Hybrid and fully electric vehicles are gaining increasing attention in today’s world due to the approaching depletion of fossil fuel sources, increasing cost sensitivity and environmental friendliness on the rise. Well performing and cost effective electric machine control is pivotal in these automotive applications.
The Field Oriented Control provides a modern and high-performance method for controlling the Permanent Magnet Synchronous Machine, as the control of speed and torque is decoupled and maximum torque and thus acceleration is available at virtually any speed. Speed and position sensors originally used in Field Oriented Control imply several disadvantages, but their use can be avoided, and Sensorless Field Oriented Control can be developed where the speed and position information is estimated based on other measured quantities, such as voltages or currents.
In this thesis, the application of PMSMs in the automotive industry is introduced compared to the Induction Machine, then modelling of the PMSM and the theory of Voltage Source Inverters, as the underlying power electronics systems is given and Space Vector based Pulse With Modulation is introduced. An overview of sensorless techniques is presented, and three methods, Back-EMF based, Model Reference Adaptive System and Sliding Mode Observer based approaches are described in detail, both in theory and through examples in the literature, and are implemented in a software test environment, where they are experimentally verified. Simulink is used for the test environment, where also the model of the PMSM, the Space Vector PWM and Field Oriented Control have been developed.