cell moduleV. THE EFFECT OF SHADING AND DUSTOn

47、e of the best features in Egypt is the dry weather thatenhances the widespread of using PV systems in electricalpower generation. As mentioned in the previous section, theselected 50 Amp.Hr Li-battery can withstand for anothercloudy day where there is weak sunlight for charging. Also,the special MPP

48、T algorithm proposed previously in 14 canbe used for cloudy and partially shaded places. It represents asimple Maximum Power Point Tracking (MPPT) trackingtechnique for partially shaded PV using two stages of theconventional perturb and observe method (P&O). The firststage searches the I-V character

49、istic of the PV arrays byscanning the whole range to detect the actual MPP using aP&O with large value of step. The second stage and afterknowing the point of the actual MPP, applies the conventionalP&O method to oscillate around it but with very small stepthat to provide very little oscillation wit

50、h a higher efficiency.Figure 13 shows the characteristic output power curve forthe solar cell from simulation under a given temperature andirradiance. MPPT control has been used and implemented forextracting the maximum power from the PV cell. The classicP&O algorithm is pretty simple 15 - 16. Figur

51、e 14 depicts aflow chart explaining it. It operates by perturbing the PV arrayvoltage (i.e. incrementing or decreasing) and comparing thePV output power with that of the previous perturbation cycle.If the perturbation leads to an increase (decrease) in arraypower, the subsequent perturbation is made

52、 in the same(opposite) direction. In this manner, the peak power is trackedcontinuously.VI. SIMULATION RESULTSThe proposed system has been simulated using PSIMsoftware to verify the performance of the proposed idea usingthe designed component values. Figure 15 shows the flowchartof the control algor

53、ithm that is implemented through themicrocontroller. The LED current is received by themicrocontroller then compared with a preset value. The switchduty cycles can be increased or decreased based on thiscomparison to attain constant LED current and thus constantillumination.Fig. 13: Plot of power ve

54、rsus voltage for the simulated PV.Fig. 14: Flowchart of the P&O algorithm.Figure 16 shows the current of the PV module due to thesunlight during the day time. The PV current is about 5 A. Thepower generated by this current is used to charge the batterythrough the boost converter. The charging curren

55、t of thebattery is shown in Fig. 17, where the constant currenttechnique is used in this example to charge it. The batterycurrent is about -2.5 A. During the night time, the batterydischarges through the boost converter to the LED lampmodule. The discharging current of the battery is shown inFig. 18

56、. The LED lamp light intensity is strongly dependent onits current so a controller must be used to control the LEDcurrent. Figure 19 shows the waveform of the LED current.The simulation results of the PV charging the battery is shownin Fig. 20. The PV output is 17 V with the perturbationsElectrical

57、characteristicsBP 485Maximum power Pmax85 WVoltage at maximum power17.8 VCurrent at maximum power4.9 AWarranted minimum Pmax80.75 WShort circuit current5.4 AOpen circuit voltage22.0 Voccurred by the MPPT algorithm as shown by the top part ofthe figure. Then the use of PCS consisting of the boostconv

58、erter is to charge the battery. The battery voltage duringcharging stage is shown in the bottom part of the figure.Fig. 18: The discharging current of the battery during night time.Fig. 19: The LED lamp currentPV Output30252015Fig. 15 The flowchart of the control algorithm of the microcontroller.105

59、0302520151050Battery charging voltage0.80.91Time (s)Fig. 20: The PV output voltage and the battery charging voltage duringday time.Fig. 16: The PV current to charge the batteryVII. EXPERIMENTAL RESULTSA laboratory prototype for the proposed system has beenbuilt and experimentally tested. Fi

60、gure 21 shows theexperimental setup. The MPPT algorithm was implementedwith a low cost microcontroller. The MPPT algorithm whichis described in the flow chart shown in Fig. 14 has beenemployed. Figure 22 shows the PV maximum output currentand voltage and maximum power, respectively. The maximumpower