Open-End Winding SyncRel Motor Drive with a Floating Capacitor Bridge for High-Speed Applications

A speed control scheme is proposed for a 3-phase 100+ krpm synchronous reluctance motor that uses an open-ended stator winding and is fed by a dual GaN inverter system comprising a three-phase three-level T-type floating capacitor bridge. The floating capacitor bridge allows the main inverter to operate at a unity power factor and extends the operating speed range of the synchronous reluctance machine. The control system coordinates both converters and maximizes the active power consistently with the current and voltage constraints. Furthermore, it keeps the DC voltages of the three-level T-type converter balanced. This paper presents a theoretical analysis and illustrates the control system of the electric drive in the frame of the «TUrBO: the next 100,000+rpm synchronous reluctance motor drives» project funded by the European Union. Simulation results confirm the validity of the developed solution.