Control Unit for Energy Harvesting for Freight Wagon

This paper is focused on hardware and software design of a control unit for an energy harvesting generator mounted on a freight wagon wheel. The generator is an essential part of diagnostic system for freight wagons fleets operated over the Europe railway systems. Main focus was placed in the direction of sufficient power provided by the generator to the on-board system during low speed motion of the wagon (lower than 10 km/h). The control unit is designed to control the AC-DC converter powered by a synchronous generator to provide the onboard power network (including energy for the backup battery system) of 24V up to 8A in a full range of wagon speed. It implements basic diagnostic of PMSM generator and converter state, and it also provides 2-axis acceleration data and wheel rpm information for IoT freight wagon diagnostic top-level unit. The unit design is modular to allow full and reduced assembly (without AC-DC converter) for diagnostics purposes of other wagon axles.