Modeling and Control of Multi-Three-Phase PMSMs for Aviation Applications

In recent years, there have been significant technological advancements in power electronics and electrical drives. This progress is driven by various programs to achieve net zero carbon emissions in transportation and energy production, striving for optimal performance while maintaining high reliability at acceptable costs. New research programs are proposing all-electric and hybrid solutions, which present increased technological challenges, particularly in safety-critical and high-power-density applications, such as aviation and aerospace. Consequently, topics like energy storage, electrical architecture, control, and thermal management of electrical drives will become even more crucial in the future. In this scenario, multi-phase motor drives are experiencing significant development in aviation and aerospace. Indeed, increasing the phase number allows high-power machines to operate at a low voltage and current levels. Besides, some multi-phase motor drives exhibit a better fault tolerance than three-phase ones, as losing one or more phases due to a fault can still guarantee the drive’s operation at even rated power levels. According to this choice, this thesis focuses on modelling, designing and experimentally validating an advanced torque controller for multi-three-phase Permanent Magnet Synchronous Machines (PMSMs) used in aviation applications. The thesis is organized as follows: •??Chapter 1: An overview of the More Electric Aircraft (MEA) and All Electric Aircraft (AEA) concepts is provided, highlighting the current state-of-the-art of these applications and future challenges. This section emphasizes the advantages of multi-phase drives, such as distributing electric power across more phases to maintain lower currents and voltages, allowing the use of power electronics technologies with high switching frequencies for better performance and efficiency. Another crucial aspect is the fault tolerance capability required in the aviation and aerospace industries. •??Chapter 2: This chapter presents different multi-three-phase modelling approaches available in the literature: Vector Space Decomposition (VSD), Multi-Stator (MS), Decoupled Multi Stator (DMS), and Adaptive-DMS (ADMS). VSD achieves harmonic decoupling in different orthogonal subspaces, while MS allows for the analysis of the machine in its modularity. DMS and ADMS maintain the modular philosophy of MS, combining decoupling like VSD. This chapter also includes a detailed mapping of motor performances. •??Chapter 3: This chapter discusses multi-three-phase machine control. Since most multi-phase control techniques are based on the VSD modelling approach, study and development of traditional and recent control techniques like Current Vector Control (CVC) and Direct Flux Vector Control (DFVC) have been implemented using an ADMS-based modelling approach. Additionally, a modified ADMS-based DFVC torque controller is proposed, implementing independent flux control for each three-phase set. Motor control techniques have been implemented in MATLAB/Simulink for a 6-phase PMSM designed by Politecnico di Torino in collaboration with GE Avio. •??Chapter 4: This chapter reports the experimental validation of the proposed ADMS-based DFVC torque controller. The experimental tests were conducted on a 12-phase PMSM available in the facilities of Politecnico di Torino. The results confirmed the benefits of the proposed ADMS-based DFVC torque controller, combining strong dynamic performance with a simple and straightforward implementation.