双转子柱体超声波电机运行机理与实验研究

环形行波型超声波电机小直径条件下，输出性能逐渐失去低速大扭矩的特点。而柱体弯曲振动超声波电机是靠圆柱定子端部的摇头振动并通过摩擦来驱动转子的，定子的直径越小，摇头振动的幅值越大，因而，小直径时更能显示出这种电机的优越性。该文阐述了双转子柱体弯曲振动超声波电机的运行机理，证明了定子表面质点运动轨迹为一椭球：利用ANSYS有限元软件分析了电机的弯曲振动模态；用阻抗特性分析仪分析了电机的阻抗特性和相位特性；制作了直径为20mm、有两个转子的柱体弯曲振动超声波电机，并对其输出特性进行了测试，最大转矩达0．16Nm、最高转速为220r／min。     

纵扭复合型超声波电机的力传递模型

复合型超声波电机是各种超声波电机中最典型的低速大力矩电机,其定转子接触方式是断续面接触,这与行波型电机连续的若干点接触不同,也是实现大力矩的根本原因,因此分析其定转子的力传递模型很重要。该文先简单叙述了以往采用等效电路描述具有的问题,其次,通过电机轴向冲量守恒建立了定转子接触角与电机预压力和摩擦材料物理参数的关系,随后利用振动周期内周向电机负载和驱动力所作的功相同的原理,给出电机负载与定子纵 扭振动和转子参数的关系,并据此确定电机转子参数和预压力,研制的复合型超声波电机(直径80mm)的堵转力矩为13.2 N穖的大力矩,空转转速为12.5 r/min。初步形成了电机转子设计的理论基础。     

A novel polyphase multipole square-wave permanent magnet motordrive for electric vehicles

A novel high-power-density permanent magnet (PM) motor drive for electric vehicles (EVs) is proposed. The motor is a polyphase multipole square-wave PM motor, which can be classified as a kind of PM brushless DC motor. The distinct features of the proposed motor as compared to those of the conventional PM brushless DC motor are as follows. First, the multipole magnetic circuit arrangement enables the minimization of the magnetic yoke, resulting in the reduction of motor volume and weight. Second, the coil span is purposely designed to be equal to one slot pitch, thus saving the amount of copper used. Third, by using a fractional number of slots per pole per phase, the arrangement of the numbers of poles and slots is so unique that the magnetic force between the stator and the rotor at any rotating position is uniform, hence eliminating the cogging torque that usually occurs in PM motors. Finally, the motor can be controlled to operate at a constant torque region and a constant power region with field weakening, thus both high starting torque and high cruising speed can be achieved. Therefore, as the proposed motor drive possesses the distinct advantages of high power density, high efficiency, and superior dynamic performance, it is very suitable for EV applications. A prototype of a five-phase 22-pole 5 kW motor drive has been designed for an experimental EV     

电动汽车驱动控制系统直接转矩控制的DSP实现

电动汽车驱动系统要求效率高、响应快。本文提出了一种适合于电动汽车的控制策略。该方法采用直接转矩控制来控制感应电机的转矩。通过对定子和转子电阻进行在线估测 ,并且使用TI公司的数字信号处理器 (DSP)TMS32 0F2 40来实现 ,结果表明 ,该方法在低速时很有效     

基于扩展卡尔曼滤波器的永磁同步电机转速和磁链观测器

为了取消永磁同步电机控制中的机械传感器，获得直接转矩控制中需要的电机磁链信息，设计了一种基于扩展卡尔曼滤波器的永磁同步电机转速和磁链估算方法。选取定子固定坐标系下定子磁链、电机转速和转子位置为状态变量，电压和电流作为输入、输出量，建立估算定子磁链、电机转速和转子位置的EKF滤波器系统。采用空间矢量调制的直接转矩控制策略，有效减小了直接转矩控制方法的转矩脉动，并保持了功率器件恒定的开关频率。实验结果表明EKF准确地观测了电机转速和磁链，所构建的无速度传感器DTC控制系统具有良好的转速和转矩控制性能。     

一种新型的磁链与速度观测器在异步电机直接转矩控制系统中的应用

文章将定子磁链观测器应和于直接转矩控制系统中,取代了传统的积分器。同时,依据磁链观测器的输出电流设计出一种新型的速度观测器。针对1．1kW异步电机,采用数字信号处理器DSP（TMS320C32）进行了数字化实现。仿真与实验表明,该方案对电机定子磁链的观测精度高,速度估计快速准确。     

永磁同步电机的无速度传感器直接转矩控制

在高性能的永磁同步电机控制系统中,机械传感器的存在会使系统的成本增加,可靠性降低,容易受到外部环境的影响.在叙述永磁同步电机直接转矩控制原理的基础上,采用了一种基于转子磁链的转速估计方法,该方法根据定子磁链角和负载角确定出转子磁链角,进而估计出电机的转速.仿真和实验结果验证了该方法能够在电机全速范围内准确地估计出转速,具有优良的动静态性能,适合于永磁同步电机的直接转矩控制.     

Induction motor drive based on the stator flux vector control

This paper presents a new torque control algorithm for induction motors, based on the stator flux vector control. For each sampling period, the value of the stator voltage is calculated to keep the stator flux equal to the reference vector, while the stator flux reference vector is calculated to keep the rotor flux amplitude constant at all operating conditions. An improved stator and rotor flux estimation algorithm is proposed, enabling robust and stable operation of the drive, even at low speeds. The induction motor torque is manipulated by variations of the flux angular velocity, enabling drive operation with fixed switching frequency and ripple-free torque in the steady state. The performance of the proposed algorithm is tested through various experimental runs, proving good behavior of the drive in both transient and steady-state operating conditions.     

Performance Evaluation of an Axial‐Type Magnetic‐Geared Motor

This paper first proposes an axial‐type magnetic‐geared motor that uses permanent magnets only in the high‐speed rotor. The operating principle of this motor is described and the torque–speed characteristics are computed by using three‐dimensional finite element method analysis. In order to increase the torque density, a novel axial‐type magnetic‐geared motor with permanent magnets on the high‐speed rotor and stator is also proposed. The torque–speed characteristics are compared to the original model with permanent magnets only on the high‐speed rotor. Finally, the computed torque–speed characteristics are verified against measurements on a prototype.     

Nonlinear adaptive state-feedback speed control of a voltage-fed induction motor with varying parameters

An adaptive nonlinear-state-feedback speed control scheme of a voltage-fed induction motor has been developed in which the control of torque and flux is decoupled. The inputs to the control algorithm are the reference speed, the reference flux, the measured stator currents, the measured rotor speed, the estimated rotor flux, and estimates of the rotor resistance, stator resistance, and load torque, which may vary during operation. The controller outputs are the reference stator voltages in rotor-flux rotating reference frame. An accurate knowledge of the rotor flux and machine parameters is the key factor in obtaining a high-performance and high-efficiency induction-motor drive. The rotor flux is estimated using the induction-motor rotor-circuit model. Although the estimated rotor flux is insensitive to the stator-resistance variation, it does depend on the rotor resistance. A stable model reference adaptive system (MRAS) rotor-resistance estimator insensitive to stator-resistance variation has been designed. Stable stator-resistance and load-torque MRAS estimators have also been developed. These estimators have been developed to constitute a multi-input-multi-output (MIMO) decoupled-cascade structure control system. This simplifies the design problem of the estimators for a stable operation from a MIMO design problem to a single-input-single-output (SISO) design problem. The continuous adaptive update of the machine parameters and load torque ensures accurate flux estimation and high-performance operation. Simulation and experimental results are presented to verify the stability of the induction-motor drive in various operating modes.     

磁动势法五相永磁力矩电机转矩分析

五相永磁力矩电机由于极数与槽数相近,含有丰富的磁动势谐波,磁动势谐波会影响电机的转矩性能。为此,采用磁动势法分析电机的电磁转矩,通过磁能和虚位移原理推导出了电机电磁转矩的解析表达式,揭示了具有相同空间次数的定子和转子磁动势谐波相互作用才能产生电磁转矩的规律。通过对五相永磁力矩电机的定、转子磁动势谐波与电磁转矩关系的分析,指出与与主波转速一致的定子和转子磁动势谐波相互作用能提高五相永磁力矩电机的平均电磁转矩。利用Ansoft有限元软件仿真分析了电机在正弦波、梯形波和方波供电下的定子磁动势、转子磁动势以及转矩性能。结果表明,非正弦供电能够增加电机的电磁转矩,但也带来了转矩脉动,验证了磁动势法分析五相永磁力矩电机转矩的有效性和正确性。     

Low-speed high-torque drive system applying vernier motor torque

The application of the direct drive system is increasing in the field of robot and factory automation because of controllability with high accuracy. However, it requires the motor high torque at low speed. Although the vernier motor presented by Lee in 1963 could produce the reluctance torque in low speed, it involved many problems to be solved. This paper studies the reluctance torque of the vernier motor using the finite-element field analysis. Since the increase of rotor slot number is effective in producing high torque, in the model here, there are not only winding slots but also small slots on the stator teeth surfaces. Also, the rotor slots are provided in the periphery of the core more than the total number of stator slots by the pole number. The calculated torques have agreed very well with the experimental results. A prominent feature of the control scheme is to control the armature current phase based on the detected rotor slot position. Thus there is no problem such as pull-in or pull-out in Lee's vernier motor. Then the instantaneous torque is controlled by the amplitude of armature current. The experimental results on both the speed control and the position control also are shown in this paper.     

Diminution of Current-Measurement Error for Vector-Controlled AC Motor Drives

The errors generated from the current-measurement path are inevitable, and they can be divided into two categories: offset errors and scaling errors. Current data including these errors cause the periodic rotor speed ripples, which are one and two times the fundamental stator current frequency. Since these undesirable ripples can harm the motor drive system, a compensation algorithm must be included in the motor control drive. In this paper, a new compensation algorithm is proposed. The principal feature of the proposed algorithm is the use of the integrator output signal of the$d$-axis proportional plus integral (PI) current regulator. This output signal is nearly zero or constant because the$d$-axis current command is zero or constant, so that the maximum torque or unity power factor can be acquired in the ac drive system. If the stator currents include offset and scaling errors, the integrator output signal of the$d$-axis PI current regulator ripples in the rotor speed of the same frequency. The proposed compensating algorithm for the current-measurement errors can be easily implemented by subtracting the dc offset value or rescaling the input measurement gain of the stator currents. Therefore, the proposed algorithm has several advantages: it is robust with regard to the variation of the motor parameters; it is applicable to steady and transient states; it is easy to implement; and it requires less computation time. The MATLAB simulation and the experimental results verify the usefulness of the proposed current compensating algorithm.     

新型平动式啮合电机的运行原理和静态转矩

针对机器人系统对驱动电机的启动性能和空间适应性的要求,提出了一种新型的平动式啮合电动机,通过定转子间磁阻的变化将电能转化为机械能,在孔销结构的约束下使转子绕定子作圆周平动,进而可直接由转子带动摆线机构,利用摆线机构的减速作用输出大扭矩的高集成度电动机.设计并加工了一台原理样机,采用有限元方法建立了样机二维磁场模型,对样机的磁场分布进行了分析.计算了不同转子位置处的磁链族,并依据磁共能方法求得样机的静态转矩值,其计算结果与实验结果相吻合.理论分析和实验结果均表明新电机具有结构紧凑,可带载启动并启动快速的特点.     

基于VPVM永磁同步电机无传感器控制策略的研究

贴面式永磁同步电机的无传感器控制在低速和静止时一直存在着转子位置难以检测和估算的问题,本文针对该情况提出了一种新的无传感器控制策略。转子初始位置检测是根据定子铁心的非线性磁化特性,采用电压脉冲矢量注入法（VPVM）。这种方法不需要电机参数和额外的硬件设施.电机开始运行时,由闭环自适应磁通观测器估算转子位置、速度.通过MATLAB仿真,从理论上验证了该方法的有效性。     

Harmonic field analysis for slip-ring motors including generalrotor asymmetry

A field analysis is presented for slip-ring induction motors with general external impedance asymmetry. The method is based upon a rotating-field theory approach including spatial MMF (magnetomotive force) harmonics. It is shown that a series of nonmains frequency voltages are induced in the stator winding for both balanced and unbalanced rotors. The method is also used to derive the harmonic equivalent circuit for a balanced three-phase slip-ring motor with a skewed rotor. The analysis is verified by comparing predicted torque and current characteristics with measured values obtained from a machine with a balanced rotor and with a rotor connected to asymmetrical external resistances. The influence of MMF harmonics on the phase equivalent circuit and the motor performance is demonstrated. Operation with an unbalanced rotor results in a loss of steady torque and the introduction of large oscillating torques     

一种感应电机转动惯量的瞬态辨识方法

为了在无速度传感器运行模式的感应电机上实现高性能控制,实现转动惯量的准确辨识,提出一种感应电机的转动惯量瞬态辨识方法。根据感应电机的定子电压、电流信号计算转子磁链、转速、转矩,构建转动惯量的自适应律。该方法能在无机械式速度传感器的前提下用于感应电机瞬态过程,仿真与实验结果表明了转动惯量自适应律的正确性和有效性。     

新型永磁复合电机研究

永磁无刷电机内嵌到同心式磁性齿轮中,形成新型永磁复合电机。电机为内定子外转子结构,外转子输出低速大转矩,适合直接驱动。采用数值解析结合法计算复合电机磁场,电机三层气隙区域无网格剖分,内外转子可自由转动,方便感应电动势计算。电动势计算波形和实验波形比较,取得很好的一致。     

电动汽车感应电机驱动系统矢量控制的双CPU实现

为电动汽车感应电动机驱动系统设计开发了一套用双CPU来实现的矢量控制系统。通过坐标变换得到了适用于矢量控制的同步旋转坐标系下的感应电动机基本数学方程,推出了转子磁链方程和转矩方程。系统软件基于这些数学模型来实现感应电动机转子磁场定向矢量控制,并给出了软件程序流程。仿真与试验结果并表明,控制系统具有良好的动态特性和较宽的调速范围以及恒转矩区域。     

基于DSP的新型无速度传感器直接转矩控制系统的研究

将磁链状态预测器应用于直接转矩控制系统中,取代了传统的积分器,同时与一种简单实用的速度估计器成功地结合在一起,实现了系统的无速度传感器运行状态,针对1.1kW异步电机,采用数字信号处理器DSP（TMS320C232）进行了数字化实现,仿真与实验结果表明,该系统对电机定子磁链的观测精度高,速度估算准确,尤其是在较低转速下仍能保持很高的性能。