Analytical Model to Calculate Radial Forces in Permanent-Magnet Synchronous Machines

There are three principal sources of noise and vibration in electrical machines: electromagnetic sources, mechanical sources, and aerodynamic sources. Nowadays, one of the major advantages of permanent-magnet synchronous machines is their torque density. This density is achieved through a high magnetic flux density in the air gap, which is achieved through hard magnets. Unfortunately, in these machines, electromagnetic forces have been identified as the main source of vibration and noise, and high magnetic flux densities make these vibrations and noises more significant. With the aim of better understanding the relationship between electromagnetic forces and design variables, this article, which is the continuation of previous work, firstly describes a study of the sources of magnetic forces in permanent-magnet synchronous machines. Subsequently, an analytical model for the computation of the radial forces originating from electromagnetic sources in permanent-magnet synchronous machines is stated. This model analyzes the forces on both the rotor surface and the base of the stator tooth. The analytical results were corroborated through simulations using the finite element method (FEM) and also by experimental tests performed over two prototypes. The results achieved by the analytical model show good agreement with both FEM results and experimental measurements

Improving Motor Current Control Using Decoupling Technique

Abstract-This paper reports advances in the design and development of decoupling method in motor control of electric power assisted steering (EPAS) systems. A motor model for permanent magnet synchronous machines (PMSM) is described. Implementation details, simulation and measurement results are also presented. Keywords-Decoupling, electric power assisted steering (EPAS) systems, field oriented control (FOC), motor control, permanent magnet synchronous machines (PMSM)

Optimization of an axial-flux permanent-magnet generator for a small wind energy application

Axial-flux permanent-magnet synchronous machines have a high torque output at low speeds and are therefore very suitable for direct drive wind energy applications. This research focuses on: measures to improve the efficiency of the energy conversion; simplification of the construction and easy maintenance by introduction of a modular stator construction; adaptations required to obtain an efficient power conversion in direct drive wind energy applications

A back to back multilevel converter for driving low inductance brushless AC machines

Traditionally, multilevel converters are utilised in medium voltage applications, allowing the DC-link voltage to exceed the switch maximum blocking voltage. Here, their application to control high- efficiency brushless permanent magnet synchronous machines exhibiting low phase inductance is explored, the relative advantages being shown to include reduced current ripple and improved harmonic spectrum. A cost benefit analysis is included along with experimental results from a prototype 5-level back-to-back converter

Towards Fully Additively-Manufactured Permanent Magnet Synchronous Machines: Opportunities and Challenges

With the growing interest in electrification and as hybrid and pure electric powertrains are adopted in more applications, electrical machine design is facing challenges in terms of meeting very demanding performance metrics for example high specific power, harsh environments, etc. This provides clear motivation to explore the impact of advanced materials and manufacturing on the performance of electrical machines. This paper provides an overview of additive manufacturing (AM) approaches that can be used for constructing permanent magnet (PM) machines, with a specific focus on additively-manufactured iron core, winding, insulation, PM as well as cooling systems. Since there has only been a few attempts so far to explore AM in electrical machines (especially when it comes to fully additively-manufactured machines), the benefits and challenges of AM have not been comprehensively understood. In this regard, this paper offers a detailed comparison of multiple multi-material AM methods, showing not only the possibility of fully additively-manufactured PM machines but also the potential significant improvements in their mechanical, electromagnetic and thermal properties. The paper will provide a comprehensive discussion of opportunities and challenges of AM in the context of electrical machines

Sensorless Control of Switched-Flux Permanent Magnet Machines

This thesis investigates the sensorless control strategies of permanent magnet synchronous machines (PMSMs), with particular reference to switched-flux permanent magnet (SFPM) machines, based on high-frequency signal injection methods for low speed and standstill and the back-EMF based methods for medium and high speeds

GA-based tuning of nonlinear observers for sensorless control of IPMSMs

The paper considers two observer-based rotor position estimation schemes for sensorless control of interior permanent magnet synchronous machines (IPMSMs). Emphasis is given to techniques based on feedback linearisation followed by Luenberger observer design, and direct design of nonlinear observers. Genetic algorithms (GAs) based on the principles of evolution, natural selection and genetic mutation are employed to address difficulties in selecting correction gains for the observers, since no analytical tuning mechanisms yet exist, with results included to demonstrate the enhanced performance attributes offered by observers tuned in this way

Detection of partial demagnetization fault in PMSMs operating under nonstationary conditions

Demagnetization fault detection of in-service permanent magnet synchronous machines (PMSMs) is a challenging task, because most PMSMs operate under nonstationary circumstances in industrial applications. A novel approach based on tracking characteristic orders of stator current using Vold-Kalman filter is proposed to detect the partial demagnetization fault in PMSMs running at nonstationary conditions. The amplitude of envelope of the fault characteristic orders is used as fault indictor. Experimental results verify the superiority of the proposed method on the partial demagnetization online fault detection of PMSMs under various speed and load conditions.Postprint (author's final draft

Lumped Parameter Thermal Model of Permanent Magnet Synchronous Machines

This paper describes a thermal equivalent circuit of Liquid Cooling Totally Enclosed Permanent Magnet Synchronous Machines (LCTE-PMSMs). Conductive heat transfer in all directions is taken into account. Specific care has been taken to represent them by equivalent circuit. The conductive heat transfer in heterogeneous media like slots and the convective heat transfer in the airgap and the end-winding are studied