A solar inverter converts direct current (DC) from solar panels into alternating current (AC) used by household and commercial appliances. This device is critical in solar power systems, transforming sunlight into usable energy. Often called the brain of a solar system, solar inverters have advanced from simple DC-to-AC converters to smart units that offer functions like data monitoring and advanced utility controls.
Solar inverters are essential because solar panels generate DC power, which cannot directly power electrical appliances. The inverter sits at the heart of a grid-connected system, extracting maximum DC power from the PV array and converting it into AC power at the correct voltage and frequency for grid feeding or domestic use.
Inverters need to handle a PV array’s power output under various sunlight conditions. They typically use Maximum Power Point Tracking (MPPT) technology to optimise energy yield. While a single inverter can suffice for a home setup, larger installations require multiple units. Efficiency, reliability, and safety are top priorities in system design. DC-to-AC conversion efficiencies can reach up to 98%, though efficiency drops below 25% of the inverter’s maximum power rating.
Types of Solar Inverters
- String Inverters
String inverters are generally mounted next to the main utility panel or the electric metre. They transform the DC output from the strings of solar panels into AC, which then supplies power to the household appliances. If a panel in the string underperforms, it impacts the output of all other panels in the given string.
String inverters are often used in unshaded, simple, and roof installations. They are usually connected to the DC power optimizer, which is responsible for regulating the amount of voltage to be converted into alternating current by the inverter, which in turn maximises production and minimises shading effects.
- Micro inverters
Microinverters are installed at the back of each solar panel, and their primary role is to convert DC to AC at the panel level. Unlike string inverters, microinverters permit every panel to run independently, therefore generating more energy. They are very flexible in terms of complicated roof structures that may involve the installation of many panels and do not suffer from performance problems due to the shading of a single panel.
- Hybrid Inverters
Hybrid inverters have the ability to perform the functions of a solar inverter and a battery inverter in one combined unit, allowing power from solar panels, batteries, the grid, and home systems to be managed together. These inverters are efficient and help in designing solar power systems with battery storage in a streamlined way. On the other hand, integrated battery inverters are being increasingly adopted, which cuts down the requirements for separate hybrid inverters.
How do Solar Inverters Function?
Solar panels generate DC electricity, but homes use AC electricity. The solar inverter converts DC power from the panels into AC power for household use. Acting as a solar converter, the inverter enables the energy produced by the panels to power home appliances. In grid-tied systems, the inverter manages the flow of electricity between your home and the grid, ensuring continuous power. If your system generates excess electricity, the inverter can send it back to the grid. During periods of low production or at night, it can draw power from the grid to meet your needs.
Solar inverters, like those found in solar power systems, have different types and features. However, there are several common ones present in modern solar inverters:
- Solar inverters change sunlight into electricity. Look for ones that do this really well to save energy.
- Some inverters keep track of how much electricity your solar panels make. They can also tell you if there’s a problem.
- Certain inverters let you control them from your phone or computer. It’s like having a remote for your TV but for solar panels.
- Solar inverters can get hot, so some have fans to keep them cool. This helps them last longer.
- These inverters can decide which things in your home get solar power first when it’s limited.
- Inverters have safety features to make sure electricity doesn’t go back into the grid during a blackout. This keeps everyone safe.
Choosing the Right Solar Inverter
- System Size and Capacity:
Your solar inverter should match or exceed the total output of your solar panels to avoid inverter clipping, where excess DC power cannot be converted to AC. For larger systems, a slightly smaller inverter might be more cost-effective, as it’s unlikely the panels will always operate at maximum output.
- Efficiency and Conversion Rates:
An inverter’s efficiency typically ranges from 93% to 99%. To enhance efficiency, choose an inverter with MPPT technology, which optimises power extraction under varying conditions like shading, light levels, and temperature.
Benefits of Solar Inverters
Solar inverters maximise energy production by tracking the optimal voltage for the panels. They also monitor system performance, allowing homeowners to see energy output and detect any issues. Inverters ensure grid safety by preventing electricity from back-feeding into the grid during outages, protecting utility workers.
Maintenance and Precautions
Make sure your solar inverter is properly weatherproofed. If it’s not fully protected from the elements, consider buying a weatherproof cage to extend its lifespan. Regularly check the display on your solar inverter. This helps you spot any operational issues early. The display shows information like system power production times, daily energy output, and total energy production since installation.
Always have a warranty for your solar inverter. Grid-connected inverters usually last 10-25 years, but warranties typically cover 5-15 years. You can often extend the warranty for an additional cost. Longer warranties offer better protection against failures. Have a qualified technician perform regular comprehensive checks to maintain optimal performance and extend the life of your solar inverter.
If you’re considering an off-grid solar system, companies like Loom Solar offer complete packages, including solar panels, inverters, and batteries. Prices start from INR 19,000 and vary based on the inverter’s capacity. It’s crucial to consider factors like your location, energy needs, backup power requirements, costs, and local regulations. Discussing these with a professional can help you decide if an off-grid system is right for you.