Search

Your search keyword '"Gerada, Chris"' showing total 575 results
Start Over Author "Gerada, Chris" Search Limiters Available in Library Collection
575 results on '"Gerada, Chris"'

9. Design Optimization of Spoke-Type Flux-Intensifying PM Motor With Asymmetric Rotor Configuration for Improved Performance

Author

Hsieh, Min-Fu, Huynh, Anh Thanh, Do, Viet-Vu, Gerada, David, and Gerada, Chris

Abstract

This article explores enhancing spoke-type flux-intensifying permanent magnet (SFI-PM) motor performance by strategically placing flux barriers (FBs) in the asymmetric rotor. Integrating multi-FBs into the conventional spoke-type PM (CSPM) rotor topology elevates the d-axis inductance ( $L_{d} \gt L_{q}$ ), intensifying flux density and improving output torque while posing challenges like increased cogging torque, torque ripple, and harmonic distortion. An asymmetric rotor design is proposed to mitigate these issues by strategically placing a higher number of FBs along the forward direction (FD) of the spoke magnet axis (q-axis). Analysis reveals that this configuration reduces torque ripple and enhances output torque. A multi-objective genetic algorithm (MOGA) is applied to optimize this asymmetric design considering mechanical constraints. The analyses are validated by manufacturing and testing a 5-kW asymmetric SFI-PM machine with a higher number of FBs along the FD of the spoke magnet axis.

Published
2024
Full Text
View/download PDF

10. Fillet Radius Impact of Rectangular Insulated Wires on PDIV for Turn-to-Turn Insulation of Inverter-Fed Motors

Author

Naderiallaf, Hadi, Degano, Michele, Gerada, Chris, and Gerada, David

Abstract

This contribution elucidates the impact of the fillet radius (FR), a geometric feature of rectangular insulated wires not commonly considered, on the partial discharge inception voltage (PDIV) in low-voltage machine turn-to-turn winding insulation. Initial PDIV tests involve edgewise-insulated wire samples with a reference FR. These measurements are performed under constant conditions: 30 °C temperature, 35% relative humidity (RH), and atmospheric pressure (1000 mbar). These tests are carried out under ac 50-Hz excitations, following IEC 60034-18-41 guidelines for inverter-fed motor insulation system qualification. Subsequently, a probabilistic PDIV predictive model is developed based on Schumann’s streamer inception criterion (SCSIC). This expanded model then analyzes and forecasts the impact of the FR on PDIV and its associated dispersion level, within the context of the two-parameter Weibull distribution and the given environmental conditions. Furthermore, a novel method is presented to understand partial discharge (PD) phenomenology and its destructive potential in rectangular insulated wires with varying fillet radii. This approach employs SCSIC-derived streamer inception parameters (SIPs): critical field line length (CFLL), air effective ionization coefficient ( $\alpha _{\text {eff}}$ ), PD inception field ( ${E}_{\text {inc}}$ ), and firing voltage ( ${V}_{\text {firing}}$ ). The developed probabilistic predictive model enables the selection of an optimal FR value, facilitating the creation of a reliable insulation system with maximum PDIV and minimal PD-related damage.

Published
2024
Full Text
View/download PDF

11. A Review of Carbon Emissions from Electrical Machine Materials.

Author

Zhang, Xuebei, Gerada, David, Xu, Zeyuan, Zhang, Fengyu, and Gerada, Chris

Subjects
CARBON emissions, MACHINING, GLOBAL warming, MACHINE design, GREENHOUSE gas mitigation, CLIMATE change, PERMANENT magnets
Abstract

As the world embarks on a global mission to tackle climate change, reducing carbon represents a key challenge given the escalating global warming. The U.K. is among many other nations that are determined to decarbonise all sectors and strive to achieve a net zero carbon target by 2050. While much attention has been paid to improving performance and reducing carbon emissions in electrical machines, the current research landscape focuses mainly on the thermal and electromagnetic facets. Surprisingly, carbon emissions from the production stage, especially those related to raw material consumption, remain a largely unexplored area. This paper wishes to shed light on a neglected dimension by providing a comprehensive review of carbon emissions in the manufacture of electrical machines, thus contributing significantly to the wider discourse on carbon emission reduction by comparing the carbon emission values associated with various materials commonly used for the main components of these machines. A further case study is included to assess and explore the impact of material alterations on a synchronous machine, from a carbon emission perspective. A reliable material guide will provide engineers at the design stage with the critical insight needed to make informed material selection decisions, highlighting the critical role of carbon emission values beyond conventional thermal and electromagnetic considerations, achieving sustainable and environmentally conscious electrical machine design. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

13. Design of an aircraft generator with radial force control

Author

Brecher, Christian, primary, Neus, Stephan, additional, Gärtner, Marcus, additional, Eckel, Hans-Martin, additional, Hoppert, Maik, additional, James, Barry, additional, Gerada, Chris, additional, Degano, Michele, additional, Ilkhani, Mohammad Reza, additional, and Di Nardo, Mauro, additional

Published
2023
Full Text
View/download PDF

14. PDIV Modeling for Rectangular Wire Turn-to-Turn Insulation of Inverter Fed Motors Through Thermal Aging

Author

Naderiallaf, Hadi, Degano, Michele, and Gerada, Chris

Abstract

This contribution develops the partial discharge inception voltage (PDIV)-finite-element method (FEM)-based model based on Schumann’s streamer inception criterion (SCSIC) with respect to thermal aging time (TAGT) or the insulation lifetime for the turn-to-turn insulation of coil winding made by rectangular insulated wires. The accelerated thermal aging is performed at 250 °C, which is 50 °C higher than the thermal class, with aging intervals of 156 and 312 h. PDIV measurements are conducted at a constant temperature of 25 °C, 40% relative humidity, and atmospheric pressure (1013 mbar). The measurements are done under ac 50-Hz excitations, following IEC 60034-18-41 guidelines for inverter fed motor insulation system qualification. Furthermore, this study analyzes streamer inception parameters such as critical field line length (CFLL), effective ionization coefficient ( $\alpha _{\text {eff}}{)}$ , partial discharge (PD) inception field ( ${E}_{\text {discharge}}{)}$ , firing voltage ( ${V}_{\text {firing}}{)}$ , and its correlation with PD charge amplitude as a function of TAGT or the insulation lifetime.

Published
2024
Full Text
View/download PDF

15. Fault-Tolerant Control for Single-Phase Open-Circuit and Short-Circuit Fault in Five-Phase PMSM With Third-Order Harmonic Back EMF Using Coefficients Reconfiguration

Author

Wang, Huanran, Gu, Chunyang, Zhao, Weiduo, Wang, Shuo, Zhang, Xiaochen, Buticchi, Giampaolo, Gerada, Chris, and Zhang, He

Abstract

For a five-phase permanent magnet synchronous machine (PMSM), the third-order harmonic back EMF is increased by changing the shape of the permanent magnet for increasing average torque in healthy operation. Additionally, in the open-circuit (OC) and short-circuit (SC) faults, the effect of injected third-order harmonic back EMF also needs to be considered. Therefore, this paper proposes a fault-tolerant control method with original transformation matrixes and coefficients reconfiguration in fundamental and third-order harmonic subspaces for both single-phase OC and SC faults. Fault tolerance can be applied by reconfiguring the relative coefficients after an OC or SC fault occurs, depending on the type of fault. Besides, the proposed method aims to optimize the OC fault tolerance strategies and effectively solve the single-phase SC fault, considering the influence in the third-order harmonic back EMF. According to experimental results, the torque fluctuation after applying the proposed method is similar to that in the healthy stage and much lower than that using most fault-tolerant control methods without considering the third-order harmonic back EMF.

Published
2024
Full Text
View/download PDF

16. Enhanced Estimation of Clamping-Force for Automotive EMB Actuators Using a Switching Extended State Observer

Author

Xu, Zhuang and Gerada, Chris

Abstract

The automotive intelligence and electrification require the braking system to cooperate with the controller to achieve regenerative and active braking functions. Hence, the range and driving safety of the electric vehicles are improved. Electromechanical brake (EMB) systems completely abandon the fluid and hydraulic elements and replace the traditional hydraulic braking system with a wire harness and electromechanical parts. The braking torque adjustment is achieved entirely by controlling the four-wheel EMBs. At present, reliability and fault tolerance are the key technical issues associated with EMBs. To eliminate the need of any clamping-force sensor due to its vulnerability and high cost, in this article, a switching extended state observer (SESO) is presented to provide rapid force estimation with higher precision. The substrates of the internal linear and nonlinear structures have been unified into a single form by using an equivalent gain method. The SESO is effective to detect the initial contact between the braking disk and pad by estimating the load torque. It is experimentally verified that the developed force sensorless control strategy is accurate and superior to the existing techniques.

Published
2024
Full Text
View/download PDF

17. Common DC-Link Capacitor Harmonic Current Minimization for Cascaded Converters by Optimized Phase-Shift Modulation

Author

Zhou, Xuanyi, primary, Choy, Wei Juin, additional, Alcaide, Abraham M., additional, Wang, Shuo, additional, Guenter, Sandro, additional, Leon, Jose I., additional, Monopoli, Vito Giuseppe, additional, Franquelo, Leopoldo G., additional, Liserre, Marco, additional, Galea, Michael, additional, Gerada, Chris, additional, and Buticchi, Giampaolo, additional

Published
2023
Full Text
View/download PDF

23. Novel End-Winding Hybrid Flux Machine

Author

Shi, Bowen, primary, Huang, Xiaoyan, additional, Li, Jing, additional, Zhang, He, additional, Zhao, Han, additional, Zhang, Xiaochen, additional, Zhang, Fengyu, additional, and Gerada, Chris, additional

Published
2023
Full Text
View/download PDF

24. Single-Phase Short-Circuit Fault Tolerant Control for Five-Phase Permanent Magnet Machines With Copper Loss Reduction

Author

Wang, Huanran, Gu, Chunyang, Wang, Shuo, Zhao, Weiduo, Bai, Shun, Buticchi, Giampaolo, Gerada, Chris, and Zhang, He

Abstract

Five-phase machines represent a widely adopted choice for fault-tolerant applications due to their extra degrees of freedom. This article deals with the single-phase short-circuit fault tolerant control using original transformation matrix for five-phase permanent-magnet machines. The proposed method first follows the fundamental phase current injection (FCI) method based on the calculated SC current. Moreover, third-order harmonic phase current injection (THCI) method is presented to reduce copper loss. The computational method of derating factor is also adopted for industrial applications. The fault tolerance and dynamic performance are also verified by the experimental results. A reduction of copper loss in THCI method by about 15% is achieved, compared with general and FCI methods.

Published
2023
Full Text
View/download PDF

32. Design of an aircraft generator with radial force control

Author

Brecher, Christian, primary, Neus, Stephan, additional, Gärtner, Marcus, additional, Eckel, Hans-Martin, additional, Hoppert, Maik, additional, James, Barry, additional, Gerada, Chris, additional, Degano, Michele, additional, Ilkhani, Mohammad Reza, additional, and Di Nardo, Mauro, additional

Published
2022
Full Text
View/download PDF

37. Design procedure and optimisation methodology of permanent magnet synchronous machines with direct slot cooling for aviation electrification.

Author

Tameemi, Ahmed, Degano, Michele, Murataliyev, Mukhammed, Di Nardo, Mauro, Valente, Giorgio, Gerada, David, Xu, Zeyuan, and Gerada, Chris

Subjects
STATORS, PERMANENT magnets, SLOT machines, OPTIMIZATION algorithms, ELECTRIC machines, ELECTRIFICATION, MACHINE design
Abstract

Electric machines are widely employed in a variety of sectors, including automotive and aerospace industry. With the rising trend towards electrification in aviation, electric machines with increased power density and efficiency are becoming key enabling technologies, requiring the development of innovative design procedures. In this study, a preliminary design procedure for Surface Mounted Permanent Magnet Synchronous Machines (SPMSMs) intensively cooled by means of oil channels placed in the stator slots is proposed. The analytical derivation of SPMSM sizing equations, including the sub‐domain model and optimisation algorithm will be reported in detail. Indeed, both the electromagnetic and thermal equations of the machine are considered for the derivation of the sizing tool. As a result, the latter allows to capture variation of the machine design not only in terms of mechanical demands, such as power and speed, but also in terms of coolant characteristics, and can be effectively employed to perform trade‐off studies at a preliminary design stage. The proposed design tool will be used for a specific case study: The design of a high‐speed machine for an aerospace hydraulic actuator. The accuracy of the proposed design tool is validated for different parameters by comparing the results to experimental measurements performed on an existing 8‐pole 9‐slot prototype SPMSM. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

38. Design of an aircraft generator with radial force control

Author

Gärtner, Marcus, Brecher, Christian, Neus, Stephan, Hoppert, Maik, James, Barry, Gerada, Chris, Degano, Michele, Ilkhani, Mohammad Reza, and Di Nardo, Mauro

Subjects
Aircraft generator, Radial force control, Bearing friction, Bearing loads, Efficiency, Validation, Test rig, Shaft-bearingsystem
Abstract

With the increasing electrical energy demands in aviation propulsion systems, the increase in the onboard generators’ power density is inevitable. During the flight, forces coming from the gearbox or gyroscopic forces generated by flight manoeuvres like take-off and landing can act on the generator’s bearings, which can lead to wear and fatigue in the bearings. Utilizing the radial force control concept in the electrical machine can relieve loads from the bearings that not only minimize the bearing losses but also increase the bearings’ life. The objective of the MAGLEV project (Measurement and Analysis of Generator Bearing Loads and Efficiency with Validation) is to study, demonstrate, and test a new class of high-speed generators with radial force control. The concept is developed in an electrical machine and is validated on a test rig by measuring required parameters like shaft displacement, vibrations and bearings’ temperature. Additionally, the friction moment of each generator’s bearings is measured and validated in a separate test rig with a precise friction force measurement system under comparable conditions to the bearings’ loads in the generator. In this paper design steps of this type of generator and its test rig are presented and the measurement methodology used for radial force control is explained.

Published
2022
Full Text
View/download PDF

43. Mild hybridisation of turboprop engine with high-power-density integrated electric drives

Author

Chen, Yuzheng, Yang, Tao, Khowja, Muhammad, La Rocca, Antonino, Nasir, Usman, Chowdhury, Shajjad, Evans, Dean, Kember, Dafydd, Klonowski, Thomas, Arnaud, Yohan, Apostin, Lucie, Liger, Thierry, Vakil, Gaurang, Gerada, Chris, Bozhko, Serhiy, Detry, Sebastien, Diette, Christophe, Wheeler, Patrick, and Cossart, Gregory

Subjects
Automotive Engineering, Energy Engineering and Power Technology, Transportation, Electrical and Electronic Engineering
Abstract

This paper shares with the aerospace community a case study of turboprop mild hybridisation using a recently developed integrated drive system in the University of Nottingham, UK, within the ACHIEVE project under EU H2020 CleanSky 2 program (project No. 737814). The developed drive system enables green taxiing of a turboprop aircraft while on the ground with its engine off, and as an electrical generator when the turboprop is in the air. The entire system is designed to be able to integrate within the power auxiliary gear box (PAGB) of a turboprop aircraft. Some of the key features of the developed system include a high-speed permanent magnet machine (up to 14,200rpm) with dual three-phase design, SiC-based high power density (11.8kW/L for the power converter, 35.3kW/L and 7.2kW/kg for the machine active parts), integrated cooling design for high-temperature operation (>130ºC ambient temperature), fault tolerance consideration with dual channel operation capabilities and sensorless control for entire operational conditions. This paper is giving an overview of the design process of the electrical machine, power converters, and its cooling of the entire drive. Numerical analysis (FEM and CFD) and some experimental results are presented to demonstrate the effectiveness and the desired performance of the developed integrated drive system.

Published
2022

44. Improved Thermal Modelling and Experimental Validation of Oil-Flooded High Performance Machines with Slot-Channel Cooling

Author

Zhang, Fengyu, Gerada, David, Xu, Zeyuan, Zhang, Xiaochen, Zhang, He, Gerada, Chris, Zhu, Mingjun, Xia, Liqun, Zhang, Wei, and Degano, Michele

Subjects
Automotive Engineering, Energy Engineering and Power Technology, Transportation, Electrical and Electronic Engineering
Abstract

Thermal management is often considered a bottleneck in the pursuit of the next generation electrical machines for electrified transportation with a step change in power density. Slot-channel cooling is considered to be an effective cooling technique, either as an independent method or as a secondary heat transfer path which compliments traditional cooling systems. The slot-channel specific geometry and position effects on the thermal benefits are not thoroughly investigated in literature, while previous work focuses on passing fluid through the un-used space left in between coils forming concentrated windings. In this paper, slot-channel cooling is implemented within an oil-flooded cooling system for a high power density motor used as a pump. A flexible and detailed lumped parameter thermal network (LPTN) is proposed for the cooling system, with the LPTN used to optimize the slot-channel dimensions and location for obtaining maximum thermal benefits. Finally, a surface-mount permanent magnet (SPM) machine with the optimized slot channel geometry is built and tested to validate the thermal model, experimentally achieving an armature continuous current density in excess of 30A/mm2.

Published
2022

Catalog

Books, media, physical & digital resources
See catalog results