Distributed control of permanent magnet synchronous motor drive systems

A vast amount of attentions has been given to permanent magnet synchronous motors (PMSM) in a variety of industrial applications due to recent developments in rare-earth permanent magnet (PM) materials and power electronics. These PM motors present numerous advantageous, such as a higher torque-to-inertia ratio and power density, over the other conventional machines used for ac servo drives. Applying the concepts of distributed control systems (DCS), wherein the control loops are closed through a network enables closing the slower speed control loop through a network. It consequently offers the capability of controlling many such systems from a single location at a lower installation and maintenance cost. This paper presents a study on the distributed control of the PMSM drive systems, using Ethernet as a remedy for common commercial fieldbus systems. However, the insertion of the non-deterministic communication network complicates the analysis and design as conventional control theories with many ideal assumptions, such as synchronized control, non-delayed sensing and actuation, must be re-evaluated. If these issues are addressed effectively, this state of the art concept may have promising applications in aero dynamic, naval, material processing etc., industries.