What Is The Difference Between Energy Storage Inverter And Photovoltaic Inverter?

As the core component of photovoltaic power generation and energy storage systems, inverters are well-known. Many people think that they are the same product because they have the same name and the same application areas, but this is not the case. Photovoltaic and energy storage inverters are both "best partners", but they also differ in actual applications such as function, utilization rate, and benefits.

Energy Storage Inverter (ESI), also known as "bidirectional energy storage inverter", is the core component for realizing bidirectional 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/DC conversion. It can directly supply power to AC loads without a power grid.

According to the application scenarios and capacity of energy storage inverters, energy storage inverters can be divided into photovoltaic energy storage hybrid inverters, low-power energy storage inverters, medium-power energy storage inverters, centralized energy storage inverters, etc.

Photovoltaic energy storage hybrid and low-power energy storage inverters are used in household and industrial and commercial scenarios. Photovoltaic power generation can be used for local loads first, and excess energy can be stored in batteries. When there is still surplus electricity, it can be selectively connected to the grid.

Medium-power and centralized energy storage inverters can achieve higher output power and are used in industrial and commercial, power stations, large power grids and other scenarios to achieve peak shaving and valley filling, peak/frequency regulation and other functions.

Electrochemical energy storage systems are generally composed of four core parts: batteries, energy management systems (EMS), Power Conversion System (PCS), and battery management systems (BMS). Energy storage inverters can control the charging and discharging process of energy storage battery packs and perform AC/DC conversion, playing a very important role in the industrial chain.

Upstream: battery raw materials, electronic components suppliers, etc.; midstream: energy storage system integrators and system installers;

Downstream Application End: wind and solar power stations, power grid systems, household/industrial and commercial communication operators, data centers and other end users.

PV inverter is an inverter specially used in the field of solar photovoltaic power generation. Its biggest function is to convert the direct current generated by solar cells into alternating current power that can be directly connected to the power grid and load through power electronic conversion technology.

As the interface device between photovoltaic cells and the power grid, photovoltaic inverters convert the power of photovoltaic cells into AC power and transmit it to the power grid, playing a vital role in photovoltaic grid-connected power generation systems. With the promotion of BIPV, in order to maximize the conversion efficiency of solar energy and take into account the aesthetic appearance of the building, the requirements for inverter form are gradually diversified. At present, the common solar inverter methods are: centralized inverter, string inverter, multi-string inverter and component inverter (micro inverter)

"Best partner": Photovoltaic inverters can only generate electricity during the day, and the power generation is affected by the weather and has unpredictable problems.

The energy storage inverter can perfectly resolve these difficulties. When the load is low, the output electric energy will be stored in the battery, and the stored electric energy will be released when the load is peak, reducing the pressure on the power grid. When the power grid fails, it will switch to off-grid mode to continue supplying power.

The requirements for inverters in energy storage scenarios are more complex than those in photovoltaic grid-connected scenarios. In addition to DC to AC conversion, it is also required to have functions such as AC to DC conversion and fast switching between grid and off-grid. 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.

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 city power fails, the photovoltaic grid-connected inverter is paralyzed, and the energy storage converter can still work efficiently;

3. In the context of the continuous reduction of grid-connected power generation subsidies, the benefits of energy storage converters are higher than those of photovoltaic inverters.