A new high‐frequency voltage injection method for sensorless drive of permanent‐magnet synchronous motors with pole saliency

This paper proposes a new sensorless vector control method for salient‐pole permanent‐magnet synchronous motors. In regard to rotor phase estimation, the sensorless vector control method is characterized by a new high‐frequency voltage injection method distinguished from the conventional ones by a unique ellipse shape of the spatial rotation, and by a new PLL method whose input is a high‐frequency current autocorrelated signal. The new vector control method established by two innovative technologies can have the following high‐performance and attractive features: (1) it can allow 250% rated torque at standstill; (2) it can operate from zero to the rated speed under the rated motoring or regenerating load; (3) it accepts instant injection of the rated load even for zero‐speed control; (4) it accommodates a load with huge moment of inertia; (5) phase estimation is very robust against inverter dead time; (6) the computational load for estimating rotor phase is very small, would be the smallest among the methods with comparable performance. This paper presents the new vector control method by focusing on two innovative technologies from its principles to design rules. Usefulness of the new vector control method is verified through extensive experiments. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(4): 62–77, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20632     

A New Speed-Varying Ellipse Voltage Injection Method for Sensorless Drive of Permanent-Magnet Synchronous Motors With Pole Saliency—New PLL Method Using High-Frequency Current Component Multiplied Signal

This paper proposes a new sensorless vector control method for salient-pole permanent-magnet synchronous motors. With regard to phase estimation, the sensorless vector control method is featured by a new high-frequency voltage injection method (i.e., carrier modulation method), which is distinguished from the conventional ones by a unique ellipse shape of spatially rotating high-frequency voltage, and by a new phase-locked-loop method as a demodulation method whose input is a high-frequency current component multiplied signal. The new vector control method established by two innovative technologies for modulation/demodulation can have the following high-performance and attractive characteristics. 1) It can allow 250% rated torque at standstill. 2) It can operate from zero to the rated speed under the rated motoring or regenerating load. 3) It accepts instant injection of the rated load even for zero-speed control. 4) Phase estimation is robust against inverter dead time, and proper phase estimate can be obtained even under circumstances where stator current crosses the zero at high frequency. 5) Computational load for estimating rotor phase is very small. Usefulness of the proposed new vector control method is verified through extensive experiments.     

New "D-State-Observer"-based vector control for sensorless drive of permanent-magnet synchronous motors

This paper proposes a new sensorless vector control method that can be applied to both salient-pole and nonsalient-pole permanent-magnet synchronous motors (PMSMs). The proposed method estimates phase of rotor flux by a newly developed flux-state observer for sensorless vector control of PMSMs, which is referred to as the "D-state observer". The D-state observer has the following attractive features: 1) it requires no additional steady-state condition for the motor mathematical model; 2) its order is the minimum second; 3) a single observer gain is simply constant over a wide operating range, and easily designed; 4) it utilizes motor parameters in a very simple manner; and 5) its structure is very simple and can be realized at a very low computational load. Usefulness of the proposed method is examined and confirmed through extensive experiments.     

一种新型的基于D状态观测器的永磁同步电机无传感器驱动向量控制方法

本文提出了一种新的能用于凸极和隐极永磁同步电机无传感器向量控制方法。这种方法通过一种新型改进的磁链状态观测器来估计转子磁链相位,用于永磁同步电机无传感器向量控制,该状态观测器被称做D状态观测器。D状态观测器有以下几个很具吸引力的特征：1)建立电机数学模型不需要额外的稳态条件；2)它的维数为最小的二维；3)在较宽的运行范围内,唯一一个观测器增益为常量,容易设计；4)以一种非常简单的方式应用电机的参数；5)结构非常简单因而能在较低的计算量下实现。通过广泛的实验验证了该方法的有效性。     

双三相永磁同步电机在混合储能系统中的转矩分配控制策略

针对电动汽车航能力差、电机控制不稳定的问题,将双三相永磁同步电机应用于电动汽车上,并设计了一种基于混合储能系统(HESS)的多相电机转矩分配控制策略。首先,利用矢量控制方式对永磁同步电机转矩与定子磁通之间的关系进行分析,得出转矩矢量表达式。其次,基于磁通和转矩的增量,提出了绕组去耦补偿、磁通观测和参数辨识方法,通过磁通参考值与磁通观测器之间的误差计算电压参值。最后,采用Matlab/Simulink软件对所提出的永磁同步电机控制系统进行仿真实验与分析。仿真结果表明:在所提控制策略下,系统负载转矩具有较强的抗干扰能力和良好的稳态性能;且具良好的电流控制效果,可在允许范围内逐步减弱至平衡状态。     

Usefulness of a frequency‐hybrid vector control for a sensorless induction motor drive

This paper examines and demonstrates the usefulness of a frequency‐hybrid vector control scheme for sensorless induction motor drive through actual‐machine‐based performance evaluation tests. The new approach utilizes a new indirect orientation scheme and a stable‐filter‐embedded direct orientation scheme, and exploits their advantages. It is confirmed through extensive tests with small and large standard motors such as 0.3, 3.7, 30 kW and special low‐voltage motors dedicated to electric vehicles that the sensorless vector control scheme has the following potential usefulness: (1) it can make machines that produce more than 200% rated torque at standstill, (2) in both motoring and regenerating modes, the rated torque can be produced even in the very slow speed range, including zero speed and zero frequency, (3) for constant speed, good linearity of torque response is attained, (4) it has the ability to track variable speed acceleration commands up to ±5000 rad/s² in the mechanical frequency sense, (5) it can accept a zero‐speed command and settles the machines to a stable standstill with no vibration, (6) it accepts instant injection of rated load even for zero‐speed control, and (7) it accommodates a load with huge inertia. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 44–58, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10073     

Minimizing Induction Motor Losses by Excitation Control in Variable Frequency Drives

For a given induction motor under a specified load condition, a combination of stator voltage and frequency exists which results in minimum power losses. This optimal operating point is calculated over the complete speed and torque range using a model of the induction machine including saturation, stray losses, and skin effect. It is shown that substantial power savings can be achieved compared to conventional programmed volts/hertz control and that main flux saturation has a dominant role in determining the optimal operating condition. A detailed analysis of the mechanisms yielding power savings is presented as well as an experimental confirmation of the theoretical results. These results are utilized to study thetinfluence of machine size, rated slip, and other factors on the optimal performance.     

Flux observer enhanced with low-frequency signal injection allowing sensorless zero-frequency operation of induction motors

In sensorless induction motor drives, flux estimators based only on the standard motor model work well at sufficiently high stator frequencies, but they fail at frequencies close to zero. To solve this problem, a new observer structure is proposed, combining a speed-adaptive full-order flux observer with a low-frequency signal-injection method. An error signal obtained from the signal-injection method is used as an additional feedback signal in the speed-adaptation law of the observer, resulting in a wide speed range, excellent dynamic properties, and zero-frequency operation capability. The enhanced observer is also robust against parameter errors. Experimental results are shown, including very slow speed reversals and long-term zero-frequency operation under rated load torque, as well as rated load torque steps and fast speed reversals under rated load torque.     

Low torque pulsation and high-power control of permanent magnet motor with distributed electromotive force

This paper describes low torque pulsation and high-power control of permanent magnet synchronous motor (PM motor) with distorted electromotive force (emf). The experimental model of PM motor is a 40-kW, 190 r/min, salient-pole, six-phase machine. An individual single-phase transistor inverter is connected to each phase of PM motor as a power source. By adopting full pitch and concentrated winding in the armature of the motor, the rate of flux utilization and output torque per mass can be increased. This winding causes trapezoidal distortion in the phase voltage waveform at no load. For realization of high-performance control of PM motor, the current waveform should be determined so as to minimize torque pulsation and to maximize the output torque of the motor under the rated current. This paper proposes also the method to determine the optimum current waveform. The currents and emfs are expressed as N-dimensional vectors (N: the number of phases). Due to the characteristics of the particular structure of the motor, the armature reaction is small enough to be neglected. In this case, the optimum current vector can be derived under two conditions: (1) the direction of the current vector always agrees with that of the emf vector; and (2) the scalar product of the two vectors is held constant. Supplying the optimum current vector provides no torque pulsation and the nearly maximum output torque under the rated current. This method also can derive the new optimum current corresponding to open-phase operation. The validity of the method is confirmed experimentally. The characteristics of the experimental model of PM motor also are described in this paper.     

Evaluation and Modeling of Cross Saturation Due to Leakage Flux in Vector-Controlled Induction Machines

A detailed magnetic reluctance-based computational model of an induction machine, into which a traditional rotor-flux-orientated vector control scheme has been grafted, is used to examine the influence of saturation of both main and leakage flux paths upon vector-controlled drive performance. Individual machine teeth, windings, and conductors are incorporated, as is pseudo-3-D modeling of skew. The cross-saturation effect is therefore determined from the basic dimensional and winding design data of the machine. Effective compensation methods can then be derived for practical implementation. Direct rotor flux orientation and magnitude control is used to ensure that inaccuracies in a machine-parameter-based vector control scheme are not reflected in the results for cross saturation. Results for a 15-kW four-pole induction motor with rotor skewed one stator slot pitch show that skew leakage flux is predominantly responsible for cross saturation. The skew leakage flux is shown to heavily saturate one end of the machine and to reduce the air gap flux density at the other. At 200% rated load current, this equates to an 11% reduction in direct axis flux if i_sd is kept constant. To compensate for this reduction, a 27% increase in i_sd would be required     

A New Self‐Tuning Power‐Factor‐Based Vector Control Method for Efficient Wide‐Speed Range Sensorless Drive of Permanent‐Magnet Synchronous Motors

As a simple sensorless vector control method for permanent‐magnet synchronous motor (PMSMs), a power‐factor‐based vector control (PFVC) method has been reported. This method has the attractive characteristics that three functions such as current limit, efficiency and sensorless drive can be performed simultaneously in a simple manner. However, it was developed under the assumption that there is no practical voltage limit, and that it cannot be applied over the rated speed. This paper proposes a new PFVC method that allows PMSMs to be driven even over the rated speed under application of a practical voltage limit, while keeping the desired characteristics. The effectiveness and usefulness of the proposed method are verified through extensive experiments.     

自适应FC的无速度传感器感应电机矢量控制系统

设计了一种二维自适应模糊控制器(FC)作为无速度传感器感应电机矢量控制系统的速度调节器.这种自适应模糊控制器可以根据速度给定和负载转矩的变化实时调节解模糊的比例因子.系统使用定转子自适应磁通观测器和转速动态估计器来估算转子磁通和转速,有两个PID控制器分别控制转矩和磁通的电流分量,输出电压空间矢量控制电机.仿真结果表明,与PID控制器比较,FC具有更好的动态性能和稳态性能,鲁棒性得到很大提高.     

感应电动机系统的变结构反推控制研究

感应电动机系统的矢量控制为了进行电流(或电压)的3/2(或2/3)坐标变换需要进行转子转差或磁链角的计算，转子转差的计算容易受转子电阻变化的影响，而磁链角的直接计算容易受定子电阻变化的影响，因此避免转子转差或磁链角的计算对于感应电动机系统的控制是非常有意义的。文中把变结构反推控制运用于感应电动机系统的转矩和磁链控制，设计方法避开了转子转差或转子磁链角的计算，通过一定的坐标变换，基于定子侧的静止坐标系实现转矩和磁链的解耦控制。变结构反推控制设计能够实现快速的速度、转矩和磁链的渐近跟踪，同时系统控制器能够保证系统性能在电动机参数和外部负载变化时具有强的鲁棒性，通过Matlab仿真验证了系统设计的有效性和可行性。     

基于DSP的异步电机无速度传感器矢量控制

讨论了一种异步电机的无速度传感器矢量控制系统,提出了一种新的实现电机矢量控制的控制策略,并且验证了基于电压型转子磁链观测方案中一种新的补偿方式。以TMS320F2407和VC33为核心构成控制器,实现了异步电机无速度传感器矢量控制系统。实验结果证明,该系统具有较好的定子磁链和转速观测精度,能改善低速时磁链畸变程度和运行特性,可以实现针对电机的无速度传感器的矢量控制。     

基于改进型MRAS无轴承异步电机矢量控制系统转速辨识研究

以改进电压模型转子磁链为基础,构建了无轴承异步电机转子磁链定向无速度传感器矢量控制系统。MATLAB/Simulink仿真结果表明:与传统方法相比,所提出的改进电压模型转子磁链提高了转子磁链的观测精度;同时,基于无轴承异步电机转子磁链定向无速度传感器矢量控制系统,在空载调速和加载情况下,辨识转速和实测转速具有很好的一致性,电机能够稳定悬浮运行,充分验证了所提方案的有效性。     

一种弱磁扩速下的异步电机磁链观测和速度辨识

针对异步电机在高速弱磁下的运行特点,提出了一种基于弱磁下的高性能的磁链观测方法。该方法在基于转子磁链定向电流模型下,设计了一个可以补偿磁链观测误差的补偿器,解决了弱磁条件下励磁磁场变化而导致磁链观测不准的问题。在改进磁链观测的基础上,运用了易于在定点芯片上实现的转速辨识算法,估算出电机转速。最后将结合改进磁链观测的速度估计器应用到无速度传感器矢量控制系统中,仿真结果表明,这种方法实现方便,能够在弱磁高速下准确的辨识磁链和转速估计,提高控制系统的动态性能。     

基于高性能磁链算法的永磁同步电动机无位置传感器控制

准确的磁链辨识是基于磁链观测法永磁同步电动机无位置传感器控制的关键,传统电压型磁链辨识算法消除了纯积分存在漂移问题,对圆形磁场的磁链可以准确辨识,但对实际中电机内普遍存在的椭圆形磁场的磁链辨识时存在稳态幅值和相位误差。分析了椭圆形磁场时磁链矢量与反电动势矢量的空间关系。对传统算法辨识椭圆形磁链的误差进行了分析,提出一种改进的新型磁链算法。改进后的新算法运算量与传统算法相当,但对圆形与椭圆形磁场的磁链均能准确辨识。将新算法应用于一台表贴式永磁同步电动机无位置传感器控制系统的转子位置估算,仿真证明,在稳态及转速突变时新算法均具有良好的位置和转速跟踪效果。利用数字信号处理器TMS320F2812DSP对其进行了数字化实现。实验结果表明,在中高速范围内,调速系统在稳态与电机转速突变时具有良好的动静态特性,但在低速区会出现系统不稳定。仿真与实验证明了新算法的有效性和实际可应用性。     

基于磁链与负载观测器的异步电机反步滑模控制

针对参数摄动及负载转矩未知且变化会影响异步电机速度控制的问题,设计了一种改进型指数趋近律的滑模转子磁链观测器,用于估算电机转子磁通值,同时将磁通观测值用于负载转矩的估计。引入磁链误差、转速误差,通过反步滑模控制算法,将转子磁通与负载转矩的观测值用于异步电机控制。在转子电阻摄动与负载转矩未知且变化的情况下,将该控制策略与自适应反步控制方法进行实验结果对比。实验结果表明,该控制策略的响应速度快且跟踪精度高,提高了异步电机速度控制系统的抗干扰性能。最后,提出一种转速软给定方法,实验表明该方法能有效抑制转速变化时刻定子电流与电磁转矩的急剧增加,进一步改善了电机系统的性能。     

交互式模型参考自适应PMSM速度辨识

提出了一种基于矢量控制的交互式模型参考自适应永磁同步电机无速度传感器控制方案.该方案利用静止α-β坐标系下的基于电压模型的反电动势估计值和基于磁链模型的反电动势估计值之差作为误差信号,交互式的构成对定子电阻辨识和转子转速辨识的自适应律,实现定子电阻和转速的估计,解决了因电机参数变化所影响速度辨识精度的问题.仿真和实验研...     

基于定子磁场定向的直接转矩控制新方法

文章根据定子磁场定向理论，介绍了一种直接转矩控制的新方法，通过动态计算电机定子端的电压矢量，实现了对异步电机的解耦控制，在低速下较传统直接转矩控制方法具有更优的控制性能，在高速下与传统直接转矩控制方法同样具有响应快、性能不受电机参数影响等优点，并与传统直接转矩控制方法的对比仿真研究，仿真结果验证了本文所叙方法是有效的。