How does a microinverter convert a direct current source into an alternating current source?
So you have read about the financial and environmental advantages of solar AC power and have decided to invest in a solar installation. At this point, you need to start researching the two main components of any solar energy system: the solar panel and the inverter.
But what does the inverter actually do? Why are they so important? What’s the difference between an inverter and a microinverter? And which inverter to choose for your installation? We’ve compiled all the most important information you need to know about inverters, solar panels and energy currents.
WHAT IS AN INVERTER? WHAT IS THE DIFFERENCE BETWEEN AN INVERTER AND A MICROINVERTER?
Inverters are necessary because the energy produced by solar panels – direct current (or DC) energy – cannot be used by most consumer electronics. DC to AC power inverters turn that DC power into AC (alternating current) power, so it can be safely routed into building outlets.
Traditional “string” inverters connect to multiple solar panels in series, absorbing all the DC power they produce and converting it into one large block of energy. Microinverters, on the other hand, are smaller and convert each panel’s energy independently. This means that they tend to be more reliable, because if one solar panel fails, energy can still be converted from all the other panels.
WHAT IS DIRECT CURRENT ENERGY?
To understand how DC to AC inverters work, you first need to understand the difference between direct current (DC) energy and alternating current (AC) energy.
When we talk about DC and AC energy, we are talking about the direction in which the energy moves.
In DC, the electrons only move in one direction. DC energy is a little more stable than AC energy, so it’s often used in situations where you need to store energy for future use — like batteries in a remote control.
Next, let’s establish how solar panels work.
In solar panels, DC energy is generated when photons (particles of light) displace electrons from the silicon atoms you find in solar panels, in a process called the “photovoltaic effect.” The metal plates on the sides of each silicon “cell” in the solar panel then transfer these displaced electrons to wires, where they can flow through the microinverter into the building (or the grid).
So, if DC power is more stable and generated by solar panels, why do we need microinverters to convert it to AC power?
WHAT IS AC POWER?
AC power is less stable than DC power. The flow of electrons in AC power changes direction periodically, which means that the voltage of the current also changes at regular intervals.
All of the outlets in your home are AC power. Why? Because DC power is much harder to transport over long distances; if you try to run DC electricity from a power plant to homes, offices, or public buildings, most of it will be lost along the way.
AC power, on the other hand, is much easier to transport over the national grid. As a result, you will rarely find a building that doesn’t run on AC power.
Here’s a summary of the differences between the two types of current:
Alternating Current (AC) Direct Current (DC)
Electron flux Changes direction periodically Stable in one direction
Voltage polarity Varies periodically Remains constant
Used in wall outlets, anything that requires long distance power transmission. Batteries, electronics, solar panels.
HOW DOES A MICROINVERTER CONVERT DC POWER TO AC POWER?
As we pointed out above, the energy generated by your solar panel is direct current. This means that the energy can be easily stored, but it is not compatible with the outlets in most buildings.
This is where a microinverter comes to the rescue. When the solar panel transmits energy to the microinverter, the DC to AC inverters work by quickly transferring energy back and forth through a transformer located between two transistors. In doing so, the microinverter forces the energy to constantly change direction-in short, creating alternating current.
Because this alternating current is created “artificially,” it’s usually a little less smooth than the alternating current created by a generator, for example. To correct for this, an inverter will then use several filters to “clean up” the current so that it changes direction in a more consistent manner, making it suitable for use in building electrical outlets.
Microinverters are also known for their maximum power point tracking or MPPT. This feature determines how much DC power a solar panel is capable of generating at any given time and then optimizes the panel’s performance so that it generates as much power as possible.
WHY ARE MICROINVERTERS SO IMPORTANT?
A good quality microinverter is vital to turning the energy absorbed by your solar panels into safe and useful electricity. If your microinverter fails, you won’t be able to get power from a proper solar panel, so it’s important to think carefully about which supplier can provide the best and most reliable service.
Most importantly, a good microinverter will convert that energy from DC to AC as efficiently as possible, minimizing the amount of energy lost in the process and maximizing the output of your solar energy system. Many microinverters can also help you closely monitor the performance of your solar installation, so they are also often used to predict any problems and find ways to maximize power output.
If you’re switching to solar power, pay close attention to your microinverters; they may not be as visible as your solar panels, but they are absolutely essential.