Axial Flux Permanent Magnet Synchronous Motor Research Articles

An Improved Two-Dimensional Simplification Calculation Method for Axial Flux Permanent Magnet Synchronous Motor

The axial flux permanent magnet synchronous motor (APMSM) has the advantages of short axial size, high efficiency, and high power density. However, the three-dimensional magnetic circuit structure of this type of motor results in a longer calculation time, which is not conducive to rapid design and optimization. In order to quickly and accurately complete the preliminary calculation and optimization of axial flux permanent magnet synchronous motors, this paper proposes an improved equivalent calculation method for two-dimensional multi-layer linear motors. This method is based on the traditional two-dimensional multi-layer linear motor equivalent method, taking into account the complexity of geometric model establishment and simulation condition settings and applying the principle of analogy to achieve significant simplification of geometric modeling and simulation settings. The article elaborates on the correlation and differences between the proposed method and existing methods and verifies the calculation accuracy through finite element calculation. The results indicate that the improved two-dimensional multi-layer linear motor equivalent calculation method proposed in this article can significantly reduce calculation time while ensuring calculation accuracy and has good application prospects in preliminary design and parameter optimization processes.

Analysis of a High-Speed Axial Flux Permanent Magnet Synchronous Motor With Cost-Effective Hybrid Magnets

This paper proposes a novel high-speed axial flux permanent magnet synchronous motor (AFPMSM) with hybrid permanent magnets (PMs) to reduce the magnet cost. Based on basic AFPMSM with sinusoidal NdFeB PMs, the proposed model is designed with an equal quantity of ferrite and NdFeB PMs, wherein the hybrid PMs are divided into parallel and vertical to the magnetization direction of the PM. Furthermore, three kinds of hybrid PM arrangements are adopted for the AFPMSM and the relative analysis of the magnetic circuits is carried out. Then the no-load, load electromagnetic performance and torque cost of the AFPMSMs with three PM arrangements are simulated and compared by the finite element method (FEM). Finally, the demagnetization and stress analysis are performed to verify the stability of the AFPMSM with hybrid PM arrangements.

Torque Control of an In-Wheel Axial Flux Permanent Magnet Synchronous Motor using a Fuzzy Logic Controller for Electric Vehicles

This paper presents the control design of an in-wheel axial-flux permanent magnet synchronous motor with one stator and one rotor, using a fuzzy logic controller for electric vehicles. In this controller, the surgeon ambiguous inference file is built by two input vectors, the stator current error and the derivative of the stator error. These input variables include five membership functions: Negative Big (NB), Negative Small (NS), Equal Zero (ZE), Positive Small (PS), and Positive Big (PB). The fuzzy logic controller was implemented using a 5×5 matrix to meet the required output stator voltage of the controller. The fuzzy logic torque controller was compared with the PI controller in stator current response, torque, and speed. The proposed controller was evaluated using simulation results from MATLAB/SIMULINK.

Thermal Analysis and Test of Axial Flux Permanent Magnet Synchronous Motor Performances

The axial flux permanent-magnet synchronous motor with amorphous alloy stators has the advantages of high power density, high efficiency, large starting torque. But the PMSM has poor performance in heat resistant and radiation. And the electromagnetic loss has a significant impact on in-wheel motor’s heat generation. To demonstrate the influence of electromagnetic loss on winding coils of the PMSM, the mathematical model of the thermal transformation was founded to illustrate the progress of temperature rising. The mathematical model and experimental test were verified mutually. The experimental prototype was manufactured and tested, including the output power model and braking energy recovery model. And the experimental prototype performed working in low rotation speed mode and middle rotation speed mode separately, when the revolving speed increased by 50% the thermal of winding raise approximately 23.5%. Further, the analytic formulas and experimental results consistent with each other approximately, in which the mathematical analysis method was verified by test value.

Investigation of the effect of demagnetization fault at Line Start AF-PMSM with FEM

In motors containing magnets, irreversible demagnetization failure is one of the factors that negatively affect motor performance. In this study, the traditional Axial Flux Permanent Magnet Synchronous Motor (AF-PMSM) rotor structure was changed and the structure that gained the feature of starting from the line was used. Line Start AF-PMSM with 5.5 kW shaft power has 4 poles and each pole consists of 5 magnets. Demagnetization failure was obtained by the flux values of the magnets in any pole are drawn to zero and virtual demagnetization failure is created at certain rates (20%, 40% and 60%). With FEM, the data of the healthy and faulty motor were obtained. The data are then presented comparatively. Obtained data showed that demagnetization fault in Line Start AF-PMSM negatively affects motor performance, and the results are given in detail in the article. The original aspect of the study is that the demagnetization fault in Line Start AF-PMSM was investigated for the first time with FEM.

Magnetic-coupling characteristics analysis of a dual redundancy axial flux permanent magnet synchronous motor

The permanent magnet synchronous motor (PMSM) is widely used as the driving device for electric vehicles, robots and other systems due to their high-power density and wide speed range. In order to improve the reliability of PMSM, redundant structure can be used. In this paper, a topology of dual-redundant axial flux PMSM (DR-AFPMSM) and a analytical method for magnetic coupling characteristics was proposed. To reduce the axial length and the magnetic coupling between the two redundancies, the middle rotor disk consists of a set of permanent magnets (PMs) embedded in a coreless skeleton. From the perspective of inductance and armature reaction, the magnetic characteristics of each redundancy and the magnetic coupling between redundancies have been analyzed by 3-dimensional finite element analysis (3D-FEA) in this paper. Tests under different conditions, namely no-load, load, and phase-to-phase short-circuit have been carried out. Results show that the prototype meets the design requirements and the proposed structure can effectively decrease the magnetic coupling between the two redundancies.

Field Oriented Control of AFPMSM for Electrical Vehicle Using Adaptive Neuro-Fuzzy Inference System (ANFIS)

Axial Flux Permanent Magnet Synchronous Motor (AFPMSM) are very attractive candidates for driving applications due to their high efficiency, high torque-to-weight ratio, high power density, small magnetic thickness, and simplicity of construction. On the other hand, AFPMSM produces undesirable torque ripple in the developed electromagnetic torque, affecting their output performance. An intelligent control method is proposed in this paper to reduce torque ripple and improve the dynamic performance of AFPMSM. The vector control, employing the Field Oriented Control (FOC) technique, was used to improve the dynamic performance of the AFPMSM. The speed and torque controllers are achieved using the decoupling method. The intelligent control was designed to improve the performance of AFPMSM obtained from PI-PSO. The Adaptive Neuro-Fuzzy Inference System (ANFIS) was used as an Intelligent controller to integrate both the speed and torque constraints in a single training procedure. Training data for ANFIS was obtained from PI-PSO with a multi-objective cost function that includes the torque ripple and speed response criteria. The approach gave great results in terms of speed performance in different operating conditions and in tracking the required speed in load and no-load. In addition, the torque ripple was reduced by 10.04% and 46.67% compared with PI-PSO and Multi-objective cost function of speed, respectively.

Performance Assessment of Axial-Flux Permanent Magnet Motors from a Manual Manufacturing Process

Implementation of a new design for the process of assembling an axial-flux permanent magnet synchronous motor (AF PMSM) may lead to unstable motor parameters during operation at low and high speeds. In this paper, experimental data related to the AFPMSM used in an electric traction motor was monitored. The paper presents tracing of machine performance in order to find quality-related issues and to evaluate the assembly process. To assess the manual manufacturing process (low-volume production) and electrical machine performance, several motors, characterized by the same size and topology, were extensively tested. Useful AF PMSM parameters such as continuous torque and continuous current were measured. The winding temperature of the stators was also monitored and carefully examined. An attempt to assess motor performance, based on measurements and aimed at the identification of the weakest parts of the electric motor design is presented. In this paper it can be seen how the subcomponents of the machine and its detailed assembly process and tolerances play key roles in achievement of the designed continuous performance with symmetrical temperature distribution in the stator winding. Selected conclusions drawn from the obtained measurements were explained by a rotor/stator misalignment study using 3-D finite element analysis.

Study on the Electromagnetic Design and Analysis of Axial Flux Permanent Magnet Synchronous Motors for Electric Vehicles

In order to provide a complete solution for designing and analyzing the axial flux permanent magnet synchronous motor (AFPMSM) for electric vehicles, this paper covers the electromagnetic design and multi-physics analysis technology of AFPMSM in depth. Firstly, an electromagnetic evaluation method based on an analytical algorithm for efficient evaluation of AFPMSM was studied. The simulation results were compared with the 3D electromagnetic field simulation results to verify the correctness of the analytical algorithm. Secondly, the stator core was used to open the auxiliary slot to optimize the torque ripple of the AFPMSM, which reduced the torque ripple peak-to-peak value by 2%. From the perspective of ensuring the reliability, safety, and driving comfort of the traction motor in-vehicle working conditions, multi-physics analysis software was used to analyze and check the vibration and noise characteristics and temperature rise of several key operating conditions of the automotive AFPMSM. The analysis results showed that the motor designed in this paper can operate reliably.

Research on Deadbeat Current Prediction Vector Control System of Axial Flux Permanent Magnet Synchronous Motor for Electric Bus Based on Efficiency Optimal Torque Distribution Method

In order to improve the cruising range of electric bus, this paper studies the deadbeat current prediction vector control system of axial flux permanent magnet synchronous motor (AFPMSM) for electric bus based on the optimal torque distribution method. Firstly, the mathematical model of the three stators-double rotors AFPMSM is established. Secondly, in order to improve the high efficiency range, the efficiency optimal torque distribution method is proposed based on the average torque distribution method and the back propagation (BP) neural network is used to find the optimal torque distribution method. Then a current control strategy based on deadbeat current prediction control is proposed to improve the torque tracking characteristics. Finally, a drive control system is developed for the proposed control strategy, and experimental research and vehicle testing are carried out. The experimental results show that the BP neural network-based torque distribution method designed in this paper increases the high efficiency range of the drive system and improves the cruising range of the electric bus. The drive system using a current controller based on deadbeat current prediction control exhibits good dynamic and steady state performance.

Research on a Sliding Mode Vector Control System Based on Collaborative Optimization of an Axial Flux Permanent Magnet Synchronous Motor for an Electric Vehicle

In this paper, a sliding mode vector control system based on collaborative optimization of an axial flux permanent magnet synchronous motor (AFPMSM) for an electric vehicle is proposed. In order to increase the high efficiency range of electric vehicles and improve the cruising range, a collaborative optimization control strategy is firstly proposed. Due to the use of a dual stator-single rotor AFPMSM, the multi-motor efficiency optimization map and torque cooperative control are used to realize the working mode conversion of single stator and double stator, and the torque ripple caused by the working mode conversion is improved by fuzzy control. In order to improve the torque tracking capability, speed limiting characteristics, and operating characteristics, a speed limit and current vector control strategy based on a sliding mode controller is proposed and studied. The dynamic performance of electric vehicles is improved by a sliding mode vector control. Finally, a drive control system was developed for the proposed control strategy, and the complete vehicle test was carried out. The collaborative optimization control experiment and torque tracking and speed limiting experiments verify the correctness and effectiveness of the proposed control strategy. The acceleration performance and endurance experiments show that the proposed control strategy can effectively improve the cruising range and the acceleration performance of electric vehicles.

Optimal Design of an Axial Flux Permanent Magnet Synchronous Motor for the Electric Bicycle

Design of an electric machine such as the axial flux permanent magnet synchronous motor (AFPMSM) requires a 3-D finite-element method (FEM) analysis. The AFPMSM with a 3-D FEM model involves too much time and effort to analyze. To deal with this problem, we apply a surrogate assisted multi-objective optimization (SAMOO) algorithm that can realize an accurate and well-distributed Pareto front set with a few number of function calls, and considers various design variables in the motor design process. The superior performance of the SAMOO is verified by comparing it with conventional multi-objective optimization algorithms in a test function. Finally, the optimal design result of the AFPMSM for the electric bicycle is obtained by using the SAMOO algorithm.

Modeling based on 3D finite element analysis and experimental study of a 24-slot 8-pole axial-flux permanent-magnet synchronous motor for no cogging torque and sinusoidal back-EMF

Modeling based on 3D finite element analysis and experimental study of a 24-slot 8-pole axial-flux permanent-magnet synchronous motor for no cogging torque and sinusoidal back-EMF

Driving‐scenario oriented design of an axial‐flux permanent‐magnet synchronous motor for a pedal electric cycle

This paper proposes a driving-scenario oriented design of an axial-flux permanent-magnet synchronous motor for a pedal electric cycle (Pedelec). Traditional motors are usually designed according to a torque and speed (TN) curve with two operation zones – constant torque and constant power, without being closely related to a driving scenario. The proposed design method defines the TN curve with three operation zones – constant torque, maximum DC current and maximum voltage, which are specified by a driving scenario, the modulation method of motor drive and basic torque and voltage equations of motors. This target TN curve provides admissible ranges for the back electromotive force constant and phase resistance of the motor to be designed. A systematic design procedure is introduced by a quasi-three-dimensional (3D) magnetic circuit model, a multi-objective optimisation process for sizing the motor and a finite element analysis for verifying and refining the design. The resulting TN curve of the proposed Pedelec motor is proved to be very close to the target TN curve that is prescribed by the driving scenario, and motor and drive parameters.

Thermal modeling of an AFPMSM: A review

This paper presents the axial-flux permanent-magnet synchronous motor (AFPMSM) and the history of axial-flux machines. Various machine structures, features of the AFPMSM over the conventional machines and disadvantages are clarified. AFPMSMs are being developed for many applications due to their attractive features; these applications are mentioned. It also reviews the studies of thermal modeling of AFPMSM and the various techniques to analyze the thermal behavior of it.

Study on the Characteristics of Electromagnetic Noise of Axial Flux Permanent Magnet Synchronous Motor

The normal electromagnetic force distribution in stator system of axial flux permanent magnet synchronous motor (PMSM) has been thoroughly analyzed in this paper. The main composition of force wave causing vibration and noise has been proposed, and at the same time a calculation method of stator natural frequency of axial flux PMSM has been raised. Through this method electromagnetic force wave, natural frequency, vibration response, and electromagnetic noise of a 15 kW axial flux PMSM with 22 poles and 24 slots have been calculated; calculations and measured values are consistent by comparison. The noise sources of axial flux PMSM have been found in this paper, which provides the theoretical support for the suppression of electromagnetic noise of axial flux PMSM.

Cogging Torque Minimization of a Dual-Type Axial-Flux Permanent Magnet Motor Using a Novel Optimization Algorithm

The design of an electric machine is a multivariable and multimodal problem that requires much time to find the optimal design result. To address this problem, we propose a novel optimization algorithm using a kriging meta-model, a contour face climb method, a reinterpolation method in an expected region, an advanced pattern search method, and a uniform search method in the entire problem space. A rapid, exact, and reliable optimization process for a multivariable and multimodal design problem is possible using the proposed novel algorithm. Its validity was confirmed by comparing the optimization results of a test function with evolutionary optimization methods. For verification of the application to an electric machine, a dual-rotor axial flux permanent-magnet synchronous motor was designed using the proposed algorithm in this paper.