Electrical Machines and Drives

Shanelle N. Foster | hogansha@egr.msu.edu | www.egr.msu.edu/emdl/


The Electrical Machines and Drives Laboratory (EMDL) is engaged in development of new design topologies and control methods that improve the efficiency and reliability of electromechanical energy conversion. The EMDL is fully equipped with a variety of dynamometers (rotating and linear), sensors, inverters and controllers, and with software for the design of electrical machines (lumped parameter and Finite Elements) and controllers (DSPs, Real Time controllers, FPGAs etc.).  The main emphasis of the research has been rotating permanent magnet synchronous machine (PMSM) drives; however, linear permanent magnet synchronous machines are also the subject of current research efforts.

Recent research efforts have focused on performance and reliability of PMSMs used in safety critical applications, characterization and optimization of axial flux permanent magnet machines, as well as design and development of high speed permanent magnet machines.

Mechanical vibrations, acoustic noise and bearing damage are often caused by torque ripple and can significantly reduce the life of a machine. A torque ripple minimization control technique was developed in the EMDL to reduce torque ripple.

 PMSMs used in safety critical applications must have a low possibility of failure, as well as continue to operate or fail safely in the event of failure. Stator winding failures are among the most common electrical machines. Most of these failures are caused by insulation degradation. Without knowledge of insulation degradation, stator inter-turn shorts can develop and lead to catastrophic failure. A technique was developed to detect high resistance stator inter-turn short-circuits during operation.

Increased machine reliability is gained by monitoring the condition of the stator winding during operation; however, it is critical for some applications to develop a safety response protocol. The EMDL team has developed a fault mitigation technique for applications where post-fault operation of the PMSM drive is desired, even if that operation is at reduced power and speed. Upon quick detection of an incipient stator winding fault, implementation of our fault mitigation technique can reduce the magnitude of circulating fault current and the magnitude of circulating fault current and the winding temperature, effectively decelerating the propagation of the fault and extended the machine’s post-fault life.