Photovoltaic System Design 1 Introduction After PV workers unremitting efforts, solar cell production technology constantly improve, and increasingly widely used in various fields. Posts and
telecommunications in particular, the telecommunications industry in recent years because of the rapid development of communication power requirements have become more sophisticated, so stable and reliable power Solar energy is widely used in communications. And how the various regions of solar radiation conditions, to the design of both economic and reliable photovoltaic power system, which is one of the many experts and scholars study the long-standing issue, but there are many excellent research results, for the development of China's photovoltaic laid a solid foundation. The author of the study at the design methodology of experts found that the design has only considered the self-maintenance of battery time (that is, the longest consecutive rainy days), without taking into account the loss of electric batteries as soon as possible after the recovery time (ie, two sets of the longest continuous rain days, the shortest interval between the days). This problem particularly in the southern China region should pay great attention to the southern region because of our rainy day is long too, and for the convenience of independent photovoltaic power system, because there is no other emergency backup power protection, so this problem should be included in the design considered together. In this paper, an integrated design method of the previous advantages, combined with the author over the years actually engaged in the design of photovoltaic power systems experience, the introduction of two sets of the longest consecutive rainy days, the shortest interval between the number of days as the basis for the design of one, and comprehensive consideration of the the impact of solar radiation conditions of the factors that made solar cells, the formula for calculating battery capacity, and related design methods. 2 Many factors affect the design Sun solar cells on the ground square on the radiation of light spectrum, light intensity by the thickness of the atmosphere (ie air quality), geographic location, the location of the climate and weather, terrain and surface features such as the impact of its energy in one day, January and a year of great change, or even years between the total annual amount of radiation There were also large differences. Square solar photoelectric conversion efficiency, by the battery itself,
temperature, sunlight intensity and battery voltage fluctuations, which is three in one day will change, so square photovoltaic solar cell conversion efficiency is also variable. Battery is charging in the float state, with the square of its voltage output and load power consumption changes. Batteries to provide energy is also affected by environmental temperature. Solar energy battery charge and discharge controller made by the electronic components manufacturer, it is also necessary energy, while the use of components of performance, quality, etc. is also related to the size of energy consumption, thus affecting the efficiency of charge. Load of electricity, but also as determined by uses, such as communications relay stations, unmanned weather stations and so on, have a fixed power equipment. Some equipment such as a lighthouse, beacon lights, civilian power consumption such as lighting and equipment power consumption are often changing. Therefore, the solar power system design, the need to consider many factors and complex. Characteristics are: the data used in most previous statistical data, the statistical data measurement and data selection are important. Designers of the mission are: In the solar cell matrix under the conditions of the environment (that is, the scene of the geographical location, solar radiation, climate, weather, terrain and surface features, etc.), the design of solar cell and battery power system matrix is We should pay attention to economic efficiency, but also to ensure system reliability. Location of a particular energy of solar radiation data to meteorological information provided the basis for the design of solar cells used phalanx. These meteorological data required to check the accumulation of several years or even decades on average. Various regions on the Earth by sunlight and radiation changes in the cycle for the day, 24h. In a square area of solar cells also have the power output 24h of the cyclical changes in its laws and sun radiation in the region, the changes of the same. However, changes in weather will affect the square of the generating capacity. If you have a few days consecutive rain days, almost square on the power generation should not rely on batteries to power, and battery depth of discharge and then need to be added as soon as possible good. Most designers in order to weather the sun to provide a daily total of radiation energy or the annual average sunshine hours as the design of
the main data. Each year because of a regional data is not the same as for the sake of reliability should be taken within the last decade of the minimum data. Under the load of electricity consumption, in sunshine and no sunshine when battery power is required. Weather provided by solar power or the total amount of radiation the total sunshine hours on the battery capacity of the size of the decision is indispensable data. Phalanx of the solar cell, the load should include all power system devices (except for use but also have a battery and electrical circuits, controllers, etc.) consumption. Matrix components of the output power and the number of series-parallel, and series are required in order to obtain the operating voltage, in parallel are necessary in order to obtain the current work, an appropriate number of components through which the composition of series-parallel connection of solar cells required phalanx. 3 Designed capacity of batteries Solar cell power supply system is the battery energy storage devices. And solar cell batteries are usually square matching job at Floating state, with the square of its voltage output and load power consumption changes. Its load capacity than the power required is much greater. Batteries to provide energy is also affected by environmental temperature. And solar cells in order to match the job requirements of long life battery and easy maintenance. (1)Battery Selection And be able to support the use of solar cells, many different types of batteries, widely used at present have lead-acid maintenance-free batteries, ordinary lead-acid batteries and alkaline nickel-cadmium batteries of three. Domestic use are mainly maintenance-free lead-acid batteries, because of its inherent "free" maintenance of properties and less polluting to the environment characteristics, it is suitable for the performance of reliable power systems solar power, especially in unattended workstations. Ordinary lead-acid batteries require regular maintenance because of its larger environmental pollution, so the main suitable for the maintenance of the ability or have the use of low-grade occasions. Although alkaline nickel-cadmium batteries have better low-temperature, over-charge, take-off performance, but because of their higher prices, only applies to more special occasions. (2)Calculation of battery capacity Battery capacity to ensure continuous power supply is very important. At one year,
the month of matrix generation has very different. Phalanx at the generating capacity can not meet the electricity needs of the month, to rely on battery power give supplement; electricity required in more than month, are relying on batteries to store excess energy. Phalanx so inadequate generating capacity and surplus value, is to determine the basis for one of the battery capacity. Similarly, the continuous overcast and rainy days during the load of electricity must also be obtained from the battery. Therefore, the power consumption during this period to determine the battery capacity is also one of the factors.
1 引言 经过光伏工作者们坚持不懈的努力，太阳能电池的生产技术不断得到提高， 并且日益广泛地应用于各个领域。特别是邮电通信方面，由于近年来通信行业的 迅猛发展， 对通信电源的要求也越来越高，所以稳定可靠的太阳能电源被广泛使 用于通信领域。 而如何根据各地区太阳能辐射条件，来设计出既经济而又可靠的 光伏电源系统， 这是众多专家学者研究已久的课题，而且已有许多卓越的研究成 果， 为我国光伏事业的发展奠定了坚实的基础。笔者在学习各专家的设计方法时 发现，这些设计仅考虑了蓄电池的自维持时间（即最长连续阴雨天），而没有考 虑到亏电后的蓄电池最短恢复时间（即两组最长连续阴雨天之间的最短间隔天 数）。这个问题尤其在我国南方地区应引起高度重视，因为我国南方地区阴雨天 既长又多， 而对于方便适用的独立光伏电源系统，由于没有应急的其他电源保护 备用，所以应该将此问题纳入设计中一起考虑。 本文综合以往各设计方法的优点，结合笔者多年来实际从事光伏电源系统设 计工作的经验， 引入两组最长连续阴雨天之间的最短间隔天数作为设计的依据之 一，并综合考虑了各种影响太阳能辐射条件的因素，提出了太阳能电池、蓄电池 容量的计算公式，及相关设计方法。 2 影响设计的诸多因素 太阳照在地面太阳能电池方阵上的辐射光的光谱、光强受到大气层厚度（即 大气质量）、地理位置、所在地的气候和气象、地形地物等的影响，其能量在一 日、 一月和一年内都有很大的变化，甚至各年之间的每年总辐射量也有较大的差 别。 太阳能电池方阵的光电转换效率，受到电池本身的温度、太阳光强和蓄电池 电压浮动的影响， 而这三者在一天内都会发生变化，所以太阳能电池方阵的光电 转换效率也是变量。 蓄电池组也是工作在浮充电状态下的， 其电压随方阵发电量和负载用电量的 变化而变化。蓄电池提供的能量还受环境温度的影响。 太阳能电池充放电控制器由电子元器件制造而成，它本身也需要耗能，而使 用的元器件的性能、质量等也关系到耗能的大小，从而影响到充电的效率等。 负载的用电情况，也视用途而定，如通信中继站、无人气象站等，有固定的 设备耗电量。而有些设备如灯塔、航标灯、民用照明及生活用电等设备，用电量 是经常有变化的。
因此，太阳能电源系统的设计，需要考虑的因素多而复杂。特点是：所用的 数据大多为以前统计的数据，各统计数据的测量以及数据的选择是重要的。 设计者的任务是： 在太阳能电池方阵所处的环境条件下 （即现场的地理位置、 太阳辐射能、气候、气象、地形和地物等），设计的太阳能电池方阵及蓄电池电 源系统既要讲究经济效益，又要保证系统的高可靠性。 某特定地点的太阳辐射能量数据，以气象台提供的资料为依据，供设计太阳 能电池方阵用。这些气象数据需取积累几年甚至几十年的平均值。 地球上各地区受太阳光照射及辐射能变化的周期为一天 24h。处在某一地区 的太阳能电池方阵的发电量也有 24h 的周期性的变化， 其规律与太阳照在该地区 辐射的变化规律相同。 但是天气的变化将影响方阵的发电量。如果有几天连续阴 雨天，方阵就几乎不能发电，只能靠蓄电池来供电，而蓄电池深度放电后又需尽 快地将其补充好。 设计者多数以气象台提供的太阳每天总的辐射能量或每年的日 照时数的平均值作为设计的主要数据。由于一个地区各年的数据不相同，为可靠 起见应取近十年内的最小数据。根据负载的耗电情况，在日照和无日照时，均需 用蓄电池供电。 气象台提供的太阳能总辐射量或总日照时数对决定蓄电池的容量 大小是不可缺少的数据。 对太阳能电池方阵而言， 负载应包括系统中所有耗电装置（除用电器外还有 蓄电池及线路、控制器等）的耗量。 方阵的输出功率与组件串并联的数量有关， 串联是为了获得所需要的工作电 压， 并联是为了获得所需要的工作电流，适当数量的组件经过串并联即组成所需 要的太阳能电池方阵。 3 蓄电池组容量设计 太阳能电池电源系统的储能装置主要是蓄电池。与太阳能电池方阵配套的蓄 电池通常工作在浮充状态下，其电压随方阵发电量和负载用电量的变化而变化。 它的容量比负载所需的电量大得多。蓄电池提供的能量还受环境温度的影响。为 了与太阳能电池匹配，要求蓄电池工作寿命长且维护简单。 （1）蓄电池的选用 能够和太阳能电池配套使用的蓄电池种类很多， 目前广泛采用的有铅酸免维 护蓄电池、 普通铅酸蓄电池和碱性镍镉蓄电池三种。国内目前主要使用铅酸免维 护蓄电池，因为其固有的“免”维护特性及对环境较少污染的特点，很适合用于 性能可靠的太阳能电源系统， 特别是无人值守的工作站。普通铅酸蓄电池由于需 要经常维护及其环境污染较大， 所以主要适于有维护能力或低档场合使用。碱性
镍镉蓄电池虽然有较好的低温、过充、过放性能，但由于其价格较高，仅适用于 较为特殊的场合。 （2）蓄电池组容量的计算 蓄电池的容量对保证连续供电是很重要的。在一年内，方阵发电量各月份有 很大差别。 方阵的发电量在不能满足用电需要的月份，要靠蓄电池的电能给以补 足；在超过用电需要的月份，是靠蓄电池将多余的电能储存起来。所以方阵发电 量的不足和过剩值，是确定蓄电池容量的依据之一。同样，连续阴雨天期间的负 载用电也必须从蓄电池取得。 所以，这期间的耗电量也是确定蓄电池容量的因素 之一。