光伏發(fā)電是利用半導(dǎo)體界面的光生伏特效應(yīng)而將光能直接轉(zhuǎn)變?yōu)殡娔艿囊环N技術(shù)。這種技術(shù)的關(guān)鍵元件是太陽能電池。太陽能電池經(jīng)過串聯(lián)后進行封裝保護可形成大面積的太陽電池組件，再配合上功率控制器等部件就形成了光伏發(fā)電裝置。光伏發(fā)電的優(yōu)點是較少受地域限制，因為陽光普照大地;光伏系統(tǒng)還具有安全可靠、無噪聲、低污染、無需消耗燃料和架設(shè)輸電線路即可就地發(fā)電供電及建設(shè)同期短的優(yōu)點。

并網(wǎng)光伏發(fā)電就是太陽能組件產(chǎn)生的直流電經(jīng)過并網(wǎng)逆變器轉(zhuǎn)換成符合市電電網(wǎng)要求的交流電這后直接接入公共電網(wǎng)。并網(wǎng)光伏發(fā)電有集中式大型并網(wǎng)光伏電站一般都是國家級電站，主要特點是將所發(fā)電能直接輸送到電網(wǎng)，由電網(wǎng)統(tǒng)一調(diào)配向用戶供電。但這種電站投資大、建設(shè)周期長、占地面積大，目前還沒有太大發(fā)展。而分散式小型并網(wǎng)光伏，特別是光伏建筑一體化光伏發(fā)電，由于投資小、建設(shè)快、占地面積小、政策支持力度大等優(yōu)點，是目前并網(wǎng)光伏發(fā)電的主流。

戶用式太陽能發(fā)電系統(tǒng)

二、光伏發(fā)電的原理

光伏發(fā)電，其基本原理就是“光伏效應(yīng)”。光子照射到金屬上時，它的能量可以被金屬中某個電子全部吸收，電子吸收的能量足夠大，能克服金屬內(nèi)部引力做功，離開金屬表面逃逸出來，成為光電子。

白天采用高能vcz晶體發(fā)電板和太陽光互感對接和全天候24小時接收風能發(fā)電互補，通過全自動接收轉(zhuǎn)換柜接收，直接滿足所有家電用電需求。并通過國家信息產(chǎn)業(yè)化學物理電源產(chǎn)品質(zhì)量監(jiān)督檢驗中心檢測合格。

光照使不均勻半導(dǎo)體或半導(dǎo)體與金屬結(jié)合的不同部位之間產(chǎn)生電位差的現(xiàn)象。它首先是由光子(光波)轉(zhuǎn)化為電子、光能量轉(zhuǎn)化為電能量的過程;其次，是形成電壓過程。有了電壓，就像筑高了大壩，如果兩者之間連通，就會形成電流的回路。

光伏發(fā)電的主要原理是半導(dǎo)體的光電效應(yīng)。硅原子有4個外層電子，如果在純硅中摻入有5個外層電子的原子如磷原子，就成為N型半導(dǎo)體；若在純硅中摻入有3個外層電子的原子如硼原子，形成P型半導(dǎo)體。當P型和N型結(jié)合在一起時，接觸面就會形成電勢差，成為太陽能電池。當太陽光照射到P－N結(jié)后，空穴由P極區(qū)往N極區(qū)移動，電子由N極區(qū)向P極區(qū)移動，形成電流。

多晶硅經(jīng)過鑄錠、破錠、切片等程序后，制作成待加工的硅片。在硅片上摻雜和擴散微量的硼、磷等，就形成P－N結(jié)。然后采用絲網(wǎng)印刷，將精配好的銀漿印在硅片上做成柵線，經(jīng)過燒結(jié)，同時制成背電極，并在有柵線的面涂一層防反射涂層，電池片就至此制成。電池片排列組合成電池組件，就組成了大的電路板。一般在組件四周包鋁框，正面覆蓋玻璃，反面安裝電極。有了電池組件和其他輔助設(shè)備，就可以組成發(fā)電系統(tǒng)。為了將直流電轉(zhuǎn)化交流電，需要安裝電流轉(zhuǎn)換器。發(fā)電后可用蓄電池存儲，也可輸入公共電網(wǎng)。發(fā)電系統(tǒng)成本中，電池組件約占50%，電流轉(zhuǎn)換器、安裝費、其他輔助部件以及其他費用占另外 50%。

三、光伏電站的類型

光伏發(fā)電系統(tǒng)分為獨立光伏發(fā)電系統(tǒng)、并網(wǎng)型光伏發(fā)電系統(tǒng)及分布式光伏發(fā)電 系統(tǒng)。

1、獨立光伏發(fā)電也叫離網(wǎng)光伏發(fā)電。主要由太陽能電池組件、控制器、蓄電池組成，若要為交流負載供電，還需要配置交流逆變器。獨立光伏電站包括邊遠地區(qū)的村莊供電系統(tǒng)，太陽能戶用電源系統(tǒng) ，通信信號電源、陰極保護、太陽能路燈等各種帶有蓄電池的可以獨立運行的光伏發(fā)電系統(tǒng)。

2、并網(wǎng)光伏發(fā)電就是太陽能組件產(chǎn)生的直流電經(jīng)過并網(wǎng)逆變器轉(zhuǎn)換成符合市電電網(wǎng)要求的交流電之后直接接入公共電網(wǎng)。

可以分為帶蓄電池的和不帶蓄電池的并網(wǎng)發(fā)電系統(tǒng)。帶有蓄電池的并網(wǎng)發(fā)電系統(tǒng)具有可調(diào)度性，可以根據(jù)需要并入或退出電網(wǎng)，還具有備用電源的功能，當電網(wǎng)因故停電時可緊急供電。帶有蓄電池的光伏并網(wǎng)發(fā)電系統(tǒng)常常安裝在居民建筑；不帶蓄電池的并網(wǎng)發(fā)電系統(tǒng)不具備可調(diào)度性和備用電源的功能，一般安裝在較大型的系統(tǒng)上。并網(wǎng)光伏發(fā)電有集中式大型并網(wǎng)光伏電站一般都是國家級電站，主要特點是將所發(fā)電能直接輸送到電網(wǎng)，由電網(wǎng)統(tǒng)一調(diào)配向用戶供電。但這種電站投資大、建設(shè)周期長、占地面積大，還沒有太大發(fā)展。而分散式小型并網(wǎng)光伏，特別是光伏建筑一體化光伏發(fā)電，由于投資小、建設(shè)快、占地面積小、政策支持力度大等優(yōu)點，是并網(wǎng)光伏發(fā)電的主流。

3、分布式光伏發(fā)電系統(tǒng)，又稱分散式發(fā)電或分布式供能，是指在用戶現(xiàn)場或靠近用電現(xiàn)場配置較小的光伏發(fā)電供電系統(tǒng)，以滿足特定用戶的需求，支持現(xiàn)存配電網(wǎng)的經(jīng)濟運行，或者同時滿足這兩個方面的要求。　　分布式光伏發(fā)電系統(tǒng)的基本設(shè)備包括光伏電池組件、光伏方陣支架、直流匯流箱 、直流配電柜、并網(wǎng)逆變器、交流配電柜等設(shè)備，另外還有供電系統(tǒng)監(jiān)控裝置和環(huán)境監(jiān)測裝置。其運行模式是在有太陽輻射的條件下，光伏發(fā)電系統(tǒng)的太陽能電池組件陣列將太陽能轉(zhuǎn)換輸出的電能，經(jīng)過直流匯流箱集中送入直流配電柜，由并網(wǎng)逆變器逆變成交流電供給建筑自身負載，多余或不足的電力通過聯(lián)接電網(wǎng)來調(diào)節(jié)。

Photovoltaic power generation is a technology that directly converts light energy into electricity by using the photogenerated volt effect of semiconductor interface.   The key element in this technology is the solar cell.  Solar cells after series packaging protection can form a large area of solar cell components, and then with the power controller and other components to form a photovoltaic power generation device.  Photovoltaics have the advantage of being less localised, since the sun shines; The photovoltaic system also has the advantages of safety and reliability, no noise, low pollution, no need to consume fuel and set up transmission lines to generate electricity and supply power locally, and the construction period is short.  

Grid-connected photovoltaic power generation means that the direct current generated by solar modules is converted into alternating current that meets the requirements of the mains power grid through grid-connected inverter and then directly connected to the public power grid.   Grid-connected photovoltaic power generation centralized large-scale grid-connected photovoltaic power stations are generally national-level power stations, the main feature of which is that the generated energy is directly transmitted to the power grid, and the power grid is unified to supply power to users.  However, this kind of power station has not been developed much because of its large investment, long construction cycle and large area.  And the distributed small-scale grid-connected photovoltaic, especially the integrated photovoltaic power generation of photovoltaic buildings, is the mainstream of grid-connected photovoltaic power generation due to the advantages of small investment, fast construction, small footprint, and large policy support.  

Image of household solar power system  

The principle of photovoltaic power generation  

Photovoltaic power generation, its basic principle is the "photovoltaic effect".  When a photon strikes a metal, its energy can be completely absorbed by an electron in the metal. The energy absorbed by the electron is large enough to overcome the metal's internal gravity to do work, leave the metal surface and escape, becoming a photoelectron.  

During the day, it adopts high-energy VCZ crystal power generation panel and solar light mutual induction docking and round-the-clock wind power generation complementarity. It can directly meet the electricity demand of all household appliances through automatic receiving and conversion cabinet.   And passed the national information industry chemical physical power supply product quality supervision and inspection center test qualified.  

An electric potential difference caused by light exposure in an inhomogeneous semiconductor or between different parts of a semiconductor bound to a metal.   It is first from the photon (light wave) into electrons, light energy into electric energy process;  Second, is the formation of voltage process.  With voltage, it's like building a dam, and if the two are connected, it creates a loop of current.  

The main principle of photovoltaic power generation is the photoelectric effect of semiconductors.  Silicon atoms have four outer electrons. If pure silicon is mixed with an atom with five outer electrons, such as phosphorus, it becomes an N-type semiconductor.  If pure silicon is mixed with atoms with three outer electrons, such as boron atoms, P-type semiconductors are formed.  When the P-type and N-type are combined, the contact surface will form a potential difference and become a solar cell.  When sunlight hits the P-N junction, holes move from the P-pole region to the N-pole region, and electrons move from the N-pole region to the P-pole region, forming an electric current.  The picture  

The polysilicon is made into silicon wafers to be processed after ingot casting, ingot breaking, slice and other procedures.  The P-N junction is formed by doping and diffusing trace amounts of boron and phosphorus on the silicon wafer.  Then using screen printing, the fine silver paste is printed on a silicon wafer to make a grid line. After sintering, the back electrode is made at the same time, and the surface of the grid line is coated with a layer of anti-reflection coating, and the cell sheet is made.  The cells are arranged and combined into battery components to form large circuit boards.   Generally, the components are surrounded by aluminum frames, the front side is covered with glass, and the opposite side is installed with electrodes.  With battery modules and other auxiliary equipment, a power generation system can be formed.  In order to convert direct current to alternating current, a current converter is required.  After generating electricity, it can be stored by battery or input into public power grid.  Battery components account for about 50 percent of the cost of a generation system, and current converters, installation, other ancillary components and other expenses account for another 50 percent.  

3. Types of photovoltaic power stations  

Photovoltaic power generation system is divided into independent photovoltaic power generation system, grid-connected photovoltaic power generation system and distributed photovoltaic power generation system.  

1. Independent photovoltaic power generation is also called off-grid photovoltaic power generation.  It is mainly composed of solar cell modules, controllers, and batteries. To power AC loads, an AC inverter is also required.  Independent photovoltaic power station includes village power supply system in remote areas, solar household power supply system, communication signal power supply, cathodic protection, solar street lamp and other photovoltaic power generation systems with batteries that can operate independently.  

The picture  

2. Grid-connected photovoltaic power generation refers to the direct current generated by solar modules that is converted into alternating current that meets the requirements of the mains power grid by grid-connected inverter and then directly connected to the public power grid.  

It can be divided into grid-connected power generation systems with and without batteries.  The grid-connected power generation system with battery is dispatchable and can be incorporated into or withdrawn from the power grid as required. It also has the function of backup power supply, which can provide emergency power when the power grid fails for some reason.  Grid-connected photovoltaic power systems with batteries are often installed in residential buildings;   Grid-connected power generation systems without batteries do not have the functions of schedulability and backup power supply, and are generally installed in larger systems.  Grid-connected photovoltaic power generation centralized large-scale grid-connected photovoltaic power stations are generally national-level power stations, the main feature of which is that the generated energy is directly transmitted to the power grid, and the power grid is unified to supply power to users.  However, this kind of power station has not been developed much because of its large investment, long construction cycle and large area.  And the distributed small-scale grid-connected photovoltaic, especially the integrated photovoltaic power generation of photovoltaic buildings, is the mainstream of grid-connected photovoltaic power generation due to the advantages of small investment, fast construction, small footprint, and large policy support.  

The picture  

3. Distributed photovoltaic power generation system, also known as distributed power generation or distributed energy supply, refers to the configuration of small photovoltaic power supply system at or near the user site to meet the needs of specific users, support the economic operation of the existing distribution network, or meet the requirements of the two aspects at the same time.   The basic equipment of the distributed photovoltaic power generation system includes photovoltaic cell modules, photovoltaic square support, DC bus box, DC power distribution cabinet, grid-connected inverter, AC power distribution cabinet and other equipment. In addition, there are power supply system monitoring devices and environmental monitoring devices.   Its operation mode is in the solar radiation conditions, photovoltaic power generation system of solar cell module array to convert solar energy output power, a dc bus concentrated into dc power distribution cabinet, by the grid inverter inverter into alternating current supply of building their own load, excess or shortage of electricity through the grid to adjust.