What’s the AC coupling from Luxpower?

Introduction:

With the widespread use of microinverters and grid-tied systems in Europe, Luxpower has developed a model suitable for direct grid connection systems. It can quickly convert existing microinverters or inverter systems into energy storage systems. Additionally, it incorporates Luxpower’s intelligent management system, which automatically updates electricity prices, provides more intelligent charging and discharging modes, integrates a UPS interface, and features a 40A Passthrough capability, ensuring normal operation in any state.

I. What is AC coupling?

II. Introduction to the features of the 3600ACS model.

III. Recommended minimum battery capacity for connection.

 

I. What’s the AC coupling?

In an AC-coupled system, the on grid PV inverter is connected to the output of the 3600ACS. The PV power is first used to supply the load and then charge the battery. Any excess PV power can be fed back to the grid.

When 3600ACS operates in inverter mode, it disconnects from the AC input and creates a local grid: a microgrid. The PV inverter accepts this microgrid, allowing it to continue operating even during power outages. The PV power can even be used to charge the battery. When available PV power exceeds the power consumed by the load, the power automatically flows in the opposite direction through the inverter and charges the battery. It is important to note that proper settings for the battery should be configured to prevent overcharging and to avoid overloading the inverter/charger.

II. Features of the 3600 ACS model

Highlight:

• A single 3600ACS unit is designed for single-phase operation. For three-phase loads, three 3600ACS units can be combined.
• The battery side supports 48V lithium-ion or lead-acid batteries, with a capacity of up to 100Ah per single unit.
• It is compatible with various lead-acid batteries and a wide range of mainstream lithium-ion batteries.
• It offers high scalability, allowing easy addition of energy storage batteries and 3600ACS to existing PV systems. This facilitates future load expansion.
• High conversion efficiency, with a maximum efficiency of up to 96%.
• User-friendly human-machine interface, supporting RS485, Wi-Fi, and CAN communication.
• In situations of severe grid power shortage, the ACS 3600 can also be used with a diesel generator.
• The 3600ACS is compatible with the majority of PV inverter systems available on the market.
• Depending on local regulations, it may be necessary to add an anti-islanding device to the system if there is excess power flowing back into the grid.

III. Recommended minimum battery capacity for connection

The minimum battery capacity for transforming the system into an energy storage system depends on the type of battery, either lead-acid or lithium.

• For lead-acid batteries, it is recommended to have a 48V/100Ah battery for every 1 kWp of solar panels.
• For lithium-ion batteries, it is recommended to have a 48V/100Ah battery for every 1.5 kWp of solar panels.

Postscript:

Introducing the operating mode of connecting a diesel generator

Solar power, energy storage batteries, and a diesel generator form a microgrid. The PV modules generate three-phase AC power for loads through a three-phase inverter or three or more single-phase inverters. When there is ample sunlight and the PV output power exceeds the load consumption, the excess energy is stored in the battery via 3600ACS. When sunlight is insufficient and the PV output is lower than the load consumption, 3600ACS can draw energy from the battery to supply the load. When the battery reaches a low level (e.g., SOC = 20%, this parameter can be adjusted through the control system), the Sunny Island can start the diesel generator, synchronize it with the AC grid produced by the diesel generator, and transmit energy to power the load.

The diesel control function of 3600ACS prevents excessive battery discharge and extends battery life when sunlight is insufficient. When connected to the diesel generator, the diesel control ensures the voltage and frequency of this independent grid. When PV power is greater than the load and the battery is fully charged, the Sunny Island can disconnect the diesel generator to avoid reverse current flowing back and reduce fuel consumption.

 

Pure off-grid mode

In off-grid systems without a diesel generator, 3600ACS can use load control functionality to prevent excessive battery discharge and prolong battery life when sunlight is insufficient.

 

Summary:

3600ACS is an AC-coupled energy storage inverter designed to connect to existing grid-tied PV systems and transform them into energy storage inverters. It finds primary applications in power-deficient areas such as islands, mines, farms, and remote regions, providing an excellent solution for upgrading grid-tied systems and addressing power grid instability.