What is a Solar Inverter?
The hardest working component of any solar photovoltaic system is the inverter. Solar PV inverters are sophisticated electronic devices that perform multiple distinct jobs. They are quietly and constantly working away to keep to maximise your power output. There are 3 common types of inverter in the UK market. String inverters such as those by SMA, Fronius, Growatt, Solax, Samil and Solis are the most common. Micro-inverters like those from Enphase, and SolarEdge inverters with panel level optimizers make up the most of the rest of the market.
Power Point Tracking
The first job of a solar inverter is to maximise solar yield. The electrical power output from solar panels is not fixed. As the sun and clouds move across the sky, and as the temperature rises and falls, the inverter is is constantly changing the load it applies to the panels to hit the sweet spot between voltage and current known as the maximum power point. Most domestic string inverters will have 2 power point trackers. Micro-inverters and SolarEdge take a panel level approach which can help to reduce losses from shading.
Power Conversion
The electricity from photovoltaic panels has current that flows in one direction, this is known as DC or direct current. This is the same type of electricity that you would get from a battery. Because of the way it is made, the electricity supplied to your home is different. The flow of electrical current from the grid changes direction 100 times per second. This switching of current direction is what is referred to as the frequency of the mains supply. In the UK this is 50 hertz, or 50 cycles per second, and is directly caused by the speed at which your turbine in your local power station is spinning. In order for electricity from your solar panels to be used by your home or fed back to the grid, the inverter must take the DC input from the solar panels and closely match the power output to the same frequency and voltage of the electricity grid network. This is done within very tight tolerances and is the reason grid connected generators like your solar inverter need to be certified to strict engineering standard of G59 or G83 or to the latest G98 or G99 standard, or G100 for grid connected house batteries.
Monitoring
Modern inverters can upload performance and error data to the cloud so that it can be accessed online or though an app on your phone. Though a solar inverter does not need web connected monitoring to work, access to the historical information can be prove invaluable for troubleshooting some performance problems such as diode failures associated with indirect lightning strikes. It also allows a better understanding of system performance over time allowing you to spot problems before generation stops. Some systems like SMA and SolarEdge monitoring will email you to let you know there is a problem with your system.
On average you should expect a good quality inverter from a European manufactured to last between 10 and 12 years. This can be quite variable however. The temperature and humidity of the environment in which the inverter operates is the main contributing factor to premature failure. Higher temperatures put more strain on the electronic components. Many inverters limit the output of the system in high temperature conditions which limits your system output and your generation tariff payments.
The hardest working component of any solar photovoltaic system is the inverter. Solar PV inverters are sophisticated electronic devices that perform multiple distinct jobs. They are quietly and constantly working away to keep to maximise your power output. There are 3 common types of inverter in the UK market. String inverters such as those by SMA, Fronius, Growatt, Solax, Samil and Solis are the most common. Micro-inverters like those from Enphase, and SolarEdge inverters with panel level optimizers make up the most of the rest of the market.
Power Point Tracking
The first job of a solar inverter is to maximise solar yield. The electrical power output from solar panels is not fixed. As the sun and clouds move across the sky, and as the temperature rises and falls, the inverter is is constantly changing the load it applies to the panels to hit the sweet spot between voltage and current known as the maximum power point. Most domestic string inverters will have 2 power point trackers. Micro-inverters and SolarEdge take a panel level approach which can help to reduce losses from shading.
Power Conversion
The electricity from photovoltaic panels has current that flows in one direction, this is known as DC or direct current. This is the same type of electricity that you would get from a battery. Because of the way it is made, the electricity supplied to your home is different. The flow of electrical current from the grid changes direction 100 times per second. This switching of current direction is what is referred to as the frequency of the mains supply. In the UK this is 50 hertz, or 50 cycles per second, and is directly caused by the speed at which your turbine in your local power station is spinning. In order for electricity from your solar panels to be used by your home or fed back to the grid, the inverter must take the DC input from the solar panels and closely match the power output to the same frequency and voltage of the electricity grid network. This is done within very tight tolerances and is the reason grid connected generators like your solar inverter need to be certified to strict engineering standard of G59 or G83 or to the latest G98 or G99 standard, or G100 for grid connected house batteries.
Monitoring
Modern inverters can upload performance and error data to the cloud so that it can be accessed online or though an app on your phone. Though a solar inverter does not need web connected monitoring to work, access to the historical information can be prove invaluable for troubleshooting some performance problems such as diode failures associated with indirect lightning strikes. It also allows a better understanding of system performance over time allowing you to spot problems before generation stops. Some systems like SMA and SolarEdge monitoring will email you to let you know there is a problem with your system.
On average you should expect a good quality inverter from a European manufactured to last between 10 and 12 years. This can be quite variable however. The temperature and humidity of the environment in which the inverter operates is the main contributing factor to premature failure. Higher temperatures put more strain on the electronic components. Many inverters limit the output of the system in high temperature conditions which limits your system output and your generation tariff payments.