新型柴油机变频起动装置中转子位置的无机械传感器检测

针对新型柴油机变频起动装置的控制要求,提出了同步电机的转子初始位置及动态位置的无机械传感器的检测方法。该方法通过深入分析同步电机内部磁路特性,建立了＂理想化＂电机模型,并最终利用定子的电流和电压,计算出转子的初始和动态位置。     

基于SMO电动汽车用内置式永磁同步电机无位置传感器控制

针对电动汽车驱动用内置式永磁同步电机,讨论滑模观测器的无位置传感器控制方法,介绍基于该方法的转子位置检测原理,给出控制算法的实现过程。通过Simulink建立内置式永磁同步电机无传感器,控制系统的仿真模型进行仿真。结果表明,基于滑模观测器的无位置传感器控制可以实现较小的估计误差,确保电机高性能运行。     

大型异同步电动机再制造成自起动永磁同步电机技术研究

对大型异同步电动机应用中存在的转子励磁系统损耗大、滑环故障率高等问题,提出仅对其转子进行改造,将其再制造成自起动永磁电机。以一台630k W-36P的异同步电机为例,通过等效安匝数原理将原电机转子直流励磁安匝数等效成永磁体激磁磁势,利用商业软件对等效永磁激励条件下的纹波转矩、气隙磁密波形、转速稳定性及运行效率等进行了仿真。结果表明,再制造后自起动永磁电机保留了原异同步电动机的优点,且效率和功率因数以及起动能力,都具有显著的提高,具有重要的工程实践和节能改造价值。     

高压起动技术在天铁4500 kW同步电机中的应用

本文针对高压大型电机起动困难的状况,分析并提出了解决问题的措施,阐述了高压软起动技术在天铁集团4 500kW同步电机中的应用.     

Magnet在励磁同步电机设计中的应用

为提供励磁同步电机的设计依据,提出了基于有限元电磁场计算软件分析其电气性能的方法。首先选取具有代表性的凸极三相4极励磁同步电机作为研究对象,构建其3D模型,设置各部分材料属性,生成线圈及设定电机初始位置,然后采取重点区域加密的自适应网格剖分方法,2D暂态求解器求解,最后采取Matlab完成数据的后处理,分析驱动电源的频率与电机转速、铜损、铁损、涡流损耗及磁场能量分布的关系,为电机设计人员提供技术支持。     

基于Simplorer的轴向分段式外永磁转子高速爪极电机联合仿真

分析了轴向分段式外永磁转子高速爪极电机的特殊结构及运行原理。由于研究对象的磁路具有非对称性,为了得到更加准确的仿真结果,在Maxwell 3D平台中按照样机的实际参数,建立了研究对象的3D模型;为实现驱动电机的目标,并考虑到电机在运行时,电机本体与控制电路产生的场路耦合效应,在Simplorer中搭建了电机的控制系统模型,对电机进行MaxwellSimplorer联合仿真并采用了无位置传感器的控制策略,控制电路包括逆变电路和换相电路以及双闭环的控制电路。从仿真结果可知,该控制系统模型可以使电机稳定运行,并且有良好的起动性能。本文的研究工作对轴向分段式外永磁转子高速爪极电机控制系统的设计与优化,及联合仿真的研究工作,具有一定的参考价值。     

基于Fluent的异步起动永磁电机温度场分析

针对异步起动永磁电机在油田抽油机中的广泛应用,从电机的三维模型出发,给定了转子铁心、机座、槽内绝缘、端盖转轴的简化方法以及电机各体分块后合理的剖分尺寸,根据温度场计算数学模型明确了基本假设和边界条件,采用半经验公式法计算了气隙的等效导热系数和机壳表面的散热系数,并考虑了定子与机壳、永磁体与转子铁心、转子铁心与轴、机座与端盖、端盖与轴承、端盖与轴6处装配间隙对电机最高温度的影响。在实测损耗值的基础上计算电机各部分热源值的大小并按照一定比例进行相应加载。最后将有限体积法得到的温度场计算结果与实验值相比较,验证了本文方法的可行性。     

基于RTDS的大型抽水蓄能机组无速度传感器SFC启动仿真

大型抽水蓄能机组对于电力系统调峰填谷起着十分重要的作用。目前抽水蓄能机组的启动普遍采用静止变频器(SFC)启动方式,该启动方式的关键是在0~50 Hz的转速变化范围内系统能否准确、快速地检测到转子位置。文中采用无速度传感器的电气方法测量出转子位置角,通过空间矢量控制对无速度传感器的大功率同步电机变频启动的控制算法进行深入研究,并通过实时数字仿真(RTDS)系统验证所提出的启动控制方案的正确性。     

直驱风力发电机无位置传感器控制

提出一种在宽转速范围内均适用的永磁同步电机位置、转速估算方法,该方法通过在低速段采用脉动高频注入法,中、高速段采用基波反电势追踪法,并且在过渡频带遵循任何时刻只采用一种位置计算结果的原则,得出位置、频率信号。仿真结果表明,该方法实现了全速范围内转子位置和速度的准确、快速检测。     

功率分流式混合动力车辆发动机起动过程优化的仿真研究

利用GT-SUITE软件建立了基于详细机理的发动机模型，用MATLAB/Simulink建立了三相永磁同步电机数学模型及其弱磁控制系统。通过解决跨平台转矩传递及步长协调等问题，建立二者耦合的混合动力车辆瞬态仿真平台。研究了发动机初始喷油转速对起动过程整车能耗、起动时间和平顺性的影响，分析了整车需求功率与经济性初始喷油转速的关系。研究结果表明：发动机倒拖至800 r/min以上开始喷油可以缩短起动时间；冲击度与发动机转矩建立时间呈负相关关系；发动机倒拖起动时最低综合能耗所对应的初始喷油转速与起动时被分配到的需求功率成正比，与固定800 r/min开始喷油的策略相比能耗可降低20%~31%。     

Application of a boundary integral method to the optimization ofsolid rotor machines

This paper is devoted to the optimization of electric machine solid rotors for high speed applications, using a boundary integral method. The method is applied to two examples: a slotted asynchronous rotor; and a salient reluctant synchronous rotor. Starting under constant voltage is especially studied in both cases. An important part of the paper deals with the asynchronous motor. An idealized stator generates a sinusoidally distributed tangential flux density, so that the optimization concerns only the rotor slotting. At constant permeability, the boundary integral method proves to be very fast and efficient for the approximate design of a slotted rotor     

Synchronous Machine steady-State parameter estimation using neural networks

An online steady-state parameter estimation technique using the ability of the neural networks to recognize patterns is presented in this paper. The method is nonintrusive. Studies on a salient pole and on a round rotor synchronous machine illustrate the effectiveness of the proposed technique. Results indicate that the steady-state parameters can be obtained without the use of rotor position.     

Starting the Single-Phase Switched Reluctance Motor Using Rotor Shorting Rings

This article presents a technique that uses rotor shorting rings to start the single-phase switched reluctance (SR) machine, from any rotor position, in a specified direction. It also outlines how the shorting rings enable starting of the machine. Transient finite-element analysis is used to illustrate the torque-producing mechanism from the aligned position using the rotor-mounted shorting rings. It is also used to determine the optimal stator and rotor pole arcs and shorting ring design for a 200-W prototype machine. An SR drive system incorporating rotor shorting rings is evaluated, and experimental results show the effectiveness of the technique     

Analysis of a Permanent Magnet Synchronous Machine Supplied from a 180° Inverter with Phase Control

Reference frame theory is used to establish the equations which describe the steady-state and dynamic behavior of an electric drive system consisting of a permanent magnet synchronous machine supplied from an inverter operating in the 180° conduction mode and with provisions to shift the phase of the stator voltages relative to the rotor position. An expression for the phase-shift angle which yields maximum torque is derived. It is shown that a comparison of the stator time constant and the no-load rotor speed without phase shift, can be used to anticipate the increase in average torque achievable by phase shifting. It is also shown that advancing the phase of the stator voltages advances the phase of the fundamental component of the stator phase currents relative to the phase voltages. A method of calculating the steady-state harmonic currents and torque is also given. The information given in this paper should serve as a guide for the operation of brushless dc motors and the design of speed or position controls that employ phase shifting techniques along with or instead of pulse width modulation.     

Simulation Studies of the Transients of Squirrel-Cage Induction Motors

A new simulation approach is proposed in consideration of a saturation and a deep bar effect for the study of transients of three-phase squirrel-cage type induction motors. The mathematical model of an induction motor is expressed by the six differential equations of three-phase instantaneous voltage and current. The torque of an electric equation is related to the motion equations of motor and driven machine in the mathematical model. The values of reactance of stator and rotor are changed by the saturation of core caused by starting current. Also both the values of reactance and resistance of rotor bar are varied by the deep bar effect in the rotor core during starting. The calculation method of circuit constant that adds the influence of saturation and deep bar effect is proposed in this paper. The circuit constant of simulation model in consideration of saturation and the deep bar effect are decided by these computation methods in accordance with the conditions of rotation speed and current. If the large current flows, the leakage reactance of the stator and the rotor decreases by saturation. Moreover, the resistance of the rotor gradually decreases when the rotational speed rises from stop to synchronous speed, and the leakage reactance increases gradually. The calculated values were compared with the observed values of the examination machine of 1100 kW4P and an excellent agreement was obtained demonstrating the accuracy of the proposed simulation. Consequently, it is shown that the saturation and the deep bar effect are the essential factors to perform the accurate simulations of the induction motor. After checking the validity of the proposed approach, the simulation of the grounding faults was performed. In this study, all the simulation programs have been developed in the Matlab/Simulink environment.     

A Finite Element based State Model of Solid Rotor Synchronous Machines

In this work, a state model which portrays the dynamic electromagnetic characteristics of a synchronous machine is derived based upon the first order finite element method. The method of finite elements is used to determine the axial component of magnetic vector potential throughout the cross section of the machine. Algebraic relationships between the winding voltages and the magnetic vector potentials are derived. These are used to establish a state model which admits winding voltages as inputs. The resulting model consists of a set of first order, ordinary differential equations which predict vector potentials at grid nodes along with the winding currents as time proceeds following arbitrary disturbances in stator or rotor voltages. As an initial verification step, this method has been applied in two linear examples. The first involves a simplified geometric representation of the synchronous machine for which an analytical solution of the defining field equations can be obtained. The second involves a more detailed geometry which includes stator and rotor slots. Numerical solutions are shown to be in excellent agreement with analytical solutions for the simplified structure. In the detailed geometry, numerical solutions are shown to compare favorably with the classical equivalent circuit representation.     

An improved model for saturated salient pole synchronous motors

An improved model for the transient analysis of saturated salient pole synchronous motors is presented. With the aid of saturation factors obtained by test or with finite elements, Park's equations for a synchronous machine are modified to independently account for the saturation of the magnetizing flux linkages in the region of the stator teeth and rotor pole face as well as saturation of the total flux linking the stator core. The model is used to calculate the starting performance for a direct online start as well as the transient performance during a load change. The model shows improvement over more traditional models, indicating that representation of both main flux and core saturation are important for synchronous machine analysis     

Performance analysis of a composite dual-winding reluctance machine

The electromagnetic energy conversion process of a composite dual-winding asynchronous reluctance machine is presented. The mechanism of torque production is explained using the magnetic fields distributions. The dynamic model developed in dq-rotor reference frame from first principles depicts the machine operation and response to sudden load change. The device is self-starting in the absence of rotor conductors and its starting current is lower than that of a conventional induction machine. Although the machine possesses salient pole rotors, it is clearly shown that its performance is that of an induction motor operating at half the synchronous speed. Hence the device produces synchronous torque while operating asynchronously. Simple tests were conducted on a prototype demonstration machine and the results obtained are seen to be in tune with the theory and the steady-state calculations.     

Determination of damper winding and rotor iron currents inconvertor- and line-fed synchronous machines

The damper winding currents of a synchronous machine with a solid iron rotor are analyzed. Based on the self and mutual inductance modelling technique, the damper currents are described by a detailed damper model taking the damper cage and the rotor iron into account. The model's component elements are determined by the finite element method. Theoretical results are verified by measuring damper bar currents of a six-phase synchronous machine fed by two six-pulse converters. For a number of different operating modes the model is used to calculate the damper current distribution of a six-phase machine     

Hybrid-State-Model-Based Time-Domain Identification of Synchronous Machine Parameters From Saturated Load Rejection Test Records

This paper presents a suitable method for time-domain identification of synchronous machine parameters from the hybrid state model recently introduced by the authors in a compact matrix form. The saturated version of this model is developed in terms of generator equivalent-circuit parameters. The load rejection test of a combined resistive/inductive load is performed for the parameter identification while the online symmetrical three-phase short-circuit test is carried out for the model cross-validation. For weak power factor initial loads connected to the generator, the rotor speed is quite constant during the full load rejection test. Thus, the mechanical transients do not have any influence on estimated electrical parameters since they are decoupled from the electrical model of the machine. The method is successfully applied for the parameter identification of 380 V, 3 kVmiddotA, four-pole, 50 Hz saturated synchronous generator.