Hybrid Excitation Flux Switching Research Articles

Design and Hierarchical Coordinated Optimization of an Outer-Rotor Hybrid-Excitation Flux-Switching Machine for In-Wheel Driving Applications

Design and Hierarchical Coordinated Optimization of an Outer-Rotor Hybrid-Excitation Flux-Switching Machine for In-Wheel Driving Applications

Design and Many-Objective Optimization of an In-Wheel Hybrid-Excitation Flux-Switching Machine Based on the Kriging Model

Design and Many-Objective Optimization of an In-Wheel Hybrid-Excitation Flux-Switching Machine Based on the Kriging Model

Electromagnetic-Thermal Analysis of a Hybrid-Excited Flux Switching Permanent Magnet Generator for Wind Turbine Application

An accurate thermal analysis needs to be performed on the machines with new structures to ensure that their electromagnetic performance is not negatively affected. In this regard, this paper details an investigation into the electromagnetic-thermal analysis of an outer rotor hybrid-excited flux switching permanent magnet generator that gains from ferrite PMs in stator yoke and neodymium PMs in rotor segments. Incorporating ferrite PMs and barriers in the stator core enhances the power density of the proposed generator compared to the basic topology. Also, the temperature of the stator and windings of the HEFSG decreases due to the presence of barriers. As a result, the HEFSG can be a potential candidate for DDWT applications. In this study, the thermal modeling started with a 3-D FEM electromagnetic analysis to calculate the losses as heat sources. Afterward, an accurate thermal network was plotted to elucidate the thermal behaviors between various parts of the generator, where the heat sources, heat transfer coefficients, thermal resistances, and heat capacitances form the thermal characteristics of the network, which was then followed by the 3-D FEM thermal analysis. Finally, the experimental test results from the prototyped generator confirmed the accuracy of the simulation results.

Performance analysis of modular mover hybrid excited flux switching linear machine

Performance analysis of modular mover hybrid excited flux switching linear machine

Design and Thermal Analysis of Linear Hybrid Excited Flux Switching Machine Using Ferrite Magnets

This paper presents a novel linear hybrid excited flux switching permanent magnet machine (LHEFSPMM) with a crooked tooth modular stator. Conventional stators are made up of a pure iron core, which results in high manufacturing costs and increased iron core losses. Using a modular stator lowers the iron volume by up to 18% compared to a conventional stator, which minimizes the core losses and reduces the machine’s overall cost. A crooked angle is introduced to improve the flux linkage between the stator pole and the mover slot. Ferrite magnets are used with parallel magnetization to reduce the cost of the machine. Two-dimensional FEA is performed to analyze and evaluate various performance parameters of the proposed machine. Geometric optimization is used to optimize the split ratio (S.R) and winding slot area (Slotarea). Genetic algorithm (GA) is applied and is used to optimize stator tooth width (STW), space between the modules (SS), crooked angle (α), and starting angle (θ). The proposed model has a high thrust density (306.61 kN/m3), lower detent force (8.4 N), and a simpler design with higher efficiency (86%). The linear modular structure makes it a good candidate for railway transportation and electric trains. Thermal analysis of the machine is performed by FEA and then the results are validated by an LPMEC model. Overall, a very good agreement is observed between both the analyses, and relative percentage error of less than 3% is achieved, which is considerable since the FEA is in 3D while 2D temperature flow is considered in the LPMEC model.

Multi-Objective Design Optimization of a Hybrid Excitation Flux Switching Permanent Magnet Motor Based on Design Sensitivity Analysis

The hybrid excitation flux switching permanent magnet (HEFSPM) motor with magneticbridge is a topology of hybrid excitation flux-switching PM machines. Despite its excellent performancesuch as high torque/ power density, high flux enhancing/ weakening capability and so on, it has receivedless attention due to its complicated structure. Therefore, its optimal design and performance all need tobe further investigated. This paper presents an optimal design of a HEFSPM motor with magnetic bridge.At first, the machine structure and basic working principle are discussed briefly. Then, a design sensitivityanalysis for geometric optimization is carried out to improve the motor performance. This optimizedmotor is compared with initial design. Finally, a prototype of the optimized proposed motor is built andtested to validate the simulation results.

Subdomain modeling of linear hybrid excited flux switching machine

PurposeThis paper aims to develop an analytical approach to validate the finite element analysis (FEA) results. FEA itself is a powerful tool to evaluate the performance of electrical machines but takes more time and requires more drive storage. To overcome this issue, subdomain modeling (SDM) is used for the proposed machine.Design/methodology/approachSDM is developed to validate the electromagnetic performance of a new linear hybrid excited flux switching machine (LHEFSM) with ferrite magnets. In SDM, the problem is divided into different physical regions called subdomains. Maxwell's governing equation is solved analytically for each region, where the magnetic flux density (MFD) is generated. From the generated MFD, x and y components are calculated, which are then used to find the useful force along the x-axis.FindingsFEA validates the developed SDM via JMAG v. 20.1. The results obtained show excellent agreement with an accuracy of 95.13%.Practical implicationsThe proposed LHEFSM is developed for long stroke applications like electric trains.Originality/valueThe proposed LHEFSM uses low-cost ferrite magnets with DC excitation, which offers better flux regulation capability with improved electromagnetic performance. Moreover, the developed SDM reduces drive storage and computational time by modeling different parts of the machine.

Analysis of Linear Hybrid Excited Flux Switching Machines with Low-Cost Ferrite Magnets

Linear hybrid excited flux switching machines (LHEFSM) combine the features of permanent magnet flux switching machines (PMFSM) and field excited flux switching machines (FEFSM). Because of the widespread usage of rare-earth PM materials, their costs are steadily rising. This study proposes an LHEFSM, a dual stator LHEFSM (DSLHEFSM), and a dual mover LHEFSM (DMLHEFSM) to solve this issue. The employment of ferrite magnets rather than rare-earth PM in these suggested designs is significant. Compared to traditional designs, the proposed designs feature greater thrust force, power density, reduced normal force, and a 25% decrease in PM volume. A yokeless primary structure was used in a DSLHEFSM to minimize the volume of the mover, increasing the thrust force density. In DMLHELFSM, on the other hand, a yokeless secondary structure was used to lower the secondary volume and the machine’s total cost. Single variable optimization was used to optimize all of the proposed designs. By completing a 3D study, the electromagnetic performances acquired from the 2D analysis were confirmed. Compared to conventional designs, the average thrust force in LHEFSM, DSLHEFSM, and DMLHEFSM was enhanced by 15%, 16.8%, and 15.6%, respectively. Overall, the presented machines had a high thrust force density, a high-power density, a high no-load electromotive force, and a low normal force, allowing them to be used in long-stroke applications.

Design and lumped parameter magnetic network model of hybrid excited consequent pole flux switching machine

PurposeThe purpose of this paper is to analyze electromagnetic performance and develop an analytical approach to find the suitable coil combination and no-load flux linkage of the proposed hybrid excited consequent pole flux switching machine (HECPFSM) while minimizing the drive storage and computational time which is the main problem in finite element analysis (FEA) tools.Design/methodology/approachFirst, a new HECPFSM based on conventional consequent pole flux switching permanent machine (FSPM) is proposed, and lumped parameter magnetic network model (LPMNM) is developed for the initial analysis like coil combination and no-load flux linkage. In LPMNM, all the parts of one-third machine are modeled which helps in reduction of drive storage, computational complexity and computational time without affecting the accuracy. Second, self and mutual inductance are calculated in the stator, and dq-axis inductance is calculated using park transformation in the rotor of the proposed machine. Furthermore, on-load performance analysis, like average torque, torque density and efficiency, is done by FEA.FindingsThe developed LPMNM is validated by FEA via JMAG v. 19.1. The results obtained show good agreement with an accuracy of 96.89%.Practical implicationsThe proposed HECPFSM is developed for high-speed brushless AC applications like electric vehicle (EV)/hybrid electric vehicle (HEV).Originality/valueThe proposed HECPFSM offers better flux regulation capability with enhanced electromagnetic performance as compared to conventional consequent pole FSPM. Moreover, the developed LPMNM reduces drive storage and computational time by modeling one-third of the machine.

Analysis of a Discrete Stator Hybrid Excited Flux Switching Linear Machine

A discrete stator hybrid excited flux switching linear machine (DSHEFSLM) is proposed in this paper. The proposed DSHEFSLM uses a discrete stator to reduce the iron loss and overall cost of the machine. Assistant teeth are used at both ends of the mover to overcome the unbalance in the three phases, which is a global issue in linear machines. Field excitation (FE) is used, which adds field regulation capability to the proposed machine and makes it suitable for a wide speed operation range. A magnetic equivalent circuit model is used to find the suitable coil combination and no-load flux linkage. The multiobjective genetic global optimization is used to optimize the design parameters of the whole machine while keeping the slot area, electric and magnetic loadings constant. A correlation table is drawn to show the impact of different design parameters on average thrust force. The optimization has increased the peak-to-peak flux linkage by 11%, average thrust force by 34.60%, thrust force density by 34.60%, decreased thrust force ripples, and detent force by 21.05% and 8.58% respectively. The proposed machine has reduced the volume of the permanent magnet by 39.18% and offers 28.09% higher average thrust force and thrust force density compared to the flux switching permanent magnet machine proposed in the literature.

Performance Analysis of a Modular E-Shaped Stator Hybrid Excited Flux Switching Motor With Flux Gaps

This paper proposes a new modular hybrid excited flux switching motor (MHEFSM) with flux gaps, adding the fault-tolerant capability to the proposed motor. The proposed motor uses an E-Shaped stator, as the middle teeth of E-core produce fault-tolerant capability, and in C-core, this capability is eradicated. The no-load flux linkage is calculated by the magnetic network model (MNM) to reduce time and disk storage. The drawback of the constant flux linkage of PM motors is overcome by employing field excitation (FE). The FE helps in regulation flux at higher speeds. The motor leading geometry variables are optimized by using Genetic Global Optimization (GGO). The GGO helped in refining the structure of the motor and has improved the flux linkage by 68.18%, average torque and torque density by 62.35% each, reduced torque ripples by 20.62%, and cogging torque by 18.52%. The volume of permanent magnet (PM) in the proposed MHEFSM is reduced by 36.24%, and 48.49% higher average torque and torque density is obtained compared to the state of art motor proposed in the literature. Furthermore, a 3D analysis of the proposed MHEFSM is done to further evaluate the electromagnetic performance.

Design and Realization of a Hybrid Excited Flux Switching Vernier Machine for Renewable Energy Conversion

This paper presents the design of a hybrid excited flux switching Vernier machine. This machine is designed to serve in renewable energy conversion applications, such as a wind turbine generator, or tidal turbine generator. After introducing this original structure, a design based on finite element models is conducted. The specifications correspond to relatively low power direct drive wind or tidal turbine applications. The rated power is set to 10 kW, with a rated speed of 300 rpm. Mainly the electromagnetic design is presented. Aspects related to the realization of a prototype are also presented, and an experimental study is included.

Analysis and optimization of a five-phase hybrid excitation flux switching machine based on the consistency and complementarity principle

In this study, the general optimal stator poles/rotor teeth (P/T) combination equation of the E-core hybrid excitation flux switching (HEFS) machines are introduced, and a new HEFS machine is proposed and optimized. Firstly, the influences of three different P/T combinations (10/18, 10/19, and 10/21) on the HEFS machines are investigated with two-dimensional (2D) finite element analyses (2D-FEA). Meanwhile, the consistency and complementarity principle of the armature windings is analyzed in detail to give reasonable explanations to the simulated results. The general optimal P/T combination equation of the E-core HEFS machines is deduced mathematically to provide an effective guidance on the selection of P/T combinations. The optimal P/T combination calculated by the general equation agrees with the simulated results which confirm the correctness of the mathematical inferences. Finally, the optimizations on the proposed HEFS machine are implemented to obtain higher output torque and better flux-regulation ratio characteristics based on which the cogging torque and torque ripple are reduced significantly.

Comparative Study on Hybrid Excitation Flux Switching Motors without and with Variably Magnetizable Permanent Magnets for Electrified Vehicle Propulsion

A demand for high efficiency traction motors has been accelerated by the promotion of electrified vehicles, such as battery and fuel cell electric vehicles. As a part of development of the high efficiency traction motor, this paper reports a comparative study on two kinds of hybrid excitation flux switching motors (HEFSM) as a variable flux machine. One is the conventional HEFSM, which consists of a stator with constantly magnetized-permanent magnets, field excitation coils (FECs) and three-phase armature windings, and a rotor with salient poles like a switched reluctance motor. The other is a HEFSM employing variably magnetizable-permanent magnets (VM-PMs) that replace a part in the FEC slot area in the conventional one. Based on the variable magnetization nature of VM-PMs, the latter HEFSM promises that the replacement of magnetomotive force (mmf) of FECs with that of the VM-PMs makes the motor efficiency better at both low- and high-speed under the low-torque condition, that is, at both urban driving or highway cruising. To verify that, finite element analysis- (FEA)-based design simulations, as well as experimental performance evaluations for the two kinds of HEFSM, were conducted under reasonable dimensional and electrical constraints. As a result, it is shown that the latter HEFSM can achieve higher motor efficiency at the low-torque and high-speed region while keeping the motor efficiency at the low-torque and low-speed region.

Design and optimization of segmented PM consequent pole hybrid excited flux switching machine for EV/HEV application

Hybrid Excited Flux Switching Machines (HEFSMs) unique feature of high torque density (T den ) of Permanent Magnet (PM) machines and flux regulation capability of wound field excitation machines. Due to aforesaid unique features, stator active HEFSMs are preferred for EV/HEV applications. In this paper a new Segmented PM Consequent Pole HE-FSM (sPMCPHEFSM) with flux bridge is proposed for EV/HEV. The developed SPMCPHEFSM exhibits improved flux modulation and flux regulation capability at reduced PM usage (suppressed PM volume by 46.52% and PM cost by 46.48%) and eliminating stator leakage flux. First, SPMCPHEFSM is geometric optimized (GO) for investigating influence of leading design with key performance indicators such as flux linkage (Φ pp ), average torque (T avg ), cogging torque (T cog ), T den , average power (P avg ) and power density (P den ) and then proceeded optimized model to structure modification for optimal stator design and position of field excitation coils (FEC). Comprehensive performance analysis reveals that the developed SPMCPHEFSM show improved Φ pp maximum up to 9.11%, improved T avg maximum up to 23.63%, truncate T cog up to 18.9% whereas T den and P den are boost up to 23.55% and 89.72% respectively.

Flux-Regulation Principle and Performance Analysis of a Novel Axial Partitioned Stator Hybrid-Excitation Flux-Switching Machine Using Parallel Magnetic Circuit

This article proposes a novel hybrid-excitation flux-switching (HEFS) machine with axial partitioned stator (APS) arrangement, which can achieve the independent accommodation of armature winding and field-excitation winding, thus enhancing the field-excitation capability and improving the winding heat dissipation. More importantly, a particular parallel-magnetic-circuit hybrid-excitation pattern consisting of the axial and radial magnetic paths is innovatively developed in the HEFS machine, which is an effective solution for improving the flux-regulation ability. Consequently, the PMC-based flux-regulation principle is comprehensively illustrated. Moreover, by investigating the flux-regulation characteristics of three structural feasible APS-HEFS topologies, the bilateral complementary structure is finally determined as the preferred option. By using the multiobjective optimization method and the three-dimensional finite-element analysis (FEA), the dimensional parameter optimization design of the proposed machine is conducted, and the performance comparison with conventional HEFS counterparts is also carried out to prove the flux-regulation superiority of the proposed design. Finally, a prototype is fabricated for experimental testing, and the measured results are in good agreement with the FEA, which verifies the validity of the proposed APS-HEFS topology and its theoretical flux-regulation principle analysis.

An On-Board Two-Stage Integrated Fast Battery Charger for EVs Based on a Five-Phase Hybrid-Excitation Flux-Switching Machine

In this article, to solve the existing problems in general on-board integrated chargers, a novel three-phase on-board two-stage integrated charger is proposed by taking the unique advantages of a five-phase hybrid-excitation flux-switching (HEFS) motor. The general topologies and newly presented integrated chargers are reviewed first, and existing problems are concluded. Then, a two-stage integrated charger is proposed, and all winding selections are thoroughly investigated by theoretical analysis, finite-element analysis (FEA), and experiments. In the proposed topology, the existing problems are all solved by employing this multiphase system, reasonable winding selection, and reconfiguring the field winding. After that, a current balance control method for charge mode without a phase-locked loop circuit is presented. The simulation results verify the effectiveness of the proposed control methods. Finally, based on a 5-kW five-phase HEFS prototype machine and two sets of the three-phase generic motor controller, an experiment platform is built. The experiment results agree well with the simulation results. Therefore, the feasibility of a two-stage integrated on-board charger that can operate at any voltage level is confirmed, where only the hybrid-exciting machine and its driving system are used without any additional power devices.

A Single-Phase On-Board Two-Stage Integrated Battery Charger for EVs Based on a Five-Phase Hybrid-Excitation Flux-Switching Machine

In this paper, to solve the existing problems in general on-board integrated chargers (IC), a novel single-phase on-board two-stage integrated charger is proposed by taking the unique advantages of the five-phase hybrid-excitation flux-switching (HEFS) motors. The general topologies and newly presented ICs are reviewed firstly, and three main problems are concluded. Then, the proposed two-stage IC is presented, and all winding selections are thoroughly investigated by theoretical analysis, finite-element analysis (FEA) and experiments. In the proposed topology, the existing problems are all solved by employing this multi-phase system, making the reasonable winding selection, and reconfiguring the field winding. After that, a control method for charge mode and two current balance control methods are developed. The simulation results verify the effectiveness of the proposed control methods. Finally, based on a 5-kW five-phase HEFS prototype machine and two sets of the 3-phase generic motor controller, an experiment platform is built. The experiment results agree well with the simulation results. Therefore, the feasibility of a two-stage integrated on-board charger that can operate at any voltage level is confirmed, where only the hybrid-exciting machine and its own driving system are used without any additional power devices.

Design and performance analysis of various high torque segmented rotor HE‐FSM topologies for aircraft applications

Electrical machines for aircraft applications require basic characteristics such as lightweight, high reliability, fault tolerance ability, and torque power and higher densities. Correspondingly, hybrid excitation flux switching machines (HE-FSMs) are capable of producing significant characteristics of high torque and power by improving flux strengthening in the iron core. However, magnetic flux cancellation and leakage in HE-FSMs cause the reduction of flux linkage created by permanent magnet (PM) and field excitation (FE), which leads to deterioration of electromagnetic torque. This study presents magnetic flux performance and comparison of various topologies of HE-FSMs by employing different positions of PMs and FE coils on the stator core. The purpose of a segmented rotor is to deliver a well-defined electromagnetic flux pathway for carrying magnetic flux to nearby armature coil on stator with rotor rotation to improve the flux strengthening. Moreover, magnetic performances of various proposed HE-FSMs at different positions of PMs are investigated and compared based on 2D finite element analysis. Subsequently, the enhanced HE-FSM III has successfully achieved flux strengthening of 22%, torque of 54% and power of 61% more than initial design of HE FSM I, respectively. In conclusion, the proposed HE-FSM structures show the capability to match high torque and power for aircraft applications.

Hybrid excitation flux switching motor with permanent magnet placed at middle of field coil slots and high filling factor windings

Design and experimental studies on a hybrid excitation flux switching motor as a traction motor for hybrid electric vehicles drive are presented. A stator body of the motor consists of not only laminated silicon-iron electromagnetic steel and three-phase armature windings, but also both of field excitation coils and permanent magnets working together as a variable field magnetomotive force source. On the other hand, a rotor is composed of just laminated silicon-iron electromagnetic steel with salient poles like switched reluctance motor. To bring out the best in drive performances of the hybrid excitation flux switching motor as a variable flux motor for the application, each material adopted for the stator and rotor body should be designed properly in terms of motor efficiency, maximum torque and power densities and so forth. As some of them, in this paper, thinner silicon-iron electromagnetic steel sheet and permanent magnets with high remanent and low amount of Dysprosium used are applied for achieving higher motor efficiency. Moreover, all coils wound flatwise and edgewise using rectangular wires are introduced to realizing high filling factor for reduced copper losses. Experimental tests using a 60kW prototype of the motor demonstrates the designed motor has good motor efficiency under frequent operating points expected for the target vehicle drive.