Parallel installation of multiple inverters in a single-phase hybrid system

Currently, many customers and partners are contemplating and frequently questioning whether it is possible to install multiple inverters in a solar power storage system. Let’s join DAT Solar in exploring the answer to this unique solution through the informative article below!

Addressing the challenge of high household electricity consumption

In most residential electrical systems, the majority of loads only require a single-phase power source for items such as lighting, fans, water pumps, air conditioning, etc. In cases where a household needs to consume a significant amount of electricity, and the area only has a single-phase power grid, what solution should be adopted?

The GoodWe single-phase Hybrid Inverter ensures continuous operation of electrical devices in the home in both On-grid and Backup modes. Furthermore, the GoodWe single-phase Hybrid Inverter can be installed in parallel with multiple inverters, offering a comprehensive solution to the challenge of high electricity consumption in households using single-phase loads.

Optimal solution by GoodWe

The solution of parallel installation with multiple GoodWe single-phase Hybrid Inverters GW5000-ES-20 can be expanded from 2 to 15 inverters within the same system. This can increase the output power and adapt to the consumption level of the loads, helping to minimize the amount of electricity drawn from the national power grid.

In this solution, the inverters prioritize drawing power from the solar panel array (PV) to supply power to both grid-connected and backup loads. In cases of low load, excess PV power is used to charge the storage battery for nighttime use or during periods of low PV power output when the load is high or during power outages.

The system using GoodWe single-phase Hybrid Inverters, in combination with a Smart Meter and current sensors (CT) for load monitoring, allows the inverter to adjust the output power accordingly. This ensures that no excess electricity is fed back into the power grid.

+ Solution 1: Inverters are installed in parallel for grid-connected and backup loads, and storage batteries are installed independently for each inverter.

• Advantages: Simplifies the electrical panel system, easy installation.

+ Solution 2: Inverters are installed in parallel for grid-connected and backup loads, and storage batteries are installed in parallel.

• Advantages:
  • Parallel storage batteries maximize the use of excess PV energy for the storage system.
  • Easily customizable for the number of storage batteries in the system.

Example: Suppose a single-phase Hybrid Inverter has a power rating of 5-10 kW, and the average household consumption is around 15 kW (normal load of 7.5 kW, backup load of 7.5 kW).

Considering a scenario where the grid-connected load is 4.5 kW, the backup load is 4.5 kW, let’s analyze the parallel installation solution in this case:

• Input devices:
  • Solar panel system generating 15 kW.
  • 3 GoodWe single-phase Hybrid Inverters GW5000-ES-20 with a total power of 15 kW.
  • 3 Pylontech US5000 storage batteries.
  • 1 Ezlink inverter management device.
• Output from the Inverters:
  • Charging power for storage batteries: 6 kW.
  • Backup load power: 4.5 kW.
  • Grid-connected power: 4.5 kW.

System operation principles:

• When the load power is greater than the PV power output: the inverters will draw additional power from the storage batteries to supply the load. If the total load is higher than the total output power of the inverter system, power will be drawn from the grid to supplement the load.
• When the load power equals the PV power output: The inverters will prioritize drawing power from the PV to supply the load, and the storage batteries will be in a standby state.
• When the load power is less than the PV power output: The inverters will draw power from the PV to supply the load, and excess PV energy will charge the storage batteries.
• Power outage scenario: Priority will be given to connecting backup loads to the inverters, which will be powered by both PV and storage batteries. The system will prioritize drawing power from the PV for the load. In case of insufficient PV power, power will be drawn from the storage batteries (acting as a backup).

Outstanding benefits of the solution:

• Increase self-consumption rate up to 80%.
• Reduce monthly electricity costs.
• Minimize excess electricity fed back into the national power grid.
• Meet the high electricity consumption needs of households using single-phase power.
• Ensure uninterrupted operation of electrical devices during power outages or unstable power grids.

Realized project implementation:

For more detailed information and advice on suitable and efficient Hybrid products and solutions, customers and partners can contact the toll-free hotline 1800 6567. DAT Solar is ready to provide comprehensive support 24/7.

Quoc Khanh Nguyen – Project Engineer