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热门关键词： 光伏太阳能板天窗 防水光伏太阳能电池板 U玻璃光伏太阳能电池板
最初，光伏模块仅用于某些离网和小型光伏系统。之后，并网光伏应用的广泛发展以及光伏组件技术的日益更新，极大地提高了组件转换的效率。特别是，一些并网发电厂会充分利用其站点资源。因此，需要更高效的组件来增加投资回报。当然，典型的离网系统具有相对较大的位置，因此对组件转换效率的要求不是很高。因此，在系统设计期间选择组件时，通常首先应考虑传统组件。
1、考虑交流负载。常见负载分为三类：电阻性负载(灯，加热器等)，电感性负载(空调，电机等)和电容性负载(计算机主机电源等)。其中，感性负载是逆变器特有的，因为感性负载最初需要额定电流的3到5倍，而普通离网逆变器的150%至200%的短期过载能力无法满足要求。需要仔细考虑。容量扩展设计(当离网逆变器连接到感应负载时，系统设计至少需要感应负载的两倍)。在离网逆变器驱动2P空调(2*750W)的项目中，额定值为3kVA或更高的逆变器是正常配置。当然，通常同时存在三种类型的负载，但是最大的负载百分比会对逆变器产生很大的影响。
2、考虑直流侧。离网型逆变器具有内置的光伏充电器，通常分为两种类型：MPPT和PWM。随着技术的更新，PWM充电器已被淘汰，使MPPT充电器成为离网逆变器的首选。
3、其他选项。除了上述两个选项外，市场上还有很多公式，在此不再赘述。但是，一般说明如下：1)根据负载的大小和类型确定离网逆变器的额定功率。2)根据负载所需的储能电池的放电时间，确定储能电池的kWh值。3)根据当地日光和充电时间要求确定充电器等的性能(例如，必须在一天之内充满电)。
1、铅酸/凝胶电池：储能系统通常选择免维护的密封铅酸电池，以减少后续维护。经过150年的发展，铅酸电池在稳定性，安全性和价格方面均具有显着优势，目前已经这种电池在二次电池应用中所占比例最高，甚至是第一类储能电池。离网光伏电池。
2、铅酸电池：从传统铅酸电池发展而来的技术。将活性炭添加到铅酸电池的负极中可以大大延长铅酸电池的寿命。但是，作为铅酸电池的技术更新，成本要高一些。
3、锂三元锂/磷酸铁电池：与上述两种储能电池相比，锂离子电池具有更高的功率密度，更多的充电和放电循环以及更好的放电深度。由于需要额外的电池管理技术(BMS)，锂/磷酸铁三元锂电池的系统成本通常是铅酸电池的成本的2至3倍。另外，与铅酸电池和铅酸电池相比，热稳定性有些不足，因此与电网无关的光伏系统的应用率不高。然而，由于技术创新，三元锂三元/锂铁电池的市场份额逐渐增加，这是新应用的趋势。
Initially, PV modules will only be used in certain off-grid and small PV systems. Later, the extensive development of grid-connected photovoltaic applications and the update of photovoltaic module technology have greatly improved the efficiency of module conversion. In particular, some grid-connected power plants will make full use of their site resources. Therefore, more efficient components are needed to increase return on investment. Of course, typical off-grid systems have relatively large locations, so the requirement for component conversion efficiency is not very high. Therefore, when selecting components during system design, traditional components are usually considered first.
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Off-grid inverter
1. Consider AC load. Common loads fall into three categories: resistive loads (lamps, heaters, etc.), inductive loads (air conditioners, motors, etc.) and capacitive loads (computer mainframe power supplies, etc.). Among them, the inductive load is unique to the inverter, because the inductive load initially requires 3 to 5 times the rated current, and the short term overload capacity of ordinary off-grid inverters of 150% to 200% cannot meet the requirements. It needs careful consideration. Capacity expansion design (when an off-grid inverter is connected to an inductive load, the system design requires at least twice the inductive load). In projects where off-grid inverters drive 2P air conditioning (2*750W), inverters rated 3kVA or higher are the normal configuration. Of course, there are usually three types of loads at once, but the maximum load percentage can make a big difference to the inverter.
2. Consider the DC side. Off-grid inverters have built-in photovoltaic chargers and are usually divided into two types: MPPT and PWM. With the update of technology, PWM charger has been eliminated, making MPPT charger become the first choice of off-grid inverter.
3. Other options. In addition to the above two options, there are many formulas on the market, which will not be described here. However, the general instructions are as follows: 1) Determine the rated power of the off-grid inverter according to the size and type of the load. 2) Determine the kWh value of the energy storage battery according to the discharge time of the energy storage battery required by the load. 3) Determine the performance of the charger etc. according to local daylight and charging time requirements (e.g., it must be fully charged within a day).
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Energy storage battery
1. Lead-acid/gel batteries: Energy storage systems usually choose maintenance-free sealed lead-acid batteries to reduce subsequent maintenance. After 150 years of development, lead-acid battery has a significant advantage in stability, safety and price. At present, this kind of battery accounts for the highest proportion of secondary battery applications, and even the first type of energy storage battery. Off-grid photovoltaic cells.
2. Lead-acid battery: A technology developed from the traditional lead-acid battery. The life of lead-acid batteries can be greatly extended by adding activated carbon to the negative electrode of lead-acid batteries. However, as a technical update to lead-acid batteries, the cost is higher.
3. Lithium terre lithium/iron phosphate battery: Compared with the above two kinds of energy storage batteries, lithium ion batteries have higher power density, more charging and discharging cycles and better discharge depth. Due to the additional battery management technology (BMS) required, the system cost of LI-ion/FE-phosphate terpolymer batteries is usually two to three times that of lead-acid batteries. In addition, compared with lead-acid batteries and lead-acid batteries, the thermal stability is somewhat less, so grid-independent photovoltaic systems are not used at a high rate. However, due to technological innovation, the market share of ternary Li-ternary/Li-iron batteries is gradually increasing, which is the trend of new applications.
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