As the core component of photovoltaic power generation and energy storage systems, inverters are famous. Many people see that they have the same name and the same field of action and think that they are the same type of product, but this is not the case.
Photo voltaics and energy storage inverters are not only the “best partners”, but they also differ in practical applications such as functions, utilization rate, and income.
Energy storage inverter
Energy storage converter (PCS), also known as “bidirectional energy storage inverter”, is the core component that realizes the two-way flow of electric energy between the energy storage system and the power grid. It is used to control the charging and discharging process of the battery and perform AC and DC switching. Transform. It can directly supply power to AC loads when there is no power grid.
1. Basic operating principles
According to the application scenarios and capacity of energy storage converters, energy storage converters can be divided into photovoltaic energy storage hybrid converters, small power energy storage converters, medium power energy storage converters, and centralized energy storage converters. flow device, etc.
Photovoltaic energy storage hybrid and low-power energy storage converters are used in household and industrial and commercial scenarios. Photovoltaic power generation can be used by local loads first, and the excess energy is stored in the battery. When there is still excess power, it can be selectively combined. into the grid.
Medium-power, centralized energy storage converters can achieve higher output power and are used in industrial and commercial, power stations, large power grids and other scenarios to achieve peak shaving, valley filling, peak shaving/frequency modulation and other functions.
2. Playing a decisive role in the industrial chain
Electro chemical energy storage systems generally consist of four core parts: battery, energy management system (EMS), energy storage inverter (PCS), and battery management system (BMS).
The energy storage inverter can control the charging and discharging process of the energy storage battery pack and convert AC to DC, which plays a very important role in the industrial chain.
Upstream: battery raw materials, electronic component suppliers, etc.;
Midstream: energy storage system integrators and system installers;
Downstream application end: wind and photovoltaic power stations, power grid systems, household/industrial and commercial, communication operators, data centers and other end users.
Photovoltaic inverter
Photovoltaic inverter is an inverter dedicated to the field of solar photovoltaic power generation. Its biggest function is to convert the DC power generated by solar cells into AC power that can be directly integrated into the grid and load through power electronic conversion technology.
As an interface device between photovoltaic cells and the power grid, the photovoltaic inverter converts the power of the photovoltaic cells into AC power and transmits it to the power grid. It plays a vital role in the photovoltaic grid-connected power generation system.
With the promotion of BIPV, in order to maximize the conversion efficiency of solar energy while taking into account the beautiful appearance of the building, the requirements for inverter shapes are gradually diversified. Currently, the common solar inverter methods are: centralized inverter, string inverter, multi-string inverter and component inverter (micro-inverter).
Similarities and Differences between Light/Storage Inverters
“Best partner”: Photovoltaic inverters can only generate electricity during the day, and the power generated is affected by the weather and has unpredictability and other issues.
The energy storage converter can perfectly resolve these difficulties. When the load is low, the output electric energy is stored in the battery. When the load is peak, the stored electric energy is released to reduce the pressure on the power grid. When the power grid fails, it switches to off-grid mode to continue supplying power.
The biggest difference: The demand for inverters in energy storage scenarios is more complex than in photovoltaic grid-connected scenarios.
In addition to DC to AC conversion, it also needs to have functions such as conversion from AC to DC and off-grid fast switching. At the same time, the energy storage PCS is also a bidirectional converter with energy control in both charging and discharging directions.
In other words, energy storage inverters have higher technical barriers.
Other differences are reflected in the following three points:
1. The self-use rate of traditional photovoltaic inverters is only 20%, while the self-use rate of energy storage converters is as high as 80%;
2. When the mains power fails, the photovoltaic grid-connected inverter is paralyzed, but the energy storage converter can still work efficiently;
3. In the context of continuous reductions in subsidies for grid-connected power generation, the income of energy storage converters is higher than that of photovoltaic inverters.
Post time: Jan-19-2024