Analysis of Torque Ripple of Permanent Magnet Brushless DC Motor

Torque tripple has significant effect on performance of permanent magnet brushless DC motor. This paper presents a mathematical model built for such a motor, the analysis of torque tripple for a brushless DC motor with sinusoidal flux distribution, which is verified by torque tripple experiments run with a test motor, and equations developed for torque tripple resulting from different sator current errors.

Temperature Research of Permanent Magnet Brushless DC Motor for Electric Balanced Vehicle

A power system structure composed of a brushless DC motor and a cycloidal reducer for electric balanced vehicle has been proposed, and the temperature of important components in this structure would be discussed. The loss generated by the cycloid reducer is negligible, it’s only need to analyze the thermal field of motor. Since the temperature change will affect the material properties of the target motor, the electromagnetic and temperature fields, involved in the motor, are selected for coupling calculation to determine whether the final temperature distribution can meet the requirements of vehicle for use.

Guaranteeing the Fault Transient Performance of Aerospace Multiphase Permanent Magnet Motor System: an Adaptive Robust Speed Control Approach

To enhance the fault transient performance of aerospace multiphase permanent magnet synchronous motor(PMSM)system,an adaptive robust speed control is proposed regardless of the phase open-circuit(OC)and short-circuit(SC)fault in this paper,which can be applied for both the redundant motor system and fault tolerant motor system.For aerospace multiphase PMSM system,besides external load disturbance and system parameter perturbation,there inevitably exists the electromagnetic torque ripple in fault transient process,which can degrade the system performance and even cause the system instability.To cope with this issue,the electromagnet torque ripple of the multiphase PMSM system in fault transient process is first analyzed.Then,by considering the electromagnet torque fluctuation caused by fault transient as a system uncertainty,a novel adaptive robust speed control scheme is proposed,while the adaptive law is constructed to emulate the total system uncertainty bound,which include the load disturbance,the parameter variation,and the electromagnetic torque fluctuation due to fault transient.The resulting control can ensure the speed control performance even in fault transient process regardless of the uncertainty,in which no prior estimation of the uncertainty bound is required.In addition,the proposed adaptive robust speed control is demonstrated by a six-phase PMSM experimental platform.The novelty of this research is to explore a novel adaptive robust speed control to strengthen the fault tolerance performance of multiphase PMSM system even in fault transient process,which requires no prior estimation of the uncertainty bound.

Properties of Brushless DC Machine Induced by Permanent Magnets Applied to a Traction Drive

The paper presents a mathematical model ofbrushless DC machine induced by permanent magnets. Its construction uses the classical model of permanent magnet synchronous machine and induced model of power inverter using the serraphil form. The results of the computer simulation were presented for such states： startup, work under active constant load and the behavior of the machine in terms of exponential and stepping change of the power inverter＇s control angle.

永磁同步电机双向DC/DC变换器混合储能设计

为了提高永磁同步电机的发电效率,设计一种永磁同步电机双向DC/DC变换器混合储能方案,并开展性能仿真分析。利用双向DC/DC变换器连接储能部件与负载母线,该变换器的控制性能对系统整体动/静态性能存在明显影响。研究结果表明:在Buck模式下仿真测试得到,双向DC/DC变换器高压侧电流逐渐升高,产生了持续上升的最高输出功率。双向DC/DC变换器与Buck电路达到了合理的参数,能够达到混合储能系统要求达到的稳定性与快速性控制标准。本设计的双向DC/DC变换器主电路与Boost电路各项参数处于较优的状态,能够实现对混合储能系统进行稳定高效控制的目标。电感与电容值满足系统运行要求,可以实现双向DC/DC变换器的快速响应,能够快速控制电流值,并获得稳定的电压参数,能够满足优异的动态调控性能。

Simplified EKF Based Sensorless Direct Torque Control of Permanent Magnet Brushless AC Drives

A simplified extended Kalman filter (EKF) based sensorless direct torque control technique for a permanent magnet brushless AC drive is proposed. Its performance is compared with that obtained with other sensorless methods for estimating the rotor speed and position from a stator flux-linkage. Since the EKF has an inherently adaptive filtering capability and does not introduce phase delay, the technique provides better speed estimates. In addition, the technique is easy to implement and requires minimal computation.

Design optimization of a slotless PM brushless motor with helical edge wound laminations for rim driven thrusters

This paper discusses the analysis and design of a very thin slotless permanent magnet （PM） brushless motor whose stator laminations are manufactured from a single strip of steel that is edge wound into a spiral （like a ＂Slinky＂） and then fitted over the windings that are preformed on the outside surface of a non-conducting former. Analytical and finite element analysis （FEA） are used to determine the con- strained optimum dimensions of a motor used to drive a rim driven thruster in which the motor rotor is fit- ted onto the rim of the propeller and the stator is encapsulated in the thin Kort nozzle of the thruster. The paper describes the fabrication of a demonstrator motor and presents experimental results to validate the theoretical calculations. Experimental motor performance results are also reported and compared with those of a slotted motor that fits within the same active radial dimensions as the slotless motor. The slotless motor, which has longer active length and endwindings, and thicker magnets than the slotted motor, was found to be less efficient and more expensive （prototype cost） than the slotted machine.

Six-step Voltage Control of PM Brushless AC Motors under High Speed Flux-weakening Operation for EV/HEV Applications

The torque-speed characteristics of brushless motor having an interior permanent magnet rotor and a sinusoidal back-emf waveform are compared experimentally when it is operated in brushless AC(BLAC) mode and brushless DC (BLDC) modes with both 2-phase,120° conduction(BLDC-120) and 3-phase,180° conduction(BLDC-180).Particular emphasis is on high-speed,six-step voltage controlled,flux-weakening operation.It is shown that for EV/HEV applications,even for interior PM brushless motors which have sinusoidal back-emf waveforms,in order to achieve maximum torque per ampere capability over wide operation speed range,it is advantageous to employ a hybrid operation mode-BLAC operation in the constant torque region and six-step voltage control(BLDC-180 operation,together with current phase control) in the flux-weakening region.

车用永磁无刷直流电机弱磁控制仿真研究

永磁无刷直流电动机的转矩与转速会对电机的控制精度造成影响,导致电机弱磁控制效果差。为了提升整体控制性能,提出车用永磁无刷直流电机弱磁控制仿真方法。分析车用永磁无刷直流电机弱磁转矩特性,获取电机电磁转矩关系。根据获取结果建立永磁无刷直流电机弱磁控制系统,利用该系统控制电机弱磁的电磁转矩与运行效率,以此实现整体控制。实验结果表明,通过对所提方法开展电机运行效率测试、电机运行稳定性测试,验证了上述方法的有效性。

计及总损耗功率的电动汽车母线电容主动快速放电方法

针对电动汽车遇到碰撞等紧急情况时,高压驱动系统母线电容电压需迅速降到安全电压(60 V),而传统基于PI控制的母线电容主动放电方法存在鲁棒性差、放电时间长和安全性低的问题,提出一种计及总损耗功率的电动汽车母线电容快速放电方法。首先,建立以永磁同步电机绕组作为泄放电阻的母线电容能量流动模型,将逆变器损耗、电机绕组铜耗、电机电感储能等损耗作为总损耗,利用扩展滑模观测器(ESMO)对总损耗功率进行估算,并通过Lyapunov稳定性理论对ESMO的稳定性进行了证明。然后,将观测的总损耗功进行前馈补偿,从而使母线电压快速降低并稳定在安全电压。仿真和实验结果表明,与现有主动放电方法相比,所提放电方法不仅显著减小了放电时间,而且提高了快速放电的鲁棒性和安全性。

应用于交流电机驱动的新型串联绕组拓扑的动态电流控制性能分析

电机绕组的动态电压是影响其电流变化能力的直接因素。为了提升电机的转矩响应速度,从直流电压利用率的角度分析串联绕组拓扑的动态电流控制能力。首先,从拓扑结构出发,相比于三相半桥拓扑,串联绕组拓扑将直流电压利用率提升了73%,这使得其动态电压更加充裕。然后,在不同的转速工况下,分析串联绕组拓扑、三相半桥拓扑以及采用电压修正策略的三相半桥拓扑的动态电流控制性能。最后,经仿真与实验证明,若采用电压修正策略来增大三相半桥拓扑的动态电压裕度,其只在转速接近额定转速时效果才凸显,且提升有限。而采用串联绕组拓扑,其在电压深度饱和下的电流动态响应时间将显著减小。

新型三定子直流无刷电机的设计与特性分析

传统直流无刷电机齿槽分布受限导致气隙磁场波动,会造成转矩输出波动较大,故需要同步匹配设计复杂的驱动控制系统与控制算法。为此,提出一种新型的三定子直流无刷电机拓扑结构。通过等效磁路法计算出三定子直流无刷电机的主要结构尺寸。设计了三定子直流无刷电机的绕线方式和换向逻辑,驱动控制简单。基于Ansoft maxwell仿真软件,建立了电机有限元模型,仿真分析了电机静态磁场分布、气隙面域磁密分布和空载反电动势等。得到了三定子直流无刷电机的转矩特性:其转矩峰值可达8.5 N·m;电感特性:其三相绕组间磁场相互解耦,互感为0,自感平均值为4.5 mH;效率与损耗特性:不计机械损耗的情况下电机理想效率可达92%。研制了试验样机并进行试验验证,有限元分析和试验结果表明:三定子结构电机磁通密度高,输出转矩大,转矩峰值较单定子电机提升了42%;输出转矩波动小,较单定子电机波动降低了30%。在额定转矩为7.5 N·m的情况下,电机转速从启动到500 r/min的响应时间仅为0.8 s;从500~1000 r/min的响应时间仅为1.5 s;从1000~1500 r/min的响应时间仅为2.1 s。

磁悬浮飞轮用BLDC系统的仿真方法与实验分析

对以数字信号处理器(DSP)为控制器的磁悬浮飞轮用无刷直流电机(BLDC)系统,提出了一种在Matlab/Simulink中新的仿真方法,并通过实验,分析了该方法的有效性和适用性。通过构建各种功能模块,如无刷直流电机模块、三相逆变桥模块、逻辑换相模块和控制模块,实现了仿真方法;通过使用C MEXS-函数和子系统封装等Simulink模型优化技术,提高了仿真精度和速度。最后仿真和实验结果吻合较好,表明该仿真方法较为正确,对磁悬浮飞轮用BLDC系统的分析和设计具有重要的实用价值。

永磁同步电机FOC控制下相电流直流分量影响与抑制策略研究

永磁同步电机在矢量控制时需要对电机相电流进行采样,采样过程中参考电平波动等诸多因素都会造成相电流中包含直流分量,此外直流电压注入法等永磁同步电机参数在线估计方法,也会在相电流中引入直流分量。本文详细分析了不同情况下直流分量的产生机理,研究了直流分量对控制效果、转矩脉动、效率等性能的影响。提出一种可滤除三相交流信号中直流分量的数据处理方法,该方法对不同因素引入的直流分量均能起到良好的抑制作用,从而增加控制稳定性,降低转矩波动,仿真和应用实践验证了算法有效性。

微型永磁无刷直流电机的设计与优化

对一款航空用微型永磁无刷直流电机进行了设计,永磁体选用钐钴进行Halbach阵列充磁,并对电机的部分参数进行了优化,与原方案相比,优化了电机的输出转矩。制作了一款实物样机,通过对样机的测试,验证了优化的可行性。

基于改进零脉冲插入法的永磁同步电机相电流重构策略

直流母线单电流采样永磁同步电机系统存在相电流重构盲区,导致电流采样失真,提出一种改进零脉冲插入法,实现相电流重构。首先,分析传统固定零脉冲插入法的缺点,由于各相插入零脉冲作用时间相同,未能发挥“双开关PWM”模式抑制电流纹波的优势;其次,通过各相PWM占空比调整零脉冲时间,延长电流采样窗口,提出改进零脉冲插入法重构策略,消除重构盲区,并针对该方法重构盲区出现其他扇区有效电压矢量的情况,分析其空间电压矢量合成关系,证明参考电压矢量合成的准确性;最后,基于戴维南电路法,提出不同电压矢量作用时的电路简化模型,对比两种方法的电流纹波幅值,并搭建永磁同步电机实验平台进行实验。结果表明,改进零脉冲插入法的电流重构误差低于3%,相比传统方法,电流纹波抑制效果达到50%,相电流畸变率从12.72%下降到6.87%。

基于ANF的共直流母线OW-PMSM低次谐波抑制研究

针对共直流母线开绕组永磁同步电机(OW-PMSM)非线性因素引起的低次谐波,采用基于最小均方(LMS)算法的自适应陷波器(ANF)对系统中3次、5次、7次谐波进行抑制。首先,分析了OW-PMSM中低次谐波产生的机理;然后,借助Matlab/Simulink探讨了120°解耦调制策略消除逆变器侧调制引起的零序电流,研究了ANF提取系统中相应频次的谐波,将提取的电流谐波补偿到电流环中;再次,抑制了由非线性因素等引起的低次谐波;最后,仿真及试验结果表明,采用ANF后系统中3次、5次、7次谐波含量明显降低。

基于混合导通的PMBLDC步进传动定位控制系统设计

本文在传统混合导通基础上提出了一种新的步进定位控制理论,并将其应用于以永磁无刷直流电机为控制对象的伺服系统场合,进行理论分析与仿真研究。以ds PIC为控制核心器件,进行了试验验证。仿真和实验结果表明,应用该步进控制理论的PMBLDC伺服系统具有良好的速度与位置可控性,能够满足现代工业对伺服系统的高要求。同时,本文的研究结果也为PMBLDC在高性能控制场合下的应用提供了参考。

基于BLDC技术自吸泵节能电动机的研制与应用

针对加油站自吸泵交流异步电动机仅存在启动和关停两种状态,无法实现变频控制,故障率高、调速范围小、效率较低等问题,研发了自吸泵永磁无刷直流电动机。现场应用表明:永磁无刷直流电动机可以实现操作人员提枪时电动机低速运转,正常加油作业时高速运转,启动转矩、运行效率、泵体温升、使用寿命等性能特性均优于传统交流异步电动机。在加油站同等操作条件下,永磁无刷直流电动机与传统交流异步电动机相比节约电能大于30%。

驱动超大惯量负载的BLDCM控制系统仿真研究

在直流电机转动惯量的研究中,当负载的转动惯量是电动机的转动惯量2个以上数量级时,永磁无刷直流电动机(BLDCM)在启动以及加、减速时,会产生很大的惯性转矩,调速系统的性能将变差。为了系统的稳定性和保证运转速度,分析研究了BLDCM的数学模型和超大惯量负载的特性,提出了模糊PID控制方法。在Matlab/Simulink中建立了控制系统的仿真模型,进行了仿真实验,仿真结果可以表明,采用模糊PID控制方法系统在调速过程中,超调较小,响应速度快,稳态时无误差。证明模糊PID控制方法适用于BLDCM驱动的大惯量负载调速系统。