How to choose the photovoltaic inverter?

In the process of building a photovoltaic power station, how to obtain the maximum profit (power generation) with the minimum investment, and which type of photovoltaic inverter to choose has become a very important link, expensive is not necessarily right, what is suitable for oneself is the best.

First, the selection of photovoltaic inverter is very important

How to choose the photovoltaic inverter suitable for your own power station? The following is an analysis of the application of different types of pv inverters in the power station.

1. Centralized inverter

Equipment requirements:

Transformer, refrigeration and ventilation equipment, including equipment, junction box, inverter room and other complicated equipment are required

Panel requirements:

The number of panels in series should be consistent, and the size of the installation site should be strict.

The tilt Angle of all the panels needs to be consistent, which requires a high level of installation personnel, installation conditions and installation equipment.

The panel model size needs to be completely consistent, and the inconsistency may lead to the failure of the power station or the serious decline of the power generation efficiency.

Large size, complex installation, the design of the power station must follow the above conditions, the entire photovoltaic power station can reach the maximum power, all the panels can work at the maximum power point.

2. Group series inverter

Simple design, different MPPT input terminal connected to the panel, can use different number, model, brand of the panel.

Ac power can be connected directly to the client in multi-point mode.

When a fault occurs in one inverter, it will not affect the normal situation of other inverters. In this case, the on-site after-sale standby machine will be used for manual replacement to ensure the continuity of power generation.

Minimize shipping and installation costs.

3. Micro inverter

No installation is required and can be directly integrated into the panel.

When a panel is damaged or blocked, it will not affect the normal operation of other inverters.

Ac plug and play, transport installation costs are extremely low.

When there is a fault, you only need to replace a single fault machine.

Dc voltage up to only 40V, safer.

Service life up to 25 years.

Second, key technical indicators:

As the main component and important component of solar pv generating point system, pv inverter can guarantee the normal operation of solar pv power generation system, which is important for the correct configuration and selection of pv inverter. The configuration of the inverter should be determined according to the technical specifications of the whole photovoltaic power generation system and refer to the product sample manual provided by the manufacturer. The following technical indicators will also be given special consideration.

1. Rated output power

The rated output power indicates the capacity of the photovoltaic inverter to power the load. Photovoltaic inverters with high rated output power can carry more power load. When selecting a photovoltaic inverter, it should first consider having enough rated power to meet the requirement of the maximum load of the equipment to the electric power, as well as the expansion capacity of the system and the access of some temporary loads. When a pure resistive load from electrical equipment or power factor is greater than 0.9, generally choose the rated output power of the pv inverter than 15% 10% of the total power ` electrical equipment.

2. Output voltage adjustment performance

The output voltage adjustment performance indicates the output voltage stability of the photovoltaic inverter. Generally, the pv inverter product gives the percentage of the fluctuation deviation of the output voltage of the pv inverter when the input voltage of dc changes in the allowable fluctuation range, which is usually called the voltage adjustment rate. The high performance pv inverter should also give the deviation percentage of the output voltage of the pv inverter when the load changes from zero to 100%, usually called load adjustment rate. The voltage adjustment rate of the photovoltaic inverter with good performance should be less than or equal to plus or minus 3%, and the load adjustment rate should be less than or equal to plus or minus 6%.

3. Overall efficiency

The whole machine efficiency represents the power loss of the photovoltaic inverter itself. The high capacity pv inverter also gives the full load and low load efficiency. Generally, the efficiency of inverters under KW level should be over 85%. The efficiency of 10KW should be over 90%. Greater power efficiency must be above 95%. The efficiency of the inverter has an important influence on the improvement of the effective power generation and the reduction of the power generation cost of the photovoltaic power generation system. Therefore, the selection of the photovoltaic inverter should be compared as far as possible and the selection of products with higher efficiency of the whole machine should be made.