Magnetic gears are slowly becoming a natural alternative to mechanical gears. Providing contactless, frictionless, and low-noise torque conversion, they are finding applications in renewable energy sources and electric vehicles, among others. This paper presents a comprehensive theoretical analysis with numerical calculations of a magnetic gear (MG) design for novel applications in telescopic camera cranes. Based on numerical simulations of selected MG variants, a potential transducer configuration was chosen that would meet the requirements of the drive transmission system-supporting the movement of the telescopic camera crane arm.

This paper describes research on a prototype of a multi-axis force and torque sensor dedicated to the support system of a telescopic camera crane arm. Based on studies conducted on an actual telescopic camera crane arm, the requirements that the sensor must meet to enable precise control of the drives in two working axes of the telescopic camera crane arm were defined. In the sensor developed, a method for measuring forces and torques using an optical displacement sensor was proposed. A simplified sensor prototype was made to verify the assumptions, and measurement tests were carried out. Additionally, the paper presents a CAD model of the sensor using an elastic pin, based on which a numerical model was developed, and calculations of displacements and mechanical stresses were performed.

Gear systems in today’s industry are one of the critical pillars providing power transformation and matching speed and torque to application requirements. Reliability, high efficiency, and low operating costs are desirable due to the prevalence of gearboxes. This paper provides a comparative analysis of selected mechanical and magnetic gears, using a specific example to point out the advantages and disadvantages of contactless power conversion. After determining the essence of the operation of the magnetic gear on the base model, two magnetic gear optimization cases are presented, testifying to the application potential. An analysis of the stress distribution in the area of the teeth of the mechanical gearbox and the most stressed element of the magnetic gear - the modulator, was carried out. The effects of temperature and load on losses were measured and simulated, and ultimately, the efficiency characteristics of the two gears were also compared.

Gear systems in today’s industry are one of the critical pillars providing power transformation and matching speed and torque to application requirements. Reliability, high efficiency, and low operating costs are desirable due to the prevalence of gearboxes. This paper provides a comparative analysis of selected mechanical and magnetic gears, using a specific example to point out the advantages and disadvantages of contactless power conversion. After determining the essence of the operation of the magnetic gear on the base model, two magnetic gear optimization cases are presented, testifying to the application potential. An analysis of the stress distribution in the area of the teeth of the mechanical gearbox and the most stressed element of the magnetic gear - the modulator, was carried out. The effects of temperature and load on losses were measured and simulated, and ultimately, the efficiency characteristics of the two gears were also compared.

This work describes a wide spectrum of issues related to the transformation of energy through the magnetic field, in particular, the work on modeling, design optimization and measurement verification of magnetic gears built at the Department of Drive Automation and Robotics at the Opole University of Technology. The introduction presents a history of magnetic gears, the principle of operation and the most important features of these converters. A significant part of the work was devoted to the presentation of the state of the art, describing the currently existing designs of magnetic gears and their classifications in relation to the commonly used mechanical transmissions. In the further part of the work, the essential characteristics and parameters of the coaxial magnetic gear are presented and discussed, also the prototype, test stand, calculation results and measurement verification are presented. Then, the influence of the design parameters of the gears was analyzed in terms of increasing the value of the magnetic torque. Discrete and physical models of magnetic gears with radial flux and axial flux, with integer and fractional ratios, are also discussed. There are also described hybrid electromagnetic transducers with a built-in magnetic gear, which are becoming more and more popular nowadays.

This paper presents a comparison of 30/8 and 12/8 AC permanent magnet motors with distributed (DW) and concentrated winding (CW) designed for electric vehicle traction. Both prototypes are based on an interior permanent magnet (IPM) motor topology and contain V-shape magnets. The radial flux AC IPM motors were designed for an 80 kW propulsion system to achieve 125 N·m. Finite element models (FEM) used to design the geometry of IPM motors and the required useful parameters of electric motors are widely investigated. The accuracy of finite element models is verified and validated on the basis of test data. Numerical simulations of healthy and faulty operation states, and studies of winding faults based on the FEM offer a deeper understanding of the associated phenomena. Therefore, in this paper, a short-circuit fault in a stator winding was simulated to investigate the transient currents under an external load collapse, for all winding phases. These simulations were used to define other important machine parameters to improve mechanical reliability of the motors and to assess the potential risk of permanent magnet (PM) demagnetization. Furthermore, the analysis of local magnetic forces affecting the PMs in the rotor and their possible displacement in a short-circuit situation were performed, also taking into account the centrifugal force. Lastly, it is demonstrated that the choice of winding configuration has a significant impact on the uncontrolled displacement of magnets in the rotor.

This paper presents a comparison of two variants of an axial flux magnetic gear (AFMG), namely, with integer and fractional gear ratios. Based on calculations derived with the use of three-dimensional numerical models, the torque characteristics of the analyzed AFMGs are computed and verified on a physical model. The greatest emphasis is put on the detailed decomposition and analysis of local forces in modulator pole pieces (also used in the structural analysis) within the no-load and maximal load conditions. The authors also describe the unbalanced magnetic forces (UMF) in the axial and radial directions resulting from the construction of the considered AFMGs variants, and their possible effects in the context of the use of additive manufacturing (AM) in prototypes. The paper also proposes an effective method for limiting the axial strain by using the asymmetry of the air gaps, which slightly reduces the torque transmitted by AFMGs. Finally, a static strength analysis was presented that allows us to assess the effects of local forces in the form of modulator disc deformation for selected cases of air gap asymmetry.

This paper presents a review of the electromagnetic field and a performance analysis of a radial flux interior permanent magnet (IPM) machine designed to achieve 80 kW and 125 Nm for an electric and hybrid traction vehicle.The motor consists of a 12-slot stator with a three-phase concentrated winding as well as an 8-pole rotor with V-shaped magnets.Selected motor parameters obtained from an IPM prototype were compared with the design requirements.Based on the electromagnetic field analysis, the authors have indicated the parts of the motor that should be redesigned, including the structure of the rotor core, aimed at enhancing the motor's performance and adjusting segmentation for magnet eddy current loss reduction.In addition, iron and PM eddy current losses were investigated.Moreover, transient analysis of current peak value showed that the current may increase significantly compared to steady-state values.A map of transient peak current load vs. torque load plotted against rotor speed was provided.Based on the numeric and analytical results of physical machine parameters, the authors indicate that collapse load during the motor's operation may significantly increase the risk of permanent magnet (PM) demagnetization.It was also found that collapse load increases the transient torque, which may reduce the lifetime of windings.

The paper presents an analysis of local and global forces acting on the ferromagnetic material of a modulator in a co-axial magnetic gear, taking several design variants and the impact of loading into account. The analyses include a modulator with cores manufactured from a soft-magnetic composite material and two variants made from electrical steel with laminations stacked in different directions. Variations of local forces acting on individual pole pieces of the modulator are analyzed at different loads, showing that the force spectra are subject to significant variation with an increasing load. The presented magnetostatic analyses are extended by structural analysis that provides estimation of stress and displacement for the modulator assembled from additively manufactured acrylonitrile butadiene styrene (ABS)-plastic parts. The analysis carried out for the least favorable design case of the magnetic circuit of the modulator shows that an application of the technology is significantly restricted by the magnetic gear torque volumetric density. Some changes to the modulator mechanical design are proposed in the paper to mitigate the drawbacks of this technology.

The article presents an analysis of selected dynamic parameters of a coaxial magnetic gear. Based on analytical relations, supported by measurements at the laboratory test stand, stiffness coefficients and undamped resonance frequency of the studied structures were analyzed. Using the approximation techniques on the basis of measured power losses, the damping coefficients of the analyzed variants of the magnetic gears were determined.

The paper contains a proposition of the application of a SRM motor with a modified stator geometry for an electric drive, in particular in an electric bicycle. The study involved a comparison of the cyclicity of the electromagnetic torque and self-inductance in the function of the rotor angle in 2D and 3D models based on the application of the finite element method.

This paper presents an analysis of efficiency for passive magnetic gear resulting from the selection of materials and structures in the magnetic circuit. A particular attention is paid to the structure of modulator, which forms the crucial element of the system, and which can be designed in a variety of ways. In this paper, the considered alternatives include a modulator design manufactured from soft magnetic composite material and from circumferentially and axially stacked lamination. Based on the experimentally determined efficiency versus load curves, the study demonstrates that the soft magnetic modulator has similar performance as for the case of a circumferentially and axially stacked lamination. The physical reasons of this result are explained by means of the finite element analysis of magnetic flux waveforms in the crucial parts of the systems.

This study presents results of modelling of heat transfer in low-power synchronous motors with internal permanent magnets (IPM). The analysis is conducted on the basis of equivalent thermal network as well as the magnetostatic finite element analysis for determination of usual electromagnetic loss components. The approach which consistently combines the two mentioned models allows for effective analysis of heat transfer in the machine at the designing stage. Special attention is focused on the method for homogenisation of a mush-wound winding and sheet stack. The results of computer simulations are positively verified by measurements carried out on the physical motor.

The work contains chosen optimization results of a permanent magnetic (PM) gear. The calculations use an evolutionary algorithm in cooperation with a parallel calculations library additionally supported by a database. Field calculations are performed using a two-dimensional finite element method. The calculations conducted for several different objective functions showed the design parameters for which the transmitted torque density is close to 100kNm/m. Optimization results of a permanent magnetic (PM) gear Słowa kluczowe: pasywna przekładnia magnetyczna, optymalizacja, algorytm ewolucyjny, metoda elementów skończonych