The joint research project effiDCent aims to increase energy efficiency and sustainability in industry by using direct current instead of conventional alternating current. The project has now been successfully completed. Together with the Technical University of Dortmund, the Ostwestfalen-Lippe University of Applied Sciences and Arts (TH OWL), Condensator Dominit GmbH and E-T-A Elektrotechnische Apparate GmbH, Kamen-based technology pioneer Paul Vahle GmbH & Co. KG has also been researching more efficient energy transmission using direct current-based busbars as the consortium leader since 2019.
The switch from alternating current (AC) to direct current (DC) results in an increase in energy efficiency of more than 10 %. At the same time, the resources required to manufacture DC-based conductor rails are significantly lower than for conventional systems. This reduces the amount of copper required by up to 50 percent. The funding project was supported by the European Union and the state of North Rhine-Westphalia.
"The energy transition is a crucial building block for the transformation of our society towards sustainability. This is precisely the direction we are aiming for with the effiDCent research project, which will result in nothing less than a paradigm shift in industrial power supply," says Achim Dries, CEO of the VAHLE Group. The name of the project is based on a combination of "efficient" and the abbreviation "DC", which stands for direct current.
Together with its partners, the Kamen-based systems supplier for mobile industrial applications has spent the past three years developing a DC-powered system consisting of a highly efficient rectifier, the conductor rail, intelligent energy storage systems for recuperation and safety devices. The aim was to significantly increase energy efficiency in manufacturing and production lines and minimize grid-related production downtimes in order to optimize the entire manufacturing process. The project partners also broke new technical ground with the integration of intelligent energy storage systems and buffer capacitors distributed along the line.
The switch from AC to DC voltage allows a significant reduction in the material used and also promises high energy savings. In contrast to alternating current, the power factor of the motors or inverters does not play a role, meaning that the current load on the line is considerably lower. Accordingly, the copper requirement of a conductor rail can be significantly reduced by reducing the cross-section in addition to saving one pole.
According to Dries, the switch to DC technology is a major step towards CO2-neutral industrial production for the industry. Up to now, the standard three-phase 400-volt AC voltage used in this sector has required a separate rectifier for each vehicle, which is no longer necessary with a central DC supply. By eliminating the rectifier, a lossy component in the overall system is saved, which has a positive effect on the overall efficiency and therefore on energy consumption.
In addition, DC technology has numerous other advantages that help to create a modern and intelligent industrial power supply network. For example, systems for generating and storing energy such as photovoltaic systems and batteries can be integrated without any problems, as they always work with DC voltage. Braking energy can be stored directly and fully utilized without lossy conversion to alternating current. Another advantage is the high system availability provided by the use of storage: buffer batteries allow DC systems to continue operating without interruption. This eliminates the need for expensive uninterruptible power supplies (UPS). There is also no need for additional investment in mains filtering and compensation. Built-in intelligent energy storage systems absorb load peaks that occur due to acceleration processes, so that the electrical connected load can be reduced and the AC grids are relieved.
As part of the research project, an 80-metre-long DC test system was put into operation parallel to an existing AC system. Energy savings of more than 10 percent were demonstrated when using direct current. In addition to leading the consortium, VAHLE was responsible for the system design, simulation and construction of the test facility. TH OWL was responsible for the construction of the highly efficient feeder, which has a 35 to 40 percent higher power factor than a standard rectifier.
TU Dortmund University is responsible for researching the intelligent energy storage system for absorbing the braking energy. The efficiency of the overall system is increased by using the braking energy via intelligent storage. This was made possible by the use of efficient energy storage devices, so-called ultracaps, which can store the braking energy for a short time and then release it again in a controlled manner. Switching on DC systems safely is complex due to high inrush currents. For this reason, a protection and pre-charging concept tailored to DC applications was developed with E-T-A Elektronische Apparate GmbH.
By participating in the research project, VAHLE is further expanding its position as a pioneer and technology leader in the field of direct current technology.
The company would also like to expressly thank the European Union and the state of North Rhine-Westphalia for their support of the project. We would also like to thank Project Management Jülich for its excellent cooperation.
The effiDCent funding project at a glance:
- Main focus of the research project: Development of a DC-fed busbar for industrial production lines.
- Project partners: Paul Vahle GmbH & Co KG (consortium leader), Dortmund University of Technology, Ostwestfalen-Lippe University of Applied Sciences and Arts, Condensator Dominit GmbH and E-T-A Elektrotechnische Apparate GmbH (associated).
- Project duration: July 2019 to June 2022.
- The project sponsor is Forschungszentrum Jülich PTJ.
- This project was funded by the European Union and the state of North Rhine-Westphalia.
