Printed circuit board (PCB) stators in coreless axial flux permanent magnet (AFPM) machines have been proposed, designed, and studied for use in multiple industries due to their design flexibility and reduction of manufacturing costs, volume, and weight compared to conventional stators. This paper investigates mechanisms and methods of approximating open circuit losses in PCB stators within example wave and spiral winding topologies for a dual rotor, single stator configuration using 3D FEA, analytical hybrid techniques and experiments. The effect of rotor magnet shape, end winding, and active conductor geometry on eddy currents is studied, and some mitigation techniques are proposed. Through stator equivalent circuit analysis, circulating current losses caused by mechanical abnormalities and magnetic circuit asymmetry are assessed. Possible strategies and schemes to minimize circulating current losses are also described. The trade-off between stator loss components and some practical design considerations are outlined in detail. The open circuit power losses of a prototype coreless AFPM motor were experimentally tested using multiple example PCB stators and emulated rotor asymmetries, with the findings being comparable to the FEA and hybrid analytical methods results.

Axial flux permanent magnet (AFPM) machines with entirely or stator coreless configurations offer significant advantages, including low rotational losses, the absence of cogging torque, minimal torque ripple, and the potential for high specific power density. Advances in permanent magnet (PM) technology and cooling techniques have enabled fully coreless AFPM machines to achieve high magnetic and current loadings without core saturation, making them suitable for high-performance applications like electric aircraft propulsion. This article reviews recent advancements in coreless AFPM machines, tracing their historical and chronological development. Various topologies, including single- and double-sided and multidisk designs, are examined to identify the advantages and emerging trends in each configuration. Different winding configurations are compared, and their performance characteristics are discussed. Recent innovations in winding materials, such as printed circuit boards (PCBs), are highlighted. The rotor configurations are reviewed, with a focus on the development of flux density equations and specific attention to the Halbach array PM rotor due to its relevance for electric aircraft propulsion. The article also discusses electromagnetic modeling techniques, including proposed analytical and 2-D approaches that reduce the computational burden of traditional 3-D calculations. Sources of power loss are identified, along with mitigation strategies based on existing literature. A preliminary design procedure and sizing evaluation are presented, utilizing analytical torque and back electromotive force (B-EMF) calculations through an equivalent 2-D linear model. Finally, recent advancements in electric machines designed for aircraft propulsion are reviewed, showcasing their electromagnetic performance and highlighting the potential benefits of coreless machines in this field.

This paper presents a large-scale multi-objective design optimization for a direct-drive wind turbine generator concept that is based upon an experimentally validated computational model for a small-scale prototype motor of the same type. By integrating an outer reluctance -type rotor and a segmented stator with toroidally wound single-coil modules containing spoke -type PMs, the design optimization aims to minimize losses, active mass, and torque ripple while adhering to a power factor constraint. The AC windings and PMs are positioned in the stator and this concept enhances flux concentration, enabling the use of more affordable high energy non-rare- earth (special type) magnets. The exterior rotor follows a simplified reluctance -type configuration, eliminating active electromagnetic components. The operational principle, described in detail, guides design studies using electromagnetic 2D finite element analysis (FEA), showcasing the potential of this configuration to match rare- earth PM performance, with special type PMs, thus addressing cost and supply challenges. Furthermore, alternative materials including the substitution of aluminum wire for copper wire, have also been investigated in this study. The proposed multi-objective design optimization uses the response surface method (RSM) to initiate the optimization and the results on a 3MW, 15 rpm generator, highlight the benefits of this topology, achieving competitive metrics like goodness, specific thrust, and efficiency without rare- earth permanent magnets.

This paper presents a comprehensive analysis of the feasibility, cost, and electromagnetic performance of five distinct types of axial flux permanent magnet (AFPM) generators designed for direct-drive wind turbines. The generator configurations investigated include a single-sided AFPM generator with a surface-mounted PM rotor (AFPMG), a double-sided AFPM generator featuring PMs on the stator and a reluctance rotor (AFPMG-RR), a coreless stator AFPM generator with surface PMs (CAFPMG-SPM), and a coreless stator AFPM generator with a Halbach PM array rotor (CAFPMG-Hal). Each generator’s operating principles and configurations are thoroughly explained and compared. Large-scale multi-objective design optimizations were conducted on each type, taking advantage of symmetric computational models and using a differential evolution algorithm based on 3D finite element analysis (FEA) to minimize cost and mass while maximizing efficiency for all designs. A comprehensive discussion of the optimization results highlights the merits of each configuration. The findings indicate and confirm that AFPM generators can potentially achieve superior performance compared to their radial counterparts, as reported in the literature, while also benefiting from more robust and compatible mechanical integration with wind turbines.

Decarbonization of existing electricity generation portfolios with large-scale renewable resources, such as wind and solar photo-voltaic (PV) facilities, is important for a transition to a sustainable energy future. This paper proposes an ultra-fast optimization method for economic dispatch of firm thermal generation using high granularity, one minute resolution load, wind, and solar PV data to more accurately capture the effects of variable renewable energy (VRE). Load-generation imbalance and operational cost are minimized in a multi-objective clustered economic dispatch problem with various generation portfolios, realistic generator flexibility, and increasing levels of VRE integration. The economic feasibility of thermal dispatch scenarios is evaluated through a proposed method of levelized cost of energy (LCOE) for clustered generation portfolios. Effective renewable economics is applied to assess resource adequacy, annual carbon emissions, renewable capacity factor, over generation, and cost to build between thermal dispatch scenarios with incremental increases in VRE penetration. Solar PV and wind generation temporally complement one another in the region studied, and the combination of the two is beneficial to renewable energy integration. Furthermore, replacing older coal units with cleaner and agile natural gas units increases renewable hosting capacity and provides further pathways to decarbonization. Minute-based chronological simulations enable the assessment of renewable effectiveness related to weather-related variability and of complementary technologies, including energy storage for which a sizing procedure is proposed. The generally applicable methods are regionally exemplified for Kentucky, USA, including eight scenarios with four major year-long simulated case studies and 176 subcases using high performance computing (HPC) systems.

On-road wireless charging of electric vehicles (EVs) in motion could potentially reduce range anxiety or battery size with widespread deployment. The planning and implementation of such systems are greatly complicated due to their susceptibility to load variation inherent to traffic flow. This article proposes a method for derisking the potential for traffic slowdowns by compensating for reduced vehicle speed and investigates how implementation may affect system performance. A load modeling case study is presented at 200 kW for a mile of high-speed roadway employing speed-based power regulation with results indicating average power usage, and maximum car hosting capability can be reduced by 20% and increased by 30%, respectively. An 85-kHz power electronics model is developed based on designs and prototypes for an 11-kW, 190-m airgap static system and a 200-kW dynamic wireless track. The simulation is validated in the 11-kW experimental prototype and modified for 200-kW operation to compare with simulated performance. Sensitivity studies are performed in MATLAB/Simulink to evaluate how parameters influence system performance and confirm the capability to reduce output power and maintain efficiency at 11 and 200 kW. The static 11-kW experimental system operates at 93.6% efficiency and multiple options exist to reduce power while maintaining efficiency greater than 90%. The capability to dynamically modify power output from wireless power transfer (WPT) coils, in an experimentally validated simulation, enables techniques to significantly mitigate load variability due to reductions in vehicle speed.