Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors

Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.

Electromagnetic Performance Prediction for the Symmetrical Dual Three-phase Surface-mounted PMSM under Open-phase Faults Based on Accurate Subdomain Model

The paper presents an accurate analytical subdomain model for predicting the electromagnetic performance in the symmetrical dual three-phase surface-mounted permanent magnet synchronous machine(PMSM)under open-phase faulty conditions.The model derivations are extended from previous accurate subdomain models accounting for slotting effects.Compared with most conventional subdomain models for traditional three-phase machines with nonoverlapping winding arrangement,the subdomain model proposed in this paper applied for the 24-slot/4-pole dual three-phase machine with symmetrical overlapping winding arrangement.In order to investigate the postfault electromagnetic performance,the reconfigured phase currents and then current density distribution in stator slots under different open-circuit conditions are discussed.According to the developed model and postfault current density distribution,the steady-state electromagnetic performance,such as the electromagnetic torque and unbalanced magnetic force,under open-circuit faulty conditions are obtained.For validation purposes,finite element analysis(FEA)is employed to validate the analytical results.The result indicate that the postfault electromagnet performance can be accurately predicted by the proposed subdomain model,which is in good agreement with FEA results.

THREE-PHASE BRIDGE INVERTER FOR 9kW DOUBLY SALIENT PERMANENT MAGNET MOTOR

The three-phase bridge inverter is used as the converter topology in the power controller for a 9 kW doubly salient permanent magnet （DSPM） motor. Compared with common three-phase bridge inverters, the proposed inverter works under more complicated conditions with different principles for special winding back EMFs, position signals of hall sensors, and the given mode of switches. The ideal steady driving principles of the inverter for the motor are given. The working state with asymmetric winding back EMFs, inaccurate position signals of hall sensors, and the changing input voltage is analyzed. Finally, experimental results vertify that the given anal ysis is correct.

Prediction of Core Losses of Three-Phase Distribution Transformer

Transformers are normally designed and built for use at rated frequency and sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause increased operational costs and additional heating in transformer parts. It leads to higher losses, early fatigue of insulation, premature failure and reduction of the useful life of the transformer. To prevent these problems, the rated capacity of transformer which supplies harmonic loads must be reduced. In this work, a typical 50 kVA three-phase distribution transformer with real practical parameters is taken under non-linear loads generated due to domestic loads. The core losses is evaluated using the three dimensional model of the transformer developed in FEM （finite element method） program based on valid model of transformer under high harmonic conditions. And finally a relation associated with core losses and amplitude of high harmonic order are reviewed ＆ analyzed and then a comparison is being carried out on the results obtained by different excitation current in transformer windings.

基于磁链相移原理的不对称交替极永磁辅助同步磁阻电机设计与分析

传统永磁辅助同步磁阻电机(PMaSynRM)无法充分利用永磁转矩和磁阻转矩,该文提出一种新型不对称交替极永磁辅助同步磁阻电机(ACP-PMaSynRM)。基于永磁磁链相移原理,将交替极永磁阵列、不对称磁极和磁障相结合,实现永磁转矩和磁阻转矩的最大值在相同电流相位下叠加,不但提高了永磁转矩和磁阻转矩的利用率,增强了电机输出转矩能力,而且减少了永磁体用量。采用有限元法对比分析了传统和新型ACP-PMaSynRM的电磁性能,验证了所提电机拓扑的可行性。最后,制造了一台48槽14极样机并对其进行了实验验证。

考虑磁链变化率的永磁同步电机失磁故障复合容错控制

针对永磁同步电机(PMSM)失磁故障中磁链变化较快,近似认为磁链变化率为0会导致传统PMSM失磁容错控制方法性能受限的问题,本文提出一种基于智能比例积分微分的无模型超螺旋滑模复合容错控制(iPID-MFSTSMC)方法。首先,构建考虑永磁体磁链变化量的PMSM失磁故障数学模型,根据这一模型设计了磁链滑模观测器,实现了对于磁链及其变化率的观测。此外,针对快速变化的负载转矩设计了负载转矩导数滑模观测器。然后,基于磁链及其变化率、负载转矩导数的观测,设计了iPID无模型容错控制方法,该方法采用超螺旋滑模算法对观测误差及其他扰动进行抑制,改善了动态性能且降低了控制器参数的设计难度。利用Lyapunov稳定性定理证明了所设计容错控制方法的稳定性,并给出了参数的设计条件。最后,在磁链以及负载转矩快速变化工况下,通过仿真和实验分析表明,该方法可以有效减少系统抖振并降低超调量。

船舶永磁同步推进电机的优化I/f起动控制方法

为解决高转矩与高转动惯量的船舶推进电机在开环I/f控制中转速和转矩波动大、电机易失步、效率低的问题,提出一种I/f控制改进方法。通过建立转矩角观测器,调节给定电流矢量的幅值,使其跟随负载转矩变化,提高系统鲁棒性。同时,将电机运行状态推进至接近最大转矩电流比状态,提高电机的运行效率;通过瞬时有功功率调节电流矢量的角速度,降低电磁转矩波动,加快电机的转速收敛过程。最后,在Matlab/Simulink中进行仿真实验,实验结果表明该方法可以显著提高推进电机运行效率和稳定性。

计及磁链和电流的PMSM DTC系统中功率器件键合线老化监测方法

在闭环控制系统中,基于电参数的功率器件老化监测方法是电力电子可靠性领域的难点之一。以永磁同步电机直接转矩控制系统为例,研究基于磁链相图和电流的功率逆变器中功率器件老化状态的在线监测方法。首先,分析功率器件老化的特征,得到键合线老化引起通态电阻增加的结论;其次,研究得到功率器件键合线老化与磁链相图、直轴电流和三相电流峰值变化的关系,进而提出功率器件键合线老化的监测方法;最后,通过多组仿真实验验证了基于磁链相图和电流的在线监测方法均可实现功率逆变器中功率器件键合线老化状态的在线监测。其中,基于磁链相图的在线监测方法需要系统磁链出现一些波动时才易观测,此时功率器件处于失效状态,该方法并不可取;而基于三相电流的监测方法能够更为精确地监测功率器件老化状况,效果更为优越。

一种基于折息最小二乘法的PMSM磁链辨识方法

永磁同步电机(permanent magnet synchronous motor,PMSM)的磁链准确辨识是实现高性能电机控制的基础。针对传统递推最小二乘(recursive least squares,RLS)法受噪声影响小但存在数据饱和,影响辨识精度和动态性问题,以及遗忘最小二乘(recursive least squares with forgetting factor,FRLS)法避免数据饱和但存在参数估计误差与动态跟踪性能矛盾的问题,文章提出一种基于折息最小二乘(recursive least squares with discount factor,DRLS)法的磁链辨识方法。该算法在FRLS法中引入加权因子构成折息因子,采用递推方法进行磁链辨识,减小参数估计误差,提高磁链辨识精度及动态跟踪能力。通过MATLAB仿真及半实物仿真试验,验证所提磁链识别方法的有效性。

Direct Torque Control System and Sensorless Technique of Permanent Magnet Synchronous Motor

The direct torque control theory has achieved great success in the control ofinduction motors. However, in the DTC drive system of Permanent Magnet Synchronous Machine (PMSM)proposed a few years ago, there are many basic theoretical problems that must be clarified. Thispaper describes an investigation about the effect of the zero voltage space vectors in the DTCsystem of PMSM and points out that if using the zero voltage space vectors rationally, not only canthe DTC system be driven successfully but also the torque ripple is reduced and the performance ofthe system is improved. This paper also studies the sensorless technique in the DTC system of PMSMand configures the DTC system of PMSM with sensorless technique including zero voltage spacevectors. Numerical simulations and experimental tests have proved the theory correct. In thecondition of sensor-less, the DTC system of PMSM is wide-rangely speed adjusting, and the ratio ofspeed adjustment is 1: 100.

Research on Open-circuit Fault Tolerant Control of Six-phase Permanent Magnet Synchronous Machine Based on Fifth Harmonic Current Injection

This paper proposes a novel control approach for fault-tolerant control of dual three-phase permanent magnet synchronous motor(PMSM) under one-phase open-circuit fault.A modified six-phase static coordinate transformation matrix and an extended rotating coordinate transformation matrix are investigated considering the influence of the fifth harmonic space on fault-tolerant control. These mathematical models are further analyzed in the fundamental space and the fifth harmonic space after the fault and to eliminate the coupling between the d-q axis voltage equation in the fundamental wave space and the d-q axis voltage equation in the fifth harmonic space, a secondary rotation coordinate transformation matrix is proposed. To achieve the purpose of reducing torque ripple, the fault-tolerant control method proposed in this paper not only takes the minimum copper loss as the constraint condition, but also injects the fifth harmonic current. The experimental result of current and torque is used to verify the accuracy of fault-tolerant control.

V型游标永磁电机功率因数内在机理及其提升方法

基于功率因数内在机理的研究,提出一种提升游标永磁电机(VPM)功率因数的设计方法,该方法采用分层优化,对影响电机功率因数的主要因素,即永磁磁链和同步电感,分别进行了理论推导和优化分析。该文首先对永磁磁链进行了优化设计,利用气隙谐波作为电机结构设计与电机电磁性能之间的中间桥梁,一方面,气隙谐波作为电机参数的设计目标,另一方面,也作为电机功率因数和其他相关电磁性能的设计变量。基于永磁磁链的分析,进一步优化相关参数对同步电感的影响,从而最终确定了VPM电机的优化设计方案。此外,为了验证该方法的有效性,对优化前后电机的电磁性能进行了分析评估。最后对优化后的电机进行了加工和实验测试,理论分析和实验结果表明所提出的VPM电机功率因数优化设计方法的有效性和合理性,提升了VPM电机在轮毂电机直接转矩驱动系统中的应用潜力。

基于磁链预测的永磁直驱风力发电机SVM-DTC技术

永磁直驱风力发电机传统直接转矩控制(DTC)通过查表法选择固定电压矢量来控制定子磁链和电磁转矩,导致磁链和转矩的双重控制要求不能同时兼顾,造成磁链和转矩脉动过大。针对传统DTC的不足,研究了一种永磁直驱风力发电机基于定子磁链预测的空间矢量脉宽调制(SVPWM)DTC方法,通过对下一个控制周期磁链矢量的预测计算需要补偿的电压矢量,并引入SVPWM模块代替查表法来合成该电压矢量。仿真和实验结果表明,此方案能明显降低磁链和转矩脉动,改善永磁直驱风力发电系统的控制性能。

Three-phase AC-DC Converter for Direct-drive PMSG-based Wind Energy Conversion System

In this paper,a wind energy conversion system(WECS)is presented for the electrification of rural areas with wind energy availability.A three-phase AC-DC converter based on a bridgeless Cuk converter is used for power extraction from the permanent magnet synchronous generator(PMSG).The bridgeless topology enables the elimination of the front-end diode bridge rectifier(DBR).Moreover,the converter has fewer components,simple control,and high efficiency,making it suitable for a small-scale WECS.A squirrel cage induction motor(SCIM)is used to emulate a MOD-2 wind turbine to implement the PMSG-based WECS.A direct-drive eight-pole PMSG is used in this study;thus,a low-input-voltage system is designed.The converter is designed to operate in the discontinuous inductor current mode(DICM)for inherent power factor correction(PFC)and the maximum power point tracking(MPPT)is achieved through the tip-speed ratio(TSR)following.The performance of the developed system is analyzed through simulation,and a 500 W hardware prototype is developed and tested in different wind speed conditions.

基于EKF的PMSM失磁故障在线诊断方法

针对永磁同步电机(PMSM)永磁体失磁故障发生时磁链信号不稳定导致难以诊断的问题,提出基于扩展卡尔曼滤波(EKF)的PMSM失磁故障在线诊断方法。构建能够在线识别并动态矫正磁链的EKF方法,该方法可以根据自适应PMSM模型跟踪永磁体磁链信号的真实状态,并且不易受电机参数的影响。同时经过辨识的永磁磁链经过故障检测模块,计算磁链的变化量,判断永磁电机是否发生失磁故障。仿真结果证明:失磁故障检测模块通过分析经扩展卡尔曼滤波动态矫正的永磁磁链,可以在0.1 s内实现高效的故障诊断。

功能磁共振成像在帕金森病患者四肢联动训练时脑功能活动区的协同作用研究

目的 通过采用功能MRI(functional MRI, fMRI)观察帕金森病(Parkinson’s disease, PD)患者四肢联动训练时脑区激活情况,探讨该疗法的干预机制。材料与方法 前瞻性纳入2021年4月至2023年2月在喀什地区第一人民医院就诊的PD患者50例作为病例组,另选取基线资料匹配的健康志愿者30例作为对照组,对两组受试者进行四肢联动时的全脑fMRI扫描。结果 对照组做四肢联动运动时,脑激活区主要有右侧初级感觉运动皮层(sensorimotor cortex, SM1)(t=14.4829, P<0.05),左侧初级感觉运动皮层(t=8.7640, P<0.05),左侧辅助运动区(supplementary motor area, SMA)(t=8.4628, P<0.05),右侧丘脑(t=9.3230, P<0.05),右侧岛叶(t=8.8615, P<0.05),左侧颞上回(t=9.0467, P<0.05)及左侧顶下小叶(t=10.8249, P<0.05)。PD患者做四肢联动运动时,脑激活区主要有右侧SM1(t=10.0234, P<0.05),左侧SMA(t=7.8221, P<0.05),右侧岛叶(t=6.3241, P<0.05),左侧颞上回(t=7.6571, P<0.05)及左侧顶下小叶(t=4.9862, P<0.05)。与对照组对比,PD患者做四肢联动运动时,激活减弱的区域有左侧SMA(t=6.011, P<0.05),右侧岛叶(t=5.610, P<0.05)及左侧颞上回(t=6.781, P<0.05),而激活增强的区域有右侧SM1(t=3.652, P<0.05)。结论 四肢联动训练使PD患者初级运动功能区功能代偿性增强,这对PD患者康复治疗具有理论指导意义。

SVM strategy and analysis of a three-phase quasi-Z-source inverter with high voltage transmission ratio

Herein,we propose a novel three-phase quasi-Z-source inverter with a high voltage transmission ratio to address challenges such as high switching loss and sizeable magnetic components in the basic quasi-Z-source inverter.The proposed circuit topology,control strategy,and related analysis are presented.The circuit topology of the inverter comprises a quasi-Z-source network with an integrated magnetic inductor,an active clamp circuit,a three-phase inverter bridge,and an output LC filter,all of which are connected in series.An improved 12-sector space vector modulation scheme is proposed based on the root-mean-square value of the voltage and the instantaneous value of the current.Furthermore,analyses of the inverter voltage transmission ratio,resonant process,and parametric design guidelines for integrated magnetic inductor and zero-voltage switching conditions are presented.Experimental results on a 1-kVA prototype inverter demonstrate that the proposed inverter exhibits a higher transmission ratio and efficiency than existing inverters;thus,the proposed inverter would have broad prospects in low-voltage DC-AC applications.

高速轴向电励磁双凸极电机设计与特性分析

现代多电飞机技术不断发展,对航空电源系统提出了更高的要求。依据航空起动发电机具有可靠性高、功率密度高、电源容量大的要求,设计了一种高速轴向电励磁双凸极电机(DSAEM)。对电机的基本结构和工作原理进行了描述,建立了电机的数学模型,并通过有限元仿真加以验证,详细分析了电机的磁场、电感、空载特性和负载特性。结果表明,高速轴向电励磁双凸极电机具有完全对称的三相磁链,可输出更稳定的电压,其电机绕组的空间利用率高、功率密度大、效率高,可满足航空电源的基本需求。

考虑磁路交叉耦合效应的永磁同步电机参数计算分析

永磁同步电机凭借其性能优势在多个场合广泛应用,而准确计算电机在不同磁路饱和程度时绕组的直轴、交轴电感和永磁体的磁链等关键参数,是永磁同步电机的高性能控制的关键。但是,在永磁同步电机的磁路交叉耦合效应影响下,绕组电感、永磁体磁链等参数的非线性特性显著,利用传统方法难以准确计算。基于有限元法,考虑电机磁路的交叉耦合效应,计算了内置式永磁同步电机在不同磁路饱和程度时的绕组交直轴电感和永磁体磁链,通过傅里叶分解对参数变化规律进行拟合并得到拟合多项式,通过三维插值多项式系数,并与有限元仿真结果对比验证了该方法的有效性,该方法能大大降低考虑磁路交叉耦合效应时参数表达难度,为高性能永磁电机控制系统的研究奠定了基础。

Current Loop Disturbance Suppression for Dual Three Phase Permanent Magnet Synchronous Generators Based on Modified Linear Active Disturbance Rejection Control

A modified four-dimensional linear active disturbance rejection control(LADRC)strategy is proposed for a dual three-phase permanent magnet synchronous generator(DTP-PMSG)system to reduce cross-coupling between the d and q axis currents in the d-q subspace and harmonic currents in the x-y subspace.In the d-q subspace,the proposed strategy uses a model-based LADRC to enhance the decoupling effect between the d and q axes and the disturbance rejection ability against parameter variation.In the x-y subspace,the 5th and 7th harmonic current suppression abilities are improved by using quasi-resonant units parallel to the extended state observer of the traditional LADRC.The proposed modified LADRC strategy improved both the steady-state performance and dynamic response of the DTP-PMSG system.The experimental results demonstrate that the proposed strategy is both feasible and effective.