OptiStore – Optimized Self-Consumption System for Commercial and Industrial Use

Duration: September 2015 - July 2019
Contracting Authority/ Sponsors: German Federal Ministry of Economic Affairs and Energy (BMWi)
Project Partners: AKASOL GmbH, Refu Elektronik GmbH, Technical University Dresden
Project Focus:
© Fraunhofer ISE
”OptiStore“ schematic diagram.

The objective of the “OptiStore” project is the development of an innovative self-consumption system based on a modular lithium-ion battery unit with the corresponding power converter for optimum use of regenerative energy sources in the commercial and industrial sector. The focus is on consequent optimization of investment and operating costs of the overall system through technical and methodical improvements in the areas of individual components and system technology as well as an innovative system management process.

Fraunhofer ISE focuses on the development of an innovative power converter unit optimized for the use in the industrial environment. The motivation for the work to be executed is the consistent optimization of investment and operating costs of the overall “OptiStore” system. The selection of an optimum switching topology for this application case as well as the development of optimized interfaces to battery system and energy management are decisive.

A switching topology is to be developed for the “OptiStore” system that is as cost-efficient as possible, but that also achieves a degree of efficiency exceeding the systems currently available on the market. These opposing requirements can only be achieved using power semiconductors of the latest generation as well as an innovative design and innovative connection technology. To save costs, the switching frequency should be selected such that the passive components can be dimensioned smaller than today, while achieving good to very good overall degrees of efficiency.

As load profiles and the corresponding requirements on output and storage capacity vary strongly for different commercial and industrial operations, the “OptiStore” system must support modular extensions. This results in different requirements on switching topology and control technology that must be considered.