May. 06, 2024
Energy
See also: What are the different types of solar inverters? and What does a solar inverter do?
See also: What are the different types of solar inverters? and What does a solar inverter do?
Inverters play a crucial role in any solar energy system and are often considered to be the brains of a project, whether it’s a 2-kW residential system or a 5-MW utility power plant. An inverter’s basic function is to “invert” the direct current (DC) output into alternating current (AC). AC is the standard used by all commercial appliances, which is why many view inverters as the “gateway” between the photovoltaic (PV) system and the energy off-taker.
Inverter technologies have advanced significantly, such that in addition to converting DC to AC, they provide a number of other capabilities and services to ensure that the inverter can operate at an optimal performance level, such as data monitoring, advanced utility controls, applications and system design engineering. Inverter manufacturers also provide post-installation services that are integral to maintaining energy production and a high level of performance for the project, including preventative maintenance, O&M services and a quick mean time to repair (MTTR).
As the price of modules fall, inverters and additional system components have become a focus in price reduction for EPCs looking for a new competitive edge. As a result, inverter manufacturerinverter manufacturers are continually trying to drive down the cost curve of products.
Some companies have been able to do that successfully with modifications to manufacturing strategies and building additional manufacturing facilities within emerging solar markets. Additionally, companies have taken the core concept of “design for manufacturability”—meaning they design a product with ease of manufacturing in mind—to design inverter products that are quicker and cheaper to produce, without sacrificing performance. Inverter manufacturers have also been able to achieve lower-cost success through well-maintained partnerships with vendors.
The continued challenge of providing higher and higher value at lower cost is something the industry must work to overcome.
Grid integration and inverters
High PV penetration and the impact it will have on our aging electric grid is another challenge the entire solar industry faces. The challenge itself isn’t specific to inverters, but the solution may be entirely inverter-driven. Because inverters serve as a gateway to the system, advanced utility controls, such as low-voltage ride through, can help mitigate the issues that stem from higher PV penetration on the grid, such as predictability of output and distributed generation. These functions help ease the transition as more solar is built, without the need for major and expensive infrastructure upgrades. Utilities are keen to support the development and use of inverters with the most proven functionalities when it comes to grid interconnection.
Design flexibility
Given the growth in distributed generation projects along with continued development of utility-scale projects, solar project developers are seeking inverter manufacturers that can provide a robust suite of commercial products and technology topologies. A flexible inverter manufacturer can offer a centralized and decentralized inverter design, referring to an architecture that uses multiple inverters throughout a project to achieve the lowest levelized cost of energy (LCOE) possible. Although there’s still growing demand for a common system architecture using a centralized inverter, designing in three-phase string inverters for a decentralized PV system design is gaining in popularity. This is particularly true in commercial applications where space is at a premium or in an odd form.
Inverters have evolved from much more than simply inverting the electrical currents of a solar energy system. Inverters must continue to innovate and bring down cost, while maintaining key attributes for a solar energy system (reliability, efficiency and features such as data monitoring), in order to drive more PV penetration.
This story was originally contributed by Mike Dooley, Vice President of Marketing at Advanced Energy. It was updated to reflect current guidelines on May 1, 2018.
Find the right inverter for your project by glancing through our easy-to-use inverter database.
For more articles, see:
What do solar inverters do?
What are the different types of solar inverters?
Q&A: Common questions about inverters and storage
What are the advantages of using string inverters in commercial and small utility projects?
What are some benefits of a centralized approach in small utility solar projects?
Step 1) The solar inverter channels DC power through its internal transformer
Step 2) The inverter transformer function is to lower the voltage and switch to AC
Step 3) The DC runs through two or more transistors
Step 4) The transistors are rapidly turned on and off to feed the transformer’s two different sides
A comparison: On grid and off grid solar inverters
Solar inverter connection to grids is gaining in popularity. The connection is made while wiring the system during installation. If the customer's solar panels produce more power than they need, it's transferred to the utility meter and then to the grid.
With an on-grid solar inverter, also known as grid-tied, they can either build credit to reduce their bills for when they need the grid – called net metering – or depending on where customers live, get paid a feed-in-tariff (FIT). The benefit here for customers is not only reducing their electric bills, but in essence, the grid acts as their battery storage. That said, it’s also possible to add a battery to this type of system and store energy yourself, but the customer will need a battery-specific inverter to convert the electricity from AC to DC to store and discharge.
An off-grid solar inverter system is connected directly to the residence or commercial site to work with the building’s mains. The customer has no access to the grid, so a battery, which isn’t cheap, is needed for storing excess energy. That still might not be enough to ensure energy will always be available, so a generator as a back-up is a good idea.
On-grid solar inverter
Off-grid solar inverter
Connected to the grid
Relies solely on the sun – ideal for people who live remotely, away from power lines
Can sell excess electricity to utility company or reduce utility bill for power used
Connected to building or home’s mains – no electrical bills
Cost effective – no batteries involved, though batteries can be added
Requires a charge controller to maintain battery at highest state of charge
Special circuitry matches the voltage, frequency and phase of the grid –will not operate if it fails to detect the grid, i.e. power outages
Unaffected by power outages
There’s also a hybrid inverter, which is grid-tied. It’s a solar inverter with battery storage. A solar inverter and battery-based inverter come together to make one piece of equipment to ensure an uninterrupted supply of power. With a hybrid solar inverter, users incorporate storage without the need for separate batteries.
The benefit of a hybrid inverter is that back-up power is available, thanks to the built-in battery – which is also a reason why these units tend to be expensive.
What are the types of solar inverters?
There are three main types of solar inverters:
Application: commercial and residential
A string inverter functions in a series circuit. The panels are installed in rows. So if there are 12 panels total, they might be installed three across in four rows. This is called a "series string," or as some people call it, a multi-string solar inverter.
Each string carries the DC power generated by the solar panels to the string inverter. The solar inverter converts the DC to usable AC power. Depending on the size of the installation, multiple string inverters might be required.
As the solar panels are all wired in a series, what happens to one happens to them all. If one panel is shaded, its sun exposure is limited, weakening not only that one panel's output, but all of the panels. Another point: if the customer wants to add additional panels at some point, a new inverter will have to be added.
To combat this problem, string inverters can be paired with power optimizers. These devices are installed at the module level. Each panel has one. They're also available already integrated into the panels. The advantage of solar power optimizers is that they mitigate the impact of shading. They achieve a high-energy harvest before sending the DC to the inverter.
Application: commercial and residential
Solar panel microinverters are similar to power optimizers, as these are module-level electronics. One is placed on each panel, though there are some that can handle two or four. Power optimizers don't convert DC to AC, but microinverters do. Conversion takes place at the panels, so if one panel is shaded, it doesn't affect the other panels' performance.
As microinverters are installed at the module level, they can also monitor the performance of each individual panel. In comparison, string inverters can only show how each string is performing, which is one reason why microinverters cost more. Installing solar panels with microinverters is also more time consuming than setting up string inverters, which adds to the cost.
Application: Industrial – typically used on solar farms
This solar power inverter installation will require a mounting pad. Central inverters are similar to string inverters. They’re larger, mounting on the ground or floor, and able to support far more strings of panels. Instead of the strings connecting directly to an inverter, they connect to a combiner box. The combiner box carries the DC power to the central inverter, which converts to AC.
They can range in power and are rated for either indoor or outdoor use. Architecture varies in structures this large, but the simplest consists of a single DC-AC conversion stage. You’ll find that some inverters have a DC-DC boost stage to increase the maximum power point (MPP) voltage range. To boost the AC voltage and provide isolation, sometimes, a low-frequency transformer is provided at the output. The disadvantage to this is that it reduces the efficiency and increases the size, weight and cost of the inverter. To get around this, inverters without transformer inverters with a front-end boost stage can be used.
Understand more about solar equipment in our guide, Types of solar equipment, explained
Inverter:
String
Microinverters
Central
Summary
-Solar panels are installed in rows, each on a string
-Module-level electronics so one is installed on each pane
-Microinverters are the smallest inverters and slowly gaining popularity and market share
-Similar to string inverters but much larger and can support more strings of panels
-This type of inverter is the largest in terms of capacity
Design
-Suitable for installations without shading issues –can be paired with power optimizers to mitigate these effects
-Available in 3 types: on-grid, off-grid and hybrid
-Good for installations with shading issues or with panels on multiple planes facing various directions
-Designed to connect directly to the electric grid. Require fewer component connections, but require a pad and combiner box
Rated power
-Range from 1kW to 100kW
-Usually range from 250W to 1kW
-Can range from 100kW to a few megawatts
Maximum input voltage –refers to the maximum DC voltage that the inverter can withstand on its input side; dictates maximum voltage that PV array can have
-1,000V
N/a: manufacturers of microinverters specify the ratings of PV modules that their microinverters are compatible with
-Usually 1,000V, though some are 1500V
Maximum Power Point Tracking (MPPT)
-Typically 2-3 MPP inputs that accommodate 2-3 PV module strings
-Best MPPT capability, as each PV module is connected to its own MPP input
-Least amount of MPP inputs and are the most inefficient in terms of optimizing the power production of PV modules. However, this is usually not a problem since central inverters are usually used where the PV module’s tilt and orientation are uniform
Cost
-Less expensive than systems with microinverters
-Efficient, but often cost more than string inverters
-Installation can be cheap and easy as microinverters are often already integrated into the panel
-Inexpensive in terms of per kilowatt cost
Reliability
-Less reliable due to single point of failure
-Highly reliable as no single point of failure
-Often placed in protective environments, though still open to single point of failure
Typically used
-Great for residential and commercial applications
-Can also be a popular alternative to central inverters in small utility installations smaller than 1 MW
-Popular choice for residential and commercial installations
-As technology improves slowly being used for commercial and even utility-scale applications
-Perfect for large installations with consistent production across the array
-Utility-scale systems such as solar farms
What is a solar inverter monitoring system?
Monitoring systems operate through the inverter. As already mentioned, microinverters monitor the performance of each solar panel. Nowadays, most solar inverter manufacturers and distributors offer a monitoring software setup that works on the cloud, and it’s an attractive feature for customers. When the solar inverter system converts DC to AC, they’re given information about power levels and the amount of power produced. They can access these details on apps and other smart devices. Monitoring systems also provide diagnostic information, which helps manufacturers identify and fix any issues.
Download free CADs and try before you buy
Download free CADs and request free samples, which are available for most of our solutions. It’s a great way to ensure you’ve chosen exactly what you need. If you’re not quite sure which product will work best for inverters for solar panel systems, don’t worry. Our experts are always happy to advise you. Whatever your requirements, you can depend on fast despatch.
You can also learn more from our Quick guide: components for your solar PV system.
Request your free samples or download free CADs now.
Questions?
Email us at sales@essentracomponents.com or speak to one of our experts for further information on the ideal solution for your application 800-847-0486.
Related links:Inverters play a crucial role in any solar energy system and are often considered to be the brains of a project, whether it’s a 2-kW residential system or a 5-MW utility power plant. An inverter’s basic function is to “invert” the direct current (DC) output into alternating current (AC). AC is the standard used by all commercial appliances, which is why many view inverters as the “gateway” between the photovoltaic (PV) system and the energy off-taker.
Inverter technologies have advanced significantly, such that in addition to converting DC to AC, they provide a number of other capabilities and services to ensure that the inverter can operate at an optimal performance level, such as data monitoring, advanced utility controls, applications and system design engineering. Inverter manufacturers also provide post-installation services that are integral to maintaining energy production and a high level of performance for the project, including preventative maintenance, O&M services and a quick mean time to repair (MTTR).
As the price of modules fall, inverters and additional system components have become a focus in price reduction for EPCs looking for a new competitive edge. As a result, inverter manufacturers are continually trying to drive down the cost curve of products.
Some companies have been able to do that successfully with modifications to manufacturing strategies and building additional manufacturing facilities within emerging solar markets. Additionally, companies have taken the core concept of “design for manufacturability”—meaning they design a product with ease of manufacturing in mind—to design inverter products that are quicker and cheaper to produce, without sacrificing performance. Inverter manufacturers have also been able to achieve lower-cost success through well-maintained partnerships with vendors.
The continued challenge of providing higher and higher value at lower cost is something the industry must work to overcome.
Grid integration and inverters
High PV penetration and the impact it will have on our aging electric grid is another challenge the entire solar industry faces. The challenge itself isn’t specific to inverters, but the solution may be entirely inverter-driven. Because inverters serve as a gateway to the system, advanced utility controls, such as low-voltage ride through, can help mitigate the issues that stem from higher PV penetration on the grid, such as predictability of output and distributed generation. These functions help ease the transition as more solar is built, without the need for major and expensive infrastructure upgrades. Utilities are keen to support the development and use of inverters with the most proven functionalities when it comes to grid interconnection.
Design flexibility
Given the growth in distributed generation projects along with continued development of utility-scale projects, solar project developers are seeking inverter manufacturers that can provide a robust suite of commercial products and technology topologies. A flexible inverter manufacturer can offer a centralized and decentralized inverter design, referring to an architecture that uses multiple inverters throughout a project to achieve the lowest levelized cost of energy (LCOE) possible. Although there’s still growing demand for a common system architecture using a centralized inverter, designing in three-phase string inverters for a decentralized PV system design is gaining in popularity. This is particularly true in commercial applications where space is at a premium or in an odd form.
Inverters have evolved from much more than simply inverting the electrical currents of a solar energy system. Inverters must continue to innovate and bring down cost, while maintaining key attributes for a solar energy system (reliability, efficiency and features such as data monitoring), in order to drive more PV penetration.
This story was originally contributed by Mike Dooley, Vice President of Marketing at Advanced Energy. It was updated to reflect current guidelines on May 1, 2018.
Find the right inverter for your project by glancing through our easy-to-use inverter database.
For more articles, see:
What do solar inverters do?
What are the different types of solar inverters?
Q&A: Common questions about inverters and storage
What are the advantages of using string inverters in commercial and small utility projects?
What are some benefits of a centralized approach in small utility solar projects?
Step 1) The solar inverter channels DC power through its internal transformer
Step 2) The inverter transformer function is to lower the voltage and switch to AC
Step 3) The DC runs through two or more transistors
Step 4) The transistors are rapidly turned on and off to feed the transformer’s two different sides
A comparison: On grid and off grid solar inverters
Solar inverter connection to grids is gaining in popularity. The connection is made while wiring the system during installation. If the customer's solar panels produce more power than they need, it's transferred to the utility meter and then to the grid.
With an on-grid solar inverter, also known as grid-tied, they can either build credit to reduce their bills for when they need the grid – called net metering – or depending on where customers live, get paid a feed-in-tariff (FIT). The benefit here for customers is not only reducing their electric bills, but in essence, the grid acts as their battery storage. That said, it’s also possible to add a battery to this type of system and store energy yourself, but the customer will need a battery-specific inverter to convert the electricity from AC to DC to store and discharge.
An off-grid solar inverter system is connected directly to the residence or commercial site to work with the building’s mains. The customer has no access to the grid, so a battery, which isn’t cheap, is needed for storing excess energy. That still might not be enough to ensure energy will always be available, so a generator as a back-up is a good idea.
On-grid solar inverter
Off-grid solar inverter
Connected to the grid
Relies solely on the sun – ideal for people who live remotely, away from power lines
Can sell excess electricity to utility company or reduce utility bill for power used
Connected to building or home’s mains – no electrical bills
Cost effective – no batteries involved, though batteries can be added
Requires a charge controller to maintain battery at highest state of charge
Special circuitry matches the voltage, frequency and phase of the grid –will not operate if it fails to detect the grid, i.e. power outages
Unaffected by power outages
There’s also a hybrid inverter, which is grid-tied. It’s a solar inverter with battery storage. A solar inverter and battery-based inverter come together to make one piece of equipment to ensure an uninterrupted supply of power. With a hybrid solar inverter, users incorporate storage without the need for separate batteries.
The benefit of a hybrid inverter is that back-up power is available, thanks to the built-in battery – which is also a reason why these units tend to be expensive.
What are the types of solar inverters?
There are three main types of solar inverters:
Application: commercial and residential
A string inverter functions in a series circuit. The panels are installed in rows. So if there are 12 panels total, they might be installed three across in four rows. This is called a "series string," or as some people call it, a multi-string solar inverter.
Each string carries the DC power generated by the solar panels to the string inverter. The solar inverter converts the DC to usable AC power. Depending on the size of the installation, multiple string inverters might be required.
As the solar panels are all wired in a series, what happens to one happens to them all. If one panel is shaded, its sun exposure is limited, weakening not only that one panel's output, but all of the panels. Another point: if the customer wants to add additional panels at some point, a new inverter will have to be added.
To combat this problem, string inverters can be paired with power optimizers. These devices are installed at the module level. Each panel has one. They're also available already integrated into the panels. The advantage of solar power optimizers is that they mitigate the impact of shading. They achieve a high-energy harvest before sending the DC to the inverter.
Application: commercial and residential
Solar panel microinverters are similar to power optimizers, as these are module-level electronics. One is placed on each panel, though there are some that can handle two or four. Power optimizers don't convert DC to AC, but microinverters do. Conversion takes place at the panels, so if one panel is shaded, it doesn't affect the other panels' performance.
As microinverters are installed at the module level, they can also monitor the performance of each individual panel. In comparison, string inverters can only show how each string is performing, which is one reason why microinverters cost more. Installing solar panels with microinverters is also more time consuming than setting up string inverters, which adds to the cost.
Application: Industrial – typically used on solar farms
This solar power inverter installation will require a mounting pad. Central inverters are similar to string inverters. They’re larger, mounting on the ground or floor, and able to support far more strings of panels. Instead of the strings connecting directly to an inverter, they connect to a combiner box. The combiner box carries the DC power to the central inverter, which converts to AC.
They can range in power and are rated for either indoor or outdoor use. Architecture varies in structures this large, but the simplest consists of a single DC-AC conversion stage. You’ll find that some inverters have a DC-DC boost stage to increase the maximum power point (MPP) voltage range. To boost the AC voltage and provide isolation, sometimes, a low-frequency transformer is provided at the output. The disadvantage to this is that it reduces the efficiency and increases the size, weight and cost of the inverter. To get around this, inverters without transformer inverters with a front-end boost stage can be used.
Understand more about solar equipment in our guide, Types of solar equipment, explained
Inverter:
Want more information on 1 phase to 3 phase inverter? Feel free to contact us.
String
Microinverters
Central
Summary
-Solar panels are installed in rows, each on a string
-Module-level electronics so one is installed on each pane
-Microinverters are the smallest inverters and slowly gaining popularity and market share
-Similar to string inverters but much larger and can support more strings of panels
-This type of inverter is the largest in terms of capacity
Design
-Suitable for installations without shading issues –can be paired with power optimizers to mitigate these effects
-Available in 3 types: on-grid, off-grid and hybrid
-Good for installations with shading issues or with panels on multiple planes facing various directions
-Designed to connect directly to the electric grid. Require fewer component connections, but require a pad and combiner box
Rated power
-Range from 1kW to 100kW
-Usually range from 250W to 1kW
-Can range from 100kW to a few megawatts
Maximum input voltage –refers to the maximum DC voltage that the inverter can withstand on its input side; dictates maximum voltage that PV array can have
-1,000V
N/a: manufacturers of microinverters specify the ratings of PV modules that their microinverters are compatible with
-Usually 1,000V, though some are 1500V
Maximum Power Point Tracking (MPPT)
-Typically 2-3 MPP inputs that accommodate 2-3 PV module strings
-Best MPPT capability, as each PV module is connected to its own MPP input
-Least amount of MPP inputs and are the most inefficient in terms of optimizing the power production of PV modules. However, this is usually not a problem since central inverters are usually used where the PV module’s tilt and orientation are uniform
Cost
-Less expensive than systems with microinverters
-Efficient, but often cost more than string inverters
-Installation can be cheap and easy as microinverters are often already integrated into the panel
-Inexpensive in terms of per kilowatt cost
Reliability
-Less reliable due to single point of failure
-Highly reliable as no single point of failure
-Often placed in protective environments, though still open to single point of failure
Typically used
-Great for residential and commercial applications
-Can also be a popular alternative to central inverters in small utility installations smaller than 1 MW
-Popular choice for residential and commercial installations
-As technology improves slowly being used for commercial and even utility-scale applications
-Perfect for large installations with consistent production across the array
-Utility-scale systems such as solar farms
What is a solar inverter monitoring system?
Monitoring systems operate through the inverter. As already mentioned, microinverters monitor the performance of each solar panel. Nowadays, most solar inverter manufacturers and distributors offer a monitoring software setup that works on the cloud, and it’s an attractive feature for customers. When the solar inverter system converts DC to AC, they’re given information about power levels and the amount of power produced. They can access these details on apps and other smart devices. Monitoring systems also provide diagnostic information, which helps manufacturers identify and fix any issues.
Download free CADs and try before you buy
Download free CADs and request free samples, which are available for most of our solutions. It’s a great way to ensure you’ve chosen exactly what you need. If you’re not quite sure which product will work best for inverters for solar panel systems, don’t worry. Our experts are always happy to advise you. Whatever your requirements, you can depend on fast despatch.
You can also learn more from our Quick guide: components for your solar PV system.
Request your free samples or download free CADs now.
Questions?
Email us at sales@essentracomponents.com or speak to one of our experts for further information on the ideal solution for your application 800-847-0486.
For more pv inverter manufacturersinformation, please contact us. We will provide professional answers.
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