A CAN star topology network in a modular battery energy storage system
TK Engineering installed TCS-10 CAN switches in an energy storage system (ESS) in the Netherlands. The system can store energy from the grid, ideally when produced by the vast quantities of local renewables, and then supply the grid with stored energy during periods of high demand. This system reduces the need for fossil based balancing plants and when used in conjunction with low-carbon renewables reduce the energy system carbon footprint significantly.
The ESS uses batteries to store electrical energy arranged in a modular architecture, with several battery units consisting of multiple racks of batteries. The power distribution unit installed at each battery string uses a controller to control and monitor battery operation. These controllers communicate over a CAN bus network in a star topology.
“By adopting TCS-10 CAN switch we were able to guarantee flawless CAN bus communication for project” stated Timo Alho, Principal Engineer, Product Development, Energy Storage & Optimisation, at Wärtsilä.
CAN bus networks, in general, offer reliable communication. Each branch of the configuration is connected to the star junction. There were some intermittent communication errors related to the project CAN communication, that were fixed with updated design of CAN networks at the site.
Measurements of various aspects of a CAN bus network
A CAN bus tester can measure various aspects of a CAN bus network and is particularly useful for debugging problems in the CAN bus physical layer. To analyze CAN signals and measure timings more accurately, an oscilloscope was used to view the signal.
A Kvaser USB CAN interface was used together with CANtrace to check for error frames while at the same time storing the communication log for future reference. One of the battery units was connected to the grid and operated at about 25 % power while monitoring the CAN traffic on TCS-10 CAN with a Kvaser CAN interface and the CAN tester.
Updated design of CAN networks at the site
After installing TKE TCS-10 CAN switches the communication problems that were discovered were solved and the CAN line was able operate without communication errors. Due to the battery system architecture, a star topology for CAN bus was the ideal solution for this project since it simplified the scalable design and reduced the wiring installation work.
TCS-10 CAN switch is an ideal solution for conveying the CAN traffic
The TKE TCS-10 CAN switch is an ideal solution for conveying the CAN traffic in the star junction in a CAN star network as it is an intelligent switch where the branch networks are electrically separated. This essentially makes each network branch an individual CAN network where the cable length limitations only need to be considered between the switch and the last node in each branch instead of the entire network.