An approach to position sensorless drive for brushless DC motors

The authors describe a brushless DC motor without a position sensor. Variable speed is achieved by adjusting the average motor voltage, just like chopper control of DC motors. The position sensorless drive proposed is based on detection of the conducting interval of free-wheeling diodes connected in antiparallel with power transistors. This approach makes it possible to detect the rotor position over a wide speed range, especially at a lower speed. Experimental results obtained from a prototype brushless DC motor of 300 W rating are shown to confirm the validity of the sensorless drive from 45 to 2300 r/min. A starting procedure of the motor is also discussed because it is impossible to detect the rotor position at standstill     

Synchronous and slip-ring induction motors drive cement mills

In the process of selecting a suitable motor for a cement mill, there are several issues to consider that, for the purpose of analysis, can be grouped into two distinct categories. The first category is the technical analysis, which is based on engineering considerations that evaluate the merits of either a synchronous or a slip-ring induction motor installation. The second category is the economical analysis, which follows closely the results of the technical evaluation with emphasis on the original investment cost and the cost of operating and maintaining the equipment over its useful lifespan-estimated as 30 years. Among the technical issues, the first should be identifying the torque requirements and initial power system limitations. The choice of motor design will largely depend on these requirements. The other issues relate to electrical energy savings. With the cement mill being the largest single power consumer in the plant, the choice of motor and drive will directly influence these savings, which can be significant. Several cement mill installations in operation today are discussed     

一种特殊直流无刷电机的驱动及调速系统

给出了一种特殊的无刷直流电动机的驱动及调速电路的解决方案 ,该电机主要用作定位系统的陀螺仪 ,由于对速度的稳定性要求较高 ,因此需要稳速电路 ,驱动电路主要用于快速起动。     

差调制无刷双馈电机转子绕组设计及性能分析

针对传统无刷双馈电机转子耦合能力差、谐波含量高,导致电机功率密度偏低的问题,提出一种磁场"差调制"条件下运行的无刷双馈发电机转子绕组的通用设计方法.介绍了磁场"差调制"和"和调制"两种无刷双馈电机的工作原理,给出了磁场"差调制"无刷双馈电机转子绕组的设计实例,与6联等匝转子绕组的性能进行了对比,并以1/5对极无刷双馈发...     

不同转子结构无刷双馈电机的运行特性对比

在阐述无刷双馈电机(BDFM)不同转子结构特点的基础上,针对无公共笼条、带公共笼条、带公共笼条公共端环、笼条加磁障、凸极加笼条、ALA磁阻等6种不同转子结构的BDFM,进行了二维瞬态电磁场有限元计算,通过气隙磁场谐波的频谱分析,比较了不同转子结构对BDFM磁场调制效果的影响.研究了不同转子结构BDFM在单馈异步运行以及双馈同步、亚同步和超同步运行时的转矩与转速动态特性.探讨了在控制绕组频率一定的情况下,控制绕组电压大小对转矩和转速稳定性的影响.通过与相关文献的对比,验证了结果的正确性.研究结果揭示了不同转子结构对BDFM磁场调制效果和动态特性的影响,为BDFM的转子结构优化设计和运行稳定性的深入研究奠定了基础.     

双定子无刷双馈发电机绕组分布对性能影响分析

针对传统无刷双馈发电机存在功率密度低的问题,提出改善功率密度的一种新型笼障转子耦合双定子无刷双馈发电机.由于该发电机输出功率与内外单元电机电磁特性一致性相关,而内外定子绕组电动势相位和幅值需满足电磁特性一致性的要求,因此需研究绕组分布对该种电机性能的影响.为此,根据电机的结构,分析该发电机不同绕组层数和不同绕组位置对电...     

Direct torque control for brushless doubly-fed machines

Work has illustrated the potential benefits of brushless doubly-fed machines in adjustable speed drive applications. While it has been shown that the drive is open-loop stable over a wide speed range, the resultant steady-state and dynamic performance characteristics are far from optimum. Thus, a closed-loop controller is desirable to achieve competitive drive performance. The controller proposed here is applicable for general purpose industrial drives in the medium to high power range. The nature of the doubly-fed machine, with two separate sources of excitation, only one of which is controllable, rules out field-oriented control strategies applied to conventional induction machines. However, the concept of direct torque control based on instantaneous error shows promise for this machine geometry. The present paper extends the concept of predictive torque control for induction machines to the doubly-fed machine. The controller calculates the value of converter voltage which leads to desired changes of flux and torque. Once the voltage is determined, conventional algorithms, such as space vector pulsewidth modulation (PWM), can be used to generate the inverter switching function     

级联式无刷双馈电机的模型与仿真研究

介绍了级联式无刷双馈电机的结构与原理,推导了该电机在转子速旋转坐标系下的数学模型.基于该数学模型,在Matlab/Similink环境下编写S函数,建立了级联式无刷双馈电机的仿真模型,并对电机的运行特性进行了验证,为该类电机用于大功率风力发电领域的研究铺垫理论基础.     

凸极转子无刷双馈电机的电感参数计算及转子设计

针对凸极无刷双馈电机两套定子绕组难于进行参数计算的问题,在传统的绕组函数法的基础上,应用分段函数来描述绕组函数以及反气隙函数,以此来计算有着两套绕组的无刷双馈电机定子功率和控制两套绕组的各自自感及互感,然后以此方法应用于转子形状的优化设计中,针对一系列极宽度不同的转子计算其自感和互感,并利用计算结果得到了最优的转子极宽度。通过与有限元数值计算方法所得到的计算结果进行对比,证明了提出方法的准确性,在计算转子极宽度最优值的应用中,体现了此方法的工程价值。     

无刷双馈风力发电机组的模糊自适应控制

针对变桨距并网型风力发电机组的最大功率跟踪及改善电能质量问题,采用新型无刷双馈电机构成风力发电机组．基于DSP控制的电力电子装置来改变无刷双馈电机控制绕组电流的频率、幅值、相位,设计了模糊控制器,使得额定风速以下时,根据风速变化,控制电机转速获得最佳叶尖速比,实现最大功率跟踪和变速恒频;额定风速及以上时,控制风轮的桨距角及风力机转速,调节叶尖速比,实现风力发电机组的恒功率输出及频率恒定。仿真结果表明,比传统PID控制器能更有效地减少振荡,较快地达到稳态,提高了风能转换系统的效率和质量。     

笼形转子无刷双馈电机启动特性分析

无刷双馈电机在启动过程中受到功率绕组和控制绕组产生的异步转矩的综合作用,使得电机启动过程比较复杂,而采用合理的启动方法是改善BDFM启动性能的根本途径.在Matlab/Simulink环境下,利用BDFM的转子速坐标系下的d-q数学模型,对BDFM在不同启动方法下的启动性能进行了仿真分析,对比研究了异步启动、直流同步、亚同步以及超同步过渡过程中电流等参数的变化规律.研究结果表明:采用单馈异步启动的方法容易实现,但可能会产生较剧烈的振荡或失步现象,转动惯量和负载转矩等参数会影响电机异步启动后的稳定速度.双馈变频启动方法虽可实现平稳启动,但控制复杂.     

多跨距无刷双馈电机转子绕组设计及特性分析

针对无刷双馈电机谐波大,效率低的问题,基于齿谐波原理和不等匝绕组理论,提出一种基于混合式转子结构的多跨距复合式的无刷双馈发电机转子设计方案,这一具有磁阻效应的混合式转子绕组结构能有效的提高转子导体利用率,提高无刷双馈电机功率绕组的输出功率,并能显著降低与无刷双馈电机两种主要基波极对数相近的谐波含量,对于降低无刷双馈电机...     

无刷双馈电动机主要尺寸的探讨

从传统电机的设计原则和无刷双电动机的基本原理出发,对无刷双馈电动机的功率关系及电磁负荷作了详细的分析和讨论,导出了该电动机计算功率,电磁负荷的选取要点,从确立了无刷双馈电动机主要尺寸确定的主要依据。     

General pole number model of the brushless doubly-fed machine

The brushless doubly-fed machine is receiving attention as a contender for several niche applications. In some cases, the speed ranges of these applications appear to be more readily met by judicious selection of the pole-pair numbers of the stator phase windings. In order to compare different proposed pole-pair configurations and to help in the development of specific designs, a general analytical model, in both dynamic and steady state forms, is presented. This model supersedes previous analyses which are restricted to the 3/1 pole-pair combination of early laboratory machines. The new model is also completely valid for both positive and negative control voltage sequences. The increased modeling flexibility enables sound estimations of the drive power converter ratings, the reduction of which is the key to the economic advantage of these machines. An example of the correlation of the performance predictions and test results encourages use of this new model     

绕线转子无刷双馈电机的d-q轴数学模型

在阐述绕线转子无刷双馈电机的定子绕组、转子绕组结构和静止a-b-c轴数学模型的基础上,推导出电机的d-q轴数学模型。这种电机模型建立在一个任意d-q轴坐标系下,使用起来方便,消除定子绕组和转子绕组之间互感矩阵的时变系数,缩短计算时间,有利于控制方法的实现,适用于绕线转子无刷双馈电机动态和稳态性能的分析研究。d-q轴数学模型的参数能根据电机的设计几何尺寸和经验公式得到。通过仿真分析结果和实验数据的对比,验证了任意d-q轴数学模型的正确性。绕线转子无刷双馈电机任意d-q轴数学模型的建立为电机性能分析和控制策略的研究奠定基础。     

A sensorless drive system for brushless DC motors using a digital phase‐locked loop

This paper proposes a sensorless drive system for Brushless DC (BLDC) motors using a Digital Phase‐Locked Loop (DPLL). The Back Electromotive Force (BEMF) voltage is measured from the motor winding to determine the permanent magnet rotor position using the DPLL, and Pulse Width Modulation (PWM) limits the motor current to control the speed of BLDC motors. The proposed method can drive BLDC motors using an open‐loop control without stepping out. Also, the proposed method is compared experimentally with a control method that uses Hall sensors. Experimental results for the BLDC motor show the effectiveness of the proposed method. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 57–66, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10074     

无刷直流电机的新型控制器

自抗扰控制（ADRC）是在继承经典PID不依赖于对象模型优点的基础上,通过改进经典PID固有缺陷而形成的新型控制技术,性能优良。在分析永磁无刷直流电机特点及使用现状的基础上,建立了基于自抗扰控制器的无刷直流电机控制系统。仿真结果表明,自抗扰控制器对无刷直流电机模型的不确定性和外部扰动变化具有较强的适应性和鲁棒性,控制器算法简单,工程适用性较强,系统具有良好的动态响应性能。     

磁阻型无刷双馈电机特殊转子优化设计

在介绍磁阻型转子无刷双馈电机的原理基础上,提出了一种新的具有隔磁桥的径向迭片磁阻转子,并提出了针对该转子进行优化设计的整套流程方法。首先应用改进绕组函数法对电机转子的外形进行设计,然后以电机的转矩最大以及脉动最小为优化目标,利用田口法分别对该磁阻型转子的5个形状参数的4组不同取值进行了分析,根据分析结果选取了最优的一组参数,从而实现了转子结构的优化设计。