Interior Permanent Magnet Type Research Articles

Development of High-Temperature Permanent Magnet Synchronous Motor for Autonomous Robotic Navigation: A Design and Finite Element Analysis Approach

The traditional industrial robots come with the prime mover, i.e. Electric Motors (EM) which ranges from a few hundred too few kilo watts of power ratings. However, for autonomous robotic navigation systems, we require motors which are light weighted with the aspect of high torque and power density. This aspect is very critical, when the EMs in robotic navigations are subjected to harsh high temperature survival conditions, where the sustainability of the performance metrics of the electromagnetic system of the EMs degrade with the prevailing high temperature conditions. Hence, this research work address and formulate the design methodology to develop a 630 W High Temperature PMSM (HTPMSM) in the aspect of high torque and power density, which can be used for the autonomous robotic navigation systems under high temperature survival conditions of 200°C. Two types of rotor configurations i.e. the Surface Permanent Magnet type (SPM) and the Interior Permanent Magnet type (IPM) of HTPMSM are examined for its optimal electromagnetic metrics under the temperature conditions of 200°C. The 630 W HTPMSM is designed to deliver the rated torque of 2 Nm within the volumetric & diametric constraints of D x L which comes at 80 x 70 mm at the rated speed of 3000 rpm with the survival temperature of 200°C with the target efficiency of greater than 90%. The FEM based results are validated through the hardware prototypes for both SPM and IPM types, and the results confirm the effectiveness of the proposed design methodology of HTPMSM for sustainable autonomous robotic navigation applications.

Robust Deadbeat Finite-Set Predictive Current Control With Torque Oscillation and Noise Reduction for PMSM Drives

This article proposes a unique control strategy for a deadbeat multiple vector finite-set model predictive current control with an embedded integral action (MV-FMPC) for permanent magnet synchronous motor drives. Torque ripple and phase current distortions in permanent magnet synchronous motor (PMSM) drives are minimized with the proposed controller by adopting the multiple vector approach to the finite-set model predictive control. The controller uses a hexagonal co-ordinate system to simplify the location and identification of the virtual vectors created, thereby eliminating the use of large look-up tables and reducing computational burden. When used with the proposed deadbeat prediction model, the overall steady-state performance, system robustness, and quality of disturbance rejection are improved compared to the state-of-the-art finite-set model predictive current control (FS-MPC) methods with pulsewidth modulation. The improvements are due to the modified deadbeat prediction model with integral action, the algorithm used for multiple virtual voltage identification and the retention of the cost function in the proposed method. The proposed deadbeat MV-FMPC method and its improvements over the conventional FS-MPC have been verified through simulation and experiments with an interior-type permanent magnet synchronous machine.

Torque imporvement of IPM motors with skewing magnetic designs

In this paper, a type interior permanent magnet synchronous motor designs is proposed for sport scooter application to improve constant torque wide speed performance. Interior Permanent Magnet machines are widely used in automotive applications for their wide-speed range operation and low maintenance cost. An existing permanent magnet motor (commercial QS Motor) is 3 kW-3000 rpm. In order to improve torque and power in wide speed range, a IPM electric motor 5.5 kW -5000 rpm can run up to 100 km/h: An Step-Skewing Interior Permanent Magnet motor alternatives is designed and optimized in detail with optimal magnetic segment V shape. The electromagnetic charateristics of Interior Permanent Magnet motors with V shape are compared with the reference Surface Permanent Magnet motor for the same geometry parameter requirements. Detailed loss and efficiency result is also analyzed at rate and maximum speeds. A prototype motor is manufactured, and initial experimental tests are performed. Detailed comparison between Finite Element Analysis and test data are also presented. It is shown that it is possible to have an optimized Interior Permanent Magnet motor for such high-speed traction application. This paper will figure out optimal angle of magnetic V shape for maximum torque and minimum torque ripple.

Reliability-Based Design Optimization of a Permanent Magnet Motor Under Manufacturing Tolerance and Temperature Fluctuation

A reliability-based design optimization (RBDO) method is proposed to ensure a given confidence level of output performances of a permanent magnet motor in the presence of operating temperature fluctuation and manufacturing tolerance. To achieve the goal, first, probabilistic distributions of material properties of motor components are investigated in accordance with the variation in operational temperature. Then, random material parameters and random design variables due to both uncertainties are incorporated into a mathematical formulation of the RBDO, and an optimal design is sought out using the Monte Carlo simulation combined with a highly accurate surrogate model. An interior-type permanent magnet synchronous motor is provided to demonstrate the validity of the proposed method by comparison with the conventional method, which adopts a deterministic optimization technique in conjunction with a safety factor.

Iron Loss Analysis of a Concentrated Winding Type Interior Permanent Magnet Synchronous Motor with Single and Dual Layer Magnet Shape

In this study, the iron losses of high flux density concentrated winding-type interior permanent magnet synchronous motors for three different magnet shapes (single-V, single-flat, and dual-delta) and rotor structures are analyzed and compared. Iron loss is analyzed using the classical Steinmetz equation (CSE) based on the frequency separation approach using the iron loss material table, and each rotor type is compared. In addition, to validate the hysteresis loss for each rotor type, two additional analyses are performed. In the methods considered, the number of minor loops is counted, and the area is calculated based on DC bias. The eddy current loss is compared using two approaches: CSE base frequency separation and the homogenization method considering the skin effect. This study primarily focuses on the comparison of relative iron losses based on different rotor topologies instead of absolute comparisons.

An Improved Hybrid Field Model for Calculating On-Load Performance of Interior Permanent-Magnet Motors

In this article, we developed an improved hybrid field model (IHFM) to predict the on-load performance of the interior permanent-magnet (IPM) motors considering both iron saturation and slotting effect. It combines the airgap analytical model based on the modified conformal mapping with the reluctance mesh method for stator and rotor. The reluctance mesh method can accurately predict the rotor saturation and tooth-tip saturation even their field distribution is complicated due to the armature reaction. Besides, IHFM will significantly accelerate computation speed using the analytical model for airgap region while keeping high accuracy. The finite-element analysis and experimental results of the flat-type and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> -type IPM motors are demonstrated to verify the effectiveness of the proposed model.

Performance Improvement of Concentrated-Flux Type IPM PMSM Motor with Flared-Shape Magnet Arrangement

This study demonstrates that the use of a flared-shape rotor structure in interior permanent magnet (IPM) permanent magnet synchronous motor (PMSM) yields better performance than the basic IPM PMSM motor, using a spoke structure with ferrite magnets. To concentrate the effective magnetic flux, the proposed rotor structure is composed of a number of ferrite magnets, which are inserted in a flared shape in the rotor core. This paper shows the comparison with the analysis results of 2D finite element method (FEM), and it is shown that the proposed IPM PMSM motor can be an effective substitute for the basic IPM PMSM motor, which requires low torque ripple and high efficiency. In particular, the proposed flared IPM PMSM motor has lower pulsation of torque and superior efficiency, as well as lower acoustic noise and vibration, compared to the basic IPM PMSM motor. To verify the performance improvement of the proposed model, a prototype of the proposed model was manufactured. It was experimentally confirmed that the proposed model has lower torque ripple and higher efficiency than the basic model. Based on this performance improvement, the proposed flared IPM PMSM motor is suitable for electric vehicles and home appliances.

Performance verification of DR-PMSM for traction system according to permanent magnet shape

Unlike the conventional railway traction motor, the concept of the dual-rotor in a dual-rotor permanent magnet synchronous motor (DR-PMSM) is that two rotors are mounted on the same rotation axis, and the outer rotor and the inner rotor rotate at different speeds. The DR-PMSM can transmit the power to the wheels in a structure that can cope with various problems of the reducer systems using mechanical gear mechanisms. In this research, the design study of the inner rotor including the permanent magnet is carried out in the application of the DR-PMSM. In designing the DR-PMSM models, surface permanent magnet (SPM) type and interior permanent magnet (IPM) type are considered according to the permanent magnet type of rotor, and IPM type is designed by dividing into bar type and V type. A comparative analysis of the three 1kW-class DR-PMSM models, in terms of electromagnetic properties, is performed to assess their general performance. The overall electromagnetic properties of the three designed models are similarly derived. But, the cogging torque and the rated torque characteristics of the IPM (V) type model are the best in comparison with the other models. In addition, the 1kW-class DR-PMSM prototype with V type magnet is fabricated to verify the validity of the analytical model and performance verification is performed.

Numerical and Analytical Approaches to the Modeling of a Spoke Type IPM Machine With Enhanced Flux Weakening Capability

Interior permanent magnet (IPM) machines with spoke-type design are very attractive for several applications, including vehicle traction, which requires a good flux weakening performance to achieve high speed. For this purpose, a high demagnetizing current is usually injected to reduce the machine flux at high speed, with detrimental effect in terms of efficiency. This problem can be mitigated by equipping the rotor with a mechanical flux weakening device, which activates during high-speed operation by centrifugal force. This paper addresses the analytical modeling of this special kind of IPM motor through a simplified magnetic equivalent circuit (MEC) approach, which incorporates saturation and slotting effects as well as the flux weakening device operation. It is shown how the MEC model can effectively describe the IPM machine behavior despite its simplicity. Results are successfully validated by comparison both with finite element analysis, which requires much more computational resources, and with measurements from laboratory prototype testing.

Modelling and co-simulation of a permanent magnet synchronous generator

PurposeThe purpose of this paper is to obtain an accurate methodology for modelling and analysis of the permanent magnet synchronous generator connected to power electronic components.Design/methodology/approachThis paper presents the methodology of the co-simulation of a permanent magnet synchronous generator. It combines Simulink, Maxwell and Simplorer software to demonstrate the electrical machine behaviour connected with the power electronics’ circuit. The finite element analysis performed on the designed machine exhibit a more accurate behaviour over simplified Simulink models. Results between both simulation and co-simulation are compared to measurements.FindingsThe co-simulation approach offers a more accurate depiction of the machine behaviour and its interaction with the non-linear circuits.Research limitations/implicationsThis paper focuses on the interior permanent magnet type of PMSG and its interaction with a passive rectifier (nonlinear circuit).Practical implicationsThe advanced capabilities of the co-simulation method allow to analyse more variations (geometry, materials, etc.), and its interaction with non-linear circuits, than previous simulation techniques.Originality/valueThe co-simulation as a tool for analysis and design of systems interconnected with unconventional and conventional electrical machines and prototypes, and the comparison of the obtained results with classical analysis and design methods, against measurements obtained from the prototype.

Design Optimization of Interior Permanent Magnet Synchronous Motor for Electric Compressors of Air-Conditioning Systems Mounted on EVs and HEVs

This paper deals with the optimization design process of an interior-type permanent magnet synchronous motor (IPMSM) for electric compressors of air conditioners applied to electric cars and hybrid vehicles. Based on a prototype IPMSM, we identified the current level for efficiency and cogging torque using finite-element analysis (FEA). The IPMSM’s main design variables are optimized to primarily satisfy the target of efficiency and cogging torque. A second optimization design is carried out using the response surface method (RSM) for the main design variables obtained from the Taguchi method analysis. As a result, the optimization design is carried out through a two-step optimization design process using the Taguchi method and RSM. The IPMSMs are analyzed using FEA, and their validity is confirmed by comparing the test results against each step-by-step model. We validate an effective optimization design process using a two-stage design process. We conclude that the proposed approach provides an effective design method for engineers.

IPMSM velocity and current control using MTPA based adaptive fractional order sliding mode controller

This paper presents a two-loop approach for velocity and stator currents control of an Interior-type Permanent Magnet Synchronous Motor (IPMSM). In the outer loop, the reference torque obtained from a conventional PI controller gives two-axis stator reference currents based on Maximum-Torque per Ampere (MTPA) strategy. In the inner loop, an adaptive fractional order sliding mode controller is designed to reach the two-axis stator currents to their reference values obtained from the MTPA method. To achieve this idea, fractional order sliding surfaces and an adaptive controller with adjustable parameters are employed. The adaptive controller is designed to increase the robustness of the proposed method against the uncertainties in stator resistance and inductances. A Lyapunov based adaptation mechanism is proposed for adjustment of the controller parameters. The optimal value of the fractional orders are obtained by optimization of an integral time absolute error performance index. The simulation results show the robustness of the proposed method against the uncertainties in stator resistance and stator inductances.

Fault Detection of Irreversible Demagnetization Based on Space Harmonics According to Equivalent Magnetizing Distribution

Efficiency, stability and reliability of interior permanent magnet (IPM) type brushless DC motor(BLDCM) are verified through a number of studies and experiment until today. In addition, IPM type BLDCM is widely used in many applications for high power and excellent control of the per unit volume. Especially, IPM type BLDCM is used as a core driving source in the factory automation and electric propulsion systems of electric vehicles due to their wide control range and high robustness. Although there is many merits, IPM type BLDC motors involve potentially risk about an irreversible magnetization. If these systems are continuously driving under the irreversible magnetization condition, the residual flux density of permanent magnet is more decreased because the demagnetizing regions are increased by overlap of inverse flux.

Efficiency Contours and Loss Minimization Over a Driving Cycle of a Variable Flux-Intensifying Machine

In this paper, experimental evaluations for the efficiency of a novel interior permanent-magnet (IPM) machine with variable-flux characteristics using low-coercive-force magnets are presented. The variable-flux characteristics allow improving the efficiency of a machine. A flux-intensifying IPM type having positive saliency is employed for a positive $d$ -axis current to mitigate a demagnetizing field in the magnet due to a $q$ -axis current. A proof-of-principle machine is designed, fabricated, and evaluated. A series of experiments are conducted to capture the magnetization and demagnetization properties of the low-coercive-force magnets by applying control $d$ -axis current pulse. The efficiency contours with different magnetization states (MSs)of the magnets are then experimentally obtained. The designed machine shows benefits in improving efficiency when the MS is optimally operated. With these results, the loss over a driving cycle is then simulated, and the benefits of changing the MS are quantified.

Optimization of Magnetic Flux-path Design for Reduction of Shaft Voltage in IPM-Type BLDC Motor

In this paper, we propose a method for suppressing shaft voltage by modifying the rotor shape and the permanent magnets in interior permanent magnet type high voltage motors. The shaft voltage, which adversely affects the bearing by occurring bearing current, is induced by parasitic components and the leakage flux in motor-driven systems as well as inherent linkage flux between main magnetic flux and shaft according to rotor configuration. Thus, shaft voltage should be analyzed and considered under inverter-driven and non-inverter-driven conditions because inherent linkage flux can analyze under non-inverter-driven condition. In this study, we designed re-arrangement magnet and re-structuring rotor to minimize the shaft voltage. In addition, we optimized the proposed models. The shaft voltage suppression effect of the designed model was validated experimentally and by comparative finite element analysis.

Design and Evaluation of a Variable-Flux Flux-Intensifying Interior Permanent-Magnet Machine

This paper presents a design approach for interior permanent-magnet (IPM) machines with variable-flux characteristics using low-coercive-force magnets for improved efficiency and extended operating speed range. A flux-intensifying IPM type with is used in the design due to positive Id operation and reduced loaded Iq effects. Design considerations of machine structures and variable-flux machine attributes are discussed. In addition, leakage flux in a rotor is particularly designed to also obtain another flux-varying capability. Evaluation of the designed machine is provided by finite-element analysis simulations and experiments on a proof-of-principle machine. The designed machine shows benefits in increasing efficiency and speed range in a low-torque region when variable magnetization control of the low-coercive-force magnets or the design of the leakage flux proposed in this paper is implemented.

Optimum Design of Interior Permanent Magnet Motor for Automotive Cooling Device

In this paper, we developed stator and rotor shapes of interior permanent magnet type brushless motor for automotive cooling device in order to obtain better performance than the prototype. Response surface methodology (RSM) is employed in this paper as an optimization method. Finite element computations have been used for numerical experiments on geometrical design variables in order to determine the coefficients of a second order model for the RSM. The optimum design results confirm that desirable improvements in cogging torque, back-EMF and THD are achieved.

Stator and Rotor Shape Designs of Interior Permanent Magnet Type Brushless DC Motor for Reducing Torque Fluctuation

This paper presents the stator and rotor shape designs in interior permanent magnet (IPM) type brushless dc (BLDC) motor for reducing torque fluctuation. The partly enlarged air-gap made by rotor unequal out diameter and stator core structure with pole shoe modification is introduced. The torque ripple reduction is achieved by upgrading torque value at minimum torque position and their detail characteristics are compared. The final stator and rotor shape of IPM type BLDC motor is decided by design of experiments (DOE) process. The magnetic field and torque characteristics are analyzed by 2 dimensional (2D) finite element analysis (FEA) and their performances are validated by experimental results.

Topology Optimization of Rotor Structure in Brushless DC Motor With Concentrated Windings Using Genetic Algorithm Combined With Cluster of Material

This paper proposes a novel topology optimization method for the material distribution of electrical machines using the Genetic algorithm combined with the cluster of material and the cleaning procedure. The cluster of several kinds of material is newly taken into account not only to form the group of iron and the group of air but also to form the group of the r-oriented, x-oriented and y-oriented magnets. Consideration of the r-oriented magnet gives a surface permanent magnet type rotor, and consideration of the x-oriented and y-oriented magnets gives an interior permanent magnet type rotor.

Study on Permanent Magnet Arrangement for IPM Type 5-DOF Self-Bearing Motor

The 5-DOF self-bearing motor possesses the functions of a motor, two radial AMBs, and an axial AMB. Therefore, it is possible to miniaturize the AMB system with maintaining high performance. In this paper, an interior permanent magnet (IPM) type 5-DOF self-bearing motor is proposed. The IPM rotor generates bias fluxes to not only the radial direction but also the overhanging stator direction without side surface permanent magnets. Optimum configuration of the permanent magnets is analyzed using 3 dimensional finite element method. The results show the feasibility of the more compact and highly-reliable 5-DOF self-bearing motor.