基于高频注入法的永磁同步电动机无传感器矢量控制

提出了一种在零速或是低速时无传感器的永磁同步电动机矢量控制方法。该方法基于永磁同步电动机的凸极效应原理,在两相旋转坐标系中注入高频信号来获取无传感器矢量控制时所需转子的精确位置和转速,并在此基础上给出了永磁同步电动机无传感器矢量控制系统。仿真结果表明,该方法能够准确估计转子位置和速度,满足矢量控制的需要。     

带参数辨识的自适应二阶滑模观测器PMSM无传感器矢量控制

针对表贴式永磁同步电机无位置传感器矢量控制系统, 提出一种具有电机参数在线辨识的基于Super-twisting algorithm的自适应二阶滑模观测器.在两相静止坐标系下,将模型参考自适应方法与基于Super-twisting algorithm的二阶滑模方法相结合,实现反电动势的准确估计.采用李亚普诺夫理论证明观测器的稳定性,并由李亚普诺夫稳定性方程推导定子电阻和转子转速的自适应律.在同步旋转坐标系下,采用二阶滑模观测器估计永磁磁链,并将其输入位置跟踪观测器估计转子位置.该算法充分抑制了滑模抖振,同时避免了低通滤波和相位补偿环节的使用,转子位置检测不受定子电阻和永磁磁链变化的影响,具有较强的鲁棒性.仿真结果验证了所提出算法的有效性.     

Fully sensorless robust control of variable-speed wind turbines for efficiency maximization

This paper focuses on a sensorless robust power generation control strategy for a variable speed wind energy conversion system based on a permanent magnet synchronous generator. The proposed control strategy combines a robust observer of the aerodynamic torque, a simple technique for extracting rotor position using electrical signals, a robust observer of rotor speed, and a sliding mode based field oriented control strategy. The robust vanishing of the observation errors and tracking error is proved. Reported numerical simulations show that the proposed control policy is effective in terms of efficiency maximization and it is robust with respect to bounded parameter variations affecting the mechanical system.     

A speed-sensorless indirect field-oriented control for induction motors based on high gain speed estimation

The authors design a new speed sensorless output feedback control for the full-order model of induction motors with unknown constant load torque, which guarantees local asymptotic tracking of smooth speed and rotor flux modulus reference signals and local asymptotic field orientation, on the basis of stator current measurements only. The proposed nonlinear controller exploits the concept of indirect field orientation (no flux estimation is required) in combination with a new high-gain speed estimator based on the torque current tracking error. The estimates of unknown load torque and time-varying rotor speed converge to the corresponding true values under a persistency of excitation condition with a physically meaningful interpretation, basically equivalent to non-null synchronous frequency. Stability analysis of the overall dynamics has been performed exploiting the singular perturbation method. The proposed control algorithm is a “true” industrial sensorless solution since no simplifying assumptions (flux and load torque measurements) are required. Simulation and experimental tests show that the proposed controller is suitable for medium and high performance applications.     

Sensorless Inverter‐Fed Compressor Drive System Using Back‐EMF Estimator with PIDNN Torque Observer

A saliency back‐EMF estimator with a proportional–integral–derivative neural network (PIDNN) torque observer is proposed in this study to improve the speed estimating performance of a sensorless interior permanent magnet synchronous motor (IPMSM) drive system for an inverter‐fed compressor. The PIDNN torque observer is proposed to replace the conventional proportional–integral–derivative (PID) torque observer in a saliency back‐EMF estimator to improve the estimating performance of the rotor flux angle and speed. The proposed sensorless control scheme use square‐wave type voltage injection method as the start‐up strategy to achieve sinusoidal starting. When the motor speed gradually increases to a preset speed, the sensorless drive will switch to the conventional saliency back‐EMF estimator using the PID observer or the proposed saliency back‐EMF estimator using the PIDNN observer for medium and high speed control. The theories of the proposed saliency back‐EMF rotor flux angle and speed estimation method are introduced in detail. Moreover, the network structure, the online learning algorithms and the convergence analyses of the PIDNN are discussed. Furthermore, a DSP‐based control system is developed to implement the sensorless inverter‐fed compressor drive system. Finally, some experimental results are given to verify the feasibility of the proposed estimator.     

A New Full‐Order Sliding Mode Observer Based Rotor Speed and Stator Resistance Estimation for Sensorless Vector Controlled Pmsm Drives

Sensorless control of a permanent magnetsynchronous motor (PMSM) at low speed remains a challenging task. In this paper, a sensorless vector control of PMSM using a new structure of a sliding mode observer (SMO) is proposed. To remove the mechanical sensors, a full‐order (FO‐SMO) is built to estimate the rotor position and speed of PMSM drives. The FO‐SMO, which replaces a sign function by a sigmoid function, can reduce the chattering phenomenon. In order to overcome time delay, we cancel the low pass filter. This sensorless speed control shows great sensitivity to stator resistance and system noise. To improve the robustness of sensorless vector control, a full‐order SMO technique has been used for stator resistance estimation. A novel stator resistance estimator is incorporated into the sensorless drive to compensate for the effects of stator resistance variation. The validity of the proposed FO‐SMO with a 1.1 kw low‐speed PMSM sensorless vector control is demonstrated by experiments. In this paper, experimental results for FO‐SMO, back‐EMF SMO and MRAS techniques were obtained with fixed point DSP‐based (TMS320F240).     

Sensorless speed control of PMSM via adaptive interconnected observer

In this article, a robust sensorless speed observer–controller scheme for a surface permanent magnet synchronous motor (PMSM) is proposed. First-of-all, following preliminary results in the framework of the induction motor that is less sensible to the position estimation error, an adaptive high gain interconnected observer is designed. It is only supplied by the electrical measurement: the motor currents and voltages. This observer estimates the rotor speed and position, the stator resistance and the load torque. A nonlinear backstepping controller is developed. The above observer is associated with this controller and the complete scheme practical stability proof is given. The overall system is tested by simulation in the framework of an industrial benchmark with a trajectory that particularly checks the motor unobservability condition. Some robustness tests have been carried out. The controller–observer scheme shows good performances in spite of the uncertainties and the unknown load torque.     

永磁同步电机脉振高频电压注入转子位置检测

永磁同步电机的转子位置检测精度直接决定了电机能否平滑起动,为提高转子位置检测精度,提出了基于脉振高频电压注入的表贴式永磁同步电机转子位置检测方法。向永磁同步电机定子绕组中注入脉振高频电压信号,通过电机d、q轴磁路饱和程度的差异,实现永磁同步电机转子初始位置的检测。实验结果表明提出方法的转子位置检测精度高,适用于永磁同步电机的无传感器起动及低转速稳态运行。     

Sensorless adaptive output feedback control of wind energy systems with PMS generators

This paper addresses the problem of controlling wind energy conversion (WEC) systems involving permanent magnet synchronous generator (PMSG) fed by IGBT-based buck-to-buck rectifier–inverter. The prime control objective is to maximize wind energy extraction which cannot be achieved without letting the wind turbine rotor operate in variable-speed mode. Interestingly, the present study features the achievement of the above energetic goal without resorting to sensors of wind velocity, PMSG speed and load torque. To this end, an adaptive output-feedback control strategy devoid of any mechanical sensor is developed (called sensorless), based on the nonlinear model of the whole controlled system and only using electrical variables measurements. This control strategy involves: (i) a sensorless online reference-speed optimizer designed using the turbine power characteristic to meet the maximum power point tracking (MPPT) requirement; (ii) a nonlinear speed regulator designed by using the backstepping technique; (iii) a sensorless interconnected adaptive state observer providing online estimates of the rotor position as well as speed and load/turbine torque. The proposed output-feedback control strategy is backed by a formal analysis showing that all control objectives are actually achieved. Several simulations show that the control strategy enjoys additional robustness properties.     

永磁同步电动机无传感器二阶滑模观测器仿真研究

针对永磁同步电动机无传感器控制采用传统滑模观测器引起的"抖振"现象,提出了一种基于二阶滑模控制方法的滑模观测器,并将其用于估算永磁同步电动机的转子位置和速度;采用Matlab/Simulink软件,分别在理想情况及存在参数摄动情况下,对永磁同步电动机采用传统滑模观测器和二阶滑模观测器控制时的转子位置和速度进行估算,结果表明该二阶滑模观测器在没有低通滤波器的情况下即可得到平滑的电动机速度和位置估算曲线,估算误差较传统滑模观测器小,且具有更高的观测精度和更好的鲁棒性。     

Grid-connected vector-controlled slip-ring induction machine drive with out speed sensor

A speed estimation method is presented in this paper for a grid-connected doubly-fed slip-ring induction machine drive. The proposed method is formulated with reactive power based model reference adaptive system (MRAS). The method does not require the estimation of stator/rotor flux. So, the integrator related problems at synchronous speed are overcome. Also, the estimation method is independent of stator and rotor resistance variation. Extensive simulation results are presented to validate the technique.     

A new scheme for sensorless induction motor control drives operating in low speed region

A novel simple stator resistance estimation technique for high-performance induction motor drives is proposed. It makes use of a synchronously revolving reference frame aligned with the stator current vector, so that the resistance can be straightforwardly derived from the mathematical model of the induction motor. A sensorless direct field orientation scheme is employed to validate the proposed solution, with the drive operating in the critical area of low speeds. A combination of two observers is used: a Kalman filter observer to estimate the rotor flux, and a MRAS observer for speed estimation. The stator resistance estimator alleviates the usual performance degradation of MRAS-based drives at low speeds, caused by the thermal drift of stator resistance. Computer simulations, including realistic disturbances, show high effectiveness of the described approach.     

永磁同步发电机风能转换系统滑模控制仿真

针对由于风速的随机波动性而使基于线性定常控制器的风能转换系统稳定性较差的问题,提出了一种基于滑模控制的永磁同步发电机风能转换系统的设计方案;分析了该系统中风力机模型、传动装置模型和永磁同步发电机模型的建立原理,介绍了滑模控制策略的具体实现。仿真结果表明,该系统具有较好的速度跟踪特性,实现了最大风能捕获。     

基于位置估计的双馈风力发电机的控制策略

为了避免由机械传感器所带来的一些控制上的问题,提出了一种基于位置估计的双馈风力发电机的控制方案。在转速控制阶段,根据双馈发电机数学模型,通过采集电网电压电流,转子电压电流,采用定子磁场定向的矢量控制策略,利用转子电流矢量综合位置与定子电压矢量综合位置,对并网前后转子位置进行估算,得到转速及功率变化规律,运用这个规律可以实现对转速的控制。最后对1 MW的风力机模型进行系统仿真实验,结果表明整个转速控制区间对转子位置的估计都满足系统要求,基本上解决了风力发电机的转速和无功功率控制难的问题,验证了方案的正确性与可行性。     

无传感器PMSM中基于IGSO优化EKF的速度估计方法

为了提高无传感器永磁同步电机(PMSM)控制系统中速度控制性能,提出一种基于改进群搜索优化(IGSO)算法的扩展卡尔曼滤波(EKF)速度估计方案。首先,分析了PMSM磁场定向控制(FOC)系统模型;然后,将电机的d-q轴电压、电流和转子速度作为状态变量,构建EKF中的状态方程来估计转速和负载。同时,为了提高EKF的估计性能,以估计值与实际值的平方误差积分(ISE)作为适应度函数,通过IGSO算法来优化EKF中的噪声协方差矩阵Q和R,以此获得最优参数。仿真结果表明,提出的控制系统能够精确估计出电机转速并进行有效控制。     

永磁同步电机系统的无速度传感器研究

为了提高永磁同步电机系统的抗干扰能力,提出一种无速度传感器方法,用于速度辨识.将滑模(SM)变结构控制与模型参考自适应系统(MRAS)方法相结合,选取电机本体作为参考模型,利用逆变器输出的电压和电流,构建基于磁链方程的可调模型,利用两模型误差运用SM变结构方法辨识速度.在Matlab仿真平台对无速度传感器方法进行了分析,研究结果表明:所提出的无速度传感器方法具有较好的动静态性能,可以实现对速度的准确辨识.     

基于DSP的自适应速度辨识直接转矩控制系统研究

异步电机直接转矩控制能产生快速且良好的鲁棒性响应,采用自适应磁链观测器,取代传统的积分器,构造了新型的速度估计器,并结合模糊控制器,实现对定子磁链准确观测和系统无速度传感器运行状态。基于DSP(TMS320LF2407A)核心芯片建立数字化控制系统。仿真与实验表明,该系统对电机定子磁链的观测精度高,转速估算准确,尤其在低速下能保持很高的性能。     

采用GA的永磁同步电机直接转矩调速

永磁同步电机直接转矩控制受定子电阻变化影响,进而影响调速系统的精度。本文采用遗传算法动态调整直接转矩控制的调速系统控制器参数的策略,使控制器参数及转矩给定值随转速的波动而调整,克服电阻变化引起磁链控制器输出不准确,达到稳定输出转速的目的。该策略在定子电阻变化较大情况下,仍具有高控制精度。仿真结果验证了这一遗传算法永磁同步电机直接转矩控制调速系统控制策略的有效性。     

永磁同步电动机直接转矩控制的效率优化

针对永磁同步电动机在轻载、高速运行时效率和功率因数下降的问题,提出了一种永磁同步电动机直接转矩控制效率优化策略。该策略通过分析电动机损耗与转矩、转速和定子磁链之间的关系,建立了考虑铁损的永磁同步电动机数学模型,导出了效率最优时的定子磁链幅值;将最优定子磁链计算模块嵌入直接转矩控制系统,构成了效率最优的永磁同步电动机直接转矩控制调速系统。仿真结果表明,该优化策略能有效降低永磁同步电动机功率损耗,提高电动机的运行效率。     

基于EKF和SMC的永磁同步电机无传感器矢量控制

采用扩展卡尔曼滤波(EKF)算法估计永磁同步电机(PMSM)转速和转子位置,构成转速、电流双闭环的无传感器矢量控制系统.针对扩展卡尔曼滤波为有偏估计、对模型误差鲁棒性差等问题,提出了基于指数趋近律的滑模转速控制器.为提高转速环抗负载转矩扰动能力,设计负载转矩观测器并将观测结果引入到电流控制器的输入端,作为速度控制器前馈补偿的控制输入.仿真实验结果表明,与传统采用PI(proportional-integral)转速控制器的系统相比,文中所提控制策略具有转速跟踪误差小、响应快、无超调、抗负载扰动能力强等优点.