A 2-in-1 Switched-Capacitor Inverter for Next-Generation Modular Motors

This paper describes a new 3-phase motor drive inverter suitable for low-voltage high-current modular motors. The inverter features a 2-in-1 combination of a switched-capacitor (SC) step-down converter to reduce the input current delivery losses and a 3-phase inverter with full drive power modulation using only 9 low-voltage switches and 3 capacitors. The flying capacitors of the SC inverter can be partially soft-charged utilizing inductance from the stator. A proof-of-concept prototype of the proposed inverter has been built in order to verify the operation and concepts of the switched-capacitor inverter. The preliminary results, including experiments with a commercial DC motor, confirm the feasibility of the design of the proposed inverter.