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Absolute Magnetics invented a new technology for rotary position sensing
by Patrick Aeschlimann of Absolute Magnetics AG

The here described magnetic encoder system consists of two parts: A magnet with a unique, multi-periodic magnetization pattern and corresponding electronics for data processing. Signal acquisition is done on only 1 single magnetic track (see figure 1). This differentiates the Absolute Magnetics Tech-nology from the Nonius / Vernier principle, which uses 2 magnetic tracks for data acquisition. Multiple magnetizations with different periods are intentionally superposed, which brings advantages in terms of robustness of the encoder. When it comes to air gap changes and eccentricity, there is no need to “avoid interference of different magnetic tracks” as with the Nonius / vernier principle. Figure 1: The multi-periodic magnetic signal in 3 axes: Radial (black), tangential (red) and axial (or-ange), acquired on only 1 single measurement track. The processing algorithm allows to simultaneously calculate a “global position” on the complete me-chanical turn, as well as a “local position” within each magnetic increment. The global position is re-sponsible for making the encoder an absolute position sensor and the local position enables high accu-racy. The presentation investigates the performance of Absolute Magnetics’ patented encoder technology in real-world scenarios, focusing on its ability to maintain reliable angle sensing despite misalignment and magnetic stray fields. Several tests were conducted to evaluate the system’s robustness under these challenging conditions. The benefits of an integrated encoder solution compared to conventional exter-nal encoders are discussed. Finally, the paper examines the advantage of using the Absolute Magnetics Encoder without the need for calibration.

High Voltage Design & Test For Power Electronic Fed Machines
by Ian Cotton of aerospaceHV Ltd

This talk will give an overview of the challenges associated with the insulation system of machines used with power electronics drawing on the substantial pool of work that has been done on this topic throughout the world by both researchers and standards committees. The talk will include reflections on the impact of environmental conditions and will discuss how test methods can be used to ensure a robust design.

Resolving a sub-synchronous generator gearbox vibration problem linked to electrical grid excitation
by Greg Nelson of Frazer-Nash Consultancy

Troubleshooting of electrical machinery in industrial applications can make use of advanced modelling and need to consider wider aspects of the system beyond the machine itself. In the following industrial case study, a turbo-generator set is used to power a small grid offshore. The operator found that whenever a particular oil heater, powered by the grid was turned on, the turbo-generator would trip off due to experiencing high vibration, despite the systems being apparently unrelated. We suggested that the problem may be due to forcing frequencies from the heater imposing an excitation on the grid, which in turn was exciting a torsional natural frequency of the generator train, with this being detected as vibration in the gearbox. We carried out torsional dynamics modelling of the power train, which confirmed the presence of a torsional natural frequency within 0.1Hz of the measured vibration frequency, and further calculation showed that the heater could draw more than enough power to create the vibration levels observed. We suggested making changes to the heater control system, which when altered, removed the excitation frequency and resolved the problem. The client’s heaters and grid now operate reliably. The case study illustrates the sorts of issues that can be faced diagnosing real-world problems related to electrical machinery, and provides some insights into routes for diagnosing and resolving them.

High-Performance Electrical Machines and Drives for the Energy Transition: From Aerospace Electrification to Scalable Industrial Solutions
by Chris Gerada of University of Nottingham

Electrical machines and drives are central to the energy transition, but aerospace applications impose some of the most demanding requirements in terms of power density, efficiency, thermal management, weight, and reliability. These constraints are driving rapid advances in machine design and system integration. This talk will set out the technical context for aerospace electrical machines, highlighting key requirements and the main technology building blocks. It will emphasise manufacturing as a critical link between design and a reliable, certifiable product, with examples from winding technologies such as Litz, hairpin, and toroidal machines, as well as assembly and joining challenges. Emerging directions such as cryogenic and hyperconducting machines, and strategies for reducing reliance on rare earth materials, will also be discussed. Finally, the talk will introduce how advanced manufacturing, testing, and validation capabilities, including the Electrical Machines Manufacturing line and the Hybrid Propulsion Building facility, support the development and industrialisation of next generation machine technologies.

Unbalanced Magnetic Pull (UMP) in rotating electrical machines
by Eldar Rahimov of University of Nottingham

Unbalanced Magnetic Pull (UMP) in rotating electrical machines arises from asymmetric airgap flux distributions that generate radial forces on the rotor. While historically treated as an undesirable phenomenon to be minimised, research over recent decades has explored the potential for actively controlling UMP - transforming it into a functional tool for vibration management, critical speed traversal, and bearingless motors applications. This talk draws on contributions from a dedicated workshop on controllable UMP in rotating electrical machines hosted in April 2026, bringing together academic researchers and industrial practitioners to examine the state of the art. We provide an overview of UMP fundamentals, survey key recent developments in active and passive control strategies and machine design and critically assess the barriers to industrial deployment, including system complexity, sensing requirements, and the gap between laboratory demonstration and field application. The talk concludes with an outlook on where research and industry collaboration could unlock practical benefits for a wide range of electrical machines.

Electrical drive train model abstractions, Reduced order modelling versus Finite element models
by Zoltan Nadudvari of Powersys

In model electrical drive train development engineers are facing different challenges to deliver safe and robust solutions which meets the requirements set by the intended applications (aerospace, automotive, robotics…). During the development different engineers from different fields must work closely together to achieve the powertrain which has high efficiency, high power to weight ratio and fulfill the safety requirements. To aid the engineers in their daily work software industry offer solutions - like SIMBA and JMAG – which have capability to integrate in a Model Based Design engineering workflow. In this presentation we compare the different fidelity level including Reduced ordered models for electrical machine and direct coupling of a power electronics simulator SIMBA with a finite element analysis tool JMAG. The presentation will give an overview about the trade off between accuracy and speed and where these models can be utilized.

Designing for efficiency in high performance AFM powertrains
by Richard Phillips of YASA

YASA’s AFM topology is well known for exceptional torque and power densities, but BEV range is determined by efficiencies at much lower load points. Certain loss mechanisms can become significant for the key motor operating points, that have otherwise not been considered in detail. This presentation shows an approach for modelling motor PWM losses, to enable simulations to be fast enough to be used at the design optimization stage.

Cryogenic Machines: Principles, Challenges, and the Path to Higher Maturity
by Chuanli Zhao of HP Drive

Considerable progress has been made in superconducting and hyperconducting electrical machine design, with advances in machine topologies, coil winding methods, and cooling concepts. Nevertheless, manufacturing considerations and fundamental engineering constraints continue to influence how effectively these designs can be translated into practical systems. The development of cryogenic machines is further shaped by limited availability of material data under extreme operating conditions, including high vacuum, cryogenic temperatures, and interactions with cryogens. Together, these underlying technology aspects support system‑level solutions and play an important role in determining achievable performance, reliability, and technology maturity.

High Fidelity Development of Preformed Hairpin Winding for High Speed Rotating Machines
by Tianjie Zou of University of Nottingham

Hairpin winding technology has emerged as a leading solution for boosting power density and efficiency of high performance traction & propulsion electrical machines. Meanwhile, transitioning from conventional stranded to hairpin windings introduces a unique challenge in development, i.e., design for manufacturing. This talk will provide a comprehensive deep-dive into hairpin windings, with a focus on introduction of E-Winding Lab, a specialized design tool developed to automate the design of hairpin windings for manufacturing. The platform enables flexible and systematic generation of hairpin winding configurations for demanding applications, particularly those requiring high slot and layer numbers. Moreover, a pure scripting based end winding CAD tool, which features rapid modelling of manufacturable 3D hairpin winding geometries, will be introduced. Furthermore, this tool will be used to analyse real-world case studies from state-of-the-art industrial products, providing a clear benchmark for current best practices in the field as well as insight for future developments.

Low speed generators for use in marine renewables
by Nick Baker of Newcastle University

Offshore wind is now well established with GW of installed capacity. Wave and tidal energy are alternative forms of marine energy which also have the potential to contribute to sustainable electricity generation. This comparatively immature technology operates at low speed, and often linear reciprocating motion. Combined with the proximity to the sea surface, the technology proposes posing unique challenges to the electrical power train. In this talk Nick will report on recent progress of developing low speed generators integrated into marine renewable energy devices. Although the work is low technology readiness level and small scale, the machines have been deployed and there is a route towards commercialization.

Quantifying The Impact Of Eccentricity, Rotor Tilt, And Magnetization Variability On Electric Drive Unit NVH
by Andrew Lawton of SMT

Electric vehicle (EV) noise, vibration, and harshness (NVH) performance is increasingly governed by electromagnetic excitation and its interaction with powertrain structural dynamics. Manufacturing and assembly deviations, such as rotor eccentricity, shaft tilt, and uneven magnetization, introduce air-gap and magnetic-field non-uniformities that alter force harmonics, potentially leading to increased tonal noise and vibration. However, the combined and relative influence of these mechanisms on system-level NVH response remains insufficiently understood, particularly under realistic operating conditions. This study presents a multiphysics simulation framework to quantify the effects of static eccentricity, dynamic eccentricity, rotor tilt, and uneven magnetization on EV powertrain NVH behavior. A structured design of experiments (DOE) methodology is employed to systematically vary eccentricity, tilt, and magnetization parameters, enabling the isolation of their individual and combined contributions to the overall NVH response. Main-effect and interaction plots are used to assess parameter sensitivity, robustness to manufacturing variability, and dominant excitation mechanisms as functions of speed and load. Campbell diagram and frequency-domain analyses provide insight into speed-dependent interactions between electromagnetic orders and structural modes. The proposed framework supports predictive assessment of tolerance-driven NVH risk, enables trade studies between electromagnetic and mechanical design variables, and advances simulation-driven workflows for early-stage development of next-generation electric drivetrains.

The tricky magnetics of motor position sensor NVH reduction (without resorting to RE magnets)
by Ari Al-Jaf of ZF Automotive UK Limited

Electrified steering systems require exceptionally low noise, vibration, and harshness (NVH) due to the direct transmission of motor torque ripple to the driver and the absence of masking engine noise in electric vehicles. Rotor angle sensing error is a key contributor, introducing phase shifts in stator excitation at audible frequencies. ZF has conducted a detailed investigation into the sources and effects of angle sensing errors in steering motors. For dipole and multipole magnetic sensing architectures, these errors arise from magnet material characteristics (including thermal stability, remanence variation, and ageing), magnetization imperfections linked to fixture design and process variability, and interactions between magnetic tracks. Additional influences include motor and ECU assembly tolerances, sensor alignment, and stray magnetic fields from internal and external sources. These challenges are exacerbated as sensing systems become more compact and integrated near high-current regions. A physics-based methodology has been applied to understand how combined error sources propagate through the system and affect NVH across operating conditions. This includes modelling magnetic fields and sensing behaviour, analysing control sensitivity to angle errors, evaluating electromagnetic motor response, and assessing the transmission of torque ripple into mechanical vibration and perceived NVH. The work integrates simulation, measurement, and experimentation to trace NVH back to root causes, informing sensing architecture selection and design trade-offs for improved system performance.

Design of an interior permanent magnet rotor
by Matthew Crossley of University of Manchester

Demagnetisation faults in interior permanent magnet machines (IPMs) can lead to downtime, increased maintenance cost, and damage to components. In order to carry out research into early detection of such faults, it is necessary to build and model IPM machines. The presentation will summarise some of the work involved in modelling and construction of IPM rotors designed for retrofit to an existing stator originally supplied with a rotor having surface mounted magnets. It will then go on to give an overview of the construction of look up tables for a hybrid dynamic model of the IPM machine before presenting test results with machine tool representative load cycles and outlining the next steps in the research project.

Improvements to Soft Magnetic Alloys using old techniques
by Chris Mahn of NiCoFe Materials Ltd

Soft Magnetic materials come with prescribed magnetic capabilities. Simple processing techniques can be adjusted to improve and enhance certified capabilities – here are a few simple steps to make your products better.

Development and Electromagnetic Analysis of Marinised Linear Switched Reluctance Generators for Wave Energy Conversion
by Mohammed Almuhamidh of Newcastle University

Wave energy converters (WECs) require robust and reliable power take-off systems capable of operating under harsh marine conditions and low-speed oscillatory motion. Direct-drive linear electrical machines are considered a promising solution due to their ability to eliminate complex mechanical transmission systems. Among the available machine topologies, switched reluctance machines (SRMs) offer advantages including simple construction, low manufacturing cost, high fault tolerance, and the absence of permanent magnets, making them attractive for marine energy applications. This work investigates the development of marinised linear switched reluctance generators for wave energy conversion. The research focuses on the electromagnetic design and analysis of linear SRM topologies suitable for direct-drive wave energy systems, while also considering the challenges associated with long-term seawater exposure, including corrosion, insulation degradation, thermal management, and sealing reliability. Initial electromagnetic modelling has been carried out using ANSYS Maxwell to evaluate magnetic flux distribution, force production, and machine behaviour under linear motion conditions. Early simulation work includes the development of a preliminary linear generator model to establish suitable geometry, material selection, and excitation configurations for future optimisation studies. The ongoing PhD research aims to contribute towards the design of durable and efficient marine electrical generators by integrating electromagnetic performance analysis with marinisation considerations for wave energy applications.

Student - Design of Linear Generators for Integration into Offshore Renewable Energy Converters
by Sajjad Sharqi of Newcastle University

Offshore energy generation technologies continue to receive attention as a potential to help the UK achieve energy independence. Wave energy offers a sustainable and environmentally friendly energy source which could be an alternative to fossil fuels and contribute to greenhouse gas emission reduction in the energy sector. The UK has an annual energy resource of wave energy equal to approximately 15% of electricity demand. Linear generators represent a transformative approach in wave energy conversion technologies. The offshore environment presents unique challenges, including hard weather condition, corrosion, limited maintenance access, and integration, which requires specialized electrical machine designs and system architectures. Bespoke machine design optimisation techniques are required to look at the feasibility of alternative linear generators for use in wave energy A tubular linear machine is being designed and investigated for use in a direct drive oscillating water column type wave energy converter. Alternative configurations and topologies based on the capabilities in low velocities and wave characteristics will be evaluated. This early stage work focuses on design methodologies and development strategies for generators used in the field of offshore energy.

Level Set Topology Optimization for Rare Earth Free Machine Design Accounting for Manufacturing Effects
by Alexander Stewart of University of Bristol

Synchronous reluctance machines provide a rare earth free topology enabling simple recyclability with a rare earth free design. The topology is characterised by lower torques and higher torque ripples than its permanent magnet counter parts. Complexity inherent in the design has led many to apply topology optimization techniques to improve performance. Manufacturing effects are commonly accounted for in design through correction factors after the design process. The novelty of the approach is through accounting for manufacturing degradation during the design process, machines can be tuned to avoid excess degradation from manufacture. The level set topology optimization framework developed allows for the computation of high torque machine topologies with 30-minute runs avoiding the need for high cost and energy, parallel computing requirements. Furthermore, incorporation of laser cutting degradation into FEA during design will be shown to implicitly reduce manufacturing degradation to the optimized design expanding the design space without significant compromise to optimization speed.

Quantifying The Impact Of Eccentricity, Rotor Tilt, And Magnetization Variability On Electric Drive Unit NVH
by Adam Szypula of JLR

With the rapid electrification of the automotive sector the, the NVH performance of Electric Vehicles has become an important design consideration, particularly due to the absence of ICE masking noise. In BEV applications with EDUs using IPMSM, electromagnetic forces acting on the stator teeth are the primary source of electromagnetic vibration and acoustic noise. This paper presents multi-objective optimization methodology focusing on rotor and stator geometry parametrization, such as slot opening, tooth depth, pole v angle, to tackle the specific forcing orders. The workflow integrates FEA software to simulate electromagnetic performance across a range of operating points. Constraints are applied to maintain torque, power and efficiency within tolerances of the baseline design. ModeFRONTIER advanced post-processing tools, such as Parallel Coordinate plots and Pareto Front analysis, are used to visualize the trade-offs between force reduction and electromagnetic performance. The results validate that selected geometric modifications can reduce exciting forces without compromising the motor’s efficiency, power or torque.

Development of traceability routes and magnetic material test systems to support Power Electronics Machines & Drives (PEMD)
by Stuart Harmon of NPL

NPL is currently developing new measurement systems that will provide underpinning cross-sector support for Power Electronics, Machines and Drives (PEMD). One focus is the characterisation of magnetic materials to address metrology challenges, critical to deliver technology roadmaps for decarbonisation of Automotive, Aerospace and Energy sectors.​ This presentation will outline the work NPL is doing to develop a new SI primary magnetic field standard to provide traceability for magnetic material characterisation and magnetic sensor calibrations. It will also cover new and extended characterisation methods and techniques for magnetic materials used in PEMD applications. It will outline the current and future activities underway as part of our existing four-year government program to characterise soft and hard magnetic materials outside of existing IEC standard conditions, under industrial operational conditions and for non-standard geometries.

Rotor-Assisted Oil-Jet Cooling for High-Power-Density Electrical Machines: Thermal Imaging, Droplet Visualisation and Windage Loss Modelling
by Sen Zhang of University of Nottingham

Oil-jet cooling is an effective thermal management approach for high-power-density electrical machines. However, conventional direct oil-jet cooling methods typically inject oil onto the stator end-windings and provide limited cooling to the rotor end-region. This study investigates a rotor-assisted oil-jet cooling structure, where oil is first injected onto the rotor end surface and then redistributed by rotor rotation towards the stator end-windings. This configuration enables cooling of both the rotor and stator end-region, making it attractive for compact, high-power-density machine applications. The cooling performance is experimentally evaluated under different operating conditions. Thermal imaging is used to measure end-winding temperature distributions and assess the influence of operating conditions on cooling effectiveness. In addition, an analytical calculation method is developed to predict the windage loss associated with oil in the rotor end-region. High-speed imaging is also used to observe the oil droplet distribution and support the understanding of oil transport and cooling behaviour.

Advanced Cryogenic Cooling Techniques in Electric Propulsion Aircraft Systems
by Boyu Qian of University of Nottingham

With the urgent need for zero emission transport, electrical machines are increasingly being adopted in aerospace applications. However, the growing demand for higher power density has made thermal management a critical challenge. Compared with conventional cooling methods, liquid hydrogen (LH₂) cooling offers significant advantages for hydrogen powered aircraft, as it can utilise the onboard cryogenic fuel as a cooling medium without requiring an additional coolant supply, while also substantially reducing electrical losses. Despite these benefits, most existing electrical machine designs are developed for room temperature operation and subsequently adapted for cryogenic environments. My PhD research focuses on developing advanced cooling technologies for cryogenic electrical machines, using both self developed analytical models and numerical methods. A key aspect of the work is the evaluation of heat transfer coefficients under cryogenic cooling conditions, an area that remains relatively underexplored in the literature. This presentation will provide an introduction to electrical machines, review a range of promising cryogenic cooling techniques, and present recent progress in understanding and characterising cryogenic heat transfer coefficients.