With the rapid development of the photovoltaic industry, the competition in the industry has gradually increased, the technical routes are diversified, and the quality of photovoltaic equipment is uneven. However, many pv users do not understand the structure of the power station and the selection of equipment types, and do not know how to identify and operate the photovoltaic products. As the core equipment of photovoltaic power generation system -- inverter, it is very important for users to have a detailed understanding of its type and applicable environment.
Concentrated photovoltaic power station inverter program
The centralized inverter has been used for more than ten years and is the most mature photovoltaic power station inverter scheme. The photovoltaic power station is composed of components, junction boxes, inverters, box changes and power grid. The centralized inverter scheme is photovoltaic module generation, which gathers the current from the junction box and transfers the dc to two 500KW inverters, and then goes through the double-split box transformation and grid-connection.
Features of the centralized inverter scheme:
1. Mature technology, suitable for large-scale ground power stations;
2. Low transmission voltage and large loss;
3. The number of MPPT(maximum power tracking) is small and the power generation is not high;
4. Centralized connection and good adaptability of power grid;
5. The inverter costs less.
A series of pv power station inverter scheme
The cascade inverter scheme is that the photovoltaic module generates electricity and then sends it directly to the inverter for inverting into alternating current, which is then transferred to the double-winding box grid-connected network through the ac junction box. Compared with the centralized type, the group series inverter has a small power, with a single inverter between 5k and 50kw. Each inverter has MPPT, so the number of MPPT in 1MW is far more than that in the centralized type, and the corresponding power generation also increases accordingly.
The characteristics of the scheme of group series inverter:
1. The inverter is small and suitable for distributed projects or domestic pv projects;
2. More power generation than centralized power generation;
3. Due to the small power of single machine, more inverters need to be equipped per MW, and the corresponding costs are relatively high;
4. Easy maintenance and direct replacement;
5. With a large number of outlets, it is easy to generate resonance and has poor adaptability to the power grid.
centralized-distributed photovoltaic power station inverter program
Compared with the centralized inverter scheme, the difference is that the centralized inverter scheme moves MPPT forward to the junction box, increases the number to be consistent with the cluster type, increases the boost function in the junction box, and reduces transmission loss. Two major shortcomings of centralism have been resolved.
Features of the centralized-distributed inverter scheme:
1. Centralized connection and good adaptability of the power grid;
2. The cost is between the centralized type and the cluster type;
3. The power generation is improved, while the loss is reduced, resulting in high system efficiency;
4. Applicable to large power stations and distributed projects.
At present, the two kinds of inverter schemes of cluster type and cluster type have gradually become the mainstream of the market. For example, 50% of the projects of "front-runner" plan are using cluster type inverter, while another investment hotspot, photovoltaic distributed projects, such as family photovoltaic power station and photovoltaic poverty alleviation projects, are also basically using cluster type inverter. For distributed inverters, there are advantages in large distributed projects and large mountain photovoltaic power stations.