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Two-blade vertical axis wind turbines (VAWTs) are well-known for their pronounced torque ripples. Left unattended, the torque ripples not only cause significant adverse mechanical effects on the drive train components, but also worsen the quality of the output power of the wind generator and the associated power converters. Moreover, the resulted power fluctuations will propagate through the distribution...
This paper presents the analysis and design of the integral cycle converter (ICC) to be used as a local point of load converter in a high frequency distributed power system. In particular, a model for the ICC is developed to investigate the degree of distortion of the input current drawn from the bus, and to study the synthesized output voltage as a function of switching sequence. An intuitive method...
In high frequency AC distributed power systems, the integral cycle converter (ICC) can efficiently synthesize low frequency AC or DC output from the high frequency link by means of soft switching. However for the ICC to operate as a local power module supplying the load, the synthesized voltage will need to be filtered to extract only the desired low frequency component. The presence of a filter network...
Torque ripple is the parasitic element that causes mechanical vibration, acoustic noise and even latent operational failure in permanent magnet (PM) machines. Consequently, considerable design efforts should be made to minimize torque ripple of the machines for high performance applications. In this paper, one cost effective torque ripple reduction technique is proposed and investigated for an axial...
In direct-drive electric propulsion systems, where there is no reduction gear to minimize and absorb the adverse effects due to cogging torque generated by the permanent magnet (PM) machine, minimization of cogging torque generation is of particular importance. In this paper, a novel axial magnet pole pairing method is proposed to minimize cogging torque generation in a special three-phase outer-rotor...
High frequency AC (HFAC) distributed power systems (DSP) have some distinct characteristics that offer specific benefits over existing DC distribution systems. Whilst some of the advantages of HFAC systems have been widely discussed in literature, there appears no systematic and quantitative study on the evaluation of these benefits. This paper proposes a systematic framework to facilitate quantitative...
Air-cored, axial flux permanent-magnet (AFPM) machines have magnetic and mechanical characteristics considered to be ideal for compact high speed electric power generation applications. To date, research on high speed AFPM machines is primarily from a mechanical perspective, with emphasis on higher power level applications such as in hybrid vehicles. Recently, there has been an increasing interest...
A novel twelve-stator-pole, twenty-two-rotor-pole (12/22) outer-rotor permanent-magnet flux-switching (PMFS) machine for electric propulsion in a lightweight electric vehicle is presented. Analytical equations are derived for the dimensioning of a 3-phase 5kW in-wheel motor. Optimisation techniques are employed to maximise the performance of the machine. The validity of the analytical equations is...
Cogging torque is a parasitic element that causes mechanical vibration, noise and undesirable starting effects in permanent magnet (PM) machines. Significant design efforts, therefore, are made to minimize cogging torque in high performance PM machines. In this paper, several cost effective displacement techniques are proposed for the design of axial-flux surface-mounted permanent-magnet (AFSMPM)...
This paper concerns the design and analysis of a 1 kW high speed air-cored surface mounted axial flux permanent magnet (AFPM) synchronous machine intended to be used in a man- portable power platform. With a double rotor and a slot-less stator structure, the machine is designed with a maximum speed of 50,000 rpm. Both analytical equations and three dimensional (3-D) electromagnetic finite element...
Research in power and energy management of multiple energy systems within electric vehicle (EV) architectures has been undertaken exclusively with scientific methodologies, with varying focuses and degree of success. However, the narrowing vision of scientific quest means other bodies of knowledge like management and economics are being largely ignored in this intriguing multi-discipline of power...
A direct torque control (DTC) based on a high frequency AC (HFAC) power converter is proposed. The scheme exploits the recent advances in soft switching and pulse density modulation (PDM). The proposed HFAC-DTC scheme demonstrates the potentials of superior performance over conventional DTC schemes, at no extra system complexity or software overhead. Significant reductions in flux and torque ripples,...
This paper introduces a novel in-wheel switched reluctance motor (SRM) with high power density and torque density. The main feature of motor is a special stator-rotor-stator structure that results in substantial reduction of iron usage for a given power output, when compared with conventional SRM and other motor types. Other benefits of this special structure, such as zero net radial force on the...
This paper presents a modular approach to the design and implementation of a power and energy management system (PEMS) for electric vehicles (EV). The model EV is powered by dual energy sources, consisting of batteries and ultracapacitors. Operation of the PEMS has been structured into modular hierarchical process shells. The energy management shell (EMS) handles the longer-term decisions of energy...
This paper offers a new design-oriented approach to address implementation issues associated with a power and energy management policy for an electric vehicle (EV) powered by a dual-sourced system. A special sequential decision process, which determines the power split ratio and reference energy levels of the dual battery-ultracapacitor sources, has been formulated as a state transition mechanism...
An alternative motor technology for electric drive-trains, in particular in use as an in-wheel drive, is presented. The technology is based on a simple double concentric stator structure with a 'yokeless' rotor, which enables the motor to develop constant power with an extended range much closer to zero speed. A distinct feature of the new motor, which is based on switched reluctance, rests on an...
Initial position is one of the key points in the permanent magnet synchronous machine (PMSM) senseless control. This paper presents a neural network method with currents difference as its inputs and the rotor position angle as its outputs. 256 different 100mus-width voltage vector pulse pairs injects into stator before position calculation. The voltage vector direction distributes symmetrically around...
An alternative motor technology for electric drive-trains, in particular in use as an in-wheel drive, is presented. The technology is based on a simple double concentric stator structure with a 'yokeless' rotor, which enables the motor to develop constant power with an extended range much closer to zero speed. A distinct feature of the new motor, which is based on switched reluctance, rests on an...
This paper offers a new design-oriented approach to address implementation issues associated with a power and energy management policy for an electric vehicle (EV) powered by a dual-sourced system. A special sequential decision process, which determines the power split ratio and reference energy levels of the dual battery-ultracapacitor sources, has been formulated as a state transition mechanism...
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