By Lois Moore
One of the issues with solar that designers like myself have had to deal with is the efficiency loss from the disadvantage of voltage drop affecting entire solar array, as it does in centralized inverter systems. This can be caused by many factors and because the panels are wired in series can affect the entire system. Meaning one bad connection in a panel or shading to any panel affects the output of the entire array.
Now however there is a new solution available they are called Micro-inverters. Because each Solar panel is equipped with its own micro-inverter, the disadvantage of voltage drop affecting entire solar array, as it does in centralized inverter systems, is eliminated. Each solar panel can work independently to produce its maximum power in all conditions. The disadvantage of possible higher initial cost is offset by increased power production from the same modules over time and the ability to monitor output at a single module level. Meaning that now these issues can be eliminated making the efficiency and therefore system payoff much more precise.
Auo’s Unison line now has two solar panel lines that produce a 220 alternating current panel thanks to these micro inverters which convert 240 watts DC (direct current) to 220 volts AC (alternating current) at each panel, so you ask what are the advantages.
First it is a plug and play application; the solar modules come pre wired with easy to use plugs that allow seamless integration. The integrated micro inverter converts module DC to grid compliant AC at each module. This increases system performance by up to 25%, reduces shading losses, and makes PV safer to install and own. Here is Auo’s listing of Features for this product
• Harvest 5 to 25% more energy than traditional systems
• Module level monitoring
• Designed for 25 Year Reliability
• Modular flexibility suits any budget or rooftop
• Simplified PV system reduces installation costs
• No high voltage DC means safe installation and ownership
• Module complies with advanced loading tests to meet 5400 Pa loading requirements
• Light Trapping Capability: Superior performance under weak light conditions such as dawn, dusk, and cloudy days.
• Enhances current transmission and module reliability
• 3 Busbar Design: Enhances current transmission and module reliability
Recently I got hands on look at these panels at a solar tradeshow and I must say I was impressed by the ease of installation and the effectiveness of the monitoring. Likewise the ability to power higher voltage appliances like electric stoves, refrigerators, and air conditioning without special inverters or electrical configurations makes this a real competitor to the home and business solar markets.
I also like the fact of the twenty five year warranty for both the panels and micro-inverters as an integrated package, meaning if there is an issue, you are not fighting between two companies as to who is responsible. If there is a problem the panel and inverter are both replaced as a unit.
In the past I have seen that solar systems can be susceptible to voltage drop issues and this can severely affect performance and cost payoff. This looks like a way to eliminate the chance of both.