The core component of a solar system is the inverter because most homes use alternating current (AC), while solar panels and batteries produce direct current (DC). Solar inverters convert direct current (DC) to alternating current (AC). There are three common types of solar inverters: off-grid inverters, grid-tied inverters, and hybrid inverters. They differ in their functions, application scenarios, and features, which are compared and summarized in detail in this blog.
Off-grid inverter
Off-grid inverters are designed for systems that are completely off the grid. These systems are typically used in remote areas, mobile homes, outdoor activities, etc. where grid access is impossible.
1οΈβ£Principle of operation
The DC power generated by the solar panels is converted through an inverter circuit to an AC power supply.
At the same time, the circuit design allows the power to be stored in the battery for use at night or on cloudy days.
2οΈβ£Features
- Independence: Off-grid and self-contained, where solar panels, batteries, and other energy sources are the onlyΒ sources of power.
- Energy storage: Off-grid inverters can be used with battery storage systems to store electrical energy and provide continuous power. They use solar energy to charge the batteries and deliver power directly from the batteries to the load.
- No grid output: Off-grid inverters do not export excess energy to the grid because they are not connected to the grid. All energy produced by the solar panels is either used immediately to power the load or stored in batteries for later use.
- Backup power: Off-grid systems themselves provide backup power because they are not dependent on the grid. The batteries store excess energy for use at night or during periods of low solar generation.
- Multiple protection functions: It has multiple protection functions such as input reverse connection protection, input under-voltage protection, and output overload protection.
- High efficiency and stability: adopting PWM control mode to improve efficiency; sinusoidal waveform output, waveform distortion rate is less than 5%.
3οΈβ£Pros
Off-grid inverters allow users to create a self-sufficient energy supply independent of the grid and are particularly suitable for remote areas or where there is no stable grid access. Especially when combined with an energy storage system. With enough solar cells, the systemΒ can discharge when solar power is insufficient, ensuring a stable power supply for the user.
Off-grid energy storage inverters are typically more economical than other types of inverters. They are simple in function and easier to manufacture, making them relatively inexpensive. Users looking for a cost-effective off-grid solar solution are well served by using these inverters to power their homes or businesses.
4οΈβ£Cons
Off-grid energy storage inverters cannot export power to the grid. Customers seeking inverters compatible with net metering should consider alternatives such as hybrid inverters, as off-grid energy storage inverters operate independently of the utility grid.
Off-grid energy storage systems require careful energy management. Since only the PV modules provide DC input, customers can only use the collected solar energy. They must carefully plan the appropriate power capacity to meet the energy consumption needs of their home or business and determine the number of batteries needed to discharge during periods of low solar input.
Grid-tied inverter
The grid-tiedΒ inverter is an inverter that converts DC power generated by distributed power sources such as solar panels into AC power and directly connects it to the public power grid. It allows users to sell excess power to the grid, realizing power recovery and revenue.Β
It is mainly applied to scenarios such as urban and industrial areas that are connected to the public power grid.
1οΈβ£Principle of operation
Using Maximum Power Point Tracking (MPPT) technology, the operating point of the solar panel is adjusted according to the light conditions to extract the maximum power.
It converts DC power to AC power and ensures that the output power matches the grid standard by synchronizing the frequency and phase of AC power with the grid.
2οΈβ£Features
- Grid connection: This type of inverter can communicate with the grid in both directions. When solar energy is available, the system will deliver it to your home and allow excess power to be sent back to the grid. If there is not enough energy available, the system will switch back to the grid.
- Power regulation: Grid-tie inverters have a power regulation feature that dynamically adjusts output power according to grid demand, ensuring a stable connection to the grid.
- Monitoring and management: Grid-tied inverters are usually equipped with a monitoring system that can monitor energy production and consumption in real-time, helping users to manage energy production and consumption.
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High inverter efficiency: Grid-tied inverters are designed to achieve efficient energy conversion to minimize energy losses and ensure efficient system operation.
Environmentally friendly: By connecting renewable energy sources to the grid, grid-tie inverters help reduce dependence on traditional energy sources, reduce carbon emissions, and become more environmentally friendly. - Wide range of applications: Grid-tie inverters are suitable for solar power systems of various sizes and can be used in different scenarios such as residential, industrial, and commercial.
3οΈβ£Pros
- Use of renewable energy: Grid-tied inverters allow DC power, such as that generated by solar energy, to be converted to AC power and connected to the public grid, promoting the use of renewable energy.
- Saves energy and reduces emissions: By integrating renewable energy sources into the grid, reliance on traditional fossil fuels can be reduced, lowering carbon emissions and contributing to environmental protection and climate change mitigation.
- Energy cost savings: By generating their electricity and selling the excess back to the grid, users can reduce their electricity bills or be reimbursed for their electricity costs, thereby saving on energy costs.
4οΈβ£Cons
- Grid dependency: Grid-tied inverters must be connected to the gridΒ to function properly, and in the event of a grid failure or power outage, the system may not be able to continue generating or delivering power.
- Safety risk: In the event of a power outage, the inverter will stop delivering power to the grid to protect line workers from electrocution, which may result in users being unable to use the power they generate.
- High system cost: Grid-tie inverters and related equipment are relatively expensive, especially in large commercial or industrial applications, and require a large capital investment.
- System Stability: The performance of a grid-tie inverter can be affected by the quality and variability of the electrical grid, and grid stability must be ensured to maintain system operation.
Hybrid Inverter
A hybrid inverter, also known as a multi-mode inverter, combines the functions of a grid-tied solar inverter and an off-grid solar inverter into one. It has a bi-directional power conversion capability that seamlessly handles power from multiple sources such as solar panels, batteries, and the utility grid. It is suitable for small commercial sites such as homes and resorts.
1οΈβ£Principle of operation
The inverter converts DC power from the solar panels to AC power to supply loads and also converts AC power to DC power to charge the solar cells. This integrated design provides a compact, versatile solution that allows homeowners and businesses to maximize the solar power generated by PV modules while maintaining a connection to the grid.Β
2οΈβ£Features
- Grid connection: Hybrid inverters are designed to be grid-tied. This means that they can export excess energy generated by the solar panels back to the grid, as well as draw energy from the grid when solar generation is low.
- Efficient use: One of the key features of hybrid inverters is their ability to integrate with battery storage systems. They can use excess solar power to charge batteries and discharge them when solar power is low.
- Flexibility: Hybrid inverters typically have multiple modes of operation, such as grid-tied (exporting excess energy to the grid), off-grid (using stored battery energy when the grid is unavailable), and hybrid (a combination of grid-tied and battery backup).
- Backup power: Hybrid inverters can use energy stored in connected batteries to provide backup power in the event of a grid outage. This is a significant advantage because it allows you to maintain power in the event of a grid outage.
3οΈβ£Pros
- Energy Storage: The Hybrid Solar Inverter's ability to operate both on-grid and off-grid gives users more options for how they want to use their solar energy - whether it's storing it, using it, or exporting it back to the grid - allowing them to enjoy a stable power supply in most situations.
- Self-sufficiency: The off-grid capability of the hybrid inverter makes it suitable for stand-alone power scenarios, allowing users to be self-sufficient where there is no stable grid access.
4οΈβ£Cons
Hybrid inverters are complex and require more specialized knowledge to properly install and operate, or you may encounter difficulties attempting to do so on your own. When in doubt, hire a professional solar installer to properly install a hybrid solar inverter system.
Key differences between off-grid inverters, grid-tied inverters, and hybrid inverters
In short, hybrid inverters function as both grid-tied and off-grid inverters. Hybrid inverters are grid-tied and can operate in different modes, including exporting energy to the grid and providing backup power. This gives the user more flexibility and stability.
Grid-tied inverters are designed to use solar energy, for example, to supplement or replace conventional grid power. It is used to connect to the public grid and promote the use of renewable energy.
Off-grid inverters, on the other hand, are designed for stand-alone systems that are not connected to the grid and rely entirely on solar and battery power.
Through the detailed explanation above, we can see that off-grid inverters, grid-tied inverters, and hybrid inverters have obvious differences in definitions, functions, working principles, application scenarios, and features. Which inverter to choose mainly depends on the specific power demand and application scenarios.
