Dual voltage/power system by battery/flywheel configuration

Flywheel Energy Storage Systems have gained more attention over the last years due to the requirement of reliable energy systems in modern society. The combination of a flywheel and a battery can be very interesting as they merge high power and high energy capabilities for use in a broad variety of applications. In Electric Vehicles, dual voltage/power systems using batteries and flywheels have already been investigated. However, different configurations can be obtained depending on the flywheel topology and the load requirements. In this paper, series and parallel connection of flywheel and battery are tested using a simulation model built in Simulink. The model includes power converters and controls, and the flywheel machine model is based on the parameters of an existent prototype. Results show that both configurations are capable to deliver the power requested by the machine load. However, total energy consumption is lower when the parallel configuration is used. This can be attributed to the higher number of switching devices existent in the series configuration.