Detailed Functions of Residential Photovoltaic Energy Storage Inverter System

When choosing the home photovoltaic energy storage inverter system, some functions are not clearly introduced in the inverter parameters or in the manual, but they are very meaningful for practical applications. This article mainly introduces the following functions:

 Unbalanced output function

 Three-phase photovoltaic energy storage system is usually the best choice for three-phase households such as Germany, Austria, or shopping malls, parking lots, stations and other industrial and commercial applications. However, to power the single-phase load in the system, different amounts of electricity need to be transmitted in each phase. We call this the "nonequilibrium output function".

In the anticounterflow scheme, if the upstream power control is phase by phase (single-phase level control), then the unbalanced output function will be critical, because the upstream power on each phase will be limited only alone. This requires that the inverter can consume different power output according to the load of each phase.

 And 100% unbalanced function

100% unbalanced output means that the output power of each phase is in the range of 0W to 1 / 3 of the nominal power of the inverter, and the maximum difference of the output power of each two phases can also reach 1 / 3 of the nominal power of the inverter.

To achieve the unbalanced output, smart meters with CT function are usually used to monitor the real-time load consumption of each phase, so that the inverter can adjust the output power of each phase accordingly.

Seamless power outage switch

Off-grid output capacity or backup power supply capacity is an important function of photovoltaic energy storage system. Especially when the power supply of the public power grid is unstable or the important household load needs the uninterrupted power supply. In this case, the energy storage inverter should have the ability of off-grid output, and the ability to automatically switch from the grid-connected state to the off-grid output state.

Seamless switching capability is often achieved by integrating Fibre Channel rather than external switches or relays, as it is difficult to synchronize operations between optical storage systems and external devices.

The UPS level switch

UPS class off-grid switching refers to the switching time of standby power supply from grid-connected mode to off-grid mode is less than 10ms, which is the time that most ordinary home loads can cross without cutting off the power supply.

Remote control

Photovoltaic systems usually require long-term and continuous operation and maintenance services. Now, a 10-year warranty is really popular all over the world. Therefore, convenient operation and maintenance solutions are very important in energy storage inverter systems. The function of remote control can greatly reduce the time cost of on-site after-sales service and the cost of the service itself.

Remote control functions usually include:

Get the running log of the system for the necessary analysis.

Remote upgrade of the energy storage inverter firmware version

Configure system settings such as working mode, power limit, etc.

The BMS for upgrading the battery remotely through the inverter.

Lithium-ion batteries on the market currently tend to be remote upgrades, some of which are connected to the network through the battery itself. Others can be achieved by communicating with the inverter, but this requires synchronous support from the inverter and the battery.

Agreement matching

Generally speaking, the photovoltaic energy storage system is a combined system of all the components in the entire optical storage system, including cells, photovoltaic modules, inverters, brackets, electricity meters, control systems, etc. Obviously, it is impossible for inverter manufacturers to provide all the equipment for the entire energy storage system. In a complete optical storage system, other components may also be needed to achieve intelligent energy management, including EMS controllers, multi-function smart meters, thermal controllers, pump controllers, etc. To achieve the maximum pv self-use rate or the specific load control.

As the energy storage industry will evolve, energy storage systems may need to upgrade. This means that energy storage inverters should be compatible with common protocols, such as Modbus TCP, Modbus RTU, SUNSPEC, etc. Furthermore, the inverter is preferably scalable for future compatibility with other protocols.

Photovoltaic energy storage systems are not just about battery charging and discharging. Within five to ten years after the completion of the energy storage system, the energy storage system will meet the new functional requirements of power generation.