同步磁阻电机定子电流最优控制

针对磁路饱和对同步磁阻电机运行特性的影响,提出了定子电流最优控制策略。通过有限元法对电感与电流的非线性关系进行拟合,并利用拟合结果得到最优定子电流随转矩变化的运行轨迹,以实现同步磁阻电机最大转矩电流比(MTPA)控制;同时对于交直轴电流环相互耦合的问题,提出磁路饱和补偿的电流环设计,以提高其动静态性能。仿真与试验结果验证了该方案的有效性。     

基于非线性模型的开关磁阻电机关断角对系统性能的影响

关断角是开关磁阻电机驱动系统中一个十分重要的控制参数,尤其是在电机的优化运行阶段,关断角的微小变化往往会影响到电机的性能指标,如有效输出转矩、转矩脉动系数、电流及转速等。基于开关磁阻电机的有限元非线性模型对系统的饱和与非线性电磁特性进行了研究,在Simulink环境下建立开关磁阻电机系统的非线性动态仿真模型,将有限元计算的静态电磁数据导入到系统模型中。在此基础上,针对关断角参数进行了仿真研究,分析了关断角对开关磁阻电机系统转矩脉动、有效输出转矩的影响。结果表明：综合考虑各性能指标,合理选择关断角有助于实现开关磁阻电机系统的优化运行,从而提高电机的运行效率。     

基于改进滑模观测器的SynRM无位置传感器控制

针对存在强耦合强非线性的同步磁阻电机无位置传感器控制问题,提出一种考虑磁路饱和的改进滑模观测方法。首先通过有限元仿真获得电流与电感的数据组合和考虑电感变化的最大转矩电流比曲线,以实现电流的最优控制;其次对传统滑模观测器进行改进,用分段指数型饱和函数替代符号函数,减少滑模的固有抖振,并采用正交锁相环技术对电机转子位置与转速进行估算。最后在Matlab/Simulink中搭建仿真模型,仿真结果表明,本文所提出的无位置传感器控制方法在同步磁阻电机转子位置与速度估算上具有良好效果。     

基于参数辨识的PMASynRM控制策略

针对永磁辅助同步磁阻电机(PMASynRM)参数变化大,依据固定参数进行控制容易导致控制精度差的问题,考虑电机磁饱和对参数的影响,基于电感参数（Ld、Lq）离线辨识技术,采用一种自适应的最大转矩电流比(MTPA)控制策略,实时动态地分配最佳的d、q轴电流,以实现对永磁辅助同步磁阻电机宽速度范围、高转矩精度、高效率的控制。通过仿真和实验,验证了所采用控制方法对永磁辅助同步磁阻电机高转矩精度控制的有效性。     

无轴承同步磁阻电机的悬浮系统控制策略

传统无轴承同步磁阻电机悬浮系统控制方案的前提都是获取转矩绕组和悬浮绕组的电流,没有考虑转矩绕组气隙磁链影响,影响悬浮系统控制精度。重新建立了基于转矩绕组磁链的无轴承同步磁阻电机悬浮力方程,采用电压-电流模型法观测转矩绕组气隙磁链,设计了新型滤波环节,实现了基于转矩绕组磁链观测的无轴承同步磁阻电机悬浮系统独立控制。对样机控制系统进行了仿真和实验研究,仿真和实验结果表明该控制方法使悬浮系统具有良好的动、静态性能。     

铁氧体辅助同步磁阻电机转子优化设计

与同步磁阻电机相比,铁氧体辅助同步磁阻电机的转子中由于含有铁氧体,其磁路及饱和程度均发生了变化,因此不能简单的认为铁氧体辅助同步磁阻电机只是在同步磁阻电机基础上插入铁氧体,而需要结合铁氧体辅助同步磁阻电机的特点进行优化设计。本文基于有限元方法,针对铁氧体辅助同步磁阻电机转子结构进行了优化设计,以提高最大转矩电流比及削弱转矩波动。考虑到铁氧体的低温退磁特性,对铁氧体辅助同步磁阻电机的最大去磁电流进行了校核,并且针对铁氧体退磁问题进行了深入地研究。最后,基于上述研究提出了铁氧体辅助同步磁阻电机的相关设计准则,并且制作样机以验证电机设计的有效性。     

考虑饱和的永磁电机直接转矩控制系统精确仿真模型

为了准确分析永磁同步电机直接转矩控制系统的实际动态特性,针对电机电感参数值会受磁路饱和的影响,给出了一种考虑饱和的永磁电机直接转矩控制系统的建模方法。结合冻结磁导率的方法利用时步有限元程序计算得到永磁电机d,q轴电感与电枢电流的非线性关系,并给出了永磁电机d-q坐标系下的非线性数学模型。利用该模型在Matlab/Simulink环境下搭建了考虑饱和的永磁电机直接转矩控制系统,并与线性永磁电机模型施加不同等级负载下的仿真结果做比较分析。结果表明该方法是正确和有效的,该模型能反应磁路饱和对永磁同步电机直接转矩控制系统运行特性的影响,对于永磁电机直接转矩控制系统的精确仿真建模有重要的参考意义。     

基于Simulink的三相开关磁阻电机调速系统仿真研究

根据开关磁阻电机的特性,建立电机数学模型,分析了电机工作原理及电机运行中的相电流、磁链和位置角三者之间的关系;在Matlab/Simulink环境下搭建开关磁阻电机调速系统模型,仿真分析了电压、开断角对电机转速、转矩、电流的影响;基于仿真分析,设计了电流、转速双闭环调速控制系统,并将其与电流斩波调速控制系统进行对比,仿真结果表明,电流、转速双闭环调速控制具有起动快、脉动小和运行稳定等优点,更适用于开关磁阻电机的调速控制。     

一种同步磁阻电机凸极比的解析计算方法

凸极比是影响同步磁阻电机功率因数和转矩性能的关键参数,本文提出了一种基于等效磁路法的同步磁阻电机交直轴电感和凸极比分析计算方法,可以分析转子磁障结构改变对凸极比和电机性能的影响,快速进行同步磁阻电机的转子结构优化设计。为验证磁路法的可靠性和准确性,论文采用有限元法对一台30 kW同步磁阻电机进行了仿真分析,计算电机在不同转子磁障层数、不同磁障宽度、不同径向磁桥数量时的交直轴电感值、凸极比和输出转矩,并与磁路法得出的结论进行了对比。     

混合励磁磁悬浮开关磁阻电机转矩建模与分析

针对传统磁悬浮开关磁阻电机的输出转矩小及转矩与悬浮的耦合问题,提出一种四相16/14/8极混合励磁双定子磁悬浮开关磁阻电机。介绍了该电机的拓扑结构、转矩原理与悬浮原理,并优化了转矩绕组的励磁方式,运用有限元法比较分析了该电机与同参数不加永磁体电机的电磁特性,包括电机的转矩特性以及解耦特性,仿真结果验证了该电机自解耦结构的合理性及能有效提高输出转矩。在麦克斯韦应力法基础上,根据电机工作时的磁通分布建立了等效磁路图,采用分段函数拟合铁芯磁化曲线,推导出了考虑磁饱和的转矩数学模型,有限元仿真分析验证了转矩模型与仿真结果较吻合,最小相差约1.4%,最大相差约26%。     

Direct Torque and Flux Control of a Four-Switch Three-Phase Inverter-Fed Synchronous Reluctance Motor Drives

This paper presents an application of direct torque and flux control (DTFC) for a four-switch three-phase inverter (FSTPI)-fed synchronous reluctance motor (SynRM) in which the saturation and iron losses' effects are involved in the machine control modeling. The DTFC switching technique for the SynRM fed by FSTPI in low-power and low-cost applications is implemented by imitating the six-switch three-phase inverter (SSTPI). By considering equal effective vectors depicted in SSTPI, the αβ stationary reference frame is represented by using six sectors. Similarly, the voltage space vector formation is constructed in FSTPI. Accordingly the SynRM performance under DTFC is precisely analyzed by considering the saturation and iron losses' effects. The DTFC behavior based on SSTPI- and FSTPI-fed SynRM is evaluated using Simulink benchmark. At different operating conditions, further simulation and experimental results of DTFC based on FSTPI dynamically confirm the effectiveness of the proposed control application on the SynRM.     

同步磁阻电机转子结构优化设计

同步磁阻电机(SynRM)具有效率高、成本低、结构简单等优点,但其存在转矩脉动大等问题,会影响电机的平稳运行。为了降低SynRM的转矩脉动,需要对转子结构进行优化。以一台22 kW四极的SynRM为例,采用田口法对不同电流负载下的SynRM转子结构进行优化。确定SynRM的转子拓扑,探究SynRM转子结构的关键参数对转矩性能的影响,初步确定转子关键参数的范围。利用田口法对不同电流负载下的电机进行试验分析,得到最优转子结构参数组合,利用有限元仿真验证优化结果。为了增强转子的机械强度,在转子结构中添加径向磁桥,探究径向磁桥对电机转矩性能的影响。     

Sensorless induction machine observation with nonlinear magnetic characteristic

This paper addresses the problem of state estimation in induction motors. Generally, the motor observer design has been dealt based on standard models neglecting the saturation effect in the magnetic characteristic. As a matter of fact, magnetic saturation cannot be ignored especially when considering control strategies (speed and torque) that involve large flux variations. Such large flux variations are necessary to meet optimal operation conditions in the presence of wide range load torque changes. On the other hand, it is well known that use of mechanical (speed and torque) sensors entails reliability issues. In this paper, a new sensorless adaptive observer is designed for induction machine based on a model that accounts for the nonlinear feature in the magnetic circuit. The observer consists of two interconnected state‐dependent gain observers and is formally shown to provide accurate estimates of the mechanical and magnetic variables using only stator current and voltage measurements. Copyright © 2013 John Wiley & Sons, Ltd.     

Evaluation of third harmonic component effects in five-phasesynchronous reluctance motor drive using time-stepping finite-elementmethod

Interaction of the third harmonic magnetic field with the third harmonic current in a five-phase synchronous reluctance motor (SynRM) can produce additional torque. However, it is still not clear about the SynRM power factor and its impact on the associated power converter because of the third harmonic components. Using time-stepping finite-element method, a mathematical model of the SynRM, which allows any desired harmonic component in computation, is presented. Performance of the five-phase SynRM with two rotor structures has been computed. The study finds that contribution of the third harmonic current to the output torque depends on the rotor structures. It is also shown that the required terminal voltage to regulate the desired current waveform is substantially increased, a result not reported before     

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     

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     

永磁同步电机初始磁极位置检测方法

根据永磁同步电机相电感的饱和效应,提出了一种恒压源作用下的相电流响应来获得电机初始磁极位置的检测方法,并针对制动器打开瞬间容易出现因磁极位置不准而造成无法定位的问题,对位能性负载提出了一种基于位置环的快速定位法。该方法根据电机实际转动的角度来反向移动给定电流矢量,实现快速定位。最后通过计算不同幅值电流矢量二次定位转过的角度来获得精确的磁极位置。所提方法能够准确获得电机初始磁极位置,可适用于不同类型的永磁电机。实验证明:该控制方法结构简单,易于数字控制实现,同时具有较强的通用性和鲁棒性。     

ANALYSIS OF A VARIABLE-SPEED SYNCHRONOUS MOTOR DRIVE INCLUDING MAGNETIC SATURATION,SALIENCY, AND CURRENT LIMIT

Abstract

A method is presented for evaluation of the performance of a voltage-fed variable-speed synchronous motor drive. Special features include a treatment of magnetic saturation in a machine with rotor saliency and the incorporation of a current limit. Ranges of load angle and frequency, or speed, are covered and a variation of rotor excitation with speed can be included. The method of computer solution is described and examples are given and compared with measured results. The work is intended for use with drives having load angle control and is particularly relevant to cases having characteristics similar to those of d.c. series motors, in which high saturation occurs at low speeds.     

A comparative performance analysis of induction and synchronous reluctant motors in an adjustable-speed electric drive

This article is concerned with comparative analysis of the energy performance of induction motors (IM) and synchronous reluctance motors (SynRM) in an adjustable electric drive. A feasibility study of an economically viable adjustable electric drive with a SynRM of improved design that is free from electric losses in rotor winding and corresponds to the highest energy-efficiency classes (IE3 and IE4 according to GOST (State Standard) R 54413-2011) is carried out. Results of the comparative analysis of operating and power characteristics of the IM and SynRM with the same stator design are presented in respect to pumps using various principles of control. It is shown that the advantage in the SynRM efficiency is achieved to the fullest extent when the electric angle between the current vector and the axis of the maximum rotor magnetic conductivity is constant. The calculations are performed on the basis of the ac-motor equivalent circuit. A calculation of equivalent circuit parameters for motors of a certain power is performed on the basis of nominal data on the IM being considered. At the same time, the SynRM parameters are calculated from the ratio of inductance parameters for a particular rotor design according to the literature. It is concluded that the SynRM efficiency can be significantly higher than that of the IM of the same power in the entire range of electric-drive speed regulation.