基于改进型积分器的永磁同步电机直接转矩控制

将改进型积分器用于永磁同步电机的定子磁链观测环节,目的在于解决纯积分器存在直流偏移的缺陷.对于系统不同的给定值,固定的截止频率导致改进型积分器的磁链幅值和最佳限幅值不恒定,针对这一缺点本文提出了根据永磁同步电机状态方程来获得磁链比较环节的定子磁链给定值,从而提高了系统的性能,使系统不再受外界给定值的影响.     

Power and energy management of grid/PEMFC/battery/supercapacitor hybrid power sources for UPS applications

This paper presents a hybrid power and energy source supplied by a proton exchange membrane fuel cell (PEMFC) as the main power source in an uninterruptible power supply (UPS) system. To prevent the PEMFC from fuel starvation and degradation and realize their seamless linking in the hybrid UPS system, the power and energy are balanced by the battery and/or supercapacitor (SC) as two alternative auxiliary power sources. Based on the modeling and sizing of hybrid power and energy components, the power and energy management strategies and efficiency measurements of four operating modes in UPS system are proposed. To evaluate the proposed strategies, an experimental setup is implemented by a data acquisition system, a PEMFC generating system, and a UPS system including AC/DC rectifier, DC/AC inverter, DC/DC converter, AC/DC recharger and its intelligent control unit. Experimental results with the characteristics of a 300 W self-humidified air-breathing of PEMFC, 3-cell 12 V/5 Ah of batteries, and two 16-cell 120 F/2.7 V of SCs in parallel corroborate the excellent management strategies in the four operating modes of UPS system, which provides the basis for the optimal design of the UPS system with hybrid PEMFC/battery/SC power sources.     

新型双凸极永磁电机线性模型及静态特性分析

新型双凸极永磁电机的永磁体放置在定子齿的表面,永磁体安装简单且适于高速运转;定子集中绕组中的磁通呈双极性变化,其功率密度比传统的双凸极永磁电机（DSPM）要高。建立了电机基本方程,提出了电机参数的线性数学模型,分析了静态特性,为进一步深入研究作理论准备。     

具有公共联接定子铁心的横向磁场永磁电机二维场模型及磁场分析

介绍一种新型具有公共联接铁心的横向磁场永磁电机的定子组成及其结构特点,主要讨论了采用传统基于单元极三维等效磁网络法进行这种特殊结构形式电机磁场分析的局限性和存在的问题;进而建立了相应的二维场物理模型,并进行了有限元计算,重点分析了公共联接铁心所造成的极间磁路耦合及其对绕组磁链和感应电动势等所产生的影响.样机试验证明了上述分析的正确性.     

电网对称故障下无刷双馈电机低压穿越分析

通过控制电机转子磁场定向得到同步坐标系下的仿射非线性状态空间模型,针对无刷双馈发电机组机侧控制器应用反馈线性化解耦控制方法。在电网电压三相对称跌落下,分析控制电机定子电流和控制电机定子反电动势的暂态响应。推导得出BDFM稳定运行时,控制电机转子磁链与功率电机定子电压满足线性比例关系,在低压穿越模式下来改善系统控制性能和稳定性,提高机组低压穿越能力。仿真结果证明了理论分析的正确性和有效性。     

Optimal Design of Coreless Axial Flux Permanent Magnet Synchronous Generator with Reduced Cost Considering Improved PM Leakage Flux Model

This paper presents an optimal design of coreless axial flux permanent magnet (AFPM) synchronous generator using particle swarm optimization method based on sizing equations of the machine. The design optimization is performed in order to reduce the active material cost of the generator. General practical and mechanical limitations are considered as optimization constraints. A magnetic circuit model based on quasi three-dimensional (3-D) model of the coreless AFPM machine is taken into account to calculate the permanent magnet leakage flux (PMLF) accuracy. A computer-aided program is evaluated according to the proposed optimized design procedure that is used to design a 2-kW, 16-pole AFPM generator with two rotors and one coreless stator. Finally, the 3-D finite-element model (FEM) of the machine is prepared to confirm the validity of the proposed PMLF model and proposed optimized design algorithm.     

Mitigation of transformer-energizing inrush current using grid-connected photovoltaic system

This paper presents a novel technique for suppressing the transformer-energizing inrush current. This technique is based on existing of a Photovoltaic (PV) generation system. Large magnitude inrush current can occur with certain combination of point of wave energization and residual core flux. The PV system is exploited to produce a magnetic flux in the core of the energized transformer in a negative direction of that produced by the main grid during grid-off. In this paper, the wave-energizing instant is optimally chosen and hence the amount of the residual flux existing in the core is controlled to be ready to sink the energizing effect. The impact of existing of PV system that connected to 280 kV, 60 Hz grid is studied at different energizing instances, different power ratings and different solar irradiances. The method is illustrated by simulation results and validated by harmonic analysis. The optimum energizing instances are explored at different working circumstances. The results at transient and steady states verify that the proposed technique enables the minimization of the inrush current by optimized grid-switching instance.     

Dual-stator Interior Permanent Magnet Vernier Machine Having Torque Density and Power Factor Improvement

—An improved topology for a low-speed permanent magnet vernier machine, called a dual-stator interior permanent magnet vernier machine, is introduced to significantly increase torque density and power factor. A dual-stator is adopted in the design for more torque and improving space utilization. An interior spoke-type magnet array in the rotor is designed for magnet flux focusing, which can effectively increase useful flux and force flux lines to pass through the entire machine during operation as opposed to two separate torque components as in a normal dual-stator permanent magnet machine. To clearly place the advantages of the proposed topology in perspective, the proposed dual-stator interior permanent magnet vernier machine is compared to a well-known dual-stator surface-mounted permanent magnet vernier machine. This article discusses the operation principle and magnetic field analysis of the proposed machine and reports comparison simulation results taken from the finite-element method. In addition, the stator tooth is optimized for further better performance on torque density and power factor.     

Permanent magnet synchronous machines with concentrated coil armature windings: analysis and test validation of Single Stator–Double Rotor,axial flux machines

Some design and operation aspects of axial flux permanent magnet synchronous machines, employing armature windings with concentrated coils wound around the stator teeth, are presented. The e.m.f. control is based on the variation of the windings flux linkage, obtained by modifying the stator (or rotor) configuration. Thanks to the high number of poles and the excellent waveform quality, even with deep field weakening, these machines exhibit a satisfactory operation at low speed, both as generators and motors. In the paper, the main constructive machine features are discussed, together with some design and FEM results. A test on a prototype has also been carried out.     

内置混合式转子可控磁通永磁同步电机--记忆电机

提出了一种内置混合式转子可控磁通永磁同步电机.其径向永磁体采用钕铁硼,切向永磁体采用铝镍钴.通过定子直轴脉冲电流控制铝镍钴的磁化方向和强弱,使钕铁硼产生的磁通部分穿过气隙而部分被铝镍钴在转子内部旁路,永磁气隙主磁通从而受控.对两种情况下的电机内部磁场的分布进行了有限元计算和分析,说明提出的设想是可行的.     

基于精确子域模型的双定子磁通反向电机磁场解析计算

双定子磁通反向电机是一种基于磁场调制原理的新型永磁电机,适用于船舶推进、风力发电等低速大转矩的应用场合.相较于传统的磁通反向电机,双定子拓扑能够解除单定子磁通反向电机永磁体和绕组的空间冲突问题,但同时也会增加其边界条件的复杂度.准确计算双定子磁通反向电机的磁场分布是设计、优化电磁性能的关键,而建立精确的数学模型则是求解...     

A simplified approach to continuous on-line tuning offield-oriented induction machine drives

A simplified approach to the continuous online tuning of rotor flux feedforward field-oriented induction machine drives is presented. The procedure offers the advantage of not requiring a special test signal or special test conditions. The approach takes advantage of the stator voltage equations which allow robust parameter-insensitive estimation of the electromagnetic torque while operating at nominal speeds for which the stator IR voltage drop is negligible (≈5 Hz and above). This torque computation is independent of the rotor flux field-oriented control. In essence, the approach uses a stator flux controller to detect improper tuning of the feedforward rotor flux controller. The theoretical and practical implementations of such a continuous self-tuning system are presented. Experimental results are based on a rotor flux feedforward field-oriented induction machine servo drive     

ROTOR FLUX COMPUTATION IN SATURATED FIELD-ORIENTED INDUCTION MACHINES

ABSTRACT

The paper discusses effects of main flux saturation in field–oriented induction machines and proposes improved schemes for rotor flux space vector calculation. Field–oriented control with rotor flux computation out of the measured quantities is elaborated. Two rotor flux computer structures are analyzed. The first one is based on stator voltages and currents as measured variables, while the second scheme carries out calculations on the basis of sensed stator currents and rotor speed (position). The sensitivity of the constant parameter rotor flux computers to saturation degree variation is investigated in detail. Modified structures of the computing schemes are then proposed, which account for change in saturation level in the machine. The modified rotor flux calculators are derived from flux state–space model of a saturated induction machine. Accurate computation of rotor flux space vector is enabled in this way, irrespective of the actual saturation level in the machine. Verification of the developed modified rotor flux computers, which account for main flux saturation, is provided by the aid of digital simulation.     

一种新型的双凸极永磁电机

本文介绍一种新型双凸极永磁电机--磁通反向电机(FRM).该电机的永磁体放置在定子齿的表面,永磁体安装简单且适于高速运转;定子集中绕组中的磁通呈双极性变化,其功率密度比传统的DSPM电机要高.文中对其基本结构、工作原理及特点作了分析.     

Evolutionary computation based multi-objective pole shape optimization of switched reluctance machine

This paper presents the application of elitist Non-dominated Sorting Genetic Algorithm version II (NSGA-II) to determine optimum pole shape design for performance enhancement of Switched Reluctance Machine (SRM). In SRM, torque output and torque ripple are sensitive to stator and rotor pole arcs and their selection is a vital part of SRM design process. The problem of determining optimal pole arc is formulated as a multi-objective optimization problem with the objective of maximizing average torque, minimizing torque ripple and copper loss. In order to account for the geometry as well as for the nonlinearity of material utilized, the Finite Element Method (FEM) is used to determine the performance of the machine. The proposed optimization technique is applied to determine optimal pole shape of an 8/6, four-phase, 5 HP, 1500 rpm SRM. The results show the effectiveness of the proposed approach and confirm the application of NSGA-II as a promising tool for solving SRM design problems. The results obtained by NSGA-II are compared and validated with classical multi-objective approach based on weighted sum method using Differential Evolution (DE) algorithm.     

考虑三次谐波转矩的双五相永磁同步电机串联系统直接转矩控制研究

针对反电动势非正弦的2台五相永磁同步电机串联驱动系统提出一种3次谐波转矩补偿型直接转矩控制策略。首先通过坐标变换建立了考虑3谐波转矩的双五相PMSM串联系统的数学模型,基于电压矢量对转矩的控制关系,分别在2个子空间计算定子磁链增量的期望值;然后根据2台电机定子电压方程,计算出2个平面内电压矢量参考值,并提出一种占空比调制型空间矢量调制算法;最后,通过仿真与实验验证了所提控制算法的可行性。     

新型双凸极永磁电机静态特性的线性分析

新型双凸极永磁电机的永磁体放置在定子齿的表面,永磁体安装简单且适于高速运转;定子集中绕组中的磁通呈双极性变化,其功率密度比传统的DSPM电机要高.文中提出了电机参数的线性数学模型,分析了静态特性.     

基于空间矢量调制的电励磁磁通切换电机转矩角增量控制策略

电励磁磁通切换电机具有转子结构简单坚固,磁链双极性、反电势正弦度高的优点,是一种新型的无刷交流电机。交流电机的2种经典控制策略中,相对于矢量控制(vectorcontrol,VC),直接转矩控制(direct torque control,DTC)具有算法结构简单、动态性能好的优点,但是其电流谐波含量高、转矩和磁链脉动大。为同时提高调速系统的动、静态性能,该文研究了一种基于空间矢量调制(space vectormodulation,SVM)的电励磁磁通切换电机转矩角增量控制策略,定义转矩PI环的输出为转矩角变化量,通过合成空间矢量对定子磁链矢量角增量的直接平滑调节,实现了对电磁转矩的直接线性调节。比较了最大合成空间矢量和基本前进矢量改变定子磁链矢量角的能力。在一台电励磁磁通切换电机上,利用TMS320F2812控制系统进行了传统DTC和该文提出算法的比较实验,验证了所提算法的正确性和有效性,新算法具有优良的动、静态性能。     

Electromagnetic Design and Analysis of a Novel Axial-Transverse Flux Permanent Magnet Synchronous Machine

This paper analyzes a novel hybrid axial-transverse flux permanent magnet (PM) synchronous motor achieving high torque density. The stator pole pitch and the rotor pole pitch are the same. The motor is suitable for vehicle traction systems. The new axial-transverse machine has a single-sided or double-sided air gap. The machine has two adjacent quasi-U stator cores with ring-type winding, and the rotor has two PM groups, one outer and one inner. The shape of quasi-U stator core allows changing the flux path without changing power supply polarity. The analytical expressions of the no-load back-EMF and the torque are derived, after the development of 3-D magnetic equivalent circuit (MEC) model. The 3-D finite element method (FEM) is used to analyze the magnetic field, torque, and cogging torque for different skewings of the PMs.