Stator Dimensions Research Articles

Feasibility analysis of the conversion of brushed to brushless direct current motor

<span lang="EN-US">This paper analyzes the feasibility of converting brushed direct current (BDC) to brushless direct current (BLDC) motor by substituting the wound rotor with a permanent magnet. The aim is to overcome the low quality of rewinding of wound rotors. The conversion was performed by redesigning the motor, referring to the old stator dimensions and motor specifications. Some suitable speed control systems were also examined. Technical analysis was executed by simulating motor characteristics, covering torque-speed curve, cogging, and ripple torques. Afterward, an economic analysis was done to determine the cost of making one rotor unit and the speed control and then compare it with the price of a new BDC motor with equivalent power. The results show that the motor produces 3.6 kW, 18.86 V, 176.71 A, and 28.53 Nm at 2,460 rpm with 2 phases configuration. The maximum cogging torque is 2.9 Nm. The cost of making one rotor unit plus speed control is higher than that of a new BDC motor. These results show that it is technically feasible to convert BDC into a BLDC motor but not economically or vice versa.</span>

Surrogate Vibration Modeling Approach for Design Optimization of Electric Machines

This article presents a surrogate modeling approach to predict the vibrational behavior during electric machine design. The methodology used in identifying and implementing the surrogate model allows a time-efficient integration of the surrogate model in multiphysics geometric optimization of electric machines, especially in scenarios of drop-in replacement. Based on the state-of-the-art review, the use of analytical or numerical techniques alone considering motor frame and support are not adequately accurate, time efficient, and flexible. The proposed method uses the 3-D finite-element (FE) structural simulations for identifying characteristic response profiles in the surrogate model and does not use structural FE simulations in the optimization loop. Experimental tests are performed on a 6/10 switched reluctance machine to validate the 3-D FE model used to identify the surrogate model. The rational fraction polynomial (RFP) method is used to fit the vibration impulse responses for a number of machines geometries defined by three stator dimensions. The impulse response of any geometry can be determined using linear interpolation of the RFP coefficients. Using the radial forces determined from the FE electromagnetic simulation, the deformation is determined using superposition.

Torque Ripple Analysis of Synchronous Reluctance Motor with Different Rotor Topologies for Application with Dimensional Constraint

Synchronous reluctance machine (SynRM) is reemerging as a thermally robust and inexpensive actuator solution mainly due to the lack of permanent magnet. Added to that, the possibilities of having different rotor topologies make it very versatile where further optimization is possible depending on the objective, be it cost, ease of fabrication, power output, or torque quality. In an application where the outer dimension of the motor is strictly limited, this paper compares quantitatively and qualitatively the torque ripple of three SynRM machines of the same stator dimension equipped with different rotor topologies: segmented, tooth and flux barrier. Using an experimentally validated FE model, the torque ripple and the ripple’s harmonic content are compared at maximum load (stator current, IS = 50 A) and load angle (β = π/4). The machine adopting the flux-barrier rotor was shown to have the best torque quality (41% ripple), followed by tooth rotor (78% ripple) and finally segmented rotor (105% ripple). The harmonic contents are also presented and analyzed.

Continuous Hydrosonic Reactor for Methyl Esters Production Process from Low Free Fatty Acid Oil Using 3D-Printed Rotor

The continuous methyl ester production process was studied using a hydrosonic reactor to determine the relationship between the rotor speed and the purity of methyl ester with TLC/FID technique. The hydrosonic reactor consisted of three main parts: a rotor, a stator, and a motor. The key part is a 3D-printed rotor; the dimensions were 60 mm in outer diameter, 50 mm in length. The rotating 3D-printed rotor was driven and axially rotated inside the stator by shaft, and 400 kW electric motor was used to blend the mixtures. The dimensions of stator were 70 mm inner diameter and 70 mm length, and 5 mm thickness. The gap distance between the rotor and stator was fixed at 10 mm. The hole on the surface of rotor was circular shape (80 holes of 6 mm diameter) and designed radically throughout the axis. The ratio of diameter to depth of the circular hole was 1.0. In the preliminary experiment, the location and dimension of holes were fixed, and 3D-printed rotor speed was varied at 1000, 2000 and 4000 rpm under the condition of 23 vol.% methanol, 10 g KOH/L and 37 L/hr RPO flow rate at 60°C. The results showed that methyl ester purification reached 93.920 wt.%, 95.325 wt.%, 96.700 wt.%, and 97.333 wt.% at 1000, 2000, 3000, and 4000 rpm of rotor speed. Therefore, over 90 wt.% of methyl esters can be produced from RPO by using rotor-stator type of hydrodynamic cavitation.

Optimal Rotor Design of Claw-Pole Alternator for Performance Improving

Abstract: The subject of this paper is to optimize the design of conventional claw pole alternator for automotive industry, especially at idle speed. Commonly, during idle speed, claw pole alternator isn’t able to sustain active electrical loads for a reasonable amount of time without excessive drain on the battery. Therefore, obtaining sufficient output power at idle speed is required. The optimization process aims to improve alternator output power, at idle speed, for given stator dimensions and footprint. To derive the optimal rotor structure, cyclic coordinate method linked with magnetic equivalent circuit (MEC) model is used, including magnetic saturation effect and leakage flux. Optimization results, which provide the optimized rotor geometrical dimensions, are discussed. Performances regarding the optimized claw pole alternator are evaluated over the entire operating speed range of the vehicle.

Sizing, Analysis, and Verification of Axial Flux-Switching Permanent Magnet Machine

This paper proposes the analytical design methods of axial flux-switching permanent magnet (AxFSPM) machines. The analytical design methods take the influences of electric and magnetic loadings into account to calculate the specific sizing and scalability of the AxFSPM machine. In addition, the winding functions are implemented to derive the self-, mutual-, d-axis, and q-axis inductances. The results of analytical design methods indicate that the magnetic loading has bigger impact on the stator dimensions of AxFSPM machines than the electrical loading. The d- and q-axis inductances of the all-pole-wound AxFSPM machines are similar under the same number of slots and turns. A prototype is manufactured using analytical design methods. The experimental results show that the prototype machine achieves target specification and the usefulness of the proposed design method is verified.

DESIGN OF A SINGLE-PHASE RADIAL FLUX PERMANENT MAGNET GENERATOR WITH VARIATION OF THE STATOR DIAMETER

This study aims to observe the influence of the changing stator dimension on the air gap magnetic flux density (Bg) in the design of a single-phase radial flux permanent magnet generator (RFPMG). The changes in stator dimension were carried out by using three different wire diameters as stator wire, namely, AWG 14 (d = 1.63 mm), AWG 15 (d = 1.45 mm) and AWG 16 (d = 1.29 mm). The dimension of the width of the stator teeth (Wts) was fixed such that a larger stator wire diameter will require a larger stator outside diameter (Dso). By fixing the dimensions of the rotor, permanent magnet, air gap (lg) and stator inner diameter, the magnitude of the magnetic flux density in the air gap (Bg) can be determined. This flux density was used to calculate the phase back electromotive force (Eph). The terminal phase voltage (V∅) was determined after calculating the stator wire impedance (Z) with a constant current of 3.63 A. The study method was conducted by determining the design parameters, calculating the design variables, designing the generator dimensions using AutoCad and determining the magnetic flux density using FEMM simulation. The results show that the magnetic flux density in the air gap and the phase back emf Eph slightly decrease with increasing stator dimension because of increasing reluctance. However, the voltage drop is more dominant when the stator coil wire diameter is smaller. Thus, a larger diameter of the stator wire would allow terminal phase voltage (V∅) to become slightly larger. With a stator wire diameter of 1.29, 1.45 and 1.63 mm, the impedance values of the stator wire (Z) were 9.52746, 9.23581 and 9.06421 Ω and the terminal phase voltages (V∅) were 220.73, 221.57 and 222.80 V, respectively. Increasing the power capacity (S) in the RFPMG design by increasing the diameter (d) of the stator wire will cause a significant increase in the percentage of the stator maximum current carrying capacity wire but the decrease in stator wire impedance is not significant. Thus, it will reduce the phase terminal voltage (V∅) from its nominal value.

Phase-to-phase fault detection method for synchronous reluctance machine using MEC method

This paper presents a novel technique for synchronous reluctance machines model (SynRMs). The model can be used in both healthy and faulty situations with phase-to-phase fault. The machine properties such as the number of poles and slots, as well as rotor and stator dimension, can be selected arbitrarily in the proposed model. Therefore, various SynRMs with selective properties can be modeled by the proposed method. Considering the nonlinear magnetic equivalent circuit, the healthy and faulty saturable machine with phase-to-phase fault between various windings is also studied. Validation is performed by finite-element method (FEM). Regarding the performed validation, very shorter processing time is obtained compared to FEM.

Comparison Between Electric Excitation and Permanent Magnet Excitation in Brushless Pulsed Alternator System

In previous studies, the field winding of the brushless pulsed alternator (BPA) is embedded in the stator slots, which is supplied by dc power or variable frequency power. The advantage is that the field current can be independently adjusted. It means that the BPA system needs a standalone excitation system, which will increase the volume and cost of the system. If we substitute electric excitation for permanent magnet excitation, not only the volume and cost of the BPA system can be decreased but the efficiency and flexibility can be enhanced. In this paper, the design schemes for electric excitation and permanent magnet excitation BPA are presented. For comparison, the stator and rotor dimensions of the two kinds of BPA are both the same. The characteristics of electric excitation and permanent magnet excitation BPA are analyzed by the finite-element method and field-circuit coupling method. Finally, the BPA systems with a resistive load are established, the performances of both the two excitation modes are compared. According to the simulation results, we conclude their advantages and disadvantages.

Development of a compact ring type MDOF piezoelectric ultrasonic motor for humanoid eyeball orientation system

A ultrasonic motor (USM) has been developed to meet the specific demands for compact actuators, which can drive humanoid eyeball to realize multi-degree-of-freedom (MDOF) motions. This USM has a ring shape composite stator, and employs combinations of axial bending mode and in-plane nonaxisymmetric mode to generate three type ellipses at four driving feet, pushing the spherical rotor to rotate around x, y and z axes respectively. FEM was used in the design process, including tuning the mode frequencies by sensitivity analysis, as well as optimizing the stator dimensions by transient simulations, where the shapes and attitude angles of the driving ellipses were retracted and analyzed with the deduced method, together with the driving effects comparison of two feasible exciting methods, achieving uniform driving behavior among the four feet. A prototype has been fabricated to verify the working principles, designs and simulations. The mechanical performance around x, y and z axis were measured under different electrical excitements and preload conditions, and typical stall torque is 17.5 mN m and the no-load speed of 82 r/min in x, y rotation, meanwhile stall torque is 12.5 mN m and the maximum speed of 43 r/min in z rotation, which meet the presented requirements.

Preliminary design of the last stage of supercritical steam turbine and proposition of anti-erosion coating for blades surface

In this article a preliminary design of the last stage of supercritical steam turbine has been presented. A computational model of supercritical thermal cycle has been created in order to determine steam parameters at the stage inlet and outlet. The model was based on the structure of German coal-fired power plant Datteln 4. Further steam-flow parame-ters and dimensions of stator and rotor blades have been calculated analytically. Stage geometry has been created and steam flow through designed stage upper-part has been simulated. Operating conditions of steam turbine last stages have been discussed and protective anti-erosion coating of blades surfaces has been proposed.

Optimized Design of Three Phase Squirrel Cage Induction Motor based on Maximum Efficiency Operating under the Rated Voltage – based on Software Platform

The efficiency maximization of thee phase induction motor operating at rated voltage and under the rated voltage is carried out with the help of JMAG Express. A computer program based on the output equations of three phase squirrel cage induction motor have been developed to check the initial design and performance of the induction motor with the help of graphic user interface (GUI). The output of GUI program is feed in the input targeted values of JMAG Express for parameter calculations and efficiency optimization. To optimize the efficiency as an objective function multiple parameters will be optimized and dimensions of stator and rotor are calculated in terms of sensitivity analysis at efficiency optimization. Calculations of under rated voltages are based on the averages voltages of the three unbalanced phases. The performance of the motor is carried out by considering the copper and aluminum cage rotor respectively. Due to reactive power demand, generally the motors which are designed for the rated voltages, but are operating under the rated voltages away from the utility center. To reduce the energy crises the aim of this research article is to improve the design quality of such type of motors with the help of JMAG Express, which distinguish it from other optimum designed processes based on programming languages, as this software is friendly user.

Optimization design of an interior permanent-magnet synchronous machine for a hybrid hydraulic excavator

A hybrid power transmission system (HPTS) is a promising way to save energy in a hydraulic excavator and the electric machine is one of the key components of the system. In this paper, a design process for permanent-magnet synchronous machines (PMSMs) in a hybrid hydraulic excavator (HHE) is presented based on the analysis of the working conditions and requirements of an HHE. A parameterized design approach, which combines the analytical model and the 2D finite element method (FEM), is applied to the electric machine to improve the design efficiency and accuracy. The analytical model is employed to optimize the electric machine efficiency and obtain the stator dimension and flux density distribution. The rotor is designed with the FEM to satisfy the flux requirements obtained in stator design. The rotor configuration of the PMSM employs an interior magnet structure, thus resulting in some inverse saliency, which allows for much higher values in magnetic flux density. To reduce the rotor leakage, a disconnected type silicon steel block structure is adopted. To improve the air gap flux density distribution, the trapezoid permanent magnet (PM) and centrifugal rotor structure are applied to PMSM. Demagnetization and armature reactions are also taken into consideration and calculated by the FEM. A prototype of the newly designed electric machine has been fabricated and tested on the experimental platform. The analytical design results are validated by measurements.

A new rotary ultrasonic motor using longitudinal vibration transducers

To simplify the design process and improve the motor performance, a rotary ultrasonic motor with rotationally symmetrical structure has been designed, fabricated, and characterized. The stator consists of four connected sandwich-type transducers and eight driving feet. The rotor, a disk, and a disk-shaft are pressed on the two sides of the stator by a nut–spring system. To drive the rotor, two orthogonal longitudinal vibration modes of the stator should be excited. The operating principle of the rotary motor was analyzed by a mathematical model. By using finite element analysis, the feasibility of the operating principle was validated, and the optimal structure dimensions of stator were determined in order to improve the driving teeth motion. The overall dimensions of the prototype stator are 30 mm (width) × 30 mm (width) × 50 mm (length). Driven by alternating current signals with the driving frequency of 50.93 kHz and voltage 300 VP-P, the motor gave a maximal no-load speed of 157.9 r/min and a maximal output torque of 11.76 mN m.

Novel Doubly Salient Permanent Magnet Machine for Wind Power Generation

This paper is derived from the design formula of 6/14 pole FRM, preliminary calculations the size of 6/14 pole FRM. For a more detailed analysis and research by changing the size of the motor stator and rotor arc, the cogging torque and the emf waveform that play a decisive role in the flux changes. This paper qualitative description different size and motor performance relationship. By the different sizes of motor performance curve analysis to finalize a more appropriate combination of stator and rotor dimensions, in order to get on better motor performance and material utilization.

Loss Minimization for Form-Wound Stator Winding of a High-Speed Induction Motor

Resistive losses in the form-wound stator winding of a high-speed induction motor (HSIM) are minimized in the design stage by using Differential Evolution (DE). Time-discretized finite-element analysis (FEA) serves as a tool to offer electromagnetic losses in the machine for the optimization process. Temperature rise of the machines is fast checked during the optimization by using a thermal network model. Insulation thicknesses and power factor are other constraints in the algorithm. Time consumption of using time-discretized FEA is still a problem when a large number of variables or motor dimensions is required for the optimization algorithm. To reduce the number of required variables, the influence of stator dimensions on the electromagnetic losses is analyzed by using the Taguchi approach. From this evaluation, the important stator parameters to be varied during optimization algorithm are determined. Finally, form-wound stator winding with a minimum loss for a HSIM is obtained within certain limitations.

Efficient Propulsion Structure with an Axial Flux Rotary Converter for HEV Drive Unit

This paper describes an efficient axial flux arrangement of the four quadrant rotary converter for hybrid electric vehicles. The design of the axial flux wound stator and both axial flux squirrel cage rotors is based on the arrangement of radial air gap induction motor and permanent magnet synchronous motor. The method of constant magnetic circuit volume is utilized for dimensions conversion, which results into basic dimensions of stator and rotor discs in axial flux conception. This allows the creation of real 3D models in the CAD application. Finally, the finite element simulation of magnetic flux density and magnetic flux vector map in the area of axial flux stator pack are presented in the concluding part of this paper.

Space Mapping Optimization of the Magnetic Circuit of Electrical Machines Including Local Material Degradation

Production processes like cutting, performed on electrical steel laminations, influence their magnetic properties locally. Since the magnetic design of electrical machines does not take this effect into account accurately, the design may be suboptimal. Therefore, the need exists to develop a numerical procedure which is capable of optimizing electrical devices, taking into account the local material degradation and featuring high accuracy and acceptable calculation time. We developed a space mapping procedure meeting these requirements and we quantified the influence of the material degradation on the design of a switched reluctance motor (SRM). The results of the optimization show that the local material degradation has a significant influence on the dimensions of stator and rotor yoke

Modelling of the travelling wave piezoelectric motor stator: an integrated review and new perspective

Articles from different areas which are closely related to the modelling of the stator of travelling wave ultrasonic motors (TWUMs) are reviewed in this work. Thus, important issues relevant to this problem are identified from the areas of vibration of annular plates, laminated plate theories, and modelling of piezoelectric transducers. From this integrated point of view, it becomes clear that there are some very important issues yet to be addressed in the modelling of TWUMs. Firstly, the influence of material properties and stator dimensions on output efficiency, electromechanical coupling coefficients (EMCC) and maximum output energy is to be investigated in more detail. Secondly, the modelling of the electric potential field (by explicitly including the charge equation) for TWUMs seems to be a must for better prediction of displacements and electric fields close to the resonance, as suggested by some recent works [1]. Moreover, the improvement of current models by using shear deformation (or higher order) laminated plate theories (LPTs) in conjunction with approximated methods of solution are discussed. In addition to analytical models, those works using Finite Element and Finite difference Methods (FEM and FDM) for the modelling and simulation of the TWUM stator dynamics are reviewed.

Evaluation of a surface acoustic wave motor with a multi-contact-point slider

Previously, the surface acoustic wave linear motor has been demonstrated and its exact pre-load conditions investigated. Based on this previous research, multi-contact-point sliders were designed and tested. A maximum output force of 0.45 N, 450 times that obtained in preliminary experiments, was successfully obtained. Simple simulation results predicted that much larger thrust would be available by increasing the actual contact point area without changing the slider and the stator dimensions. The calculated output force was 10 N, roughly twenty times that observed experimentally. To realize the required stator texture of the contact surface, a silicon micro-machining technique or other conventional methods would be applicable.