SMA Becomes the First Manufacturer Worldwide to Receive UL Certification for Its Transformerless Inverters

This UL certification can be seen as laying the foundation for the safe and widespread use of transformerless inverters in the U.S. Due to the special requirements of American standards, up until now PV plants in the U.S. were almost always designed using transformer-based, galvanically isolating devices. In comparison, transformerless inverters are more efficient (among other benefits), which means the operators will benefit accordingly as a result of increased energy yield. In addition, their reduced weight will make it significantly easier for installers to mount the devices.

UL is one of the world's most renowned product safety certification organizations, and working together with SMA, developed a highly complex testing procedure for transformerless inverters. In addition to other things, monitoring residual currents and ground faults were integrated, which means maximum safety for the user. As a result, the UL 1741 Standard of Safety was expanded to include the requirements of the IEC 62109 Standard. In contrast to string inverters offered by other manufacturers, SMA's certified inverters also have an attractive price-performance ratio and class-leading efficiency. The Sunny Boy 8000TL-US and Sunny Boy 9000TL-US feature unmatched weighted efficiencies of 98 percent according to the California Energy Commission (CEC), while the Sunny Boy 10000TL-US achieved 97.5 percent.

"Thanks to the OptiTrac MPP tracking procedure, which is patented in the U.S., and the OptiCool™ active cooling system, we ensure that our inverters have above-average efficiency, even when used in areas with high ambient temperatures above 45 degrees Celsius (113 degrees Fahrenheit), which means we are way ahead of other manufacturers from a technological standpoint," says Bernd Engel, senior vice president of technology and development at SMA Solar Technology AG.

The first UL certification for transformerless inverters is not just significant for SMA, but also for the entire North American market.

"For the first time, highly efficient SMA transformerless inverters can be used in the U.S.,” says Engel. “This represents both a reduction of system costs and leap ahead technologically. In addition, the Sunny Boy 10000TL-US was developed based on SMA’s transformerless Sunny Mini Central, which is now the best-selling and most successful inverter worldwide.”

Ultimately, the close cooperation between SMA and the certification organization UL, which SMA has worked with for many years, is crucial to its success. "These projects are characterized by their transparent dialog between experts from both companies, and experiences are shared in an open and honest manner. Doing so offers the best conditions from which to design demanding testing procedures and high-quality inverters." In reality, it is difficult for products which have not received UL certification to be successful in the US market. In addition, according to Engel, UL certification is not only in demand in the US, but in Canada as well. "In light of this fact, certifying our transformerless US inverters also represents a further milestone in expanding our leading position in the market," concludes Engel. SMA certified inverters, which can be finely adjusted from 8 to 10 kW, are especially suited to use in PV plants from the medium power range to the megawatt class, and are shipped with a DC disconnect as well as a Combiner Box.

About SMA

The SMA Group generated sales of more than sales of 934 million Euro in 2009 and is the worldwide market leader for photovoltaic inverters, a key component of all solar power plants. It is headquartered in Niestetal, near Kassel, Germany, and is represented on four continents by 13 foreign subsidiaries. The Group employs a staff of over 4,000 (incl. temporary workers). SMA’s product portfolio includes the most comprehensive range of inverters on the market, offering a compatible inverter for every type of photovoltaic module and for all plant sizes. The product range covers both inverters for photovoltaic plants connected to the grid as well as inverters for off-grid systems. Since 2008, the Group’s parent company SMA Solar Technology AG has been listed on the Prime Standard of the Frankfurt Stock Exchange (S92) and also in the TecDAX index. In recent years, SMA has received numerous awards for its excellence as an employer.

www.SMA-America.com