The aim of this study was to carry out the investigation and analysis of two-stage magnetic precession gear dynamics and the determination of the resonance frequencies, which can be a cause of the powertrain system failures. Graphical interpretation of the two-stage precession gear is presented, and two equations of the dynamics of the movable elements of the presented gearbox were determined. On the basis of these equations, the stiffness coefficients and resonance frequencies of the presented gearbox were mathematically derived. The next step was to develop a numerical model of the magnetic precession gear dynamics in the environment of MATLAB Simulink. The elaborated model allowed us to analyze the influence of varying the input speed and the load torque on the operation of the magnetic precession gear. The performed analyses of the dynamics of the magnetic precession gear showed the occurrence of a resonance phenomenon under the influence of load torque ripples with a frequency close to the natural frequency of the studied system.

This paper contains research on the development of a fault-tolerant six-phase synchronous reluctance motor (SynRM) based on the stator adopted from a general-purpose three-phase induction motor. In the design and calculation process, an extended Clarke transformation was developed for a six-phase asymmetrical system. To verify the proposed design approach, a field–circuit model of electromagnetic phenomena in the studied motor was developed and used to study the motor performance. The increased torque value and reduction in torque ripples were confirmed by comparison to the classical three-phase SynRM design. To illustrate fault tolerance capabilities, the operation of the studied three- and six-phase synchronous reluctance motors under inverter-fault conditions was examined. The conducted analysis shows, among other things, that from the electromagnetic performance point of view, only the proposed six-phase machine is able to properly operate under inverter-fault conditions. The results of the winding design calculations, the performed simulations of six-phase motor operation, and the preliminary tests of the prototype motor are presented and discussed.

The paper presents the results of numerical simulations carried out to investigate the influence of selected geometric parameter–precession angle and dimensions of the magnetic circuit of a two-stage magnetic precession gear on the magnetic torques acting on its active components. The operating principle of the proposed gear and the developed numerical model based on the 3D finite element method (FEM) are discussed. The study focuses on the effects of air gap length, magnet dimensions, pole pitch coverage and precession angle. The results confirm a strong correlation between these parameters and the transmitted torque, providing valuable guidelines for the optimal design of high-torque, compact and efficient magnetic precession gears.

The paper deals with analysis of radial forces in the multi-phase synchronous reluctance machines (SynRM). SynRM of three-, six- and nine-phase windings were studied. The field models were developed to determine normal and tangential components of magnetic flux density vector in the air-gap of the studied machines. The selected research results have been presented and discussed.

The paper deals with research on the direct and quadrature axis cross saturation effect in the synchronous reluctance machine (SynRM). The comparative analysis between the performance of the 4-pole SynRM of 3-phase and 6-phase windings have been conducted exploiting developed 2D finite element models. In the numerical models of the studied machines, the locked rotor method was adopted in which the direct (d ) and quadrature (q) axis currents iq and id were forced to determine magnetic fluxes in the d-q axes, respectively. Next, determined magnetic flux maps have been used to determine a simple analytical model taking into account the cross-saturation effect. The quality of the proposed analytical description of the cross-saturation phenomenon has been evaluated by comparison to the results of simulations in order to assess the possibility of adapting this description in the control algorithms of SynRM drives.

The article discusses the synthesis and analysis of a high-power-density axial flux permanent magnet synchronous motor (AFPMSM) with active cooling. The research included electromagnetic and thermal analysis. In the electromagnetic part, numerical analysis employing 3D finite element method were carried out to analyze the influence of machine geometry and current density on the overall machine performance and the achieved power density. In the thermal approach, an active cooling concept with a cooling channel located in the winding was analyzed. Numerical thermodynamic models of the winding were developed, based on which the various approaches of the investigated solution were considered and their impact on improving the power density of the machine assessed.