Vector Control and Operation Strategies for Interior Permanent Magnet Machine with Axial Flux Regulator

This paper presents a detailed field-oriented control scheme for an Interior Permanent Magnet Machine with Axial Flux Regulator (IPMAFR). Contrary to the conventional dualstator PMSM control, which is complicated due to strong magnetic coupling influences, the FOC approach for IPMAFR leverages its distinct structure to facilitate effective decoupled control. The design structure of this machine allows two separate inverters to independently provide d-axis and q-axis currents to the radial and axial stators, achieving full decoupling. The distinctive feature of this machine is the presence of an axial stator, which acts as a flux regulator, offering a shunted flux path that improves PM flux utilization, boosts output torque, and facilitates extensive flux regulation. According to the system design of this machine, it is possible to impose demagnetized or magnetized d-axis current in either the radial or axial stator, not only during field weakening but also at lower speeds to meet specific control or flux regulation requirements. The study of the proposed FOC for IPMAFR reveals that if a dualstator PMSM is designed with minimal inter-stator coupling, its control complexity can be significantly reduced. This study also investigates the machine's operational modes, control domains and decoupling characteristics. Extensive simulations and experimental validations are performed to confirm the validity of the proposed approach in achieving effective motor control and enhanced torque and flux regulation