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.

Study of Steady-state Performances for a Novel Line-start Single-phase Permanent Magnet Synchronous Motor With Three Parallel-connected Windings

对于三相感应电动机的单相运行,学者们已经提出了多种实用的接线方式,比如Smith接法、SEMIHEX接法。然而,对于三相异步起动永磁同步电动机的单相运行,很少有合适的接法提出。将并联式接法应用于三相异步起动永磁同步电动机的单相运行,提出了一种新型三绕组并联式异步起动单相永磁同步电动机。分析了三相异步起动永磁同步电动机同步运行时以及起动瞬间的正序、负序阻抗,基于对称分量法,对该接法电机的对称运行条件进行分析,得出了电容的确定方法,并利用遗传算法对电容值进行优化。提出了该新型电机稳态性能的计算方法;设计了一台高功率因数和一台低功率因数三相异步起动永磁同步电动机作为样机,并分别将其改接为三绕组高效单相永磁同步电动机,进行实验研究。实验结果表明,低功率因数的异步起动永磁同步电动机更适合改接成新型三绕组并联式单相永磁同步电动机。由低功率因数三相永磁同步电动机改接成的单相异步起动永磁同步电动机在额定负载下运行时,具有与同容量三相永磁同步电动机相近的效率和更高的功率因数。

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.

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.

A Novel Sinusoidal-Wave Permanent Magnetic Motor with High Power Density

A novel high power-density PMSM (permanent magnetic synchronous motor) with independent magnetic flux path for each phase is proposed in the paper. The complex ma thematic model of PMSM is simplified by decoupling of magnetic flux paths between motor phases. In addition, harmonic components are lowered through optimum design of EMF (electric motive force) wave. Thus the ripple torque caused by EMF wave distortion is suppressed. Key words PMSM (permanent magnetic synchronous motor) - phase decoupling - optimum design of back EMF(electric motive force)

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.

Sensorless Control of Four-Switch Inverter for Brushless DC Motor Drive and Its Simulation

The major function of this proposed research is to control the speed of the brushless DC motor with sensor less control for four-switch three phase inverter. This proposed system is simplified the topological structure of the conventional six-switch three phase inverter. In this proposed method, a new structure of four-switch three phase inverter [1] with reduced number of switches for system is introduced to reduce the mechanical commutation, switching losses that occur in the six-switch method. The proposed inverter fed brushless DC motor used in sensorless control schemes which is used for sensing positioning signals. To improve sensor less control performance, four-switch electronic commutation modes based proportional intergral controller scheme is implemented. In this four-switch three phase inverter reduction of switches, low cost control and saving of hall sensor were incorporated. The feasibility of the proposed sensor less control four-switch three phase inverter fed brushless DC motor drive is implemented, analysed using MATLAB/SIMULINK, effective simulation results have been validated out successfully.

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.

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。

开绕组BLDCM直接转矩控制电压矢量特性研究

基于直接转矩控制(DTC)的开绕组无刷直流电机(BLDCM)具有运行效率高、电压矢量多样、控制结构简单等优点,适用于工业领域。根据共直流母线开绕组BLDCM控制拓扑搭建了相应的数学模型,对该拓扑下电压矢量的特性进行理论分析及分类,并将电压幅值不为零的电压矢量分为大、中、小三类。分析结果表明:在相同的运行条件下,大矢量作用下转矩变化率最大,小矢量作用下转矩变化率最小,中矢量居于两者之间。仿真结果验证了理论分析的正确性和控制方法的可行性。

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。

BLDCM两相短路的四步换相容错运行方法

无刷直流电机运行过程中发生相短路,易引起二次故障,造成电机控制系统的功能丧失。针对无刷直流电机绕组两相短路故障情况,提出一种四步换相容错控制策略,确保电机故障后系统继续运行。通过在电机绕组设置电流检测元件,对三相电流进行检测,将连续两次检测值的差值作为特征量进行故障定位;根据定位结果,改变逆变桥功率管导通次序、导通时间,实现对电机两相短路情况下的容错控制,同时实现故障隔离。针对电机容错运行时转矩脉动较大的问题,采用H_PWM-L_ON调制方式并在换相时刻优化占空比,进行转矩脉动抑制。详细阐述电机两相短路容错控制策略的工作机理与换相过程,并对提出的四步换相容错控制策略进行仿真和实验,结果表明,电机容错运行时非故障相相电流峰值接近电机正常运行时的1.5倍,故障相相电流峰值接近电机正常运行时的1.25倍,转矩脉动增加20%,转速波动在5%以内。

基于半桥和全桥斩波非导通相状态分析的BLDCM特性比较

本文根据非导通相的状态,分析了无刷直流电机(BLDCM)半桥斩波(以上桥斩波为例)和全桥斩波控制方式下非导通相端口电压。半桥斩波中,上桥斩波关断时,非导通相正向续流结束后,中性点电压为零。此时非导通相反电动势过渡为负值后,下桥臂续流二极管在负的反电动势作用下正偏,将在非导通相中产生正向电流,使电机有制动电流和转矩,减小了有效出力。全桥斩波中,非导通相续流结束后,中性点电位为电压源逆变器(VSI)直流侧电压的一半,非导通相所在桥臂的上下两个续流二极管均处于反偏状态,不能导通。非导通相反电动势过渡期间,不会产生制动电流和转矩。仿真结果验证了两种斩波方式下BLDCM的运行特性。

无位置传感器BLDCM反电势信号相移补偿研究

无位置传感器无刷直流电机(BLDCM)大多采用反电势过零点法检测转子位置,为消除干扰需对反电势过零信号进行滤波,而滤波电路使反电势的过零点产生与速度有关的相移.针对滤波后反电势过零点的相移问题,本文提出电机在低速段和高速段采用不同滤波器的新方法,解决了动态相移对换相过程的影响.最后给出以TMS320LF2407A为控制核心的实验平台,实验结果表明该方法的正确性和有效性.

基于相位检测的BLDCM滑模控制系统

为提高无刷直流电机(BLDCM)的控制性能,设计了基于新型相位检测方法的滑模控制器。将电机转子相位误差作为基于指数趋近律的滑模控制器的输入信号,同时提出了一种基于状态机的相位检测方法,能够有效提高相位检测的实时性。仿真结果表明,与传统的PID控制系统相比,采用这种方法的BLDCM滑模控制系统动态反应快、无超调,系统的抗干扰能力显著增强,对于适应电机电阻参数的变化具有良好的鲁棒性。实验结果验证了所提出方法的有效性。

新型集成式DRV8301驱动BLDCM的控制器设计

针对无刷直流电机BLDCM(brushless DC motor)的精确控制和快速动态响应的需求,设计了一种新型集成式DRV8301驱动BLDCM的控制器。在分析PID控制算法的基础上,采用增量型PID算法实现速度闭环调节;采用TMS320F28035型DSP为控制器主控芯片,设计了高集成度的驱动保护电路、三相桥式逆变电路以及转子位置检测电路,简化了硬件电路结构,并完成了控制器的软件设计。实验结果验证了所设计的BLDCM控制器具有良好的控制精度和动态响应性能。

基于BLDCM驱动故障容错切换后的转矩脉动抑制

为了抑制无刷直流电机驱动故障容错切换后的转矩脉动,在传统容错状态工作特性的基础上,提出了一种准Z源网络三相四开关逆变器的容错方法.通过故障相的诊断分析,设计了基于准Z源网络三相四开关逆变器的容错拓扑结构.利用MATLAB模拟故障容错状态,并建立了模拟遁甲钻井系统中无刷直流电机的控制系统实验平台进行实验验证.实验结果与仿真结果具有一致性,验证了准Z源网络三相四开关逆变器的容错方法在抑制转矩脉动,减小电机抖动和噪声上的可行性和有效性.

基于EKF相位增益校正的无传感器BLDCM速度控制

通过实验验证了无刷直流电机其反电势为正弦波,因此,非线性观测方程可以通过泰勒级数线性化。在扩展卡尔曼滤波(EKF)估计直流无刷电机转子位置和速度的基础上,对由于端电压检测电路低通特性造成的相位滞后和幅度畸变按转速的不同进行校正,大大提高了转子位置和速度估计的准确性,与电机运行特性媲美具有位置传感器控制。

基于改进型MPC策略的BLDCM转矩脉动抑制

针对无刷直流电机在运行过程中产生的换相转矩脉动,提出了一种基于改进型模型预测控制的控制策略。首先对无刷直流电机换相转矩脉动产生的具体原因进行分析,通过对电机位置传感器信号的检测来确定换相的起始时刻,然后利用推导得出的模型预测方程得到非换相相电流和电磁转矩下一时刻的预测值,并在代价函数中最小化上述两个参数预测值的误差平方以此来决定开关管的最佳开关状态,进而使非换相相电流不发生波动,以此来降低转矩脉动。通过仿真和实验得到:当电机负载转矩为1.5 N·m,以3000 r/min高速运行时,转矩脉动率降低约33%;当电机在400 r/min低速运行时,负载转矩为1.5 N·m,转矩脉动率降低了约23%。该控制策略在全速阶段都能够有效抑制电机运行过程中产生的换相转矩脉动。