逆变器供电永磁直线同步电动机谐波分析

以脉宽调制电压型逆变器供电的永磁直线同步电动机（PMLSM）为求解对象，用分离变量法求解电动机的电流解析表达式，在此基础上分析了电动机的谐波磁场特性及逆变器供电电源产生的推力谐波分量。分析表明，电源的非正弦畸变引起电动机磁场畸变并使电动机推力产生波动。解析结果与有限元方法结果有较好吻合。     

Iron loss analysis of interior permanent-magnet synchronous motors-variation of main loss factors due to driving condition

In this paper, the authors investigate the iron loss of interior permanent magnet motors driven by pulsewidth modulation (PWM) inverters from both results of the experiments and the finite-element analysis. In the analysis, the iron loss of the motor is decomposed into several components due to their origins, for instance, the fundamental field, carrier of the PWM inverter, slot ripples, and harmonic magnetomotive forces of the permanent magnet in order to clarify the main loss factors. The Fourier transformation and the finite-element method considering the carrier harmonics are applied to this calculation. The calculated iron loss is compared with the measurement at each driving condition. The measured and the calculated results agree well. It is clarified that the iron loss caused by the carrier of the PWM inverter is the largest component at low-speed condition under the maximum torque control, whereas the loss caused by the harmonic magnetomotive forces of the permanent magnet remarkably increase at high-speed condition under the flux-weakening control.     

Iron Loss Analysis of Permanent Magnet Motors Fed by PWM Inverter

Carrier harmonic losses that consist of iron loss, eddy current loss, and ac copper loss are produced in a permanent magnet machine driven by a PWM inverter. It is already known that a higher motor inductance can lead to lower carrier harmonic losses. This paper investigates the carrier harmonic loss composition of two motors with identical dimensions but different inductances. The results of finite element analysis (FEA) showed that the eddy current loss in the iron core accounts for most of the carrier harmonic loss. It is also shown that the carrier harmonic loss of the iron core is quantifiable using theoretical calculations.     

基于SVPWM的时间谐波对永磁电机损耗的影响

针对在变频器驱动永磁电机因时间谐波引起的附加谐波损耗大小及分布问题,对基于SVPWM变频器电路输出的电流波形,采用傅里叶计算方法,分析不同变频器参数下的各次电流时间谐波分布规律及波形畸变程度,与SPWM对比发现SVPWM优化谐波程度高,且直流母线电压利用率较优。以一台5kW、3000r/min表面式永磁同步电动机为例,运用场路耦合联合仿真方法,研究附加谐波损耗在永磁电机中的分布特性,计算电机定子铁心各区域的磁通密度变化情况,附加谐波损耗以永磁体涡流损耗为主,其次集中于定子齿顶。参考电机损耗计算的国家标准搭建样机试验平台,通过有限元计算与试验结果的对比分析,校核附加谐波损耗计算结果。     

变频器供电永磁直线同步电动机谐波特性分析及计算

研究了变频器输出谐波电源对永磁直线同步电动机的磁势、电流、损耗、效率等的影响,分别计算了同台永磁直线同步电动机在传统正弦波电源与变频器输出非正弦电源下的效率、功率,分析了谐波问题的影响。给出了补偿变频器输出谐波的方案,采用基于瞬时无功功率理论的ip-iq的谐波电流检测法对谐波进行检测,仿真结果为提高变频器供电电机的绝缘及永磁直线同步电动机的推广应用提供了依据。     

Behavioral modeling of permanent magnet synchronous motor fed by PWM inverters considering iron losses due to carrier harmonics

This paper proposes a new method for behavioral modeling of a permanent magnet synchronous motor (PMSM) fed by a PWM inverter considering the iron losses due to carrier harmonics. In the proposed method, an inductance is connected in series with an iron loss resistance in the equivalent circuit of the PMSM to suppress the harmonic current due to carrier harmonics. The effectiveness of the proposed method is investigated by comparing the numerical results of iron losses of the PMSM obtained using a finite-element method and the newly derived equivalent circuit.     

基于MRAS和SVPWM永磁同步电动机无位置传感器控制

依据永磁同步电动机的动态耦合关系,提出一种模型参考自适应辨识算法来估算转子的位置。永磁同步电动机无位置传感器的调速系统采用空间矢量脉宽调制策略以减小逆变器输出电压的谐波成分,降低转矩脉动。仿真结果证实了模型参考自适应辨识算法对转子位置跟踪准确,系统具有很强的鲁棒性,是实现永磁同步电动机无位置传感器控制的一种实用方法。     

An approach to real-time position estimation at zero and low speedfor a PM motor based on saliency

This paper presents a magnetic saliency-based position estimation approach for a permanent magnet (PM) motor fed by a voltage-source pulse width modulation (PWM) inverter. The proposed real-time estimation algorithm detects motor current harmonics and calculates the inductance matrix, including rotor position information. Position estimation can be performed every period of PWM or carrier cycle. An experimental system using an interior permanent magnet (IPM) synchronous motor has been constructed. Experimental results verify that position estimation within 10° in electrical angle is obtained at standstill and at speeds as low as 1 r/min by the proposed approach     

基于NPC三电平九相磁通切换永磁电机的控制

多电平逆变技术是大容量变频调速的首选方案,结合多相电机技术可以进一步提升调速系统的容量。本文对中点钳位(neutral point clamped,NPC)型三电平逆变器供电的10 k W、九相磁通切换永磁(flux-switching permanent magnet,FSPM)电机调速系统进行了仿真和实验研究,探索结合多电平逆变技术和多相电机技术的调速方案。在三相FSPM电机矢量控制的基础上扩展建立了九相FSPM电机的定子磁场定向矢量控制方法,分析了调速系统采用两种载波PWM方式下产生的电压和电流波形。另外,3、5、7次谐波电流的解耦闭环控制成功消除了直流侧中点电位偏移。最后仿真和实验结果证明了理论分析的正确性和有效性。     

Characteristics of PM synchronous motor drives with a trapezoidal EMF

A permanent magnet synchronous motor (PMSM) with nonsinusoidal electromotive force (EMF) generates torque ripple even if the sinusoidal PWM inverter drives the PMSM. A new modified trapezoidal modulating signal for PWM inverter suitable for PMSM drive with nonsinusoidal EMF is proposed in this paper. A new modulating signal for the PMSM drive is determined by the condition of reducing torque ripple of the motor with various trapezoidal EMF. When the PWM inverter using modified trapezoidal modulating signal drives the PMSM having a nonsinusoidal EMF, the torque ripple of the motor can be reduced, the DC link voltage utilization is improved, and reduction of switching loss can be obtained. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(1): 62–71, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20441     

动磁式永磁无刷直流直线电机的齿槽力最小化

为提高永磁无刷直流直线电机的性能，必须研究减小其齿槽定位力(齿槽力)的技术措施。根据电磁弹射系统需要推进大质量载荷的要求，提出了1种大推力的动磁式永磁无刷直流直线电机模型。用有限元方法计算了磁极端部与定子齿槽相互作用形成的3种齿槽力分量，由傅里叶变换得到了各分量的功率谱。在对各分量进行频谱分析的基础上得出了产生齿槽力的主要原因是电机推力的二次谐波这一结论，提出了优化磁极宽度以减小齿槽力的方法。对优化设计后的电机模型进行了有限元计算和频谱分析，分析显示该电机模型推力的二次谐波已被大大削弱。计算了不同磁极宽度情况下的电机推力，结果表明采用该方法可以有效减小电机的推力波动。     

基于谐波注入算法的变频器驱动下PMSM损耗抑制方法

永磁同步电机(PMSM)在变频器驱动下运行时,受变频器所产生的含量较高的时间电流谐波影响,电机的损耗会大幅增加,这将严重影响到电机运行的安全性与稳定性,而通过对电机本体结构进行优化的传统方法所带来的损耗抑制效果有限,不足以解决问题。针对此,从电机的控制策略出发,提出了一种基于谐波注入算法的PMSM损耗抑制方法,通过对成分含量最高的5次、7次时间电流谐波进行抑制,来降低变频器驱动下电机的损耗。以场路耦合联合仿真模型为计算工具来验证算法的有效性,结果表明在加入谐波注入算法后电机的损耗降低了24.9%,所达到的效果较好,为电机的损耗抑制提供了一种参考。     

Analysis of PWM GTO Current Source Inverter-Fed Induction Motor Drive System

A GTO current source inverter which consists of six main GTO's, two auxiliary GTO's, and three capacitors is presented. This inverter can supply both the sinusoidal voltage and current to the motor by pulsewidth modulation (PWM) techniques. The normal PWM pattern produced by two control signals with the carrier and the modulating waves and the optimal PWM pattern determined by the harmonic analysis are described. The experimental waveforms for 2.2-kW induction motor drives are given and the circuit operation of this inverter in the PWM technique is clearly shown. In addition, the steady-state characteristics of this inverter-induction motor drive system are analyzed by the state-variable methods, and a close agreement between the analyzed and the experimental waveforms is obtained. It is shown that the harmonic components are eliminated or reduced by using the optimal PWM pattern, and the new inverter with sinusoidal current and voltage is very excellent for ac motor drive.     

Energy‐Saving Technologies for Inverter Air Conditioners

Almost all residential air conditioners in Japan are inverter air conditioners in which a permanent magnet synchronous motor (PMSM) is driven by a PWM inverter. The inverter technology can reduce the energy consumption to less than half that of air conditioners driven by a constant‐speed induction motor (IM). This paper reviews the trends and the latest energy‐efficient technologies for the motor and the power converter that achieve considerable energy saving. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于混合有限元解析法的永磁同步电机永磁体电涡流损耗估计

永磁同步电机永磁体受限于热约束,无法在温度较高的环境下运行,故需减少永磁体上的电涡流损耗,从而降低永磁体上的温度。针对使用有限元法对永磁体电涡流损耗估算时间较长,以及使用解析法估算时难以达到与有限元法相同的精度,采用混合有限元解析法估算永磁体上的电涡流损耗。结合电涡流的反作用,在模拟电机旋转时,无需重复划分三角形区域;使用MATLAB软件仿真模拟,将混合有限元解析法与Galerkin有限元法对比,减少三角形区域划分的个数。由此验证了永磁体上电涡流损耗符合端部效应以及集肤效应的特征,在保证精度的同时,减少了仿真的时间。     

用谐波注入抑制永磁同步电机转矩脉动

气隙磁场的畸变和逆变器的非线性特性使永磁同步电动机（permanentmagnetsynchronousmotor,PMSM）电流中含有大量高次谐波,电流波形发生畸变,导致电机电磁转矩脉动。针对这一问题,提出了一种新颖的谐波抑制算法,在建立PMSM谐波数学模型的基础上,利用注入谐波电压的方式来抵消电机运行时电机电流中的谐波分量,改善电机电流波形,抑制电机电流谐波分量和电磁转矩脉动。通过仿真及实验验证了该算法的有效性。该算法不需要增加任何硬件和离线实验测量,具有较强的灵活性和适应性。     

电动助力转向电机控制系统死区效应研究

在汽车电动助力转向(EPS)系统中,逆变器的死区问题是影响转向电机输出性能的主要因素,表现为电流谐波含量增加,引发电机转矩脉动,增加电机附加损耗。双三相永磁同步电机采用2套定子绕组相移30°结构,通过双d-q坐标变换控制使6次谐波电流含量降低,电磁转矩总谐波含量减小。仿真结果验证了所提方法的正确性和有效性。     

坦克用高压两级式矢量控制策略研究

在坦克供电系统中一般为电压等级为900V直流母线电压,传统SVPWM策略需采用两电平高压变频器,以增加功率管数量来承受系统的高压,带来了器件的均压、均流等问题,同时输出电压中谐波含量较高,功率管开通关断也会引入较大的电压尖峰。因此,本文先针对SVPWM输出的PWM波谐波进行了分析,得到了针对THD的最优调制比。提出前级BUCK变换器,后级为三相全桥逆变器两级式拓扑,对比分析两级式拓扑的控制策略与传统单级式控制策略在高压条件下的性能优劣。最后,进行了仿真和实验,结果显示两级式拓扑的永磁同步电机控制策略相比于传统基于三相全桥逆变器的永磁同步电机控制策略,THD得到改善。     

PWM逆变器供电引起的轴向磁通非晶电机谐波损耗的解析计算

非晶合金材料具有出色的低损耗特性,适于用作高频电机的铁心,但PWM逆变器供电会导致高频电机谐波损耗严重增加。在电机初始设计阶段,快速准确计算出谐波损耗是轴向磁通非晶合金永磁电机设计及优化的关键。针对3D时步有限元计算耗时长的问题,改进现有多环等效模型的计算方法,推导了考虑PWM逆变器供电高次谐波电流影响的气隙磁通密度解析计算方法,并在此基础上推导了定子铁心损耗及考虑涡流反作用影响的转子涡流损耗的解析计算方法。将谐波损耗的解析计算值与样机实验值以及3D有限元计算值进行对比,结果显示谐波损耗的平均计算误差仅为9.69%,解析模型具有较高的计算精度。     

适用于电动汽车的PMSM宽转速最优PAM控制

脉宽调制电压型逆变器(PWM-VSI)主要用于变速永磁同步电机(PMSM)驱动中。然而,当PMSM端电压超出直流母线电压时将无法工作。这里提出一种优化的脉冲幅度调制(PAM)控制方法,利用Buck-Boost DC/DC变换器来调整逆变器直流母线电压。考虑到电动汽车上应用需求,该变换器还可实现功率的双向流动。在低速范围内,该系统能减小电压指令的总谐波失真,使电枢电流波形得到改善,转速范围得到扩展。为验证所提出的方法,最后给出了实验结果。