Outer-rotor Configuration Research Articles

Analysis of SPMSMs with Outer Rotor Configuration by Analytical Model and Finite Element Technique

Analysis of SPMSMs with Outer Rotor Configuration by Analytical Model and Finite Element Technique

Design and FEA analysis of hub based dual rotor machine for optimal energy generation in four wheeled electric vehicle application

This research article focuses on the design and Finite Element Analysis (FEA) analysis of a hub-based Dual Rotor Machine (DRM). Conventional, electric machines can perform either motoring or generating operations at an instant of time for electric vehicle (EV) applications. However, the proposed DRM can perform both motoring and generating modes of operation simultaneously. For this dual operation, a power rating of 15 kW Brushless DC Machine is selected with outer rotor configuration to achieve high starting torque in motoring operation and a power rating of 6 kW Permanent Magnet Synchronous Machine is considered for generating operation with an inner rotor. Based on theoretical results, the design of DRM is developed and analysed using FEA software programs such as MagNet, Jmag and ThermNet. By using a two-dimensional (2-D) transient solver, the proposed DRM performance is simulated and validated with cogging torque, electromagnetic, thermal and stress analysis. The performance of the proposed DRM model is also tested with drive cycle data of WLTP-II (Worldwide Harmonised Light Vehicle Test Procedure) in ANSYS Motor-CAD software. The simulation results confirm the proposed DRM can consume only 252 Wh over 405 Wh energy consumed by a single rotor machine and ensuring its applicability for EV applications.

Sizing of a Traction Switched Reluctance Motor for an Electric Refuse-Collecting Vehicle Application

Refuse-collecting vehicles are significant polluters due to their expected drive cycles involving frequent stops and long idle periods. Electric refuse-collecting vehicles, still in their infancy, promise to address this through the replacement of internal combustion engines with batteries and electric traction motors. Today, typical motors for these vehicles involve heavy use of rare earth permanent magnets, which are subject to high price volatility, environmentally damaging mining practices, and occupational health hazards associated with refinement. The switched reluctance motor, which makes use of no permanent magnets, is a suitable substitute. This type of motor technology offers several advantages such as simple and robust construction, the ability to operate at high speeds and high temperature conditions, fault tolerance capability, and lower production costs in comparison with other technologies. This paper focuses on the design process of a switched reluctance motor for a battery electric refuse-collecting vehicle. The designed motor has a 36/24 outer rotor configuration, and its electrical and mechanical characteristics are based on the commercial traction motor TM4 SUMO HD HV3500-9P. The performance of the motor is evaluated using simulation tools such as JMAG and MATLAB/Simulink.

Permanent Magnet Flux Switching Torque Performance Indicator

Flux switching machine (FSM) offer advantages such as rotor robustness and simple driving circuit compared to competing machine. This paper attempts to process the torque, volume and current information from 35 latest Permanent Magnet (PM) FSM publication into a standardized Torque Performance Indicator (TPI), which are torque density, torque constant, torque constant density and torque-magnet ratio. The distribution median shows that torque density, torque constant, torque constant density and torque-magnet ratio are 23.24kNm/m3, 0.43Nm/A, 0.616Nkm/Am3 and 30.79Nm/kg respectively. Among many design variation, outer rotor configuration produces good values as overall in the TPI. This information can be used to guide the machine designer to compare and compete based on the standardized TPI.

Design and Investigation of Outer Rotor Permanent Magnet Flux Switching Machine for Downhole Application

Permanent magnet flux switching machine (PMFSM) is a joint venture of switch reluctance machine (SRM) and permanent magnet synchronous machine (PMSM). It has become a prominent research topic for various applications because of robust rotor structure, high torque and power densities but few were developed for downhole applications mainly due to harsh environmental conditions. Formerly, most of developed PMFSMs for downhole applications were mainly concentrated on inner-rotor type design, and difficult to find research work on outer-rotor configuration. Therefore, this paper introduces the design and investigation of PMFSM with outer-rotor configuration for downhole application. Primarily, the geometric topology of proposed design is described in detail. Then, the no load and load analysis are implemented in order to investigate the initial performance of the proposed design.

Analysis of Permanent Magnet Demagnetization Effect Outer-rotor Hybrid Excitation Flux Switching Motor

This paper addresses the irreversible permanent magnet (PM) demagnetization analysis of hybrid excitation flux switching motor (HEFSM) with outer-rotor configuration. PM demagnetization cause the PM strength used in the motor significantly reduces and hence contributes less torque performance. The study is focused on thermal analysis and conducted at various temperature up to as high as 180 degrees Celsius which has a tendency to be demagnetized. Therefore, PM demagnetization is among a critical issue and influences the choice of the applied motor. The analysis is carried out based on finite element method (FEM) and percentage of PM demagnetization is then calculated. Finally, based on simulated and calculated results the final design outer-rotor HEFSM has only 0.85 percent PM demagnetization at very high temperature and obviously the is no PM demagnetization at normal operating conditions.

A new outer-rotor flux switching permanent magnet generator for wind farm applications

In this paper a 1.5 kW flux switching permanent magnet (FSPM) generator is presented for direct drive small scale wind turbine applications. For maximizing induced voltage and the output torque while minimizing cogging torque and unbalanced radial magnetic force (UMF), the proposed machine exhibits a new 6/19 stator pole/rotor teeth number and an outer rotor configuration. At first, in the paper an analytical design has been developed, then a finite element method (FEM) analysis is carried out for validating the analytical procedure and for design improvement. The simulation results extracted by FEM confirm the theoretical analysis procedure and help in the understanding of the performance analysis of the machine against the variations of the design variables. Furthermore, an experimental laboratory prototype of the proposed FSPM is implemented to confirm the analytical design and FEM modelling approaches. A comparison of induced voltage, torque, UMF and cogging torque produced by different FSPM configurations present in literature respect to the proposed generator has been developed. The results show the goodness of the adopted methodology and prove that, because of suitable electromagnetic performance of the proposed FSPM generator, it could be counted as a proper candidate for small scale wind turbine applications. Copyright © 2016 John Wiley & Sons, Ltd.

Performance Comparison of 12S-14P Inner and Outer Rotor Field Excitation Flux Switching Motor

Hybrid excitation flux switching machines (HEFSMs) have a several advantages such as robust rotor structure, high torque and power capabilities, and high efficiency suitable for light load and heavy industry applications. However, the general structure of HEFSMs employed with three main flux sources namely permanent magnet (PM), field excitation coil (FEC) and armature coil located on the stator body causes high manufacturing cost. Therefore, a new non-PM field excitation flux switching machine (FEFSM) consists of rugged rotor structure suitable for high-speed operation with capability to keep similar torque and power density of HEFSM is proposed and examined. In this paper, performances of both outer and inner rotor 12S-14P FEFSMs are analyzed and compared. As conclusion, the inner-rotor topology provides much higher torque and power when compared with outer rotor configuration.

A Novel Approach to the Design of Axial-Flux Switched-Reluctance Motors

This paper presents the design of a new axial-flux switched-reluctance motor (AFSRM) topology for in-wheel drive vehicle applications. The features of the topology include a short flux path and an outer-rotor configuration. The proposed topology also uses a sintered-lamellar soft magnetic composite core material, and permits displacement of the rotor along the suspension axis, which reduces damage to the stator caused by impacts and vibrations. The combination of these features makes this new topology competitive with other in-wheel motors in regard to torque density, durability, and cost. To describe the behaviour of the topology, a model of the topology is developed using a new integral inductance function. That model is used to select the design parameters of an 8/6 AFSRM, for which a fuzzy controller is also developed to control the phase current. Several simulations of the 8/6 AFSRM are performed to calculate its energy conversion efficiency, thermal performance, and torque density, and results indicate that the new AFSRM has a higher energy conversion efficiency, and can produce more torque/kg than other switched-reluctance motors used for in-wheel drive vehicle applications.

Analysis of a New Dual Excitation Flux Switching Machine with Outer-Rotor Configuration for Direct Drive EV

This paper presents the design improvement and analysis of dual excitation flux switching machine (DEFSM) with outer-rotor configuration for direct drive electric vehicle (EV). Deterministic design improvement approach based on two-dimensional (2-D) finite element analysis (FEA) is applied to obtain optimal torque density and power density of the proposed machine to meet the requirement of direct drive propulsion of EV. The performance comparison of the original design machine with the improved design machine is also addressed. The improved design machine has achieved 10.19 Nm/kg and 4.74 kW/kg of maximum torque density and maximum power density, respectively..

Genetic algorithm‐based output power optimisation of fault tolerant five‐phase brushless direct current drives applicable for electrical and hybrid electrical vehicles

This study presents a method to improve the output power of five-phase brushless direct current (BLDC) motors under different faulty conditions. Different machine connections are considered while having open-circuit fault in one and two stator phases, and both fundamental and third harmonic component of stator currents are controlled to improve the amplitude and quality of generated torque under faulty conditions. Rated root-mean-square value of stator phase currents is considered as the main limiting factor of generated electrical torque. Genetic algorithm is used in the optimisation procedure of stator reference currents to gain more output power under the fault. Automotive applications are kept in mind, and to verify the theoretical developments, experimental tests are conducted on a five-phase BLDC motor with in-wheel outer-rotor configuration.

Investigation of Torque Characteristics in a Novel Permanent Magnet Flux Switching Machine With an Outer-Rotor Configuration

This paper comprehensively investigates the torque characteristics of a novel permanent magnet flux switching (PMFS) machine with outer-rotor configuration. Due to the nature of severe magnetic saturations in the machine, it is of particular interest to ascertain the extent of impact of the load conditions on the overall torque output as well as its component parts. The frozen permeability techniques are implemented in finite element analysis (FEA) to segregate the output torque of the outer-rotor PMFS machine into three parts: cogging torque, reluctance torque, and permanent magnet torque. 2-D FEA is first employed to reveal the effects of phase current amplitudes and angles on those three torque components as well as the overall torque, while the 3-D FEA is carried out to further uncover the influences of end effects on the torque characteristics of the machine. Finally, experimental tests on a prototype machine are performed to validate the torque characteristic predictions by FEA.

A Novel Permanent-Magnet Flux Switching Machine With an Outer-Rotor Configuration for In-Wheel Light Traction Applications

This paper proposes a novel permanent-magnet (PM) flux switching (PMFS) machine with an outer-rotor configuration for in-wheel light traction applications. The geometric topology of the outer-rotor PMFS machine is introduced, and the analytical sizing equations are derived to determine the main design parameters of the machine. Two-dimensional finite-element analysis (FEA) models are developed to investigate and optimize the machine performance. Furthermore, the flux-weakening capability of the machine is analyzed and further improved by segmental PMs with iron bridges. The machine performance predictions by 2-D FEA models are validated by experimental tests on the prototype machine. The suitability of the proposed outer-rotor PMFS machine for in-wheel light traction application is demonstrated.

Torque And Force Distribution in the Superconducting Alternator

There is continuing world-wide interest in the superconducting machine; but many problems, both theoretical and practical, remain to be solved before a large superconducting alternator can be successfully designed. One of the major problem areas relates to the rotating screening system and it is now widely accepted that there will be two rotor screens to shield the superconducting field winding from armature-excited transient magnetic fields. The mechanical construction of these concentric rotating screens is complex and the knowledge of the types and magnitudes of the torques and forces which these shells have to withstand during the operation of the alternator under power-system conditions is essential at the design stage. In this paper torque and force distribution are examined for both fixed and free outer rotor configuration taking into consideration the mechanical stiffness between the turbine shaft and (i) the inner rotor and (ii), in the case of the former, the outer rotor. Detailed representation of the inertias and stiffnesses of the turbine shaft are not included. To see the effect of inertia and stiffness of the outer and the inner screens on the torques and forces, both these inertias and stiffnesses are varied over a reasonably wide range. Special attention is given to the peak torque experienced by the weaker member, the inner rotor screen. Damping and stability are studied with the help of a linearized model.

Torque and Force Distribution in the Superconducting Alternator

There is continuing world-wide interest in the superconducting machine; but many problems, both theoretical and practical, remain to be solved before a large superconducting alternator can be successfully designed. One of the major problem areas relates to the rotating screening system and it is now widely accepted that there will be two rotor screens to shield the superconducting field winding from armature-excited transient magnetic fields. The mechanical construction of these concentric rotating screens is complex and the knowledge of the types and magnitudes of the torques and forces which these shells have to withstand during the operation of the alternator under power-system conditions is essential at the design stage. In this paper torque and force distribution are examined for both fixed and free outer rotor configuration taking into consideration the mechanical stiffness between the turbine shaft and (i) the inner rotor and (ii), in the case of the former, the outer rotor. Detailed representation of the inertias and stiffnesses of the turbine shaft are not included. To see the effect of inertia and stiffness of the outer and the inner screens on the torques and forces, both these inertias and stiffnesses are varied over a reasonably wide range. Special attention is given to the peak torque experienced by the weaker member, the inner rotor screen. Damping and stability are studied with the help of a linearized model.

Transient and small perturbation behaviour of superconducting turbogenerators

An improved method is used capable of calculating any form of generator transients. In this method, based on a two-dimensional model, solid conducting parts of the rotor are represented by multiple thin conducting layers. The resulting non-linear differential equations are solved numerically for the recently proposed new rotor arrangement with independently rotatable (free) outer rotor. The results are compared with the previously accepted arrangement having rigid connection of outer to inner rotor showing that the free outer rotor arrangement greatly relieves the inner rotor of transient torques and that its steady-state stability, although inferior to the rigidly fixed outer rotor configuration, is nevertheless quite adequate: it compares very favourable with that of the conventional generator, being markedly superior on underexited operation.