Prototype Motor Research Articles

Optimised design, analysis, fabrication and experiments on a tubular linear induction motor prototype

Optimised design, analysis, fabrication and experiments on a tubular linear induction motor prototype

Optimization Design and Control of Six-Phase Switched Reluctance Motor with Decoupling Winding Connections

In this paper, a design optimization method is proposed to reduce the current asymmetric and consequent torque ripple for a six-phase Switched Reluctance Motor (SRM). First, the inconsistent current phenomenon of the investigated SRM is introduced, and the relationship between the magnetic distribution and the phase currents is investigated by magnetic circuit analysis. Then, for the reduction in computational cost, a surrogate model is utilized to establish the response surface model between the optimization objectives and variables. Furthermore, multiobjective optimization is performed based on structural design optimization and asymmetric control, and the best design solution is selected for the drive system. Compared with the traditional symmetric control, it can be found that the proposed asymmetric control can mitigate the inconsistent phase currents and reduce the torque ripple. Finally, a prototype motor is manufactured and tested. Both the simulation and experimental results verify the effectiveness and the reasonability of the analysis and the optimization.

A Novel High-Voltage Gain Circuit Topology for Commutation Torque Ripple Reduction

The electronic commutation and the low inductance nature of the brushless dc motor (BLDC) deteriorate the expected performance. The ripples in the current waveshape are primarily due to the commutation of the phases, which is carried to produce a synchronously rotating magnetic field. This commutation ripples lead to mechanical pulsation and noise on the rotor side. This article presents a novel strategy for reducing the commutation torque ripple. The proposed topology uses a hybrid Ćuk voltage gain dc–dc converter at the front end, which has high voltage gain and which reduces voltage ratings of the dc supply. An auxiliary switch is connected across the dc link of the inverter to control the rate of rising incoming phase current during the phase change of the inverter with the help of the dc–dc converter. A prototype of a 1HP BLDC motor is used to validate the proposed topology both analytically and experimentally.

Low-Voltage, High-Frequency Synchronous Motor for Aerospace Applications

This article details the design of a permanent magnet synchronous electric motor prototype dedicated to the direct drive of the propeller for VTOL (Vertical Take-Off and Landing) and CTOL (Conventional Take-off and Landing) aircrafts. Our main aim is to maximise the power-to-weight ratio whilst not compromising the efficiency and the reliability. The originality of the research is based on the implementation of an armature winding using solid copper bars; we show that it is possible to use such an approach in an electric machine operating at very high frequency (1800 Hz) through a precise study on the shape of the bars to counter the additional losses. A prototype has been successfully manufactured; manufacturing details and some of the experimental test results are presented here.

Development of a dual-stator piezoelectric motor operated in resonance and quasi-static states

A dual-stator piezoelectric motor that can work in resonant and quasi-static states is proposed in this study to achieve high speed and high resolution cross-scale output. Two piezoelectric stators with a frequency of 1:2 and a vibration amplitude ratio of 2:1 are used for driving the sliding table with multipoint friction coupling to produce asymmetric sawtooth wave vibration. Then, they are used with the inertia force of the sliding table to achieve stepping motion. A dual-stator piezoelectric motor prototype is designed, and modal analysis is conducted using ANSYS software to obtain the resonant frequencies of the longitudinal vibration modes of the two stators. The dynamic model is established, and the numerical analysis is performed to obtain the trajectory and output characteristics of the sliding table. Finally, the prototype of the piezoelectric motor is constructed. Experimental results show that the minimum speed of the piezoelectric motor is 0.013 mm/s, the resolution is 0.5 μm, the maximum speed is 11.14 mm/s, and the maximum load is 40 g.

Bidirectional linear inertial impact piezoelectric motor with multimodal resonance.

A new multimodal bidirectional linear inertial impact motor with bidirectional motion based on self-clamping control driven by a single-harmonic signal was designed and manufactured. By applying driving signals of different resonant frequencies to the piezoelectric plate of a piezoelectric motor combined with the unique structural design of the motor, the piezoelectric motor has multiple modes and has the ability of two-way movement. First, the overall structure of the motor is introduced, and its working principle and theoretical displacement characteristics are presented through the periodic motion diagram of the piezoelectric motor. Second, the simulation analysis is carried out to determine the working modal of the proposed motor with COMSOL5.2. Finally, a motor prototype is developed, and the accuracy of the working principle and the simulation analysis is verified through experimental tests. When the motor has no load, the driving voltage is 200Vp-p. The maximum speed when moving to the right reached 3.125 mm/s when the preload is 2 N, and the driving frequency is 96Hz. The maximum speed when moving to the left reached 4.301 mm/s when the preload is 4 N, and the driving frequency is 148Hz. In the load capacity test of the motor prototype, the maximum load of the piezoelectric motor prototype moving to the right and left can reach 0.4 and 0.6 N, respectively. Compared with similar inertial impact motors, the proposed motor achieves flexible control of driving and switching of two-way movement conveniently and has a certain driving ability.

Design and Optimization of Double-Stator Vernier Permanent Magnet Motor With Improved Torque Characteristics Based on Flux Modulation Theory

In this article, based on flux modulation theory, torque characteristics improvement method is proposed for double-stator vernier permanent magnet (DS-VPM) motor. Also, the detailed torque production mechanism of DS-VPM motor is derived. Based on theoretical analysis results, key design parameters which possess significant influence on motor torque characteristics are selected to be further optimized purposefully. Non-dominated sorting genetic algorithm is then adopted to obtain increased output torque and reduced torque ripple of inner, outer, and total DS-VPM motor. Besides, based on finite-element analysis, motor performances before and after optimization are compared in detail. Finally, a prototype motor is built and corresponding experiments are carried out. Both theoretical analysis and experimental results verify the effectiveness of the proposed torque characteristics improvement method, which provides a potential research path for the design optimization of high-performance VPM motors.

Solar PV-Fed Reverse Saliency Spoke-Type PMSM With Hybrid ANF-Based Self-Sensing for Water Pump System

In this work, a reverse saliency (RS) spoke-type permanent magnet (PM) synchronous motor (PMSM) besides its hybrid adaptive notch filter (HANF)-based self-sensing for driving a solar photovoltaic water pump system (WPS) is presented. The conventional spoke-PMSM-driven WPS experiences two types of problems. First, the motor is operated with a flux-weakening current to produce positive reluctance torque, thereby increasing the PM demagnetization risk. Second, an encoder is used to sense the rotor angle, which, in turn, affects the cost and reliability. To solve the first problem, the RS-PMSM is presented, which operates with a flux-intensifying current to produce positive reluctance torque, while the second issue is resolved by using the HANF-based rotor angle estimation. Although conventional methods give an estimate of rotor angle, they do not eliminate both the dc offset and dominant harmonics. The superiority of both the RS-PMSM and HANF over existing solutions is shown, respectively, by using finite-element methods and MATLAB-/Simulink-based performances. Besides, a prototype motor is also manufactured. The performance of the RS-PMSM prototype along with its HANF-based self-sensing is obtained in the laboratory, and various test results are reported. Meanwhile, a comparison of the HANF with available self-sensing techniques is also performed.

A Generalized Open-Circuit Fault-Tolerant Control Strategy for FOC and DTC of Five-Phase Fault-Tolerant Permanent-Magnet Motor

A generalized fault-tolerant control (FTC) strategy for the field-oriented control (FOC) and direct torque control (DTC) of five-phase fault-tolerant permanent magnet (FPFTPM) motors under various open-circuit faults is presented in this article. Most previous studies regarding FTC target a specific primary control algorithm and involve different reduced-order transformation matrices and additional current controllers, which increase the complexity of the entire drive system. In this study, a solution to the aforementioned problems is devised by developing optimal fault-tolerant voltages, which are derived from fault-tolerant mechanism analysis and steady-healthy design. Because the coordinate transformation need not be changed and additional voltage compensation is not required, a minimal control drive system reconfiguration under various open-circuit faults can be achieved to avoid accommodating the change of the primary control algorithm. The proposed control strategy not only improves the torque performance and dynamic response under healthy and fault conditions, but also adapts to both FOC and DTC. Experimental results for a 2 kW FPFTPM motor prototype are provided to evaluate the proposed strategy.

Resonant-type inertial impact linear piezoelectric motor based on coupling of driving and clamping parts

A resonant-type inertial impact linear piezoelectric motor based on coupling of driving and clamping parts was designed and manufactured. The motor mainly includes stator (coupling of driving and clamping parts), mover (slider) and auxiliary parts. The driving part works in the resonant state under the excitation of single harmonic, which mainly realizes the function of reciprocating driving. Similarly, under the single harmonic driving, the clamping part also works in the resonant state to realize the clamping function. Through the coupling between the two parts of the stator, the mover is driven to move continuously in one direction. The inertial impact piezoelectric motor works in the resonant state because the driving and clamping parts work in the resonant state respectively. Compared with the traditional quasi-static inertial impact motor, this study novelly changes the working state of the inertial impact motor. Through the finite element simulation software COMSOL 5.2, the resonant frequency coupling of the driving and the clamping part is consistent. An experimental platform was built to verify the feasibility of the principle by testing the motor prototype. The experiment results show that: The maximum speed reaches 78 mm s−1 when the motor prototype is operated at the frequency of 810 Hz with a preload of 2 N and the working voltages of clamping and driving parts of motor were set at 80 and 220 Vp-p respectively. Meanwhile, the maximum load of the motor prototype can reach 5 N. The minimum resolution of the motor prototype is 6.379 μm.

A laminated ultrasonic motor operating in face expanding and face bending modes

In this work, a laminated ultrasonic motor operating in face expanding and face bending modes was designed, and a 5-layered ultrasonic motor prototype was fabricated and tested. By applying a sinusoidal electric field, the stator of the ultrasonic motor would produce the expanding/bending microscopic movement, then this microscopic movement was transformed into linear movement by friction force. Experimentally, the proposed ultrasonic motor revealed excellent performance under a relatively low driving voltage, where the maximum achievable output force and linear speed were respectively 1.5 N and 100 mm/s, under a sinusoidal driving voltage of 20 Vpp and 44.5 kHz. Compared with the previously reported ultrasonic motor, the proposed ultrasonic motor reveals many advantages, such as simple structure, excellent performance, and low driving voltage, demonstrating its promising applications in precise driving, high accuracy positioning, non-magnetic interference driving, etc.

Rotor Surface Optimization of Interior Permanent Magnet Synchronous Motors to Reduce Both Rotor Core Loss and Torque Ripples

This article describes rotor shape optimization of interior permanent magnet synchronous motors to reduce both rotor core loss and torque ripples. The experimental verification by the prototype motor is also carried out to confirm the validity of the optimization. It is clarified that both the rotor core loss and the torque ripples under typical driving conditions can be significantly reduced by optimizing the rotor surface without considerable deteriorations of the other important characteristics. The mechanism of the design tradeoff for the torque ripples under different driving conditions is also clarified.

Electromagnetic Performance Analysis of 6-Slot/2-Pole High-Speed Permanent Magnet Motors With Coil-pitch of Two Slot-pitches

In this paper, a high-speed permanent magnet (HSPM) motor having 6-slot/2-pole (6s/2p) number combination and 2 coil-pitch windings are developed for domestic appliance application. Two HSPM motors with different layouts of 2 coil-pitch windings are optimized and their electromagnetic performances are evaluated. The best winding configuration is then identified for shorter motor axial length and larger torque density. Since 3-slot/2-pole (3s/2p) HSPM motors with non-overlapping windings have the same winding factor, a comparison between 3-slot and 6-slot motors is also conducted, particularly for torque density, losses, and unbalanced magnetic force (UMF). It shows that 6s/2p PM motors with 2 coil-pitch windings are suitable for high-speed application without UMF and less rotor PM loss. Finite element predicted electromagnetic performances are validated by experiments made on two prototype motors.

Comparative Analysis and Design of Partitioned Stator Hybrid Excitation Axial Flux Switching PM Motors for In-Wheel Traction Applications

A comparative study of new partitioned stator hybrid excitation axial flux switching permanent magnet (HEAFSPM) motors with different partitioned excitation stator topologies for in-wheel traction applications is presented in this paper. The realization approaches of the partitioned stator HEAFSPM motor are discussed, and the motor topology with windings and permanent magnets (PMs) separately setting on different stators is selected in view of the advantageous structure for thermal management. On this basis, two partitioned excitation stator topologies including C-type tooth core and T-type tooth core stator configuration are proposed, and the air-gap flux modulation and flux regulation principle of the motors are analyzed. In addition, the design method of the partitioned stator HEAFSPM motor considering the effect of hybrid excitation sources is provided, and the two motors with different tooth cores are designed respectively. Meanwhile, for a fair comparison, the multiple objectives optimization method coupled with the sensitivity analysis is employed to optimize the two motors. The electromagnetic performances, anti-demagnetization capability, and flux regulation performance of the two motors are all investigated in detail. Finally, two prototype motors are fabricated and tested. Both the theoretical analysis and experimental results verify the effectiveness and reasonability of the motor.

전동휠체어 구동용 표면 부착형 영구자석 동기전동기 최적 설계

This paper proposes the optimal design of a surface-mounted permanent magnet synchronous motor for electric wheelchair applications. The Finite Element Method (FEM) ensures an accurate analysis of the motor. However, its calculation time is too large. Moreover, as the objective function or design variable increases, the computation time increases exponentially. Therefore, a multi-objective function optimization algorithm was applied to reduce the FEM’s analysis time. The optimal design is compared with a commercial motor with the same power output. The stacking length was reduced by 42.0% and the volume was reduced by 34.3%. To validate the proposed design’s functionality, a prototype motor was fabricated and tested. The experiment’s results demonstrated a high similarity to those of the theoretical analysis.

Effect of Pole Shaping on Torque Characteristics of Consequent Pole PM Machines

Consequent pole (CP) permanent magnet (PM) machines offer scope for reducing the quantity of PM material and hence cost compared to more conventional PM machine topologies of the same rating. In this type of machine, the rotor pole arc is usually optimized to realize the largest output torque with pole shaping methods used to reduce torque ripple. However, such approaches tend to be limited by constraints imposed on the pole shapes. It is a common practice to adopt similar PM and iron pole shapes, an approach that does not fully account for the different characteristics of PM and iron poles in CPPM machines, often leading to large even order harmonics in the airgap flux density. This article proposes a shaping method with a variable rotor profile and pole arc span being established by means of optimization by Genetic Algorithm. It is demonstrated that for a fixed quantity of PM material, different PM and iron pole shapes in combination with optimal PM and iron pole arc spans are essential for ensuring both maximum output torque and lower torque ripple when the due account is taken of flux leakage. It also demonstrates that since the flux density in the region under a PM pole is governed by the magnetic potential produced by magnets while it is governed by magnetic reluctance under iron pole, different PM pole and iron pole shapes are necessary to reduce the even-order harmonics in a CPPM machine and consequently to reduce torque ripple. The performances of optimized and more conventional CP machines are compared by finite-element method on 12-slot/8-pole prototype motors.

Simulation Analysis of Fault-tolerant Control for Dual Three- Phase Permanent Magnet Synchronous Motor

According to the demand of aerospace electromechanical servo system, a new type of fault-tolerant dual three-phase permanent magnet motor(PMSM) and its control system with simple structure, high reliability and high power density are proposed. The dual three-phase PMSM's structure and control model are introduced, the fault-tolerant control algorithm for dual three-phase PMSM is proposed, the simulation model is built and the fault-tolerant control simulation analysis is carried out, Based on the dSPACE control platform, the performance of the synchronous motor prototype is tested, the motor test results show the feasibility of the dual three-phase PMSM and its fault-tolerant control algorithm, which establishes the engineering foundation for the further study of high-reliability electromechanical servo systems.

Self‐compensation of torque reaction in an induction contra‐rotating propulsion motor

Torque reaction is one of the most critical issues with current aerial and undersea vehicles. Contra-Rotating Propulsion (CRP) systems are the most popular technique for compensating the torque reaction of floating vehicles. However, the unbalanced load conditions are inescapable in CRP systems, which eliminate the net zero torque reaction and impulse unwanted spinning on vehicle. A new single-phase dual rotor axial flux induction motor has been investigated in this paper that has the ability of self-compensate reaction torque against unbalanced loads. The proposed motor can eliminate the requirement for complicated torque reaction control systems. Finite element simulation shows the expected performance of proposed motor under unbalanced conditions. The simulation results have been verified by experimental testing of a motor prototype.

Rapid Calculation and Optimization of Vibration and Noise of Permanent-Magnet Synchronous Motors for EVs Based on Equivalent Structural Network

Optimizing electromagnetic performance and vibration noise performance simultaneously is important when designing the drive motor for electric vehicles (EVs). This has not been fully explored, and there are only a few relevant studies. To achieve simultaneous optimization, this paper proposes an equivalent structural network (ESN) of stator assembly to calculate the modal distribution and harmonic response transfer functions. Based on the ESN model, the motor’s electromagnetic vibration noise harmonic response, such as acceleration and equivalent radiated power level (ERPL), can be quickly calculated. The feasibility of the established ESN model is verified by structural-field finite-element method (FEM) and modal hammer tests. Based on the modern optimization algorithm and the ESN model, an improved multi-physics and multi-objective optimization design approach is proposed for an optimized design of a 30 kW interior permanent-magnet synchronous machine (IPMSM). The motor’s maximum output torque and ERPL were selected as optimization objectives, and then the ERPL and acceleration were recalculated using structural-field FEM to validate the accuracy of the optimal design. Finally, vibration acceleration tests were carried out on a manufactured prototype motor to verify the feasibility and validity of the proposed optimization design method.

Suppression of Torque Ripple of a Flux-Switching Permanent Magnet Motor in Perspective of Flux-Modulation Principle

In this article, the suppression mechanism of torque ripple for the flux-switching permanent magnet (FSPM) motor is investigated. According to the flux modulation principle, the generation principle of torque harmonics is analyzed, which is generated by the interaction between the radial and tangential airgap harmonics. Based on the analysis, a method to suppress the torque ripple of the FSPM motor is proposed, where the airgap harmonics are newly applied to be the bridge to establish the relationship among torque ripple, torque harmonic components, and key design parameters. To confirm the effectiveness of the proposed method, an FSPM motor with the V-shape permanent magnet (VS-FSPM) motor is selected as the research example. The leading torque harmonics and leading airgap harmonics of the VS-FSPM motor are picked out effectively. Some key design parameters are selected according to the flux modulation principle to improve the leading airgap harmonics and reduce the corresponding torque ripple successively. Furthermore, the torque ripples of the initial and improved VS-FSPM motor are calculated and compared in detail. Finally, a prototype motor is built and tested. Both the theoretical analysis and experimental results verify the effectiveness of the proposed new method.