Modeling and Control of Variable Flux PMSM under Asymmetrical Magnetization

The rapid advancements in electric mobility and the increasing demand for high- efficiency, high-performance traction systems are driving car manufacturers to explore innovative motor technologies. In this context, Variable Flux Permanent Magnet Syn- chronous Machines have emerged as a promising alternative to conventional PMSMs, offering improved efficiency and an extended speed range by dynamically adjusting their magnetic flux. This thesis explores the characteristics, modeling, and control of VF-PMSMs. The study, conducted as a part of a collaborative research project with Volvo Cars, begins with an overview of VF-PMSMs, detailing their classification and working prin- ciples. A case study motor is introduced, followed by the development of its dynamic model. Next, different Simulink-based modeling approaches are presented, with a strong emphasis on magnetization state modeling, which plays a crucial role in capturing the dynamic behavior of the machine and its overall performance. To validate the developed models, a comparison is conducted between Simulink and JMAG finite element simulations, analyzing key performance metrics such as open- circuit characteristics, demagnetization and remagnetization behavior. Finally, control strategies for VF-PMSMs are investigated, including a modified Field Oriented Control scheme that leverages Magnetization State estimation for improved control performance. This thesis aims to provide a comprehensive framework for VF-PMSM analysis, contributing to the development of more efficient and adaptable electric drive systems.