Control of Permanent Magnet Machines

This thesis deals with the design and analysis of control system structures for electric drives equipped with permanent-magnet synchronous machines (PMSMs) in automotive applications. Sensorless control is considered and a speed and position estimator of phase-locked loop type is analyzed thoroughly. The theory of loss minimization by means of control is applied to a PMSM drive intended for propulsion in a hybrid electric vehicle. The study shows that the additional inverter losses reduce the potential to minimize the total losses considerably. A review of fault-tolerant PMSM drives is presented and control algorithms are proposed for achieving sensorless control, closed-loop field-weakening control, and maximum utilization of the inverter voltage for a drive that, for redundancy, adopts an additional inverter leg connected to the machine neutral point. The impact of various electrical faults in a vehicle equipped with in-wheel motors and individual steering actuators is also investigated. Here, it is shown that vehicle stability can be maintained with only minor displacements using a closed-loop path controller and an optimal approach to allocate tire forces.

Autorentext

Oskar Wallmark, born in 1976, received his M.Sc. in Engineering Physics in 2001 and his Ph.D. in Electric Power Engineering in 2006, both from Chalmers University of Technology, Göteborg, Sweden.