CERES :: Browsing by Author "Luk, Patrick Chi-Kwong"

Browsing by Author "Luk, Patrick Chi-Kwong"

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Open Access
Advanced control of a multi-sourced multi-level source inverter system for high performance electric vehicles.
(2016-06) Bendyk, Maciej Szymon; Luk, Patrick Chi-Kwong
At present, electric vehicles are getting very popular and there is a high demand for related technologies. Therefore, car manufacturers are looking for cost- effective solutions to improve the efficiency and performance of drive trains. One of the biggest challenges is to create an efficient, reliable and robust system architecture integrated with energy management systems to maximize its performance. Thus, in the last decade technologies started evolving towards use of higher voltage levels with multiple energy sources, which involve complex control and power electronics capable of performing sophisticated functions. In the quest for a new electric drive-train technology, a system architecture together with power and energy management has been identified as a key area of research. This work investigates problems related to the complexity of energy management for power-limited energy sources to improve performance in the whole operation envelope. The widely accepted solution of using multiple energy storage systems is discussed and found to relate to more complicated and expensive power electronic hardware. Furthermore, to achieve high power with reasonable efficiency it is necessary to use high voltage, which is difficult to attain. This work proposes an electrical system with integrated motor control and energy flow management between multiple electric sources with the aim to increase the power capability of an electric drive train. To reach good performance and high efficiency the multilevel, cascaded Voltage Source Inverter with multiple sources is introduced to provide instantaneous proportional power split and to boost voltage for the electric motor at the same time. Whilst there are existing examples of multilevel inverters with electric motor drives, none of them has successfully found their way to mainstream vehicles due to the intricacy and many unresolved technical challenges. This thesis contributes to the field of power electronics in the following areas. Firstly a detailed mathematical analysis of hybrid cascade multilevel inverter with variable voltage ratio between sources has been performed to find its the sources. Secondly, based on the derived equations a new multilevel inverter control and modulation strategy to increase the transient power capability by distributing power between the battery and ultracapacitors has been developed. The method has been validated first through a simulated model in Matlab/Simulink and subsequently by experimental work on a specifically designed and built hardware platform. The results showed that the proposed architecture with modest increase in complexity can markedly improve the system’s transient power capability, and contribute to higher maximum output voltage availability and at the same time minimize Total Harmonic Distortions and switching losses.
Open Access
Advanced quadrotor control strategies for health monitoring of overhead power lines.
(Cranfield University, 2021-07) Foudeh, Husam; Luk, Patrick Chi-Kwong; Whidborne, James F.
Research into autonomous control and behavior of mobile vehicles has become increasingly widespread. In particular, unmanned aerial vehicles (UAVs) have seen an upsurge of interest and of the many UAVs available, the multirotor has shown significant potential in monitoring and surveillance tasks. The objective of this research’s programme is to develop novel control that enable quadrotors to track and inspect on high voltage electricity networks. This is a research application that has elicited little attention. This thesis provides a succinct and comprehensive literature research in both state-of-art overhead power lines (OPL) inspection technologies, and quadrotor design and control. It proceeds to motivate, develop and evaluate a learning algorithms controller which exploit the repeated nature of the fault-finding task. Very few iterative learning control (ILC) algorithms have been implemented in this area, and no analysis or practical results exist to specifically investigate UAV performance to modelling uncertainty and exogenous disturbances. In particular, novel contributions are made in ILC algorithms are derived and validated by experimental results on an AscTec Hummingbird quadrotor. It has taken a robust comparisons among several ILC approaches (gradient-based, norm optimal and Newton method ICLs), and the comparisons are largely based on analytical calculated results. In the case of optimal ILC approaches, a new algorithm for nonlinear MIMO systems is developed to cope with exogenous disturbances and noise severely affect UAV as well as a novel tuning method for bnew variation is formulated and applied to the problem of reference tracking for a 6-degree-of-freedom UAV with a two-loop structure. The first loop addresses the system lag and another tackles the possibility of a disturbance commonly encountered when inspection of OPL. The new algorithm contributes to good trajectory tracking and very good convergence speed while minimizing disturbance effects. A linearisation design approach has been extended to enable new updates using quadcopters dynamics. Then constraints have embedded to meet the application demands. After overcoming this deficiency, the ILC controller is further extended based on point-to-point through a straight conductor to fulfil the full task and perform a 2-3 sequence of operations. Finally, the ILC development results are given follow-up using 3D analysis approach where these results are the first ever in this key area.
Open Access
An advanced unmanned aerial vehicle (UAV) approach via learning-based control for overhead power line monitoring: a comprehensive review
(IEEE, 2021-09-03) Foudeh, Husam A.; Luk, Patrick Chi-Kwong; Whidborne, James F.
Detection and prevention of faults in overhead electric lines is critical for the reliability and availability of electricity supply. The disadvantages of conventional methods range from cumbersome installations to costly maintenance and from lack of adaptability to hazards for human operators. Thus, transmission inspections based on unmanned aerial vehicles (UAV) have been attracting the attention of researchers since their inception. This article provides a comprehensive review for the development of UAV technologies in the overhead electric power lines patrol process for monitoring and identifying faults, explores its advantages, and realizes the potential of the aforementioned method and how it can be exploited to avoid obstacles, especially when compared with the state-of-the-art mechanical methods. The review focuses on the development of advanced Learning Control strategies for higher manoeuvrability of the quadrotor. It also explores suitable recharging strategies and motor control for improved mission autonomy.
Open Access
Analytical and experimental evaluation of SiC-inverter nonlinearites for traction drives used in electric vehicles
(IEEE, 2017-10-23) Ding, Xiaofeng; Du, Min; Duan, Chongwei; Guo, Hong; Xiong, Rui; Xu, Jinquan; Cheng, Jiawei; Luk, Patrick Chi-Kwong
This paper investigates the inverter nonlinearities in a drive system based on silicon carbide metal-oxide-semiconductor field-effect transistor (SiC-mosfets) and compares its performance with that of an equivalent silicon insulated-gate bipolar transistor (Si-IGBT) system. Initially, a novel comprehensive analytical model of the inverter voltage distortion is developed. Not only voltage drops, dead time, and output capacitance, but also switching delay times and voltage overshoot of the power devices are taken into account in the model. Such a model yields a more accurate prediction of the inverter's output voltage distortion, and is validated by experimentation. Due to inherent shortcomings of the commonly used double pulse test, the switching characteristics of both SiC-mosfets and Si-IGBTs in the pulse width modulation inverter are tested instead, such that the actual performances of the SiC and Si devices in the motor drive system are examined. Then, the switching performance is incorporated into the physical model to quantify the distorted voltages of both the SiC-based and Si-based systems. The results show that, despite its existing nonlinearities, the SiC-based drive has lower voltage distortion compared to the conventional Si-based drive as a result of its shorter switching times and smaller voltage drop, as well as a higher efficiency. Finally, the overriding operational advantages of the SiC-based drive over its Si-based counterpart is fully demonstrated by comprehensive performance comparisons.
Open Access
Analytical investigation of sideband electromagnetic vibration in integral-slot PMSM drive with SVPWM technique
(Institute of Electrical and Electronics Engineers (IEEE), 2016-09-13) Liang, Wenyi; Fei, Wei-Zhong; Luk, Patrick Chi-Kwong
This paper provides a comprehensive investigation into the electromagnetic vibration associated with the sideband harmonic components introduced by space vector pulse width modulation applied in integral-slot permanent magnet synchronous machine drives. The critical permanent magnet, armature reaction, and sideband magnetic field components, which are the primary causes for sideband electromagnetic vibration in integral-slot permanent magnet synchronous machines, are identified. The analytical derivations of the magnetic field components are carried out, and amplitudes and frequencies of the resultant sideband radial electromagnetic force components are obtained. Furthermore, the proposed models of the sideband radial electromagnetic force components are incorporated into the vibration model to analytically evaluate the corresponding sideband electromagnetic vibrations of the machine. Experimental tests on an integral-slot permanent magnet synchronous machine drive are comprehensively performed to confirm the validity and accuracy of the analytical models. Not only can the validated analytical models offer insightful details in understanding the impacts of the key factors, such as operation conditions, machine geometry, electromagnetic and power converter parameters, on the sideband electromagnetic vibration, but also can be readily extended to assess and reduce noise in integral-slot permanent magnet synchronous machine drives.
Open Access
Analytical modeling of current harmonic components in PMSM drive with voltage-source inverter by SVPWM technique
(IEEE, 2014-04-22) Liang, Wenyi; Wang, Jianfeng; Luk, Patrick Chi-Kwong; Fang, Weizhong; Fei, Wei-Zhong
The sideband current harmonic components would inhere in permanent-magnet (PM) synchronous machine systems driven by a voltage-source inverter with space vector pulsewidth modulation (SVPWM). However, these harmonics could potentially deteriorate the overall performance of the drive system by increasing the resultant losses, torque ripple, and electromagnetic and acoustic noises. The main sideband harmonic voltages and currents in PM synchronous machine driven by voltage-source inverter with SVPWM technique, are analytically derived and expressed in both stator and rotor frame. The experimental results are carried out to underpin the validity of the analytical model. The analytical model could be employed to assess the influencing factors of current harmonics. In addition, it offers insightful guidance to the effective reductions of harmonic losses, torque ripples, and electromagnetic noises.
Open Access
The analytical study of stator tooth modulation on electromagnetic radial force in permanent magnet synchronous machines
(IEEE, 2020-12-02) Liang, Wenyi; Wang, Jianfeng; Luk, Patrick Chi-Kwong; Fei, Wei-Zhong
The electromagnetic radial force acting on the stator inner periphery will induce radial vibration and acoustic noise in permanent magnet machines. The radial force components are transmitted through the stator teeth to the yoke to introduce deformations. The influence of the stator tooth structure can be considered as an equivalent mechanical modulation effect on these electromagnetic radial force components. As a result, high-order electromagnetic radial force components can be modulated and potentially result in eminent stator low-mode vibration. In this paper, an analytical model is developed to offer an intuitive knowledge of stator tooth modulation effect on electromagnetic radial force. The validity of the proposed analytical method has been underpinned by both finite element analysis and experimental results. Such an effective yet simple analytical model can be of significant benefit for the stator radial vibration analysis. It can be employed to not only promptly investigate the stator radial vibration characteristics but also perform effective optimization on stator radial vibration reduction in permanent magnet machines
Open Access
Application of Norm Optimal Iterative Learning Control to Quadrotor Unmanned Aerial Vehicle for monitoring overhead power system
(MDPI, 2020-06-22) Foudeh, Husam A.; Luk, Patrick Chi-Kwong; Whidborne, James F.
Wind disturbances and noise severely affect Unmanned Aerial Vehicles (UAV) when monitoring and find in faults in overhead power lines. Accordingly, we propose repetitive learning as a new solution for the problem. In particular, the performance of Iterative Learning Control (ILC)that are based on optimal approaches are examined, namely (i) Gradient-based ILC and (ii) Norm Optimal ILC. When considering the repetitive nature of fault-findin tasks for electrical overhead power lines, this study develops, implements and evaluates optimal ILC algorithms for a UAV model.Moreover, we suggest attempting a learning gain variation on the standard optimal algorithms instead of heuristically selecting from the previous range. The results of both simulations and experiments o gradient-based norm optimal control reveal that the proposed ILC algorithm has not only contributed to good trajectory tracking, but also good convergence speed and the ability to cope with exogenous disturbances such as wind gusts.
Open Access
Cogging torque suppression in a permanent-magnet flux-switching integrated-starter-generator
(2010-09-13T00:00:00Z) Jin, Meng-Jia; Wang, Y.; Shen, Jian-Xin; Luk, Patrick Chi-Kwong; Fei, Wei-Zhong; Wang, Can-Fei
Permanent-magnet flux-switching (PMFS) machine offers high torque density, impressive flux-weakening capability and mechanical ruggedness because of its distinctive configuration, and is potentially suitable for the application in automotive integrated-starter-generators (ISGs). However, the PMFS machine generally exhibits higher cogging torque compared with other machines commonly used in ISGs. Minimisation of the cogging torque in the PMFS machine for its utility in ISGs is therefore of particular importance. Four rotor topologies are proposed here as cost-effective means to suppress the cogging torque of a PMFS ISG. The validity of the proposed techniques has been confirmed by both two- dimensional finite-element analysis and experimental results. Moreover, the influence on the back electromagnetic force by these techniques is also investigated.
Open Access
Control strategy for a modified cascade multilevel inverter with dual DC source for enhanced drivetrain operation
(IEEE, 2017-05-04) Bendyk, Maciek; Luk, Patrick Chi-Kwong; Alkhafaji, Mohammed
This paper presents a new control strategy for a modified cascade multilevel inverter used in drivetrain operations. The proposed inverter is a three-phase bridge with its dc link fed by a dc source (battery), and each phase seriesconnected respectively to an H-bridge fed with a floating dc source (ultracapacitor). To exploit the potentials of the inverter for enhanced drivetrain performance, a sophisticated yet efficient modulation method is proposed to optimise energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimise switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications.
Open Access
Control strategy for a modified cascade multilevel inverter with dual DC source for enhanced drivetrain operation
(IEEE, 2017-02-16) Bendyk, Maciej; Luk, Patrick Chi-Kwong
This paper presents a new control strategy for a modified cascade multilevel inverter used in drivetrain operations. The proposed inverter is a three-phase bridge with its dc link fed by a dc source (battery), and each phase series-connected respectively to an H-bridge fed with a floating dc source (ultracapacitor). To exploit the potentials of the inverter for enhanced drivetrain performance, a sophisticated yet efficient modulation method is proposed to optimise energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimise switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications.
Open Access
Cooling of concentrated photovoltaic cells - a review and the perspective of pulsating flow cooling
(MDPI, 2023-03-18) Ibrahim, Khalifa Aliyu; Luk, Patrick Chi-Kwong; Luo, Zhenhua
This article presents a review to provide up-to-date research findings on concentrated photovoltaic (CPV) cooling, explore the key challenges and opportunities, and discuss the limitations. In addition, it provides a vision of a possible future trend and a glimpse of a promising novel approach to CPV cooling based on pulsating flow, in contrast to existing cooling methods. Non-concentrated photovoltaics (PV) have modest efficiency of up to around 20% because they utilise only a narrow spectrum of solar irradiation for electricity conversion. Therefore, recent advances employed multi-junction PV or CPV to widen the irradiation spectrum for conversion. CPV systems concentrate solar irradiation on the cell’s surface, producing high solar flux and temperature. The efficient cooling of CPV cells is critical to avoid thermal degradation and ensure optimal performance. Studies have shown that pulsating flow can enhance heat transfer in various engineering applications. The advantage of pulsating flow over steady flow is that it can create additional turbulence and mixing in the fluid, resulting in a higher heat transfer coefficient. Simulation results with experimental validation demonstrate the enhancement of this new cooling approach for future CPV systems. The use of pulsating flow in CPV cooling has shown promising results in improving heat transfer and reducing temperature gradients.
Open Access
Design and analysis of a new outer-rotor permanent-magnet flux-switching machine for electric vehicle propulsion
(2011-01-31T00:00:00Z) Fei, Wei-Zhong; Shen, Jian-Xin; Wang, Can-Fei; Luk, Patrick Chi-Kwong
Purpose − The purpose of this paper is to propose a new outer-rotor permanent- magnet flux-switching machine for in-wheel electric vehicle propulsion. The paper documents both the design procedure and performance investigation of this novel machine. Design/methodology/approach − The topology and preliminary sizing equations of the outer-rotor permanent-magnet flux-switching machine are introduced. Both the number and width of rotor poles are then optimized using comprehensive two-dimensional FEA. The machine losses are particularly investigated by transient FEA for the optimal design. Findings − A outer-rotor permanent-magnet flux-switching machine, with 12 stator poles and 22 rotor poles, is most suitable for the proposed application. The analytical sizing equations are quite efficient with a suitable level of accuracy for preliminary design. The optimal rotor pole width from the FEA results is nearly 1.3 times of the original one. The efficiency of the proposed machine under rated load is relatively low, nearly 85%, as a result of significant eddy current losses in the permanent magnets, which can be effectively suppressed by implementing segmentation. The predicted outstanding performance implies that by adopting magnet segmentation the proposed machine is a leading contender for direct electric vehicle drives. Research limitations/implications − The end effects, which could be considerable in the machine with relatively short axial length, are neglected during the study. In addition, due to the high current density and deep slot, proximity losses in the winding which is not issued in this research could be significant. All the limitations mentioned above could bring corresponding errors to the results. Although the research is concentrated on the application of electric vehicle drive, the techniques can be potentially employed for other applications. Practical implications − The practical implementation of such a machine is confronted with several mechanical hurdles, especially the thermal issues which can be addressed by implementing innovative cooling system. Originality/value − The outer-rotor permanent-magnet flux- switching machines so far have not been addressed yet. This research provides designers with the technical background and another alternative for electric vehicle
Open Access
Design and analysis of high-speed coreless axial flux permanent magnet generator with circular magnets and coils
(2010-11-29T00:00:00Z) Fei, Wei-Zhong; Luk, Patrick Chi-Kwong; Jinupun, Ken
A high-speed coreless surface mounted axial flux permanent magnet generator with circular magnets and coils is proposed and studied. The performances of the machine are estimated and optimised by approximate theoretical analysis and comprehensive three-dimensional (3D) electromagnetic finite element analysis (FEA). Mechanical stresses in the rotor disc developed at high rotational speed are analysed and evaluated by 3D mechanical FEA to ensure the rotor's integrity. Finally, a prototype machine is constructed and tested. Both the experimental and predicted results have shown that the proposed generator possesses distinct advantages such as simple structure and high efficiency. The prototype also demonstrates its utility as a very low-cost generator.
Open Access
Design and optimisation of electric drive system with high performance and low cost.
(2017-12) Wu, Demin; Luk, Patrick Chi-Kwong
As the main component in the global trend of electrification, the electric machine will experience growing demands in many applications such as industrial equipment, domestic appliances, electric vehicles and renewable energy systems. However, nowadays the majority of electric machines are induction machines, which are robust, low-cost, but with relatively low efficiency compared to PM motors, and they face challenges to meet the stringent efficiency mandatory standards. Synchronous machines with rare-earth permanent magnets are the most promising to improve efficiency and fulfil mandatory requirements, but the price of rare-earth materials is every high and volatile. The low-price and abundant ferrite magnet offers a promising solution for non-rare-earth permanent magnet synchronous machines to replace induction machines with similar material cost but higher efficiency. The ideas of high performance and low cost are not only limited on the machine body itself, but also include the considerations of its whole life cycle, such as motor design, motor manufacture, and motor controller. In the thesis, the particle swarm optimisation algorithm is applied in the ferrite IPM machine design, and with the help of VBScript programming language, a time-efficient electric machine design method is proposed to reduce substantially the designer’s designing time and hence the total cost of machine design. The design of experiment (DOE) assisted Six Sigma DMADV method is proposed for the quality control of the electric machine, and the motor quality is improved by realistic adjustment of the tolerances to minimise variations in output performance. The iron loss analysis considering the effects of press fitting stress, shrink fitting, and PWM harmonics results in accurate loss estimation and provides useful advice for implementation of vector control for high performance of the motor. To lower the controller cost, optimised speed and current sensing algorithms are developed based on low-cost Hall Effect speed feedback and single-shunt current sampling. Finally, a prototype machine is manufactured and extensive tests are undertaken to validate the proposed low cost and high performance motor technology.
Open Access
Design and optimization of switched-mode circuits for inductive links
(Cranfield University, 2014-01) Aldhaher, Samer; Luk, Patrick Chi-Kwong
Wireless power transfer (WPT) via magnetic induction is an emerging technology that is a result of the significant advancements in power electronics. Mobiles phones can now be charged wirelessly by placing them on a charging surface. Electric vehicles can charge their batteries while being parked over a certain charging spot. The possible applications of this technology are vast and the potential it has to revolutionise and change the way that we use today’s application is huge. Wireless power transfer via magnetic induction, also referred to as inductive power transfer (IPT), does not necessarily aim to replace the cable. It is intended to coexist and operate in conjunction with the cable. Although significant progress has been achieved, it is still far from reaching this aim since many obstacles and design challenges still need to be addressed. Low power efficiencies and limited transfer range are the two main issues for IPT. A tradeoff is usually associated with these two issues. Higher efficiencies are only achieved at very short transmission distances, whereas transferring large amounts of power at large distances is possible but at reduced efficiencies. This thesis addressed the limitations and design challenges in IPT systems such as low efficiency and short transmission range, in addition to poor power regulation and coil displacement and misalignment sensitivity. Novel circuit topologies and design solutions have developed for DC/AC inverters and DC/AC rectifiers that will allow for increased performance, higher efficiencies and reduced sensitivity to coil misalignments and displacements. This thesis contributes in four key areas towards IPT. Firstly, a detailed mathematical analysis has been performed on the electric circuit model of inductively coupled coils. This allows for better understanding on how power is distributed amongst the circuit’s elements. Equivalent circuit representations were presented to simplify the design process of IPT systems. Secondly, a review of the different classes and configurations of DC/AC inverters that can be used as primary coil drivers in IPT systems were presented. Class E DC/AC inverters were mathematically analysed in great detail and their performance as primary coil drivers in IPT systems was investigated. Thirdly, novel electronic tuning methods were presented to allow Class E primary coil drivers to operate at optimum switching conditions regardless of the distance between the coils of an IPT system and the value of the load. The saturable reactor was used as the electronic tunable element. Lastly, Class D and Class E AC/DC rectifiers have been used for the first time in IPT systems. Detailed mathematical analysis and extensive experimental results show their superior performance over the conventional half-wave and full-wave AC/DC rectifiers.
Open Access
Design and performance analysis of concentrated photovoltaic cooling.
(Cranfield University, 2023-01) Ibrahim, Khalifa Aliyu; Luk, Patrick Chi-Kwong; Kahagala Gamage, Upul
The use of solar energy as a global energy source has increased over the past two decades. Photovoltaic cells, which utilise the sun to generate electricity, are a promising alternative to fossil fuels that contribute to climate change. However, the high intensity of concentrated solar radiation can cause overheating in photovoltaic cells, reducing their efficiency and power output. Researchers worldwide are improving cooling in concentrated photovoltaic cells (CPV) to enhance temperature uniformity and improve power output. Previous studies have demonstrated that pulsating flow can effectively enhance heat transfer in various fields, including electronics, mechanical engineering, and medicine. In this research, three flow patterns (continuous flow, uniform pulsating flow, and bio-inspired pulsating flow) were studied in both simulation and experimental designs. Two cooling designs were considered: the conventional design (C- Design) and the parallel design with baffles (W-B) and without baffles (Wout-B). With the implementation of 30 pulses per minute bio-inspired pulsating flow a reduction of 1.96% in solar cell temperature was observed when compared to continuous flow. This reduction in temperature was consistently observed across a range of flow rates from 0.5 to 2.5 L/m, employing the parallel Wout-B design. Notably, the bio-inspired pulsating flow shows better performance in comparison to uniform pulsating flow, as well as the conventional designs with continuous flow and uniform pulsating flow, resulting in notable improvements in cooling efficiency of 1.22%, 2.14%, and 4.00%, respectively. In terms of a direct comparison, the implementation of uniform pulsating flow in the parallel Wout-B design exhibited a maximum cooling improvement of 0.74% when contrasted with continuous flow. Furthermore, when assessing uniform pulsating flow against the C-design with uniform pulsating flow in the parallel Wout-B design, a noteworthy enhancement of 0.93% was observed. Remarkably, the C-design with uniform pulsating flow demonstrated a superior effectiveness of 1.90% when compared to the C-design with continuous flow.
Open Access
Design challenge of high-speed high-power density motor for advanced electrical submersible pump
(IEEE, 2023-09-06) Luk, Patrick Chi-Kwong
Electrical Submersible Pumps (ESP) have been widely used in oil and gas extraction as a reliable and efficient method of artificial lift to enhance flow rate of oil and gas from a well. However, as the world shifts towards a less fossil-fuel based future, the role of ESP will need to evolve in order to continue to play an important role in the transitional period. One key challenge facing ESP technology is the increasing depth of exploitable oil reserves, with many new ones located at depths of 3km-4km. This implies the need for more advanced ESP technology that operates at high-speed and high-power density to generate additional artificial lift while keeping a compact and robust structure. These competing features demand a disciplined design methodology. This paper presents the electromagnetic design considerations of a 150kW permanent magnet (PM) motor driving an advanced centrifugal pump at 10,000rpm through a 90mm tubing. Three motor designs are undertaken, and their performances are compared. The results show all three designs meet the target specifications. However, the most optimal option will be dependent on its adaptability in integrating thermal management on the cable length and the operating voltage.
Open Access
Design issues of an IPM motor for EPS
(Emerald Group Publishing Limited, 2011-12-31T00:00:00Z) Wang, Can-Fei; Shen, Jian-Xin; Luk, Patrick Chi-Kwong; Fei, Wei-Zhong; Jin, Meng-Jia
In electric power steering (EPS), permanent magnet (PM) brushless ac (BLAC) motors offer distinct advantages over other electric motor types in terms torque smoothness, reliability and efficiency. The design procedure of an interior permanent magnet (IPM) motor used in EPS is presented in this paper. The requirements of the steering system are first introduced, and the machine's specifications are then derived. Critical issues which have considerable impacts on the machine's performance, such as operation mode, rotor structure and slot/ pole combination, are analyzed. Subsequently, a 12-slot/10-pole sinusoidally excited IPM machine with concentrated windings is proposed and optimized based on finite element analysis (FEA) modelling. The losses and efficiency are then computed. Performance predictions from the FEA results confirm all the requirements are met or exceeded. A prototype motor has been built for validation.
Open Access
Design of a multi-layer interior ferrite permanent magnet synchronous machine for traction applications
(IET, 2014-04-10) Xia, Bing; Fei, Wei-Zhong; Luk, Patrick Chi-Kwong; Wu, D
A novel design of interior ferrite permanent magnet synchronous machine with multi-layer configuration is proposed for traction applications. Although the ferrite magnet can be disadvantaged by its low residual flux density and energy product, it is proposed that flux-focusing and multi-layer configurations can be utilized to harness both permanent magnet (PM) torque and reluctance torque to recoup the loss of the PM torque due to its intrinsic property. The machines with up to three-layer magnets are presented and evaluated comprehensively. The results suggest that the two-layer machine provides the best performance among the three configurations. Furthermore, compared against a commercial rare-earth equivalent, the proposed ferrite machine is shown to have nearly the same torque with 32% less electromagnetic losses. The findings underpin interior ferrite permanent magnet synchronous machine as an attractive alternative for traction applications