SolarEdge

SolarEdge offers a distributed grid intertie system that combines module-level DC-DC power optimizers and monitoring with specialized DC-AC string inverters. The SolarEdge system maximizes energy yield of a PV installation with maximum power point tracking (MPPT) on each module to mitigate partial string shading, module mismatch, uneven soiling or aging variance, and with fixed string voltage to ensure that the inverter always operates at its peak efficiency voltage, regardless of the number of modules in the string, and prevents under-voltage power losses.

The system is designed to automatically maintain the optimum string DC voltage for the inverter, regardless of shading, temperature, or string length. This allows flexible string length ranging from 8 to 25 modules of any voltage or orientation, removing traditional design constraints. The installation is scalable and facilitates expansion because future modules need not match existing ones. Installing a SolarEdge system typically reduces time and cost by decreasing the number of strings, DC disconnects and other balance of system elements.

The SolarEdge built-in SafeDC feature ensures installer and firefighter safety at all times by automatically shutting off the PowerBox's DC current and voltage if they sense excessive heat or when the SolarEdge inverter is turned off or disconnected from the grid. A safe module voltage of 1 VDC per module (up to 25 VDC max per 25-module string) eliminates electrocution risk during installation and servicing. This feature also provides a handy way to check for correct string wiring before commissioning and before high voltage DC is present.

SolarEdge's new OP series power optimizers (replacing the AOB series PowerBoxes) have an improved maximum power optimizer efficiency of 99.5%, courtesy of its new ASIC chipset. The improved MPPT algorithm dynamically tracks the global maximum operating point for both modules and inverter. The OP power optimizers can be used with older units with the same inverter or string. Because SolarEdge inverters are "transformerless" all PV array wiring must use double-insulated PV Wire (including factory-installed module wire leads).

SolarEdge OP power optimizers also provide PV array arc-fault protection, which is soon to be code required for certain types of installations. Once a power optimizer detects an arc, it automatically shuts the module down, effectively terminating the arc and preventing its re-occurence.

The SolarEdge power optimizers have a 25-year warranty and the SolarEdge inverters have a 12-year warranty (extendable to 20 years). Power optimizers and inverters are Listed to UL 1741 for the U.S. and Canada.

SolarEdge Components

SolarEdge OP power optimizers can be used with most crystalline silicon or thin-film module. OP power optimizers can be connected to one or several crystalline silicon modiles as long as the total wattage and the open circuit voltage do not exceed the wattage and voltage limits of the optimizer used. Available with either MC4, Tyco, Amphenol H4, or H&S Radox modules input connections, all units have MC4 connectors on the output side. All OP Series power optimizers are NEMA4 rated.

The OP250-LV optimizers have a PV module input range of 5-55 VDC and up to 250 W of power output. This unit is the best choice for standard 60-cell PV modules with power outputs of 250 W or less, but can also be used with one or more smaller modules so long as the total power rating is 250 W or less, the total temperature-corrected open-circuit voltage is below 55 VDC, and the maximum amperage does not exceed 10 A.

The OP300-MV optimizers have a PV module input range of 5-75 VDC and up to 300 W of power output. This unit is the best choice for standard 60-cell PV modules with power outputs between 250 W and 300 W. They are also the best choice for high-voltage 72-cell modules, like the SANYO N-Series and A-Series modules. This optimizer can also be used with one or more smaller modules so long as the total output and voltage does not exceed the above limits and the current output is under 10 A.

The OP400-MV optimizers have a PV module input range of 5-75 VDC but up to 400 W of power output. This unit is the best choice for standard 60-cell or 72-cell PV modules with power outputs between 300 W and 400 W. This optimizer can also be used with one or more smaller modules so long as the total output and voltage does not exceed the above limits and the current output is under 10 A.

The OP400-EV optimizers have a PV module input range of 60-125 VDC, and are for modules up to 400 W of power output. This unit is the best choice for 96-cell modules like the SANYO Bi-Facial modules, or one or more Thin-Film PV modules totaling up to 400 W. This optimizer can also be used with one or more smaller modules, so long as the total output and voltage does not exceed the above limits and the current output is under 5.5 A. For instance, two 72-cell 175 W modules could be wired in series and used with a single OP400-EV power optimizer.

SolarEdge inverters are the only inverters designed to work exclusively with power optimizers. These simple, reliable, ungrounded inverters perform only DC to AC inversion of incoming power from one or multiple strings, because MPPT and voltage management are handled by the power optimizers. They work with 208, 240, and 277 VAC systems, and include a code-compliant AC/DC disconnect, Ethernet interface, and RS-485 serial port, weigh 52 pounds and reach 97.5% CEC weighted efficiency. All SolarEdge inverters are Listed to UL 1741 for the U.S. and Canada and are NEMA 3R rated.

SolarEdge Module-Level Monitoring

SolarEdge's monitoring system is a web-based application that provides PV performance monitoring, fault detection and troubleshooting at module-level, string-level and system-level. Web-based software provides real-time monitoring, facilitating increased system uptime and lowering maintenance costs. Installation feedback and troubleshooting are immediate and accurate. Remote fault detection allows faster fault resolution via a semi-automatic troubleshooting process that pinpoints the location of underperforming modules on a PV site map.

No additional hardware or wiring is required between the SolarEdge power optimizers and inverter because the monitoring sensors and transmitters are built in, and data is transmitted over the regular DC power lines. Connection between the inverter(s) and the internet can either be by RS-232 to a modem (one inverter only with a max distance of 50 ft), or by Ethernet with connection between multiple inverters with CAT5 cable using their RS-485 connection ports. Wireless connection is also possible using ZigBee interfaces.

ZigBee technology enables connection of up to 32 inverters as a wireless mesh network. One of the ZigBee modules must be configured as a coordinator (master) and the other modules as routers (slaves). Each ZigBee module operates as a repeater for its neighboring ZigBee module, extending the range of the network as far as needed. The external antennas allow for wireless transmission up to a 250 m (820 ft) range between ZigBee modules. No external power is required. The ZigBee transceivers also provide communication between the inverter(s) and an Ethernet gateway. Data can be transmitted to a ZigBee equipped modem, or use the ZigBee-to-Ethernet interface. For remote installation sites, a GSM modem can be used for connection to the Internet.

SolarEdge Software Tools

A free iPhone app is available as a download from the Apple iTunes Store. Registered users can monitor multiple sites from their iPhone, anytime, anywhere. The application provides an at-a-glance view of past and present energy production. Current weather conditions and forecasts are also presented to aid in assessing the system's performance.

Site Mapping Tool software is also available free on the SolarEdge website, which allows barcode scanning for creation of a virtual site map using an iPhone. The Site Designer software and an Inverter Configuration Tool for on-site configuration and module-level installation verification are available free online as well.

Also look for SolarEdge Smart Monitoring Combiner Boxes, which are due to launch in early 2012. These provide a high level of system performance monitoring and exceptional system safety in larger systems using central inverters.