While researching different solar panel systems, you’ve probably come across the term “inverter.” There are string inverters, hybrid inverters, and microinverters. They are three different pieces of technology, but they all do the same thing. They convert DC (direct current) power into AC (alternating current) power from the sun to your home.
It’s important to understand that the inverter type is what defines your solar system. A string inverter goes with a string inverter system, and a microinverter is an important part of a microinverter solar system. And if you’re interested in understanding the difference between a string inverter system and a microinverter system, you can read more about it here – Microinverter vs. String Inverter.
Microinverter solar systems are the latest advancement in solar panel technology and the industry is buzzing about what they can do. But what can they do?
Like Kal-El (aka Clark Kent, aka Superman) of planet Krypton, they harness the power of Earth’s yellow sun. The panels absorb the sun’s ultraviolet radiation, and like Kal-El, the more sun exposure they get, the more power they acquire and the stronger they become. Like the famous Kryptonian’s alien physiology, microinverters convert that energy into power. But how does it happen?
The main steps are:
- How sunlight is converted to energy.
- Converting DC to AC.
- How power travels through your home.
By the end of the article, you’ll understand the process of collecting energy from the sun, from warm rays to light switches. Up, up, and away!
How Does Sunlight Convert to Energy in My Solar Panels?
Earth’s sun is about 150,000,000 kilometres away, give or take a few thousand k’s. Ultraviolet radiation travels through our atmosphere as sunlight and hits the solar panels. Solar panels are made up of individual solar cells, composed of silicon semiconductors.
The sun’s energy, in the form of UV radiation (sunlight), excites the electrons in the solar cells. The electrons circling their atoms break free, becoming negatively charged and leaving behind a hole where they used to be that becomes positively charged. The free electrons move towards the surface of the solar cell while the holes they left behind are pushed in the opposite direction, away from the surface. This creates a current. This is how DC electricity is produced.
At the surface of the solar cell, a metal gridwork collects the free electrons. This gridwork made up of strips called busbars and thin wires that connect the solar cells to each busbar called fingers. The busbar is usually made of silver, though some can be copper or aluminium. A busbar collects energy and redistributes it.
The busbar directs the energy to a central point in the solar panel. This central point is called the junction box. The energy is still at DC at this stage. From there, it’s routed to the microinverters.
How Does the Microinverter Convert DC to AC?
The DC energy exits the panel and goes straight into the microinverter. It’s the microinverter’s job to optimise and convert that energy to AC. Energy is optimised by a power point tracker. Every microinverter has its own power point tracker to keep the array operating in the ideal voltage range. It takes that information from the power point tracker and uses it to convert the DC energy straightaway into AC energy.
This is the heart of the microinverter’s function: converting DC to AC electricity.
DC electricity behaves differently from AC electricity. Imagine that DC electricity travels in a straight line while AC electricity is a series of waves. The microinverter turns this straight line into a ‘wavey’ line. That’s its job. This is achieved through a method known as pulse width modulation (PWM), which generates an alternating current (AC) waveform from direct current (DC) electricity. In essence, it transforms DC electricity to mimic the AC waveform.
The process begins with a reference signal, which is in waveforms since that’s the ultimate output of the microinverter. The microinverter then compares this reference signal with the DC electricity it receives. When it detects a discrepancy between the two, it generates an error signal. In response, the microinverter recognizes the mismatch and initiates corrective actions to align the signals.
The microinverter then generates high-frequency pulses (blue line) that change the frequency of the DC current (red line). It’s adjusted to create a smooth wave signal that matches the reference signal from the grid. This newly formed wave signal is an alternating current (AC electricity) (green line).
The AC electricity generated by the microinverter must be in sync with the grid’s AC frequency and phase. In Australia, that frequency is 50 Hz. If they are out of sync, the power flowing through the circuitry cannot be absorbed by connected devices. Microinverters sync their AC output with the grid’s. This makes sure there’s a smooth integration of solar-generated electricity with the grid.
How Does the Electricity Travel to My Home?
Once the AC electricity is outputted by the microinverters, it then goes to a trunking cable. Every microinverter in the solar array is plugged into the same trunking cable that ends up connecting to your switchboard. It’s like a train track where each microinverter is a station and the electricity is boarding.
All that power is sent directly to the switchboard. Like water flowing downhill, the electricity will find its way to the nearest appliance through the path of least resistance.
Because the electricity works like water in your pipes by following the path of least resistance, the energy your home uses will first come from solar energy. If your solar system is producing more than you’re using at home, it will first supply your home and then any excess will go back to the grid.
The AC electricity becomes part of the electricity available for powering your lights, appliances, and other devices, just like the electricity supplied by your utility company. Everything in your home runs on AC power.
Is a Microinverter System Right for You?
Now you know how important the microinverter is on the journey sunlight takes to reach your lights and appliances. Understanding microinverter systems’ role in converting sunlight to energy reveals their importance in increasing energy efficiency and harnessing solar power. Just as Kal-El’s unique abilities set him apart, microinverters are vital components in transforming solar energy into usable electricity for your home.
Whatever solar system you choose, make sure you ask questions and do your research. Microinverter systems are a remarkable advancement in solar technologies, but they aren’t a perfect fit for everyone.