Flux-switching Motor Research Articles

Optimization of the Thrust Ripple of a Tubular Flux-Switching Permanent Magnet Linear Motor

The effective optimization methods are needed to reduce the thrust ripple for the tubular flux-switching permanent magnet linear motor (TFSPMLM), which is significant for reducing the vibration, and improving the reliability. The auxiliary teeth and core bridge are set and analyzed for the bipolar and single-polar winding structures. On this basis, this paper focused on a new method of the secondary pole pitch fine-tuning which can overcomes the disadvantages of increasing the volume, decreasing the average thrust, adding the cost, and so on. The influences of tuning the secondary pole pitch on the average thrust and the thrust ripple for the different winding structure motors are calculated and analyzed. The conclusion can provide reference for the application of the method of tuning secondary pole pitch to the TFSPMLM for different background demands.

Modeling of Flux Switching Motor with Selection of Pole Arcs for Maximum Torque Production

Flux Switching Motors (FSM) are gradually emerging in recent years due to their inherent simplicity, rugged construction and low cost power converter. The main focus of this paper is to optimize the design of 8/4 pole FSM by varying its pole arcs for the production of maximum torque. The sensitivity of the pole arcs on the performance of the FSM is performed by cyclically varying the stator and rotor pole arcs. A comprehensive program based on Genetic Algorithm (GA) technique is developed in MATLAB to compute the torque and the results are presented. Further the performance of the machine with the optimal combination of pole arcs is modeled and analyzed using two dimensional transient Finite Element analyses (FEA) for the production of maximum torque. The effectiveness of the results obtained from GA is validated using FEA.

Back EMF Analysis of a Novel Linear Flux Switching Motor With Segmented Secondary

A novel linear flux switching motor (LFSM) with simple passive segmented secondary (SSLFSM) is presented in this paper. In this motor, the armature and field winding concentrated coils are wound around mover (primary) teeth alternatively. The structure of this linear motor is different from other types of LFSMs presented in previous research. All LFSMs are suffering from unbalanced back electromotive force (EMF) waveform. The same problem appears in SSLFSM. In this paper, the influence of secondary segments number on back EMF waveform of designed SSLFSM is derived analytically. It is found that the secondary segment numbers have a strong effect on generated back EMF waveform harmonic contents and phase balances. These effects are evaluated by finite-element analysis for different configurations of SSLFSM as well. With analytical and numerical evaluations, a suitable number of secondary segments for minimum harmonic contents and phase unbalances is obtained.

Analytical Modeling of Flux-Switching In-Wheel Motor Using Variable Magnetic Equivalent Circuits

Flux-switching motors (FSM) are competitive candidates for in-wheel traction systems. However, the analysis of FSMs presents difficulty due to their complex structure and heavy magnetic saturation. This paper presents a methodology to rapidly construct, adapt, and solve a variable magnetic equivalent circuit of 12-stator-slot 10-rotor-tooth (12/10) FSMs. Following this methodology, a global MEC model is constructed and used to investigate correlations between the radial dimensions and the open-circuit phase flux linkage of the 12/10 FSM. The constructed MEC model is validated with finite element analysis and thus proved to be able to assist designers with the preliminary design of flux-switching motors for different in-wheel traction systems.

Study on a Long Primary Flux-Switching Permanent Magnet Linear Motor for Electromagnetic Launch Systems

Based on the principle of rotational flux-switching permanent magnet machines, a novel double-sided long primary flux-switching permanent magnet linear motor (FSPMLM) is proposed for electromagnetic launch systems (EMLS). Compared with traditional induction and synchronous linear machines used in EMLS, the proposed motor is more suitable for EMLS because of its high thrust density and simple structure of the secondary. First, the structure and operation principle of the proposed FSPMLM are given and analyzed. Second, considering the longitudinal end effect, the thrust components are analyzed and derived. According to the generation principle of the thrust components, the optimal methods, implemented to reduce the thrust ripple, are obtained and analyzed. In addition, a 2-D transient finite element method is used to investigate the dynamic electromagnetic characteristics of the FSPMLM and the process of electromagnetic launch. Finally, a prototype of single-sided FSPMLM is employed to validate the thrust performance of the proposed machine.

Comparison of Complementary and Modular Linear Flux-Switching Motors With Different Mover and Stator Pole Pitch

Linear flux-switching permanent magnet (LFSPM) motors with both permanent magnets and armature windings on the short primary mover have attracted considerable attention due to their simple and cheap stator which only consists of iron. Hence, this kind of liner motor is very suitable for long stator applications such as in urban rail transportations. However, the conventional LFSPM motors directly split from rotary FSPM motor suffer from drawbacks such as unbalanced magnetic circuit of end coil, heavy mover, and bigger cogging force and force ripple. Modular LFSPM (MLFSPM) motors can mitigate the problem of unbalanced magnetic circuit of end coil. But some MLFSPM motors with different stator/mover pole pitch τs/τm=12/14, 12/10 don't have complementary phase armature windings, which will lead to asymmetrical and non-sinusoidal back-electromotive force, bigger cogging force and thrust force ripple. The key of this paper is to propose, investigate, and compare four complementary and modular structures for the LFSPM motors with different τs/τm . The electromagnetic performance and dimensions of the proposed complementary MLFSPM motors with different τs/τm are investigated, compared and confirmed by the means of finite element analysis and experimental results. Based on the analysis results, two complementary MLFSPM motors with τs/τm=12/13 are chosen to be the two best motors, which can offer the biggest thrust force, relatively smaller cogging force and thrust force ripple, and shorter mover length.

Design Optimization Studies on High Torque and High Power Density Hybrid Excitation Flux Switching Motor for HEV

Abstract This paper presents design optimization studies on high torque and high power density hybrid excitation flux switching motor (HEFSM) as a candidate for traction drives in hybrid electric vehicles (HEVs). Firstly, the construction and the basic working principle of the selected HEFSM are overviewed. Then, under some design restrictions and specifications for the target HEV drives, the initial performances of the selected HEFSM are evaluated based on 2D-FEA. As the initial motor fails to achieve the target performances, design parameters are set and treated by using deterministic optimization approach. After several cycles of iteration, the target torque and power of 333Nm and 123 kW respectively, are achieved with much higher power density when compared with existing interior permanent magnet synchronous motor (IPMSM) used in HEV.

Development of High Torque and High Power Density Hybrid Excitation Flux Switching Motor for Traction Drive in Hybrid Electric Vehicles

This paper presents design feasibility study and development of a new hybrid excitation flux switching motor (HEFSM) as a contender for traction drives in hybrid electric vehicles (HEVs). Initially, the motor general construction, the basic working principle and the design concept of the proposed HEFSM are outlined. Then, the initial drive performances of the proposed HEFSM are evaluated based on 2D-FEA, in which the design restrictions, specifications and target performances are similar with conventional interior permanent magnet synchronous motor (IPMSM) used in HEV. Since the initial results fail to achieve the target performances, deterministic design optimization approach is used to treat several design parameters. After several cycles of optimization, the proposed motor makes it possible to obtain the target torque and power of 333 Nm and 123 kW, respectively. In addition, due to definite advantage of robust rotor structure of HEFSM, rotor mechanical stress prediction at maximum speed of 12,400 r/min is much lower than the mechanical stress in conventional IPMSM. Finally, the maximum torque and power density of the final design HEFSM are approximately 11.41 Nm/kg and 5.55 kW/kg, respectively, which is 19.98% and 58.12% more than the torque and power density in existing IPMSM for Lexus RX400h.

Impact of Rotor Pole Number on the Characteristics of Outer-rotor Hybrid Excitation Flux Switching Motor for In-wheel Drive EV

This paper present the impact of rotor pole number on the characteristics of outer-rotor hybrid excitation flux switching motor (ORHEFSM) for in-wheel drive electric vehicle (EV) applications. In recent years, researches on in-wheel motor for EV drivetrain system become more popular due to their several advantages of independent wheel controllability and higher efficiency. In addition, it provides more cabin space caused by elimination of mechanical transmission gears as conventionally use in the most of existing EV with single motor propulsion system configuration. Moreover, the proposed motor has single piece of rotor making the motor more robust and suitable for high speed applications. Under some design restrictions and specifications, design principles and initial performances of the proposed motor at various rotor pole numbers with 12 stator slots are demonstrated. Initially, the coil arrangement tests are examined to confirm the operating principle and polarity of each armature coil phase of the proposed motor. Furthermore, the profile of flux linkage, induced voltage, cogging torque and torque characteristics at various field excitation current density conditions are analyzed based on 2D- finite element analysis (FEA). The results obtained show that the appropriate combination of stator slot-rotor pole configurations are 12S-10P which initially provide highest torque and power density. Thus, by further design refinement and optimization it is expected that the motor will successfully achieved the target performances.

Nonlinear Performance Characteristics of Flux-Switching PM Motors

Nonlinear performance characteristics of 3-phase flux-switching permanent magnet motors (FSPM) are overviewed. These machines show advantages of a robust rotor structure and a high energy density. Research on the FSPM is predominated by topics such as modeling and machine comparison, with little emphasis given on its performance and limits. Performance characteristics include phase flux linkage, phase torque, and phase inductance. In the paper, this analysis is done by a cross-correlation of rotor position and armature current. Due to the high amount of processed data, which cannot be handled analytically within an acceptable time period, a multistatic 2D finite element model (FEM) is used. For generalization, the most commonly discussed FSPM topology, 12/10 FSPM, is chosen. Limitations on the motor performance due to the saturation are discussed on each characteristic. Additionally, a focused overview is given on energy conversion loops anddq-axes identification for the FSPM.

Optimum Shape Design Solution of Flux Switching Motor Using Response Surface Methodology and New Type Winding

This paper deals with optimum design criteria for maximum torque density and minimum torque ripple of a flux switching motor (FSM) using response surface methodology (RSM) and finite element method (FEM). The focus of this paper is to find a design solution through the comparison of torque density and torque ripple according to rotor shape variations. Then, a new type winding method and optimum turns of armature/field winding are introduced, and numerical analysis and experiment are conducted to confirm the appropriate solution for the optimized model. The proposed procedure allows the definition of the optimum rotor dimensions and armature/field turns starting from an existing motor or a preliminary design.

An Axial-Flux Hybrid Excitation Flux-Switching Machine

A flux switching permanent magnet (FSPM) machine has the advantage of high power density, high torque density, inherently sinusoidal back EMF, stable structure, and the disadvantage of magnetic field uncontrollable. This paper proposes a novel axial-flux hybrid excitation flux-switching (AFHEFS) motor, which offers three phase symmetrical sinusoidal flux linkage and linearly regulated electromagnetic torque as well as excellent flux regulation capability and even field elimination ability with a size ratio of 1:2 between PM stator and electrical stator. The results are validated by 3D finite element (FE) analysis.

플럭스 스위칭 전동기의 고효율 드라이브에 대한 연구

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan and pump application because of green policy. This motor offers advantages of high-power density and relatively high efficiency compare with induction motor, low cost and simple motor structure compare with bldc motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Finally, test results of the prototype motor are provided to verify a validity of the fan application with TMS320F2812 DSP and inverter.

Optimum Design Criteria for Maximum Torque Density & Minimum Torque Ripple of Flux Switching Motor using RSM & FEM

This paper deals with optimum design criteria for maximum torque density & minimum torque ripple of Flux Switching Motor (FSM) using RSM & FEM. The focus of this paper is to find a design solution through the comparison of torque density and torque ripple according to rotor shape variations. And then, a central composite design(CCD) mixed resolution is introduced, and analysis of variance (ANOVA) is conducted to determine the significance of the fitted regression model.

A Novel Hybrid Excitation Flux-Switching Motor for Hybrid Vehicles

Flux-switching permanent magnet (FSPM) motor is a relatively novel brushless machine having magnets and concentrated windings in the stator instead of the conventional rotor-PM topology, which exhibits inherently sinusoidal PM flux-linkage, back-EMF waveforms and high torque capability. However, since the airgap field is produced by the stator-magnets alone, it is difficult to be regulated. Hence, a hybrid excitation method, i.e., by introducing a set of field windings into FSPM motor is employed. In this paper, a novel hybrid excitation flux-switching (HEFS) motor is proposed, in which the airgap field can be easily controlled and is favorable for hybrid vehicles. The preliminary topology, operation principle, design and static characteristics including phase flux-linkage, back-EMF waveforms under different excitations as well as cogging torque are evaluated based on finite element (FE) analysis. The results confirm the excellent field-regulation capability of a ldquoproof-of-principlerdquo HEFS motor.

A Study on a Flux Switching Motor Drive for Fan Application

A new class of electronically commutated brushless motors, the flux-switching motor (FSM), is gradually emerging for use in power tools and household appliances especially fan and pump application thanks to green policies. This motor offers such advantages as high-power density and relatively high efficiency compare to induction motors, and low cost and simple motor structure compare to the BLDC motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Test results of the prototype motor are provided to verify the validity of the fan application with a TMS320F2812 DSP and inverter.

선행각을 이용한 팬용 플럭스 스위칭 전동기 드라이브에 대한 연구

최근에는 파워툴(power tools)과 가전 제품에 있어서 전자적인 전류(commutation)를 사용하는 새로운 형태의 브러시리스 전동기인 플럭스 스위칭 전동기(Flux switching motor)에 대한 관심이 점차적으로 증가되고 있으며, 특히 팬과 펌프 시장에 있어서는 그린 정책으로 인하여 플럭스 스위칭 전동기에 대한 관심이 급격히 증가되고 있다. 플럭스 스위칭 전동기는 유도전동기에 비해서는 높은 전력 밀도(power density)와 상대적으로 높은 효율, 그리고 브러시리스 DC 전동기에 비해서는 간단한 전동기 구조와 가격 경쟁력이라는 장점을 가지고 있다. 따라서 본 논문에서는 팬 용도로 제작된 12/6 폴을 가지는 플럭스 스위칭 전동기의 드라이브 설계와 동작원리에 대해서 나타내고, 팬 용도로 제작된 프로토타입 플럭스 스위칭 전동기의 타당성을 검증하기 위해서 TMS320F2812 DSP와 일반적인 인버터를 이용한 실험 결과를 제시한다.

Flux-Switching Motors for Automotive Applications

This paper presents a new class of brushless motor as an alternative to the permanent-magnet brushed motor used in the automotive industry. The new flux-switching motor is a very simple motor to manufacture, and, coupled with a powerelectronic controller requiring only two power semiconductor switches, it has the potential to be extremely low cost in high volume applications. The design of the motor and its simulation using coupled circuit and time-stepping finite-element analysis is presented. Tested performance has matched well with design targets and with simulation and is delivering performance comparable to a permanent-magnet brushed motor. The new motor and drive are very robust, requiring only two power MOSFETs and a simple microcontroller to create an extremely low-cost variable-speed drive for automotive applications

Design of High-Power Density and Relatively High-Efficiency Flux-Switching Motor

A new class of electronically commutated brushless motor, namely, the flux-switching (FS) motor is gradually emerging in power tools and household appliances. This motor offers advantages of both high-power density and relatively high efficiency. There are a number of papers introducing this new class of motor. However, almost all of these papers focused on the analysis, and not the design, of the FS motor. Thus, this paper presents the design and analysis of the FS motor. Design equations are analytically derived for initial calculations of the main dimensions, number of turns, and inductances of the FS motor. Furthermore, a comprehensive time-stepping finite element (TSFE)-behavioral model is developed and utilized for detailed analysis and design refinements of a prototype 8/4-pole FS motor. Finally, test results of the prototype motor are provided to verify the design equations and efficacy of the design methodology.

Comparison of the acoustic noise of a flux-switching and a switched reluctance drive

This paper describes the results of a comparison between the acoustic noise produced by a two-phase switched reluctance drive and a flux switching motor and drive. For the comparison, two external rotor machines were constructed from identical mechanical parts, and the same lamination stacks. Test results show that there is over 2 dB less acoustic noise from the flux switching topology relative to the equivalent two-phase switched reluctance machine. Finite element analysis is used to calculate the radial force profiles of the two motors during normal rotation and it is shown that further analysis of this data provides supporting evidence to the measured data and confirms the experimental results. The improved acoustic noise and vibration characteristics, coupled with the dramatic simplification of the power converter offered by the flux switching drive makes it a very attractive, low cost, low acoustic noise, variable speed drive.