|
 |
greenpowerZONE Products for the week of July 14, 2008
National Semiconductor Says…
Photovoltaic Market Entry with Technology That Maximizes Solar Energy Production
Upcoming customer field trials to demonstrate how National’s SolarMagic technology enables today’s solar systems to extract significantly more energy from variable light conditions
National Semiconductor Corp. has announced that it has entered the photovoltaic market with new technology designed to increase the overall energy output of solar electric power generating systems. National’s SolarMagic technology extracts the maximum power efficiency of each photovoltaic panel, even when some panels in the array are compromised by shading, debris or inherent panel-to-panel mismatch.
Today’s solar installations are disproportionately impacted by non-uniformities, caused by shading, panel mismatches or dirt accumulation. For example, a small amount of shading in the array can cut the energy harvest of a system in half. This significantly limits the energy output, design and location of typical residential solar installations. Shading conditions can even invalidate local utility and governmental incentives, making certain installations cost-prohibitive. National’s SolarMagic technology recoups up to 50 percent of the lost energy thereby minimizing the economic impact of shading and other real-world conditions.
“National’s entry into the photovoltaic market is a natural extension of our focus on energy efficient systems,” said Brian L. Halla, National’s chairman and CEO. “Our technologists solved this real-world problem and are enabling consumers to produce more energy under adverse conditions and reduce the payback time of their investment with an environmentally friendly source of power.”
SolarMagic technology is a per-panel electronics solution that maximizes power output of multi-panel installations. It is compatible with today’s solar architectures regardless of the underlying solar cell technology.
National has entered field trials with its SolarMagic technology. REgrid Power, Inc., one of the largest solar installers in California, has begun system testing of National’s SolarMagic technology.
“We are impressed with National’s SolarMagic technology in our field trials and have seen a significant performance improvement in our solar installation,” said Tom McCalmont, president and chief executive officer of REgrid Power, Inc. and founder and executive chairman of SolarTech, a Silicon Valley consortium. “We have observed energy output improvements of up to 44 percent during shaded conditions and 12 percent overall versus the same system running without SolarMagic technology.”
Several additional solar companies are slated to join the field trials over the next several months, and National will expand field trials to include installers in other countries with high adoption rates of solar. Later this year, National plans to introduce SolarMagic products for solar installers and system providers to include in their installations.
EN-Genius Says…
 One of the reasons I haven’t put solar panels on my house is the beautiful maple tree that sits in my backyard and casts shade on various parts of the south-facing part of my roof at one time of the day or another. Although the overall solar input an array would see is more than enough to make it worthwhile, the intermittent shade from the maple tree would reduce a conventional panel’s actual output by half or more. From what I can have been able to learn from National, their new SolarMagic technology could help make solar panels in less-than-perfect locations like mine feasible, and help extract much more power from many other new and existing installations.
Unlike the many exotic photovoltaic cell technologies currently under development, SolarMagic is an unglamorous, pragmatic and cost-effective way to improve the efficiency and overall output of today’s solar systems. Actually, it might even help make some of those exotic photovoltaic technologies more cost-effective. National will be making the actual product announcement a bit later this year but the technology they’ve announced here is so interesting that it’s worthwhile giving you a taste of things to come.
 I am surprised that it took so long for someone to come up with a distributed maximum power point tracking system since the losses that occur in nearly every solar system due to mismatches in panel output, which are a long-standing and well-known problem within the industry. There have been some attempts to fix the problem by equipping each panel with its own inverter but, for obvious reasons, that’s proved to be prohibitively expensive. National gets around this by performing a (relatively) simple dc-dc conversion at the panel outputs to a common intermediate voltage that gets fed to the inverter. This allows the SolarMagic module to adjust its impedance so that it can coax the peak power output from the panel: regardless of what voltage or current it’s capable of producing at the moment.
 National’s initial results of a side-by-side test between a conventional multi-panel array and a SolarMagic-equipped array are certainly promising. The output curves clearly show the improved efficiency that you get when you allow each panel to produce the voltage and current it needs to deliver maximum power without dragging down its neighbors.
De-coupling panels from each other using something more sophisticated than an isolation diode gives solar system designers much more leeway in what they can do with an installation. For example, they can now use custom-shaped panels with different outputs, varying string lengths, and use more precious roof space to generate power, even if some of it is occasionally subject to partial shading conditions. In large-scale industrial applications which might not have the same shading problems as residential systems, SolarMagic may still prove cost-effective in helping a system maintain peak efficiency as its outputs start to diverge due to aging. Utility-sized installations should also benefit from per-panel optimization: especially if the panels are mounted a hillside or other uneven terrain where sun angles can vary significantly. 
For the moment, National is keeping the details of how SolarMagic works under wraps. I speculated part of the system used sophisticated PWM techniques National has already developed for their other dc-dc converter applications but they refused to say anything other than “it’s not exactly like that” and “there are multiple control loops involved.” National was equally mum about SolarMagic conversion losses but the performance of their other dc-dc products and the relatively compact size of the converter module would lead me to believe it eats up 4% - 5% (and perhaps even less) of the panel’s output. If SolarMagic actually lives up to its promise to reclaim much more of the energy that would be otherwise lost it seems like a fair deal to me. Hopefully, I’ll be able to give you enough details on the converter architecture and its operating efficiency to determine whether SolarMagic can really deliver on its promises when National releases the actual product later this year.
 The first version of SolarMagic is expected to be a stand-alone module that can be attached to nearly every solar panel. Even with the anticipated cost-adder of around 10% of the cost of the solar panel (or around 5% of a complete system), it should rapidly pay for itself since initial tests indicate that it cuts a solar system payback time by 10% - 30%.
The math should get even better once National is able to sell their technology directly to solar equipment makers who will integrate it into their panels during manufacture at an even lower per-unit cost. If we can believe National’s findings that SolarMagic typically improves a panel’s payback period by around 20%, the technology becomes a no-brainer choice for many solar installations. Of course the economics will change a bit as the silicon shortage eases and other technologies allow the cost-per-watt of a photovoltaic system to decline over the next few years. Nevertheless, I expect that the anticipated rise in electricity pricing should still make SolarMagic look like a bargain.
SolarMagic Home Page
|
|
|
|
|
