Decided to switch to solar power? Well, that is surely a good idea. Solar energy is a self-sustaining power resource but unlike your main power line supply you cannot just use solar energy to power your house. Yes, solar energy is converted into direct current by solar panels and most appliances are not designed to work on this form of electricity. Now what? Calm down because the solar panel system is backed with a solar inverter for this purpose. You are aware of inverters, but what are solar inverters? Do they also need sun to work? Come find out about this along with types of solar inverters and other related things.
What are Solar Inverters?
Basically, inverters are devices that convert the direct current (DC) to alternating current (AC) so that it can be used by appliances. Normal inverters use direct current from their batteries, but solar inverters are a bit different. They receive direct current from solar panels that convert solar energy into electric energy. Solar inverters also perform the same function of conversion but instead of taking current from the batteries they feed the solar batteries to charge them.
Whether a solar battery is AC-coupled or DC coupled, both types of power can be transmitted from a solar inverter to charge these batteries. Solar inverters transfer the alternating current to the utility grid and from there it is supplied to household appliances. In the case of an off-grid solar panel system, AC is directly supplied from the solar inverter to the appliances.
7 Types of Solar Inverters: Which One Suits Your House?
Different types of solar inverter serve the same purpose of converting DC to AC. Based on the system with which they are paired with, there are basically 3 types of solar inverters.
1. Battery Based Inverters
These bidirectional inverters include a battery charger and inverter. This type of solar inverter needs batteries to work and can be used in both off-grid and on-grid solar panel systems. However, this is decided on the basis of their UL rating and design. These inverters provide the power backup along with converting it.
Benefits: With this, your grid power consumption is reduced, and it provides a constant power supply. Also, it provides load management, and its operating cost is affordable. Plus, they are easy to maintain.
2. Central Inverters
These larger versions of string inverters are much larger than them and are capable of supporting numerous strings on the panels. In central inverters, string from solar panels is connected together in a combiner box from where DC from panels enters the inverter. Central inverters are suitable for large applications where regular solar power harvesting is done.
Benefits: They have the highest capacity and are suitable for utility-scale systems like solar farms. Their capacities can range from 100 kilowatts to megawatts. Central inverters are packaged with a power station as they are designed to be linked directly to the grid. They are less expensive per kilowatt along with being easy to install and manage.
3. Grid Tie Inverter
These inverters are designed to match the phase with a utility-charged sine wave and are mostly used with on-grid solar power systems. Grid tie inverters are ideal for residential, commercial, and office applications. They can easily support small to medium-scale operations.
This inverter stores the surplus generated solar power into the utility grid. In an on-grid solar power system, the utility grid acts as a virtual battery and all stored power from the solar inverter is converted into power credits. The solar inverter uses these credits to take clean energy from utility providers when needed without actually paying for it. If by the month’s end, solar credits are not exhausted, they will be adjusted in the monthly electricity bills.
Benefits: This inverter is cost-effective in comparison to off-grid solar inverters. There is no need for batteries and maintenance costs are also minimal. It is easy to install and manage, which is why it is most suitable for residential purposes.
4. Hybrid Inverters
These types of solar inverters are designed to handle the hybrid solar system. A hybrid solar inverter performs the same function of converting DC to AC. Along with conversion, this inverter transfers this power to the battery to charge them. Yes, as the name suggests, a hybrid solar inverter does a dual job by charging the battery and powering the appliances at the same time.
Hybrid solar power provides a constant power supply to your house. With this inverter, you can sell excess-produced solar electricity to the utility provider. Also, this inverter converts from solar to grid, and the grid to the battery if required (during power outages at night when there is no solar power generation) with an automatic changeover switch.
Benefits: Hybrid solar inverters can provide a constant power supply. With this inverter, you can save surplus generated solar power, and nothing goes to waste. Yes, they are costly, but they are worth the price.
5. Micro Inverters
These tiny solar inverters are attached to each panel and conversion is done individually. With this, there is no need for other inverters to convert the energy as a whole. With micro inverters, there is the least impact on the overall energy output of other solar panels even if a few of them are shaded. Since conversion is done individually, those shaded panels do not alter the performance of other unshaded panels even if the panels are series connected. With such efficiency, these inverters are a bit costly in comparison to our traditional string solar inverters.
Benefits: These solar inverters can find the ideal voltage for each system and then generate the maximum peak power voltage (VPP). They are featured with MPPT (Maximum Power Point Tracking) which allows them to track real-time sun intensity along with varied cell temperatures throughout the day. One of its main advantages is its individual monitoring that enables early diagnosis of defects in solar panels.
6. Stand-Alone Inverter
These types of solar inverters are also known as off-grid solar inverters. They are designed for solar systems in rural and village electrification in isolated areas. Mostly those regions where there is no utility grid or connection to it are nearly impossible. A stand-alone solar inverter is also suitable for a home solar system if you are planning to go completely off-grid. These inverters are free from grid connection and thus do not require anti-islanding protection. Such inverters are usually backed with solar batteries. Power received from PV panels and converted into AC is transmitted to the loads. But surplus power needs to be stored for powering the house at night when solar power generation is not possible.
Benefits: It is suitable for places where the grid connection is not possible. If you are not budget-bound, then this inverter can be the best option because when paired with a power generator it can give you hours of backup in case there is insufficient solar power generation.
7. String Inverters
This traditional solar inverter is good for series-connected solar panels. Multiple strings from all solar panels in a solar array are connected to one string inverter. DC power from each panel is transferred from the string to the string inverter where it is converted into AC as a whole. The number of string inverters required for the solar power system depends on the size of the system. For a large solar array, you may need more than one string inverter and each of them will receive DC from a few strings attached to it.
String inverters are suitable for residential and commercial applications. Also, string solar inverters can be paired with power optimizers that are module-level power electronics. They are attached to individual panels and gather DC individually from each panel. This is beneficial because if some panels are damaged or under shade, this way they would not affect the efficiency of other solar panels.
Benefits: String inverters are considered the most reliable and easy to use. Plus, they are the most affordable option for solar inverters in the market. Well now that you know about types of solar inverters, come find out about how they work. After this, the solar inverter working principle.
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What is Solar Inverter Working Principle?
Solar inverters convert DC from solar panel to AC power and this is basically their working principle. Solar panels convert photons from sunlight into electric current that is transferred through strings to the solar inverter. There the conversion takes place and generated power ranges from 250V to 600V. The conversion can be done with a set of IGBT (Insulated Gate Bipolar Transistors). Direct Current oscillates to Alternating Current when IGBT is connected in a form of an H-bridge.
Now to obtain the AC power and transfer it to the grid a step-up transformer is used. With technological advancement, new inverters are designed to be used without step-up transformers without any compromise on efficiency.
Lastly, a pre-programmed microcontroller is used for executing different algorithms together. With the help of an MPPT controller algorithm output power from the solar panels is increased. And the converted power is then transferred to batteries and charged and the remaining is supplied to the utility grid.
Solar inverters work constantly because during the day until sunset when panels are generating power, they carry on the conversion and transmission process. In case there is a power outage, the load is shifted from the utility grid to batteries by the inverter and the reverse when power is back.
Also See: Understanding Off Grid Solar System Working Principle
What are Solar Inverters Made Of?
A solar inverter is the product of customization of EMC/EMI materials, heat dissipation, and electrical insulation.
1. Multilayered or discreet insulation products
These products are added for temperature resistance and dielectric strength. These materials also make it resistant to tearing and puncturing during its assembly. Electrical grade coated clothes, paper, laminates, films, tapes for core, magnetic wire insulation, and phase separators, along with barrier layer, and lead pads are the products in this category that are added to all types of solar inverters.
2. Thermal management materials
Products like wire mesh, metal-filled elastomers, and foil tapes are added to help in transferring away the heat from components. Electrical tape with aluminum and copper backings is used for bonding and grounding along with EMI shielding. Conductive and non-conductive adhesive systems are available along with laminated or custom die-cut to other materials. After this, let’s see what are solar inverters made of. Now, let’s also look at solar inverter pros and cons.
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What are Solar Inverter Pros and Cons?
After learning about what are solar inverters made of, let us find out about their pros and cons. Different types of solar inverters have their pros and cons that you should consider before buying one. Here are the main advantages and disadvantages of solar inverters.
1. Advantages
- Does not emit harmful gases, thus reducing global warming and carbon footprint.
- Help to save money by reducing electricity bills in the long run. With an off-grid solar inverter, electricity bills are completely eliminated. (Note: In some regions, it may be against the law to go completely off-grid. Consult with the local installer and utility provider before making the decision.
- It is beneficial for people living in remote areas in catering to electricity shortages.
- Output waves of solar inverters are AC pure sine waves which are similar to the power we receive from traditional power supplies. Thus, it can run different types of loads used at residential, commercial, and industrial levels.
- They are cost-effective and require less maintenance in comparison to diesel inverters.
- You can sell the AC power converted by solar inverters to electric power utility providers.
- You can sync solar inverters to other devices or use them alone. It can also be sourced in a wide range of power capacities which means it can be used for residential as well as large electrical distribution companies.
Also See: 3 Amorphous Solar Panels Advantages and Disadvantages
2. Disadvantages
- The cost of solar inverter makes up about 30% of the whole system. Solar inverters are costly, and their price varies depending on the efficiency ratings.
- The solar inverters conversion process takes place only when solar panels produce DC power in the presence of sunlight. For it to work efficiently, DC power from solar panels’ output voltage must match the lower DC voltage levels of the solar inverter.
- Requires batteries to power the house during the night when there is no solar power generation, and this makes the system more expensive. After learning about solar inverter pros and cons, let us move ahead to know how long they last.
Also Read: 3 Mono PERC Solar Panel Advantages and Disadvantages
What is Solar Inverter Lifespan?
Different types of solar inverters have varying lifespans. This depends on several factors like brand, material, manufacturer, humidity (at the place of installation), maintenance, heat, operations, load, and some related factors. Residential string inverters have a lifespan of several years but not more than solar panels. Yes, residential solar panels can last up to 15 years and sometimes double this time period. And as for string inverters, you will have to replace them after 10–15 years.
The average lifespan of micro inverters is around 20–25 years and is backed by a 20-year warranty. DC optimizers can also last up to 25 years.
To ensure that your solar inverter lasts long and stays in good condition, you need to keep up with maintenance and install it in a place that suits your requirements. Mostly it needs to be installed in a cool place.
Also See: How Long Do Solar Generators Last?
Note: Maintenance and installation need to be done by a licensed professional technician.
So, today you got to know that there are 7 types of solar inverters. String, central, microinverters, stand-alone, battery-based, grid-tie and hybrid solar inverters are different types of solar inverters available in the market in different wattages to suit your requirements. All inverters serve the same purpose but on different scales because some of them are fit for small-scale systems whereas others are ideal for large-scale operations like solar farms. Solar inverter working principle is the same irrespective of its type because it will use DC from solar panels and convert it to AC. The lifespan of solar panels differs and depends on a number of factors. And do not forget to consider the pros and cons.
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