逆变器作为光伏电站的电能转换设备,在整个电站中占据着举足轻重的地位。光伏逆变器是将组件产生的低压直流电转换为交流电的电力电子设备,接入负载或者并入到电网中,是光伏系统中的核心器件。并网逆变器有以下的主要功能:
将光伏组件产生的直流电转换为交流电
通过最大功率跟踪器,动态地查找和利用最大功率点(MPP)来实现可用功率的最大化
记录运行数据
提供电流、电压及当地电网的相关保护
逆变器的分类有哪些?
就产品类型而言,目前逆变器产品主要分为四类,即:
集中式逆变器(功率范围在250KW-10MW ,主要用于大型地面电站)
集散式逆变器(功率范围在1MW-10MW,主要用于复杂的大型地面电站)
组串式逆变器(功率范围在1.5KW-250KW,主要用于户用、工商业分布式和地面电站等)
微型逆变器(功率范围一般在4kW以下,主要应用于分布式等中小型电站。基于对光伏安全问题考虑,也越来越多被应用于大型工商业分布式电站)
微型逆变器可对系统中每块组件进行逆变并进行独立的MPPT控制,能够大幅提高整体效率,同时也可以避免传统逆变器具有的直流高压、弱光效应差、木桶效应等。
昱能科技微型逆变器系统优势视频
逆变器的安装位置在哪里?
常见地面分布式项目的安装方案
可以就近安装在某一串组件下方,采用固定支架安装或采用抱箍式安装直接将设备固定在立柱上。这种方案需要注意支架和抱柱强度及光伏逆变器离地高度,防止放置太低在暴雨天雨水淹没设备。
大型的工商业厂房安装方案
大型工商业屋顶一般屋顶空旷,无顶棚和女儿墙,光伏逆变器可悬挂之处,出于减少线缆成本的考虑,一般都需要自制安装支架,并将逆变器悬挂在自制支架上,支架需考虑逆变器承重和固定形式以及在沿海地区抗台风能力。
常见的家庭分布式项目屋顶电站安装方案
光伏逆变器尽量安装在南边的墙上,其面板要朝北,少晒太阳。机器的安装离地面要有合适的高度,以便观察和读取LED的显示。 室外安装时,逆变器上面要装防雨防晒棚,避免阳光直射和雨水浸泡。
采用微型逆变器的系统
微型逆变器可直接安装在组件下方的支架上,或与组件集成实现模块化设计、实现即插即用。微逆体积小,基本不独立占用安装空间,分布式安装便于配置,能够充分利用空间和适应不同安装方向和角度的应用。
As the power conversion equipment of photovoltaic power station, inverter occupies a pivotal position in the whole power station. Photovoltaic inverter is a power electronic device that converts low-voltage direct current generated by the module into alternating current. It is connected to the load or incorporated into the power grid. It is the core device in the photovoltaic system. Grid-connected inverter has the following main functions:
The direct current generated by photovoltaic modules is converted to alternating current
Through the maximum power tracker, the maximum power point (MPP) is dynamically found and utilized to maximize the available power
Recording Running Data
Provide current, voltage and local grid protection
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What are the classification of inverters?
In terms of product types, inverter products are mainly divided into four categories at present, namely:
Centralized inverter (power range: 250KW-10MW, mainly used in large ground power stations)
Distributed inverter (power range: 1MW-10MW, mainly used in complex large ground power stations)
Cluster series inverter (power range is 1.5KW-250KW, mainly used for household, industrial and commercial distributed and ground power stations, etc.)
Micro inverter (power range is generally below 4kW, mainly used in distributed small and medium-sized power stations. Based on the consideration of photovoltaic safety, it is more and more applied to large industrial and commercial distributed power stations.)
The micro inverter can invert each component in the system and carry out independent MPPT control, which can greatly improve the overall efficiency, but also avoid the traditional inverter some DC high voltage, poor light effect, barrel effect, etc.
Watch the following video to learn more about micro inverters.
Renesola micro inverter system advantages video
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Where is the installation position of the inverter?
Common installation schemes for distributed ground projects
It can be installed nearby under a string of components, and the device can be directly fixed to the column by using a fixed bracket installation or hoop installation. This scheme needs to pay attention to the strength of the support and holding column and the height of the photovoltaic inverter from the ground, so as to prevent the equipment from being placed too low in heavy rain days.
Large industrial and commercial plant installation program
Large industrial and commercial roofs are generally empty, without roofs and parapets, where photovoltaic inverters can be suspended. For the purpose of reducing cable costs, it is generally necessary to install self-made supports, and hang the inverters on the self-made supports. The supports need to consider the bearing and fixed forms of the inverters and the resistance to typhoon in coastal areas.
Common household distributed project rooftop power station installation scheme
The photovoltaic inverter should be installed on the south wall as far as possible, and its panel should face north to avoid sunshine. The machine should be mounted at a suitable height above the ground for viewing and reading the LED display. For outdoor installation, the inverter must be equipped with a rain-proof sunscreen shed to avoid direct sunlight and rain.
A system using miniature inverters
The micro inverter can be directly installed on the bracket below the component, or integrated with the component to achieve modular design and realize plug and play. The micro inverse has a small volume and does not occupy the installation space independently. Distributed installation is easy to configure, and can make full use of space and adapt to different installation directions and angles.