The article deals with designing rotor disks of a double-sided axial flux permanent magnet machine, based on their deflection, due to the pull forces between opposite rotor disks, caused by the permanent magnets. Permanent magnets cause the magnetic flux density to flow between the magnets and its size determines the size of the pull force. That is why it is essential to determine the size of the axial component of magnetic flux density in the middle of the clearance between opposite rotor disks in order to calculate the deflection of the rotor disks. The article presents a new method for determining the size of the axial component of magnetic flux density, based on a simplified finite element method and an approximation method as well as modified equations for determining the deflection of rotor disks. The method is used to determine the pull forces between rotor disks and based on the deflection of the disks an optimum rotor disk thickness can be selected in order to reduce the weight of the machine.

Axial flux permanent magnet machines have garnered significant attention in recent years due to their numerous advantages in various applications, including electric vehicles, wind turbines, and robotics. However, one of the critical challenges associated with these machines is the presence of cogging torque, which can hinder their efficiency and performance. This review article provides a comprehensive overview of the state-of-the-art techniques employed for cogging torque reduction in Axial Flux Permanent Magnet Machines. Different techniques are described, encompassing geometric optimization, magnet placement, and skewing methods. Firstly, the significance of Axial Flux Permanent Magnet Machines is described, as well as the issue of the cogging torque. In the methods section, a review of the strategies for the reduction of cogging torque is described from various articles, and finally, in the discussion section, a list of actions is presented for cogging torque reduction for different topologies. The novelty of the study is that it combines strategies for cogging torque reduction in a single article.

This article proposes a methodology for the design of double-sided coreless axial flux permanent magnet synchronous machines, which is based on a developed model for calculating the axial component of the magnetic flux density in the middle of the distance between opposite permanent magnets, which also represents the middle of the stator. Values for different geometric parameters represent the input data for the mathematical model in explicit form. The input data are calculated by using a simplified finite element method (FEM), which means that calculations of simplified 3D models are performed. The simplified model consists of two rotor disks with surface-mounted permanent magnets and air between them, instead of stator windings. Such a simplification is possible due to similar values of permeability of the air and copper. For each simplified model of the machine the axial component of the magnetic flux density is analyzed along a line passing through the center of opposite permanent magnets and both rotor disks. Values at the middle of the distance between the opposite permanent magnets are the lowest and are therefore selected for the input data at different stator, rotor disks and permanent magnets (PM) thicknesses. Such input data enable the model to consider the nonlinearity of materials.

This article presents the research on the optimum distance (fictitious air gap) between permanent magnets of the coreless axial flux permanent magnet machine with a double rotor and single stator. Magnetic flux density of the permanent magnets follows the mean flux path between the opposite magnets. The size of the leakage flux depends on the axial distance between the magnets, the distance between adjacent magnets and the back iron of the rotor disks. If the fictitious air gap (clearance between opposite permanent magnets) is too large, the flux path will close through the adjacent magnet and not the opposite one. The article presents the finite element analysis of the magnetic flux density between the permanent magnets mounted on the rotor disks where the fictitious air gap thickness was set as a variable to determine the maximum clearance. Connection between bending (pull) forces of rotor disks and fictitious air gap thickness is also presented with the mechanical stress analysis of rotor disks.

This paper presents the mechanical stress analysis (MSA) of a rotor disk in a double-sided axial flux permanent magnet machine (AFPMM). The analysis considers the rotor of a prototype AFPMM with a double external rotor and single internal stator. Rotor disks of the prototype AFPMM are construct- ed of two 11.6 mm-thick steel disks and represent around 50% of the total weight of the machine. The new rotor disk thickness was determined based on a rotor axial displacement due to the attractive force between the permanent magnets on opposite rotor disks.

This paper presents a data-driven probabilistic framework for analysing power system faults using Monte Carlo simulations. The study evaluates the operational reliability of multiple high-voltage switchgear topologies—including single-busbar systems, double-busbar systems, and ring-type configurations—by modelling the stochastic behaviour of disconnectors, circuit breakers, busbars, and withdrawable switching elements with bypass arrangements. Realistic unavailability parameters derived from statistical reliability data are used to generate fault intervals for each device, enabling the simulation of millions of operational scenarios and capturing both full and partial outage events. The proposed methodology quantifies outage probabilities, identifies critical components, and reveals how devices count, switching logic, and system redundancy influence overall resilience. Results show significant reliability differences between topologies and highlight the importance of optimized substation design for fault tolerance. The developed probabilistic framework provides a transparent and computationally efficient tool to support planning, modernization, and predictive maintenance strategies in transmission and distribution networks. Findings contribute to improved fault diagnosis, enhanced grid stability, and increased reliability in both conventional and renewable-integrated power systems.