HIGH SPEED INDUCTION MOTOR DRIVE WITH ACTIVE MAGNETIC BEARINGS AND SLIDING MODE DECENTRALIZED CONTROL

ABSTRACT

Active magnetic bearings are credited with high performance in terms of low energy consumption, high speeds, increased reliability and low maintenance costs.

This paper discusses a high-speed induction motor with active magnetic bearings: both radial and axial. The decentralized control system of active magnetic bearings is based on sliding mode variable structure principle to provide robustness to parameter detuning and perturbations.

Test results on a laboratory model of 300 W and 25000 rpm motor designed and built for the scope are very promising for applications to high speed machine tools, vacuum pumps etc.     

异步电机矢量控制系统速度辨识研究

本文针对无速度传感器异步电机矢量控制系统，提出了一个基于卡尔曼滤波器的异步电机速度辨识方法。利用电机机端的定子电压和电流，运用卡尔曼滤波辨识速度。为提高算法的快速法，采用了降低观测器方法，该方法具有较高的精度，仿真结果表明，转速在全速度范围内都有较好的辨识精度。     

电动车用感应电机磁场定向矢量控制研究

电动车用感应电机参数变化易引起电机振荡现象，文中以含微分运算的三相感应电机模型为基础，提出了一种具有转差频率控制的转子磁场定向矢量控制方法，给出了相关的理论推导及实验结果。该方法能够有效地抑制由于电机参数变化过大导致的电机振荡现象，能使电机可靠地运行于弱磁区域，可满足高功率密度、高转速电动车用感应电机的控制要求。实验结果验证了该方法的正确性及有效性。     

感应电机调速系统新型滑动模解耦与自校正控制

文音分析和设计了一类新型感应电机调速系统,整个系统分成内、外环。论文首先通过适当选择坐标框架,提出一个简明的鹫电机数学模型,并以此为基础,在内环设计了一个滑动模转矩控制器,因而它不但可实现转矩和磁通的解耦控制,而且对电机参数变化和外界干扰还具有较强的鲁棒性。外环的设计则引入自校正控制器－－－零极 点配置控制器（含实时参数辨识）。仿真结果表明,整个系统在外环采用自校正控制后能进一步提高系统的鲁棒性和     

DESIGN OF VARIABLE SPEED INDUCTION MOTOR DRIVE WITH A CURRENT-FED INVERTER

ABSTRACT

A closed-loop speed control scheme with reversing and regenerating capability for a squirrel-cage induction motor is described. The scheme makes use of a fully-controlled bridge for a.c. to d.c. conversion, a currend-fed inverter for generation of variable frequency a.c. supply for motor and an analogue tachogenerator for speed feedback signal. The current-reference signal is generated by a novel slip calculator. This paper describes the slip calculator and the design of controllers based on an approximate model of motor. Experimental results validating the methods used for design of controllers are also presented.     

永磁同步电动机的非线性PI速度控制

永磁同步电动机(PMSM)是典型的非线性系统，该文考虑了齿隙转矩、谐波转矩等转矩波动和各种不确定扰动，建立了包含非线性不确定项的PMSM数学模型。针对所提模型，采用非线性PI控制方法实现速度控制，得到具有鲁棒性能的控制器。非线性PI控制摒弃了传统自适应控制方法对不确定系统控制时所采用的参数辨识加反馈控制器设计的结构，不需要知道非线性不确定函数的具体形式，通过确定该函数的界来设计控制器的参数，使系统能够达到全局渐近稳定或者实现对参考信号的跟踪。仿真结果表明了控制算法的有效性。     

新型双凸极永磁电机调速系统的变参数PI控制

双凸极永磁电机转矩和转速之间具有强烈的非线性关系，采用常规线性PI控制器难以得到令人满意的控制特性，为此根据PI控制器各参数在调节过程中的不同作用，提出了适于单片机上实现的变参数PI控制模型，并用遗传算法求解其参数，理论分析与实验结果均表明，变参数PI控制器比常规PI控制器具有更强的自适应性，双凸极电机调速系统具有优良的稳态和动态性能，该文所提出的控制模型及其算法是正确和有效的。     

多区域互联电力系统的PI滑模负荷频率控制

提出了一种用于多区域互联电力系统的负荷频率综合PI滑模控制方法,该方法同时发挥了基于新区域控制偏差的比例积分控制和滑模控制的优点,选用带积分的滑模超面方程使系统从一开始就进入滑模状态,当系统进入滑模状态后,转化为基于新区域控制偏差的比例积分控制。在考虑发电机变化率约束和具体控有控制死区条件下,所提出的综合控制方法仍能使系统取得较好的性能,而且克服各自单一控制的不足,仿真结果显示该方法是简单的、有效的、并且能够保证整个系统是渐进稳定的。     

基于电压解耦原理的感应电机无速度传感器矢量控制

文中提出了一种基于电压解耦原理的简化的感应电机模型。通过在定子电压指令中增加解耦项，即在励磁和转矩信号输入端增加一个标量解耦环节，以消除感应电机的内部耦合。根据该模型，设计了一个转子磁通t轴分量控制器，获得了转子速度的辨识方法。另外，在动态过程中，当电机参数特别是转子电阻发生变化时，通过加入转子磁通角偏移的补偿环节，可以确保转子磁通获得快速、准确的定向。同时，也分析了转子电阻变化对速度辨识精度所产生的影响。仿真和实验验证了所提方案的有效性。     

SPEED AT BREAKDOWN TORQUE OF A SINGLE-PHASE INDUCTION MOTOR

ABSTRACT

The purpose of this paper is to present an “exact” analytical expression to calculate speed at breakdown torque and the breakdown torque of single-phase induction motors. From the theoretical expression for torque developed by a single-phase motor, a sixth order polynomial in speed at breakdown torque is obtained, and solved, using a well known method. A real root for per unit speed, i.e. the ratio of speed to the synchronous speed, that lies between 0 and 1 is selected and the actual breakdown torque is determined by substituting it in the torque equation. The breakdown torque, also termed as maximum torque, so obtained has been found to yield better correlation between the predicted and the tested results than the only existing empirical relation. Steps to calculate speed at maximum torque are also suggested. For an arbitrarily selected single-phase induction motor, a curve of speed at breakdown torque as a function of r₂/X is also included for the purposes of illustration and understanding.     

FIELD-ORIENTED CONTROL OF INDUCTION MACHINES IN THE PRESENCE OF MAGNETIC SATURATION

ABSTRACT

This paper presents derivation of the equations which describe field-oriented control of saturated induction machines. Field-oriented control principles are applied on the saturated model of induction machine and new equations are obtained, which differ significantly from the well-known model valid when the main flux saturation is absent or neglected. Rotor flux oriented control of voltage-fed and current-fed saturated induction machines is discussed. New decoupling circuits which are needed under saturated conditions are presented. Simulation results, which show the influence of main flux saturation on transient behaviour of the drive and which verify the theoretical results are included.     

OPTIMAL STATE FEEDBACK CONTROL OF A CURRENT SOURCE INVERTER-FED INDUCTION MOTOR DRIVE USING A NEW ROTOR CURRENT OBSERVER

ABSTRACT

ABSTRACT The design, implementation and performance of a multivariable optimal state feedback controller for a Current Source Inverter-fed Induction Motor (CSI-IM) drive using a new reduced order observer to estimate rotor currents have been reported in this paper. A quadratic performance index together with a set of prescribed closed loop eigenvalues for placement are considered for application to a d-q axes state space linearized model of the drive to derive the control law - for achieving prescribed degree of stability in contrast to an earlier design with only pole-placement. The optimal control law derived is a function of all the states, the inaccessible states like d-q axes rotor currents being estimated by a new observer whose structure is simpler than that of one used in an earlier case. The controller-observer is implemented using an inexpensive microprocessor kit and the experimental results are presented along with the digital simulation results for the controlled drive to show its performance under step changes of load torque and references.     

一种感应电机的解耦控制方法

交流电机是一种机电能量转换的重要装置，它有极强的电磁耦合性。该文在交流电机转子磁场定向控制的基础上，根据控制原理的不变性原理提出了一种感应电机偏差解耦控制方法，给出了算法的推导过程，对所提方法的鲁棒性进行了分析，对解耦方式与矢量控制系统结构，影响解耦因素进行了探讨。计算机仿真对解耦效果进行了比较。物理实验对所提方法进行了验证。理论分析和实验结果表明所提方法具有良好的解耦控制方法。     

一种改进的感应电机最大效率控制技术研究

在分析感应电机最大效率控制技术基础上，提出了两项改进措施。首先针对传统方法搜索慢，收敛性能差的缺点，提出了一种混合搜索技术，即通过电机损耗模型离线计算励磁电流设定值的下限，采用黄金分割法在已经缩小的范围内进行搜索；其次针对搜索过程中转矩脉动问题，提出了一种转矩电流前馈补偿方案。为了获得良好的暂态响应，在转矩或者设定速度发生改变时，励磁电流重新恢复到额定值，详细的切换方案也被提出。实验和仿真验证了方案的实用性和有效性。     

用张量法仿真变频器-异步电机调速系统

根据克朗的张量电网络理论,建立了变频器－－异步电机调速系统的数字仿真模型。该模型通过物二次变换,可自动处理由开关元件组成的时变拓扑网络,并通过与异步电机方程耦合,建立了系统的统一状态方程本文将该模型应用于一仿真实例分析,仿真结果与实际结果吻合较好。     

使用基频电流注入的感应电机无速传感器驱动

该文结合基频电流注入新策略与磁链估计方法对感应电动机提出了一种无速度传感器控制策略.在电机低速区域,通过在d轴注入基频定子电流以及使用信号处理方法实现转子磁链位置估计.在高速区域,基于定子电压和电流信息通过转子磁链估计方法推算出转子磁链位置.基于转子磁场定向控制的系统实验结果验证了该方案的正确性.     

IN-PHASE COMPENSATION FOR A HIGH SPEED LINEAR INDUCTION MOTOR

Abstract

The performance of a high speed linear induction motor is considerably degraded due to end-effects. This is particularly so as regards the force produced. In this paper, a new method called “In-phase compensation” method has been described to eliminate the end-effect force. Unlike the conventional methods, this method does not require phase angle control but only magnitude control of compensating current even for varying slips. A comparison of developed forces by this method of compensation has been made with an equivalent uncompensated LIM.     

PERFORMANCE ANALYSIS OF LOAD COMMUTATED INVERTER FED CAGE INDUCTION MOTOR DRIVE

ABSTRACT

An approach, to analyse the performance of a variable speed cage induction motor drive fed from load commutated inverter (LCI), is presented. Induction motor with an appropriate capacitor across its stator terminals constitutes the load on the inverter. A fully controlled bridge converter, supplied by a variable dc voltage source, commutated with the back emf of the motor, acts as an inverter. An algorithm to compute the motor performance, is developed using equivalent circuit representation of the system. Strategies for the selection of control variables, in order to achieve the desired speed range for satisfactory performance of the drive are given. The performance of a 3-hp, cage induction motor fed from LCI is computed, using the developed algorithm for wide range of speed; and is verfied experimentally.     

多套交交变频同步电机矢量控制系统网侧合成电流谐波分析

在工业生产,特别是在冶金行业中,交交变频同步电机矢量控制系统已成为大型轧钢机主传动发展的必然趋势。为实现连轧机主传动调速系统的国产化,当前急需研究相应的控制策略和电网谐波治理方案,并尽愉应用于待改造连轧机上。在对单套系统网侧功率因数的谐波研究的基础上,分析了多套系统联合运行时网侧电流谐波的状况,并且研究了各套系统整流变压器疗养接组别的最优选择问题。