无刷直流电动机动态性能分析

针对无刷直流电动机实际运行过程中存在的脉动和非平滑现象,基于内部结构特征和工作原理,研究了无刷直流电动机的运动特征和动态特性.从电机齿槽结构、绕组形式、转子位置、换相过程等方面分析了气隙磁场分布特征和对相电流、反电动势波形的关联作用,阐述了造成转速变化和产生脉动转矩的影响机理,讨论了单闭环控制与双闭环控制方式下的电机运行特性.通过搭建系统仿真模型,获得了空载启动、突加负载、变转速等控制要求下电机转速、定子电流和转矩的运行曲线和变化规律.理论分析和仿真实验均有效地阐明了无刷直流电动机的动态性能.     

无刷直流电机转矩脉动抑制研究

在电力电子技术发展的研究中,无刷直流电机系统具有转矩电流比高、转速高、动态性能好、可靠和易于控制等优点,在中小功率驱动场合应用广泛;但缺点是换相转矩脉动大,一定程度上制约了无刷直流电机的应用。为提高电机精度和稳定性,针对无刷直流电机换相转矩脉动的问题,采用补偿方法,分析了HPWM-LON调制方式对无刷直流电机换相转矩脉动的影响,提出了一种直接面向转矩脉动的补偿方法,建立了Psp ice仿真模型,通过对仿真结果的分析和比较,得出了这种转矩脉动补偿方法能有效的抑制转距的脉动,提高性能精度,消除了转矩脉动产生的噪音。     

直流无刷电机的DSP模糊控制系统

基于DSP设计了直流无刷电机的模糊控制系统,阐述了系统硬件主电路设计,以及软件实现的设计方法,为解决直流无刷电机控制中难题,进一步提高系统控制性能,采用了无刷直流电机电流、转速双闭环控制及模糊自整定PI算法的控制策略,较好实现了直流无刷电机控制系统的智能控制。应用了PWM控制的重叠换相法抑制转矩脉动。实验结果及仿真结果表明,该系统控制效果良好,转矩脉动抑制明显,运行可靠的特点,验证了该设计的快速稳定和鲁棒性。     

无刷直流伺服电机换向最优控制

为改善无刷直流伺服电机的换向转矩性能,本文利用逆变器电压控制矢量优化调制的思 想,提出了基于非换向相电流的恒频采样PWM控制的最优换向方案,该方案能有效地抑制换 向转矩脉动,缩短换向时间.实验结果表明,上述方案是可行的.     

无刷直流电机换相转矩脉动抑制的研究

针对无刷直流电机换相时产生的转矩脉动,采用自抗扰控制技术设计出一种自抗扰控制器来消除转速响应的超调,同时通过自身的扩张状态观测器检测系统的相电流脉动和自身的非线性状态反馈控制律对检测到的电流脉动误差值进行补偿抵消,以达到抑制相电流脉动的效果,从而抑制电机的转矩脉动.仿真结果表明,自抗扰控制比PI控制能更好地抑制转矩脉动,提高电机转速的稳定性和系统的可靠性.     

永磁无刷直流电机PWM_ON_PWM调制方式研究

由于非导通相续流电流使得永磁无刷直流电机运行中存在的转矩脉动问题,为了有效抑制转矩脉动,本文通过分析无刷直流电机的工作原理,建立了其数学模型。按照数学模型对现有的几种PWM调制方式进行了比较分析。通过分析可知现有的PWM调制方式都不能够完全消除非导通相续流电流,针对这一问题本文提出了PWM_ON_PWM调制方式。并通过实验证明了该调制方式,可以有效减小或消除由于非导通相续流引起的非换相期间的转矩脉动。     

无刷直流电机转矩脉动的机理及仿真分析

无刷直流电机(BLDCM)以其体积小、可靠性及效率高和其输出转矩大的特性在机器人、精密仪器设备等很多领域中得到了广泛的使用,但其固有的电磁转矩脉动却也限制了其应用的范围,这也是对其研究的重点和难点.介绍了无刷直流电机转矩脉动的成因,并对4种PWM调制方式下产生的转矩脉动进行分析得出最佳的控制方案,最后利用Matlab/Simulink进行建模仿真,对分析结果进行了验证.     

16/12极开关磁阻电机调速系统设计

影响开关磁阻电机推广的主要因素之一就是其转矩脉动较大.为了降低转矩脉动,在传统四相8/6极开关磁阻电机基础上,提出了四相16/12极开关磁阻电机的新型结构.电机控制单元采用处理速度较强的STM32F051C作为该型电机的控制芯片,并通过直接转矩控制算法对电机转矩进行控制.通过在测功机上的空载和加载试验,得出电机在不同工作状态下的绕组电流波形,经测试分析,该系统调速性能良好.     

无位置传感器直流无刷电动机控制系统研究

在分析无位置传感器直流无刷电动机的反电动势换相和启动原理的基础上,建立了利用反电动势换相的换相模块,启动采用“三段式”启动技术。在双闭环调速系统中,电流环采用电流滞环控制,转速环采用PID控制器。仿真结果表明：这种基于反电动势换相的无位置传感器直流无刷电动机控制系统能够正常启动,具有同有位置传感器直流无刷电动机控制系统同样好的静态、动态特性。     

Compensation of torque ripple in high performance BLDC motor drives

Brushless DC motor drives (BLDC) are finding expanded use in high performance applications where torque smoothness is essential. The nature of the square-wave current excitation waveforms in BLDC motor drives permits some important system simplifications compared to sinusoidal permanent magnet AC (PMAC) machines. However, it is the simplicity of the BLDC motor drive that is responsible for causing an additional source of ripple torque commonly known as commutation torque to develop. In this paper, a compensation technique for reducing the commutation torque ripple is proposed. With the experimental results, the proposed method demonstrates the effectiveness for a control system using the BLDC motors that requires high speed and accuracy.     

Simulation and analysis of brushless DC motor drives using hysteresis,ramp comparison and predictive current control techniques

The brushless DC motor with a permanent magnet rotor is considered for the present study. Because of the special structure of the motor, it produces a trapezoidal back electromotive force (EMF). The applied current waveform is rectangular-shaped. Non-ideal effects in the trapezoidal back EMF and motor currents generate a pulsating torque. The reduction of the torque ripple is important from a speed and position control point of view. In the present paper a brushless dc motor drive is simulated and analyzed using hysteresis, ramp comparison and predictive current control schemes. By comparing the results obtained using these techniques, advantages and disadvantages of each technique and its range of applications are discussed.     

基于Magnet的六相感应电动机建模及仿真研究

在Magnet环境中建立六相感应电动机模型,并采用梯形波相电流对其驱动;分析了转矩电流和转子电流的关系,表明梯形波相电流实现了励磁电流和转矩电流的分立控制;对电磁场进行2D瞬态磁场仿真,分析了等磁势分布情况、磁感应强度波形、稳态电磁转矩和转矩电流的关系;添加Motion单元,对电动机的启动性能进行2D动态仿真。仿真结果表明,电动机空载和负载运行时电磁转矩响应速度快,无明显电磁转矩脉动和转速脉动,说明采用梯形波相电流驱动电动机的方法切实可行,仿真参数设置合理,为最终实现电动机的性能优化提供了参考。     

基于动态换向策略的开关磁阻电机控制方法

针对开关磁阻电机(SRM)的自身结构造成的转矩脉动问题以及驱动系统的抗干扰能力,提出了一种基于改进的动态换向策略与改进小波神经网络(WNN)的控制器方案。基于直接瞬时转矩控制(DITC)系统设计了一种动态的换向策略,减少关断以后的相电流,增加开通相电流的被激励程度,进而抑制系统的转矩脉动。此外基于小波神经网络改进了速度控制器,并将系统的输出转矩引入,使得系统能更好地应对扰动,增强系统的鲁棒性。仿真结果表明,与传统直接瞬时转矩控制和基于小波神经网络的转矩控制相比,转矩脉动减少了22.12％到64.14％,负载突变后静态误差仅为0.02r/min到0.01r/min,可以有效减弱转矩脉动且系统的抗扰能力显著提高。     

基于脉冲注入的无位置传感器SRM转矩优化研究

位置传感器的引入,使得开关磁阻电机(SRM)结构复杂,可靠性降低,研究了非导通相注入脉冲的转子位置估计方法,该方法不受电机控制方式,以及绕组电流超越饱和阈值的影响.针对响应脉冲电流产生的扰动转矩,设计了基于脉冲注入法的开关磁阻电机转矩优化系统.通过转速环将转矩差转换为给定转矩,建立合理的转矩分配机制,得到给定相转矩,并将直接瞬时转矩控制(DITC)与电流闭环控制相结合使转矩准确吻合给定相转矩,从而实现电机的循环控制,有效减小了脉冲电流产生干扰转矩对转矩波动的影响.建模仿真验证了方法的可行性:对基于脉冲注入的无位置传感器开关磁阻电机的转矩脉动具有良好的抑制效果.     

基于ANSYS的工业机器人PMSM转矩波动抑制技术

针对当前PMSM控制技术在抑制PMSM转矩波动的过程中,容易受到磁链波动的影响,导致输出绕组电流范围较小,PMSM转矩波动抑制效果差的问题,提出了基于ANSYS的工业机器人PMSM转矩波动抑制技术;通过分析工业机器人机械臂模态结构和静力模型,设计封闭曲柄差动轮系的摆线针轮减速器的传动装置,利用腕部驱动结构,实现工业机器人转动和直线升降运动;分析PMSM转矩波动惯量及力矩,根据PMSM工作流程,为PMSM提供稳定的交流电流;通过构建PMSM数学模型,运用ANSYS有限元分析软件中宏命令,确定磁链矢量方向及定子同步旋转坐标系,对PMSM电机电磁转矩、磁链和转动力矩进行计算,结合转矩方程抑制波动,通过引入负载角改善电机运行性能,实现PMSM转矩波动抑制;实验结果表明,基于ANSYS的工业机器人PMSM转矩波动抑制技术抑制后最高输出绕组电流为24 A,最低为-22 A,与理想输出结果一致,能够有效增大输出绕组电流范围,具有较好的PMSM转矩波动抑制效果.     

永磁无刷电机方波和正弦波驱动的转矩研究

使用电磁场分析软件和Matlab/Simulink仿真工具,分别对永磁无刷电机方波和正弦波驱动时的稳态电磁转矩和动态电磁转矩进行了仿真分析,对两种驱动方式下的稳态电磁转矩的大小、转矩脉动进行了比较。结果表明,正弦波驱动较方波驱动稳态电磁转矩值及转矩脉动减小,动态电磁转矩脉动频率增加,但脉动幅值也同时增加。     

无刷直流电机控制系统的仿真

在Matlab/Simulink环境下,基于无刷直流电机的驱动原理,构建其控制系统模型并进行仿真分析.根据电机转子的位置信号,利用PWM调制方法对无刷直流电机的定子各相绕组电压进行控制,从而达到控制电机转速并获得性能较好的转速曲线.     

A new approach for commutation torque ripple reduction of FPGA based brushless DC motor with outgoing phase current control

Brushless Direct Current Motor (BLDC) has been deployed across several kinds of applications. However, attaining a smooth torque ripple with fast response is relatively tough, as usually this is based on the varied slew rate line current in the commutation period. Hysteresis Current control has been widely used in earlier works for the maintaining incoming and outgoing phase current at the same rate throughout the commutation period. Additionally, this also helps in reducing the commutation torque ripple and delivers successful commutation. The proposed work here uses a relatively simple control technique that is primarily derived on the basis Outgoing-phase Current Discharge Hysteresis Control (OCDHC). This has been characterized to produce low response time and reduced torque ripple which has been suggested to execute in both conduction and commutation intervals. For the implementation of digital controller, we chose Xilinx Spartan 6 FPGA board. The digital controller algorithm is written using VHDL and is dumped on the FPGA. For this purpose we use Xilinx ISE and iMPACT tools. FPGA receives hall sensor output and current from BLDC motor with reduced torque ripple and generates the gate pulses which drive the IGBT switches using OCDHC control. This condition shows that the performance of the system is not primarily based on the motor parameters, excluding the stator resistance. Lastly, results obtained from the simulation and experimental results validate the significance of the proposed control technique based on response time at load conditions that vary at different junctures.     

A new fuzzy logic estimator for reduction of commutation current pulsation in brushless DC motor drives with three-phase excitation

Under the operation of brushless DC motor with three-phase excitation, commutation current pulsation is produced at each commutation at high-speed region. As it can be eliminated when the current slew rates are made equal, a simple and effective fuzzy logic estimator (FLE) is presented first time in the literature to reduce such current pulsation. Its function is to simply regulate the commutation angle accurately to maintain the same current slew rates of commutated phases during commutation, thereby keeping the other phase current unchanged. Unlike previous studies, the presented method does not require torque observer or detection circuits for sensing commutation interval, in addition to commutation time calculation. A genetic algorithm is employed for optimal definition of the FLE’s rule base. The presented method is tested by the accurate simulation, and it is proved that the proposed method is quite capable of reducing the commutation current pulsation and improving the motor output power.

     

ANFIS based multi-sector space vector PWM scheme for sensorless BLDC motor drive

This paper presents a design and development of Multi Sector Space Vector Pulse Width Modulation scheme (MS-SVPWM) for the speed control of brushless direct current (BLDC) motor drive. This control scheme is developed to enhance the performance of BLDC under wide range of speed and load variation. The hardware prototype is developed for 400 W, 30 V, 3000 rpm BLDC motor. The drive consists of uncontrolled rectifier unit for providing DC source to inverterunit. The proposed drive control has been done by implementing MS-SVPWM scheme using ANFIS control. The main function of ANFIS controller is to select the suitable sector for the drive and also predict the mismatching pulses by comparing conventional SVPWM and MS-SVPWM switching patterns. This new switching control technique helps to reduce switching losses of inverter and also improves an efficiency of BLDC system. This MS-SVPWM reduces the DC voltage ripple; Total Harmonic Distortion (THD) and torque ripple to the standard level. To verify and validate the practicality of the proposed system, the simulation is first performed using MATLAB Simulink tool. The hardware system is developed for the MS-SVPWM using DSPIC30F4011controller, the simulation and experimental results are presented.