Energy Storage Power Electronics: Page 5 of 6
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Schneider Electric’s roots date back to 1836 when two brothers, Adolphe and Eugene Schneider, acquired mines, forges and foundries and became part of the Industrial Revolution. At the time, the company’s main markets were heavy industry, railroads and shipbuilding. Today, Schneider Electric is a global manufacturer of power distribution and automation systems. Headquartered in Rueil-Malmaison, France, Schneider entered the solar industry with its 2008 acquisition of Xantrex Technologies (Xantrex acquired Trace Engineering in 2000).
Schneider offers two inverter/charger lines suitable for residential energy storage applications. For nonexport systems, its Conext SW-NA hybrid inverter/charger line offers models with nominal dc input voltage of 24 Vdc or 48 Vdc and continuous output power classes of 2,400 W and 3,400 W at 24 Vdc and 3,800 W at 48 Vdc. The inverter/chargers have split-phase 120/240 Vac output and are compatible with flooded and VRLA lead-acid battery types. The Conext SW-NA supports ac- and dc-coupled configurations and enables grid backup, self-consumption with solar prioritization, peak shaving and ac engine generator assist.
The more feature-rich utility-interactive Schneider Conext XW+ NA inverter/charger line was one of the first to support integration of lithium-ion battery types. As such, complete energy storage hardware and software solutions from other vendors commonly integrate with this equipment. Like Schneider’s Conext SW-NA inverter/chargers, the Conext XW+ NA supports ac- and dc-coupled configurations and enables grid backup, self-consumption with solar prioritization, peak shaving and ac engine generator assist. It can also export power to the utility grid.
Schneider offers system integration panels for its inverter/chargers, as well as two MPPT solar charge controllers that customers can network with the overall power electronics system. The MPPT 60 150 controller has a maximum PV array open-circuit voltage rating of 150 Voc and a maximum output power rating of 3,500 W. The MPPT 80 600 model has a maximum PV array open-circuit voltage rating of 600 Voc and a maximum output power rating of 4,800 W at 48 Vdc nominal. Schneider Electric’s MPPT charge controllers carry a standard 5-year warranty. Its Conext SW-NA and XW+ inverter/chargers carry a 2- to 5-year warranty, depending on the country of installation.
Schneider Electric • Andover, Massachusetts • solar.schneider-electric.com
Founded in 1981, SMA Solar Technology has its global headquarters in Niestetal, Germany, and its US division is headquartered in Rocklin, California, with a US production facility in Denver. SMA was the first manufacturer to offer high-voltage string inverter models in the US market. It also pioneered the use of ac-coupling grid-direct string inverters with battery-based inverters and energy storage, a configuration common to many of the systems highlighted in this article. SMA has significant experience with self-consumption and energy storage systems in Europe and plans to offer additional equipment, such as its Energy Meter, in the US as markets develop.
SMA America offers single-phase Sunny Boy string inverter models, in power classes from 3,000 W to 11,000 W, that are suitable for ac-coupled residential PV applications. It also offers two models of its Sunny Island battery-based inverter/chargers—the 4548-US and 6048-US, with rated power outputs of 4,500 W and 5,750 W, respectively. SMA designed both models for operation with 48 Vdc nominal battery banks. They are compatible with lead-acid, nickel-cadmium and lithium-ion battery types as well as external battery management systems. Sunny Island inverter/chargers have single-phase 120 Vac output. Split-phase 120/240 Vac applications require two Sunny Island inverters or an autoformer.
In ac-coupled utility-interactive systems where one or more Sunny Boy inverters are connected to the ac side of a battery-based Sunny Island system, the Sunny Island limits string inverter output power via frequency shift if the batteries are at a full state of charge and the grid is unvailable. The Sunny Boy string inverter identifies and analyzes the frequency adjustment. When the power frequency increases and exceeds a defined value, the Sunny Boy limits its power accordingly. The result is well-regulated and optimized battery charging.
SMA plans to release a high-voltage Tesla-compatible battery-based inverter for the US market in early 2017. Coupled with SMA’s energy-management platform, the power electronics and storage energy solution will enable streamlined integration with existing PV systems as well as cost-effective new solar-plus-storage projects.
SMA America • Rocklin, California • 916.625.0870 • sma-america.com