New Industry Products

1.7kV SiC FETs Enable 1.5kV-Input DC-DC Optimizer for Solar + Storage and Microgrids

April 02, 2018 by Paul Shepard

Alencon Systems LLC will unveil the latest generation of its dc-dc optimizer, the SPOT-ES V5, at the Energy Storage Association's (ESA) Annual Conference, April 18 - 20 in Boston, MA. The newest generation of the SPOT-ES features several exciting features and enhancements specifically targeted at achieving more cost effective and reliable dc-coupled solar + storage and microgrid projects.

The Alencon SPOT - which stands for String Power Optimizer and Transmitter - is a string level dc-dc optimizer which optimizes the power from four PV string inputs with voltages ranging from 600- to 1500-Volts. The SPOT outputs power through two outputs at any range of voltage that is completely configurable from one deployment to the next.

The ES suffix designates "Energy Storage." The SPOT-ES family of products has been specifically designed for the needs of dc-coupled solar + storage deployments. The improvements in the SPOT-ES V5 are vast from previous generations of the SPOT family of products.

The enhancements include a true 1500-V input based on 1700-V SIC MOSFETs, a unique ability to map a wide battery charge/discharge voltage range, reliability enhancements developed in concert with leading solar + storage technology providers and integrators as well as more flexible communications options for better integration with solar + storage and microgrid control systems.

"There is great industry demand for deploying more dc-coupled solar + storage plants as well as Microgrids due to the many, well documented economic and technical benefits these topologies provide. However, to date, there have been very few, if any, appropriate pieces of technology to facilitate such deployments," says Alencon Systems President Hanan Fishman.

"The SPOT-ES V5 specifically addresses that gap in the market with a unique and cost-effective string level dc-dc optimization solution that allows system designers to integrate solar and storage on the dc side in an intuitive manner that is also battery chemistry agnostic," Fishman continued.

Higher Input Voltage

The SPOT-ES V5 is the first utility scale PV dc-dc optimizer capable of supporting true 1500-V string input. The SPOT-ES 1500 can accept four 1500-V string inputs and provides the two outputs.  Two outputs have been provided to allow for the use of standard rated PV connectors at high power and current.

Wide Voltage Control Range

The SPOT-ES V5 takes advantage of Alencon's patented galvanically isolated design.  The SPOT-ES's galvanic isolation concept completely isolates the PV input from the output by attaching isolation transformers to each PV input. This technique provides for a particularly unique benefit in the dc-coupling of solar + storage because the integral magnetics to the SPOT can be easily configured from one deployment to another to easily support a broad battery charge/discharge dc-bus voltage, where the voltage range could vary by as much 20% from complete discharge to full charge.

This feature provides a significant benefit when connecting lower voltage batteries to 1500-V PV systems.

Enhanced Solar + Storage Reliability Features

The SPOT-ES V5 includes a new, ultra-fast circuit to protect the SPOT from sudden system power output overloads. Such overloads can happen with greater frequency in dc-coupled solar + storage and microgrids than traditional PV installations due to the increased complexity of such systems. The result of such occurrences can have very grave consequences to the entire system and hence the SPOT's ability to better protect itself in such events offers a great deal of additional reliability.

Improved Communications Architecture

Communications between major components in solar + storage systems and microgrids is critical. Such systems typically utilize master system controllers that directly interface with all components in the system including the battery, inverter and of course the SPOTs.

The SPOT-ES V5 features enhanced communications features to allow it to be interfaced with third party system controllers via either Modbus TCP, for communicating to the SPOTs wirelessly, or Modbus RTU, which allows for hardwire communication to each SPOT directly.  The enhanced communication functionality offered in the SPOT-ES V5 allows for unprecedentedly granular control over the PV including the ability to curtail production at the string level.