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太陽光發電系統介紹. Solar cell 篇 Motech Industries Inc. Solar cell 種類. Solar Cell 製作. A. 將 n-type 摻雜,塗佈在 p-type 之表面。 B. 印刷導引線 ( 光與電阻性損失最小 ) 最大光吸收及電流收集。. Solar cell 比較. PV Module Performance Rating. 測試環境 1. The peak watt (Wp) rating A. Temp B. Solar radiation (AM1.5)
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太陽光發電系統介紹 Solar cell篇 Motech Industries Inc.
Solar Cell 製作 A. 將n-type摻雜,塗佈在p-type之表面。 B. 印刷導引線(光與電阻性損失最小) 最大光吸收及電流收集。
PV Module Performance Rating • 測試環境 1. The peak watt (Wp) rating A. Temp B. Solar radiation (AM1.5) 但如此實驗室的狀態不實際。 2. NOCT-normal operating cell temperature 在一定之室外溫度下所測得之最大功率,雖較 Wp 為低,但較真實。 3. AMPM standard global-average day : light level, ambient temperature, air mass
Electrical Performance • 1. Power Output:一天內產生之peak power or avg power。 (watts) 2. Energy Output: (Wh) 在一定之週期下評估以上3項目 3. Conversion efficiency: energy output from array energy input from sun 評價單位:1EEE、ASTM (American Society for Testing and Materials) 100% x
I 2ND Quadrant: Generation 1ST Quadrant: Dissipation V 3D Quadrant: Dissipation 4TH Quadrant: Generation Power is either generated or dissipated, depending on the quadrant you are in.
I I V Power Dissipating Region Power Generating Region V Power Dissipating Region Dark CharacteristicLight Characteristic
The VI characteristic of a solar cell is usually displayed like this: I V V I The coordinate system is flipped around the voltage axis.
Power is a function of position along the VI characteristic. At the intercepts, it is minimum - zero - increasing to a max near the knee of the curve.
Set #1: ISC , PMAX , VOC ISC PMAX (0V, 150 mA) V I = 0 mW (0.43 V, 142 mA) V I = 61 mW Some typical values (0.5V, 0 mA) V I = 0 mW VOC
The short circuit current ISC is a linear function of sunlight intensity. The open circuit voltage VOC is not. (VOC is weakly dependent on temperature.) Recall from Part I that sunlight intensity is measured in terms of a solar constant with units such as mW/cm2.
Answer to Question #1: I = ISC R = 0 Does it surprise you that the current at short circuit is not infinite? Or that a current can flow with no voltage? Where does the energy originate?
Answer to Question #2: I = 0 + _ R = V = VOC
Answer to Questions #3 and #4 (cont’d): Hyperbola for P = PMAX ISC Point of tangency Current at max power VOC Voltage at max power
Set #2: RS , RSH RSH ISC The slopes of these lines are characteristic resistances. RS VOC
Questions: 1. Which resistance is higher, the measurement at ISC or the measurement at VOC ? Remember: R = V/I ! 2. Physically, what do you think these resistances represent? 3. As a solar cell designer, what is your preferred ideal value?
Answers to Questions #1 - #3: The resistance at ISC is extremely high. In an equivalent circuit model of a solar cell, it represents a shunt resistance. The resistance at VOC is extremely low. In an equivalent circuit model of a solar cell, it represents a series resistance. Both of these resistances are internal, and represent energy dissipation mechanisms in the cell. Ideally, a designer would like zero series resistance and infiniteshunt resistance.
Cell RS RLOAD RSH ISC Cell Equivalent circuit for a solar cell with load. Internal resistances RS and RSH represent power loss mechanisms inside the cell.
RS = 0 RLOAD RSH = ISC The ideal solar cell would have no internal losses at all! What would the VI characteristic of THIS cell look like?
The Ideal Solar Cell ISC RSH = RS = 0 VOC
The Ideal Solar Cell ISC Notice that the area under the rectangle = PMAX for the ideal cell. For this cell, PMAX = VOC ISC VOC
Set #3: Fill Factor ISC In fact, PMAX/(ISC VOC) measures the cell’s quality as a power source. The quantity is called the “Fill Factor.” Can you see why? VOC
Questions: 1. What is the ideal fill factor? 2. Can the ideal cell ever be built? Why or why not? 3. For a cell with these parameters: (0V, 150mA), (0.43V, 142mA), and (0.5V, 0mA) calculate the fill factor.
Answer to Question #1: The ideal fill factor is unity. Why? Answer to Question #2: An ideal cell might be approximated, but never actually built. Nature is never ideal as humans think about “ideal.” Answer to Question #3: The fill factor is: (0.43V 142mA)/(0.5V 150mA) = 0.81 = 81%
太陽光發電系統介紹 Inverter 篇 Motech Industries Inc.
變流器技術 • 太陽光電池與電池產生直流電壓與電流,然而負載所需為交流功率時,那麼就需要Inverter來轉換DC/AC,一般來說可利用Inverter轉換DC電源成為交流單/三相、50/60Hz、117/220V,而轉換功率可從數百Watts到數千KWatts,較大功率輸出的Inverter其輸出電壓可達480V甚至更高。
變流器的功率額定 • 1.功率是時間的函數 • 2.突波功率 • 3.溫度對額定功率的影響
變流器的效率 • 1.效率視負載而定 • 2.電感性對電阻性負載 • 3.效率測量的設定
變流器的波形 • 1.方波 • 2.修正方波或修正弦波 • 3.弦波
變流器電路 • 1.先變頻再變壓 • 2.先變壓再變頻 • 3.波寬調變 • 4.多工變壓器
市電併聯混合型變流器 • More flexibility on power management. • Provides limited power for critical loads incase of power failure. • Requires Battery maintenance schedule.
變流器特徵總合 • AC OUTPUT PARAMETERS • DC INPUT PARAMETERS • PROTECTION • GENERAL SPECIFICATION
AC OUTPUT PARAMETERS • Output Voltage • Output Frequency • Continues AC output rating • Waveform • Output Power Factor • THD • DC control injection • Efficiency
DC INPUT PARAMETERS • Input Power control • MPPT Range
PROTECTION • Internal Protection System • Anti islanding • Protection signals/contacts • Internal Shutdown
GENERAL SPECIFICATION 1 • Parallel Operation • Local Operator Interface • Front Panel LCD Display • Computer Ports Isolation • Remote Access • Parameters Fault log • Communications
GENERAL SPECIFICATION 2 • Output Date Files • Operating Temperature Rang • Humidity • Enclosure • Printed Circuit Boards • Standby Tare Losses • Noise • Aux. ADC Port
選擇變流器特性之進一步探討 • 1.直流輸入電壓 • 2.電壓調整率 • 3.可服務性 • 4.臨界點調整 • 5.併聯成較大功率源