A German research team is conducting practical tests to see how solar modules with integrated radio technology can be linked to form an overall network. The “communicative” panels should represent a simple and cost-effective solution for monitoring and controlling small-scale photovoltaic systems.
JULY 16, 2024 JOCHEN SIEMER
Image: Leibniz Universität Hannover, Tobias Brinker
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From pv magazine Germany
On the roof of the Institute for Solar Energy Research (ISFH) in Hamelin, Germany, solar modules have been connected post-installation to form a mesh network of several subnetworks.
The research institute is testing this solution for building-integrated photovoltaic (BIPV) applications, which often involve small, differently aligned, or shaded sub-areas. Electronics close to or integrated within the module allow each module to be controlled and monitored according to changing radiation conditions. Additionally, the entire installation remains accessible for network operators.
Funded by the German Federal Ministry for Economic Affairs and Climate Protection and started in March 2020, the project aims to develop new solutions for “smart” photovoltaics. Project coordinator Jens Friebe from Leibniz University Hannover explained the goal is to “integrate inverters and digital technology directly into the PV module, thereby improving reliability, increasing efficiency and at the same time reducing costs.” Wireless communication between components and a flexible network setup enable quick installation, with cost reduction to be addressed in potential series production.
The fully integrated solar modules developed for Voyager-PV include a micro inverter and radio technology operating in the license-free 2.4 gigahertz band, enabling connection between modules and components like gateways. Software updates can be performed wirelessly within the mesh.
Specialized project partners developed the necessary slot antennas, capacitively fed via a circuit board through the back of the module. German engineering company WHO provided the radio technology, while the Institute for High Frequency Technology and Radio Systems at Leibniz University Hannover developed the slot antenna solution. Optimel, a potting technology specialist, handled the encapsulation technology for electronics. Connecting power electronics directly to individual solar cell strings allowed the omission of bypass diodes, reducing defect potential and increasing energy yield.
The Institute for Drive Systems and Power Electronics at Leibniz University Hannover developed the power electronics, using gallium nitride (GaN) power semiconductors in the inverter. SMA Solar Technology contributed expertise in inverters and system technology, and the University of Stuttgart focused on reliability. ISFH was responsible for PV module technology research.
Since May, the demonstrator system in Hamelin has been transmitting data, allowing monitoring of power electronics and reading of operating data such as module current, voltage, and temperature.
“With the mesh network set up at the ISFH, stability and communicative self-optimization across several PV modules could be demonstrated,” the researchers said. Various project participants could access the network simultaneously from their respective locations.
