一、系統構成

     離網型太陽能光伏發電系統主要由太陽能電池板、蓄電池組、太陽能控制器、變換器和監控系統等五大部分組成。圖一為光伏發電系統示意圖，圖二為系統構成原理框圖。各部分的功能和作用是：

1、 光伏電池板：它是光伏發電的核心，其作用是太陽輻射能直接轉換為直流電能供給負載或儲存在蓄電池中。

2、 光伏控制器：由于一般的單晶硅或多晶硅光伏電池板輸出為電流源型，不能直接輸出給負載和電池，需要通過光伏控制器將其變換為蓄電池可接受的穩定的電壓或電流，實現蓄電池的有效充電或供給外接負載。光伏控制器還能實現對蓄電池組的過沖和過放保護功能。

3、 逆變器；如果要求輸出為直流，則可以通過該部分將蓄電池的電壓轉換成不同的直流電壓以適應不同的負載設備。如果輸出為交流，則可通過直流電變為交流電 220V(單相）、380V（三相），對于家庭用，該部分一般采購交流逆變器。

4、監控系統：該部分的主要作用是監控各部分的工作參數和工作狀態，同時提供人機操作界面。

 

圖一  離網型光伏發電系統示意圖

圖二、離網型光伏發電構成原理圖

二、系統功能及特點 

1、能實現對蓄電池組的恒壓、恒流充電和充電過程的自動管理；  

2、具有太陽能最大功率點跟蹤控制功能（ MPPT），發揮光伏電池的最大功效；  3 、逆變器交流輸出波形正弦度好，輸出電壓穩定，抗擾能力強； 

4、保護功能完善，具有蓄電池過充、過放、輸出過壓、過流、短路等多種保護；  

5、具有交流電網供電后備功能，當多日無太陽光照，蓄電池儲存電能無法滿足輸出供電時，系統可自動切換為交流市電供電，由于采用直流側無間斷切換，交流輸出無間斷現象；  6、友好的人機操作界面、完善的監控功能，系統采用大尺寸觸摸液晶屏，操控方便、顯示直觀；  

 

三、系統適應領域 

1、家庭供電：特別適用于獨立式居住的家庭，如城市別墅區、農村家庭。對于城市居民小區，居住在頂樓的住戶或私家陽臺較大的家庭也較合適；  

2、學校供電：特別適用于中小學和幼兒園，在這些地方，一般白天用電較多，且用電量不大；  

3、醫院供電：可與醫院的應急供電系統融合在一起，可有效提高醫院的應急電源的可靠性和經濟性；  

4、城市小區公共供電：可安裝在城市小區公共部分，接入小區的公用電房，作為小區公用電使用；  

3、政府部門、企事業單位辦公大樓供電：集中安裝在辦公大樓的頂層，作為公用電接入大樓低壓配電柜中。

I. System structure  

 

Off-grid solar photovoltaic power generation system is mainly composed of solar panels, batteries, solar controller, converter and monitoring system.  Figure 1 is a schematic diagram of photovoltaic power generation system, and Figure 2 is a block diagram of system composition.  The functions and functions of each part are:  

 

1, photovoltaic panel: it is the core of photovoltaic power generation, its role is to directly convert solar radiation into direct current power supply load or stored in the battery.  

 

2, photovoltaic controller: because the output of the general monocrystalline silicon or polysilicon photovoltaic panel is the current source type, it can not be directly output to the load and battery, it needs to be transformed into a stable voltage or current acceptable to the battery through the photovoltaic controller, to realize the effective charging of the battery or supply external load.   The photovoltaic controller can also realize the protection function of overshoot and overdischarge of the battery.  

 

3. Inverter;  If dc output is required, the battery voltage can be converted to different DC voltages through this part to adapt to different load devices.  If the output is AC, it can be changed into AC 220V(single-phase) and 380V (three-phase) through direct current. For family use, ac inverters are generally purchased for this part.  

 

4, monitoring system: the main role of this part is to monitor the working parameters and working status of each part, while providing man-machine operation interface.  

 

 

 

FIG. 1 Schematic diagram of off-grid PHOTOVOLTAIC power generation system  

 

 

The picture  

 

 

 

Figure 2. Schematic diagram of off-grid photovoltaic power generation  

 

The picture  

 

Ii. System functions and characteristics  

 

1, can realize the battery constant voltage, constant current charging and charging process automatic management;  

 

2, with solar maximum power point tracking control function (MPPT), to maximize the efficiency of photovoltaic cells;  3, inverter AC output waveform sine, stable output voltage, strong disturbance resistance;  

 

4, perfect protection function, with battery overcharge, overdischarge, output overvoltage, overcurrent, short circuit and other protection;  

 

5, with ac power supply backup function, when there is no sunlight for many days, the battery storage energy can not meet the output power supply, the system can automatically switch to AC power supply, because the DC side without interruption switch, AC output without interruption phenomenon;   6, friendly man-machine interface, perfect monitoring function, the system uses large touch LCD screen, easy to control, intuitive display;  

 

 

 

Three, system adaptation field  

 

1, home power supply: especially suitable for independent living families, such as urban villa areas, rural families.  To city dweller village, the household that lives in the top floor or the family with bigger private balcony is more appropriate also;  

 

2, school power supply: especially suitable for primary and secondary schools and kindergartens, in these places, generally during the day more electricity, and electricity consumption is not large;  

 

3, hospital power supply: can be integrated with the hospital emergency power supply system, can effectively improve the reliability and economy of the hospital emergency power supply;  

 

4, urban community public power supply: can be installed in the public part of the urban community, access to the community of public electricity room, as the community of public electricity use;  

 

3, government departments, enterprises and institutions office building power supply: centralized installation in the top floor of the office building, as a public power access building low-voltage power distribution cabinet.