A German research team is conducting practical tests to see how solar modules with integrated radio technology can be linked into a total network. The “communicative” panels should provide a simple and cost-effective solution for monitoring and controlling small-scale photovoltaic systems.
On the roof of the Institute for Solar Energy Research (ISFH) in Hamelin, Germany, solar panels are connected after installation to form a mesh network of several sub-grids.
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 into the module allow each module to be controlled and monitored based on changing radiation conditions. Moreover, the entire installation remains accessible to grid operators.
The project, funded by the German Federal Ministry of Economic Affairs and Climate Protection and started in March 2020, aims to develop new solutions for ‘smart’ solar photovoltaics. Project coordinator Jens Friebe from Leibniz University Hannover explained that the goal is to “integrate inverters and digital technology directly into the PV module, improving reliability, increasing efficiency and simultaneously reducing costs.” Wireless communication between components and a flexible network configuration enable rapid installation, addressing cost savings in potential series production.
The fully integrated solar panels developed for Voyager-PV include a microinverter and radio technology operating in the license-free 2.4 gigahertz band, allowing connection between modules and components such as gateways. Software updates can be performed wirelessly within the mesh.
Specialized project partners developed the necessary slot antennas, capacitively powered via a printed circuit board via the back of the module. German engineering firm WHO supplied the radio technology, while the Institute for High Frequency Technology and Radio Systems at Leibniz University in Hannover developed the slot antenna solution. Optimel, a specialist in the field of potting technology, provided the encapsulation technology for electronics. By connecting power electronics directly to individual solar cell strings, bypass diodes could be eliminated, reducing the risk of failure and increasing energy yield.
The Institute for Drive Systems and Power Electronics at Leibniz University in Hannover developed the power electronics, using gallium nitride (GaN) power semiconductors in the inverter. SMA Solar Technology brought expertise in inverters and system technology, while the University of Stuttgart focused on reliability. ISFH was responsible for research into PV module technology.
Since May, the demonstrator system in Hamelin has been transmitting data, allowing the power electronics to be monitored and operating data such as module current, voltage and temperature to be read.
“The mesh network established at the ISFH can demonstrate stability and communicative self-optimization across different PV modules,” the researchers said. Several project participants could access the network simultaneously from their respective locations.
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