2013 String Inverters - Developments and Specifications

Integrators working in the North American market have a wide range of options and choices to make when it comes to string inverters. Our 2013 dataset contains extensive specifications for 111 single- and 3-phase models from 16 manufacturers.

The solar industry news wires have been buzzing in recent months with announcements of inverter manufacturer acquisitions and reports of fragmentation of the inverter supplier base due to shifts in sales capacities in core markets such as Europe, Asia and North America. For example, according to IMS Research, the total global market share for the 10 largest inverter manufacturers fell more than 4% in 2012.

While these developments—and their potential impacts on the solar industry—are fascinating to watch, many integrators are more interested in changes and advancements in the specific products they install. In this regard, the past year has been a great one for the industry. Several string inverter manufacturers have brought new products to market that offer higher power capacities and interconnection voltages, and features that increase design flexibility.

The core of this article presents comprehensive electrical, operational and mechanical specifications for 111 single- and 3-phase string inverters currently available in North America. Before you dig into the specs, the following information will help orient you to some of the high-level and model-specific changes that have occurred.

Notable Acquisitions and US Market Entries

Noteworthy developments in inverter manufacturing include Advanced Energy’s acquisition of REFUsol and ABB’s acquisition of Power-One. In addition, SolarMax, a Swiss inverter manufacturer, recently announced plans for a North American market entry.

While Advanced Energy’s announcement that it was acquiring REFUsol caught many industry pros by surprise, the pairing appears to be a great fit. REFUsol’s 3-phase 480 Vac inverters have been gaining traction in the US market and round out the commercial and utility-scale product portfolio of AE Solar Energy, Advanced Energy’s solar division. Advanced Energy noted that the acquisition would extend its geographical distribution into growth markets where REFUsol has a strong presence, including India, Asia and Eastern Europe.

At the time of publication, ABB’s acquisition of Power-One is still in process and the two companies are acting independently until the merger is complete. Therefore, related products are listed under Power-One in the following dataset. Once completed, the acquisition will establish ABB, a global power and automation technology group, as the second largest inverter manufacturer in terms of global market share.

Another recent development is an announcement by SolarMax, an established brand outside North America, of plans to expand into the US. SolarMax will be introducing a line of 1,000 Vdc string inverters with rated power capacities ranging from 12 kW to 18 kW. The products will have multiple MPPT inputs and NEMA 4X enclosures. A 75 kW 3-phase 480 Vac central inverter is also scheduled for launch in 2013.

US Market Exits

The 2012 version of our string inverter dataset included 121 products from 18 manufacturers, with six manufacturers entering the US market that year: Carlo Gavazzi, Chint Power Systems, Eaton, Eltek, Growatt New Energy and REFUsol. This represented a 33% increase in the number of string inverter manufacturers operating in North America compared to the previous year. In 2013, the number of manufacturers offering string inverter products in the US headed the other direction and fell by two, for a current total of 16. The number of available models dropped to 111.

Over the last year, three string inverter manufacturers either have discontinued production or no longer have a distribution presence in North America. Delta Energy Systems ceased the distribution of its Soliva string inverter line in North America, but continues to supply versions of these models to the European, Australian and Indian markets. Exeltech’s non-isolated XLGT string inverter is no longer in production. Additionally, there is currently no US distribution for Growatt New Energy inverters due to contractual issues between the joint venture partners. However, a resolution of these issues is reportedly under way.

Changes in String Inverter Portfolios

Several manufacturers have changed up their North American string inverter lineup since we published our 2012 dataset. The following highlights do not include enhancements made to existing models.

AE Solar Energy (AESE). With the acquisition of REFUsol, AESE added four high-capacity, 3-phase 480 Vac string inverters to its portfolio. As part of its overall market strategy, AESE discontinued production of all nine of its PVP string inverters. This move marks AESE’s clear shift out of the residential market and points to a new core focus on string and central inverter solutions for commercial and utility applications.

Danfoss. Danfoss manufactures 1 MW–1.5 MW SLX central inverters at its Illinois facility. In 2012 the company began branding and distributing four Eltek string inverter models (2 kW–4.4 kW) in the US. While these products are rebranded, we include them in our dataset to familiarize integrators with Danfoss DLX string inverter models.

Eltek. Two additional single-phase string inverter models from Eltek (2 kW and 2.9 kW) are now available in the US market.

Ingeteam. Ingeteam added three non-isolated string inverters (7.5 kW, 8.6 kW and 10 kW) to its US product lineup.

KACO new energy. KACO new energy teamed up with Tigo Energy to develop 6400M and 7600M (6.4 kW and 7.6 kW) models, which feature an integrated Tigo Maximizer Management Unit for use with Tigo’s module-level electronics. In addition, KACO new energy recently released its TL3 3-phase central inverter models (32 kW, 40 kW and 50 kW). These models are listed for 1,000 Vdc applications and are available with one or three MPPT channels. However, because the products are ground mounted, they are not included in our 2013 string inverter dataset.

Motech Americas. To streamline its US product offerings, Motech discontinued the distribution of its 3 kW, 3.8 kW, 4 kW and 5 kW string inverters in North America. Its current lineup includes six models ranging from 2.9 kW to 7.5 kW.

Power-One. Power-One recently launched its 3-phase 480 Vac Aurora Trio string inverter products in the US. The 20 kW and 27.6 kW models are the only string inverters currently listed for 1,000 Vdc applications in the US.

SMA America. It has been a long run, but SMA is officially retiring its SB 700-US (700 W) model. In the last year, SMA added several string inverters to its lineup, including three non-isolated models (3 kW, 4 kW and 5 kW) that feature an integrated arc-fault circuit interrupter and a Secure Power Supply function that provides up to 1,500 W of power during grid failures, given that there is sufficient solar irradiance. SMA also introduced 6 kW, 7 kW and 11 kW non-isolated products. Four non-isolated 3-phase 480 Vac Sunny Tri-power models (12 kW, 15 kW, 20 kW and 24 kW) are scheduled for launch in Q3 2013.

SolarEdge Technologies. For commercial and industrial projects, SolarEdge introduced three non-isolated 3-phase string inverters (9 kW, 10 kW and 20 kW) that work in conjunction with the company’s module-level power optimizers.

2013 String Inverter Specifications

Products included in SolarPro’s 2013 string inverter dataset have to meet these criteria: They are listed to the UL 1741 standard; are included in the CEC’s list of eligible inverters per SB1 guidelines as of April 15, 2012; are in production and available in the North American market; are wall mountable; and have an output rating of up to 30 kWac.

We include specifications for both single- and 3-phase string inverters in the dataset. This 2013 version includes specifications that indicate a model’s topology (isolated or non-isolated), the number of MPPT channels and the number of ac output phases. Notably, 48% of the listed models have non-isolated topologies, and five manufacturers now offer products with two independent MPPT channels. Additionally, six manufacturers have products with 3-phase ac outputs.


Joe Schwartz / SolarPro magazine / Ashland, OR / solarprofessional.com

String Inverter Manufacturers

AE Solar Energy / 877.312.3832 / advanced-energy.com

Carlo Gavazzi / 847.465.6100 / gavazzionline.com

Chint Power Systems / 855.584.7168 / chintpower.com/na

Danfoss / 855.335.2912 / danfoss.us/solar

Eaton / 855.386.7657 / eaton.com

Eltek / 469.330.9100 / eltek.com

Fronius USA / 877.376.6487 / fronius.com

Ideal Power Converters / 512.264.1542 / idealpowerconverters.com

Ingeteam / 408.524.2929 / ingeteam.com

KACO new energy / 415.931.2046 / kaco-newenergy.com

Motech Americas / 302.451.7500 / motechsolar.com

Power-One / 805.987.8741 / power-one.com

Schneider Electric / 888.778.2733 / schneider-electric.com

SMA America / 916.625.0870 / sma-america.com

SolarEdge Technologies / 877.360.5292 / solaredge.com

Solectria Renewables / 978.683.9700 / solren.com

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