Decoupled Control of Two Series Connected Split-Phase Synchronous Machines From a Single Six-Phase Inverter

Multiphase machines have advantages such as lower torque ripple, enhanced fault tolerance, higher power to weight ratio, and lower DC-link voltage requirement. These factors make the split-phase machine drives an attractive alternative to conventional three-phase machine drives. In this paper, a decoupled control scheme of two series connected split-phase synchronous motors is presented. In split-phase machines, the fifth and seventh order torque ripple are completely eliminated, allowing the machine to be used for high performance drive applications. In the proposed series connected topology, two motors are connected in different phase sequences, allowing the fundamental component of the winding currents to produce torque in the first machine, and fifth and seventh harmonic currents to produce torque in the other motor. In this paper, both the motors used are synchronous machines which allows for higher efficiency, easier control, and greater tolerance to parameter variations as compared to induction machines. This paper, presents fully decoupled field-oriented control scheme for dual split-phase synchronous machines. The proposed method can be easily extended to other synchronous machines such as permanent magnet machines and reluctance machines. Exhaustive experimental results are presented to validate the proposed scheme.