Position-controlled synchronous reluctance motor without rotationaltransducer

This paper presents a position sensorless control scheme of a synchronous reluctance motor (SynRM) combining a high-frequency current injection method in the low-speed region and the flux estimation method based on the stator voltages in the high-speed region. The rotor has inherent saliency, and its angle can be estimated from d-axis stator current injection and the appropriate signal demodulation in a low-speed region. In the high-speed region, the rotor can be estimated by the stator flux from the voltage information. The scheme gives a robust and dynamic estimation of the rotor angle, independent of the operating conditions, including speed and load conditions. Experimental results of closed-loop speed and position control with a 3.75 kW axially laminated SynRM are given to verify the proposed scheme     

Design of a synchronous reluctance motor drive

A segmental-rotor synchronous reluctance motor is used in a variable-speed drive with current-regulated pulse-width-modulated (PWM) control. The low-speed torque capability is compared with that of an induction motor, a switched reluctance motor, and a brushless DC PM motor of identical size and copper weight. A particular point of interest is the comparison of motors of different types, all with essentially the same frame size and tested under identical conditions. The results suggest that many of the desirable properties of the switched reluctance motor can be realized with the synchronous reluctance motor but with using standard AC motor and control components. The torque capability is lower, but so is the noise level     

Identification of linear synchronous reluctance motor parameters

This paper deals with experimental methods for the identification of linear synchronous reluctance motor (LSRM) parameters. A magnetically nonlinear two-axis dynamic LSRM model is derived. This model accounts for the effects of slotting, saturation, cross-saturation, and the end effects. The parameters of the obtained model are not constant. They are given by the characteristics of the flux linkages, thrust, and friction force depending on the mover position and the direct (d) and quadrature (q) axis currents. These characteristics are determined experimentally by a controlled voltage-source inverter employing closed-loop current control in the d-q reference frame. The proposed model, experimental methods, and determined characteristics are confirmed through a comparison between the measured and calculated results. Two tests are performed: a test at the locked mover, and kinematic control at low speed. The effects of cross saturation under dynamic operating conditions and the effects of slotting can be clearly seen in the measured and calculated results.     

On-line efficiency optimization of a synchronous reluctance motor

This paper deals with an on-line optimum-efficiency control of a synchronous reluctance motor drive. The input power minimization control is implemented with a search controller using Fibonacci search algorithm. It searches the optimal reference value of the d-axis stator current for which the input power is minimum. The input power is calculated from the measured dc-bus current and dc-bus voltage of the inverter. A rotor-oriented vector control of the synchronous reluctance machine with the optimization efficiency controller is achieved with a DSP board (TMS302C31). Experimental results are presented to validate the proposed control methods. It is shown that stability problems can appear during the search process.     

A synchronous reluctance motor with a laminated rotor

Optimal tooth factors and polar overlap are obtained using numerical calculations of an in-plane magnetic field in the active volume of a synchronous reluctance motor (SRM) with a laminated rotor using FEMM 4.01 (Finite Element Method Magnetics, Version 4.01) software. Recommendations for improving the technical and economic indices of an SRM with laminated rotors at the expense of cutouts in ferromagnetic rotor packs and placing compensatory permanent magnets on the way of transverse magnetic flux closure are given.     

Sensorless vector controller for a synchronous reluctance motor

A new high-performance sensorless speed vector controller that implements the maximum torque per ampere control strategy for the inverter-driven synchronous reluctance machine is presented in this paper. It is based on a parameter-dependent technique for online estimation of rotor position and angular velocity at the control rate. The current ripple principle is used to estimate position. The estimates are fed to a conventional closed-loop observer to predict the new position and angular velocity. The very high accuracy of the sensorless control algorithm at both low and high speeds is confirmed by experimental results     

PWM逆变器——磁阻同步电动机驱动系统运行稳定性的分析

研究了由PWM逆变器供电的磁阻同步电动机的运行稳定性,导出了dq0坐标系中PWM 逆变器-磁阻电动机的小信号模型,以稳定度λ作为稳定性能的指标,应用Rout-Hurwitz判据判定系统的稳定性,并分析了电机和系统参数对运行稳定性的影响,所得结论对变频磁阻电动机的设计具有参考价值。     

A permanent magnet‐assisted synchronous reluctance motor

Permanent magnet motors have attracted a lot of attention recently for their potential for saving energy. However, they are only used for certain applications because the magnets are expensive. This paper discusses the optimum design of the low‐cost, highly efficient magnet‐ assisted reluctance motors with a minimum amount of magnets. The motor considered in this study is a multi‐flux barrier reluctance motor. The configuration by which permanent magnets are embedded to the innermost side of the rotor to obtain maximum output with the minimum amount of magnets was evaluated through simulation and experiments with a prototype motor. As a result, we established a method for designing motors capable of realizing the same efficiency as permanent magnet motors with only one‐fourth the amount of magnets. In our experiments, we achieved a high efficiency of 94.5% with a 750‐W motor. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 142(4): 66–74, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10123     

车用永磁同步磁阻电机转子的优化设计

永磁同步磁阻电机充分利用磁阻转矩,有效提高了电机功率密度和降低电机成本。本文首先对永磁电机的磁阻转矩影响因素进行分析,建立了3种不同结构转子模型,利用二维有限元法对电机的重要参数进行了计算和对比分析。综合比较后,对其中一种转子结构进行了优化,通过调整直轴和交轴磁路,提高了电机磁阻转矩的比例及弱磁性能。     

Performance analysis of a reluctance synchronous motor under abnormal operating conditions

In recent years, the application of reluctance synchronous motors to ac drives has been gaining importance. In this paper, the performance of such motors under abnormal operating conditions (such as voltage unbalance) is analyzed and compared to their performance under normal conditions by means of motor current signature analysis. In order to permit an objective comparison of the simulation and experimental results, the influence of the supply time harmonics and constructional asymmetries of the machine is also considered. Detailed mathematical proofs are provided to support the results. Such analysis will be helpful for understanding and identifying stator inter-turn faults unambiguously. To the best knowledge of the authors, such an analysis has not been carried out previously.     

同步磁阻电机混沌系统的自适应滑模控制

针对同步磁阻电机系统在特定条件下出现的混沌现象,提出一种自适应滑模控制方法,构建了同步磁阻电动机混沌系统模型.在此基础上,设计了同步磁阻电机混沌系统的自适应滑模控制器,并运用MATLAB仿真对该控制方法进行了验证.结果表明,该控制方法具有良好的稳定性、准确性与快速性.     

Steady-state performance of a line-start synchronous reluctance motor with capacitive assistance

This paper sets forth the steady-state performance analysis of a connection scheme that improves the power factor and torque with a lower magnetizing current for a line-start synchronous reluctance motor. The machine stator winding is split into two equal halves, one connected to the mains and the other connected to a balanced capacitor. Performance of the machine is improved if the capacitor value is such that the winding to which it connected operate at or very close to resonance in the d-axis. Current in both windings contributes positively to torque production and external control circuitry is not required. Steady-state equations arising from the d–q model gives a direct insight on the operating limits and how this capacitance aids the machines torque and power factor by boosting its direct axis reactance while the quadrature axis reactance remains fairly constant. An equivalent circuit is also deduced from the steady-state equations from which an explicit expression for input impedance of the new machine can be derived. Conditions for unity-power factor at varying load conditions are also examined. A comparison with conventional single-winding synchronous reluctance motor is given. Such comparison is fair because both machines have the same amount of copper and iron. Experimental results are provided to validate the analytical results.     

基于Ansoft的永磁同步磁阻电机建模与仿真

采用Ansoft公司的maxwell 2D模型建立永磁同步磁阻电机模型,构建一个完整的仿真系统.通过对PMa_SynRM模型的有限元分析,得出反电势曲线,以及转子位置变化对应的转矩与磁场的分布情况,并得到最大转矩下弱磁控制角度,仿真结果为PMa_SynRM的优化设计及进一步研究提供了理论依据.     

Vector control of a synchronous reluctance motor includingsaturation and iron loss

The application of vector control to a conventional synchronous reluctance motor (VCSynRM) is presented with emphasis on the effects of saturation and iron losses. It is shown experimentally that these parasitic effects can significantly influence the performance of a VCSynRM. A synchronous reference frame steady state model of SynRM including saturation and iron losses is developed. The behavior of a vector-controlled SynRM is analyzed based on the model. It is observed that saturation and iron losses can have a significant effect on the performance of a VCSynRM. To verify the validity of the model for vector control, a digital signal processor (DSP) based vector controller was built for a 7.5 hp SynRM to experimentally evaluate performance. Experimental results concerning optimal torque/ampere and optimal efficiency operation are shown to be in general agreement with the predictions of the model     

Performance of PM-assisted synchronous reluctance motor forhigh-efficiency and wide constant-power operation

This paper examines the design and the performances of a permanent-magnet assisted synchronous reluctance motor (PMASRM) for wide constant-power operation. The effects of properly adding magnets into the rotor of a synchronous reluctance motor are examined by several experimental results and analyses on the prototype machines. The proposed machine can offer a large constant-power speed range, high-efficiency and high-power-factor operation in comparison to the complete synchronous reluctance motor. It was shown that the problems such as the decrease of efficiency at light-loads and the uncontrolled generator mode operation, which occur in the high-speed flux-weakening operation of the conventional PM motor drives, can be eliminated in the PM-assisted synchronous reluctance motor     

Analysis of a polyphase synchronous reluctance motor with two identical stator windings

This paper presents the performance analysis of a cageless two-stator-winding reluctance motor which is capable of developing reluctance torque at good power factors in the absence of inverter control. The machine stator has two separate identical polyphase windings whose pole numbers are the same as that of the cageless rotor. The machine performance is investigated using the traditional circle diagrams, and the d–q rotor reference frame equations derived in space-vector form by applying the concept of winding functions. Core loss and saturation are accounted for in the developed dynamic model. It is shown that if one winding is connected directly to the supply and the other fed with a balanced capacitor, the developed torque is superior to a brushless doubly-fed reluctance machine (BDFRM) of similar size. Other motor characteristics, its line-start behaviour and torque ripples are also presented and discussed. Experimental results corroborate the simulations.     

大功率永磁辅助同步磁阻牵引电机磁极优化

永磁牵引系统是下一代轨道交通的发展方向,但高速惰行、带速重投和匝间短路等难题阻碍了永磁牵引的应用,永磁辅助同步磁阻电机是解决上述难题的最佳选择。总结了永磁辅助同步磁阻电机的设计方法,设计了3层U型磁障大功率牵引驱动电机,给出了各层磁障对应的极弧系数和磁障张角以及永磁体最佳尺寸比。提出用偏心气隙结合不均匀磁桥对磁极结构进行优化。发现气隙比为1.63时,抑制转矩脉动的效果最佳;而不均匀磁桥不仅可以降低转矩脉动,还使转子的机械强度得到提高。对所设计的380 kW永磁辅助同步磁阻牵引电机的分析表明,所提出的方法可有效地降低转矩脉动。     

电动汽车用永磁同步磁阻电机电感测试方法

基于电动汽车用永磁同步磁阻电机运行区域内磁路饱和程度与交叉磁化程度变化较大,目前没有理想的测试设备和方法能够准确地获得电机工作域内d、q轴电感参数,需要完成大量的控制器标定实验工作才可以实现最优控制.因此通过公式推导及测试方法研究,提出两种适用于这类电机的电感测试方法.一种方法是在电机无法驱动的情况下静态测试,通过对电...     

Control of synchronous reluctance machines

This work develops a comprehensive approach to the control of inverter-fed synchronous reluctance machines (SYNCREL), based on the machine's ideal model. From the theory a control simulation is designed. Simulation and experimental results are presented. The effects of saturation and iron losses are briefly considered     

Optimum design of a multilayer interior permanent magnet synchronous motor using reluctance torque

The report analyzes the results of experiments done with an inverter drive interior permanent‐magnet (IPM) motor. We examine results of both FEM (finite element method) simulation and experiments using a prototype motor with identical conditions set for stator and magnet volume. The results indicated that with magnets implanted inside the rotor, the values for the d‐axis inductance of the motor remained roughly the same, unaffected by the shape or number of layers. However, the q‐axis inductance exhibited significant change. This research report compares an IPM motor having two layers of permanent magnets with a motor having a single layer. The dual layer shows a 30% or greater increase in torque using the same current. These results indicate that this motor is especially effective for such applications as robots, plant machinery, compressor motors, and electric vehicles. © 1999 Scripta Technica, Electr Eng Jpn, 127(1): 64–72, 1999