Study of permanent magnet machine based flywheel energy storage system for peaking power series hybrid vehicle control strategy

Transit agencies are increasingly focused on making bus fleets cleaner, more efficient and cost effective by incorporating new clean propulsion technologies. Increased maintenance cost and lower lifetime of battery packs in existing hybrid electric buses have been major bottlenecks in motivating transit bus operators to rapidly switch to this energy efficient technology. Understanding the demerits of the current battery based energy storage technology and merits of the prospective flywheel based energy storage technology for transit bus application, this paper puts an effort to study the permanent magnet synchronous machine based flywheel energy storage system for the aforementioned application. A series transit hybrid bus with peaking vehicle control strategy has been taken into consideration with a macro objective to compare the performance of the battery based and flywheel based hybrid transit bus in terms of fuel consumption and cost of the installed system. However, the focus of this paper remains on the development and study of a 100 kW flywheel energy storage system based on vector control technique which forms the first step towards this macro objective.