无轴承异步电机新型直接转矩控制研究

针对无轴承异步电机(Bearingless Induction Motor,BIM)传统直接转矩控制中转矩脉动大,悬浮性能不佳等问题,提出了一种基于滑模变结构的直接转矩控制方法 (SMVS-DTC)。首先根据转矩误差和磁链误差构造出相应的滑模切换面,然后采用指数趋近律设计了直接转矩控制器。在此基础上对所提方法进行了仿真和实验研究。仿真和实验结果表明,该方法有效地减小了转矩脉动和磁链脉动,并且提高了BIM转速动态响应和稳定悬浮性能。     

New hybrid fuzzy controller for direct torque control induction motor drives

A new hybrid fuzzy controller for direct torque control (DTC) induction motor drives is presented in this paper. The newly developed hybrid fuzzy control law consists of proportional-integral (PI) control at steady state, PI-type fuzzy logic control at transient state, and a simple switching mechanism between steady and transient states, to achieve satisfied performance under steady and transient conditions. The features of the presented new hybrid fuzzy controller are highlighted by comparing the performance of various control approaches, including PI control, PI-type fuzzy logic control (FLC), proportional-derivative (PD) type FLC, and combination of PD-type FLC and I control, for DTC-based induction motor drives. The pros and cons of these controllers are demonstrated by intensive experimental results. It is shown that the presented induction motor drive is with fast tracking capability, less steady state error, and robust to load disturbance while not resorting to complicated control method or adaptive tuning mechanism. Experimental results derived from a test system are presented confirming the above-mentioned claims.     

感应电机直接转矩控制系统中的模糊控制研究

对模糊控制在直接转矩控制系统中的应用做了全面分析和总结,重点讨论了各种模糊直接转矩控制方案的特点和不足之处.最后指出,这些方案都能改善系统性能,但无疑增加了系统的复杂性.     

感应电机直接转矩控制系统中的模糊控制研究

对模糊控制在直接转矩控制系统中的应用做了全面分析和总结,重点讨论了各种模糊直接转矩控制方案的特点和不足之处。最后指出,这些方案都能改善系统性能,但无疑增加了系统的复杂性。     

A novel torque-ripple reduction strategy for direct torque control[of induction motor]

This letter presents a simple duty-cycle control scheme for the direct torque control of an induction motor. The scheme reduces torque ripple, controls the average output torque, and reduces the variation in switching frequency. The effectiveness of the proposed technique is demonstrated through experimental results     

A dead-beat type digital controller for the direct torque control of an induction motor

In this paper, a dead-beat type digital controller has been introduced to overcome the problems of a conventional direct torque controller. The proposed induction motor drive with a digital dead-beat controller shows good transient response and negligible steady-state error even at a low switching frequency, which is needed for high power machines used for transportation. Including the rotor dynamics, the stability condition and steady-state error of the proposed control system have been examined in the z-plane. In addition, the good performance has been verified through the simulation and experiment. The flux and torque controllers have been designed with only stator voltage equations in the stator flux reference frame in order to take advantages of the direct torque control. Therefore, the proposed flux and torque controllers have simple forms and can be easily designed and implemented.     

Enhanced inverter switching for fast response direct torque control[of induction motor drives]

In classical direct torque control (DTC), an inverter switching event can occur once in each control update period. Because the nature of the inverter switching event is unconstrained, it is essential to limit the inverter switching frequency, and hence the control update period, to ensure that under no circumstances is the allowable switching frequency of any individual power device exceeded. Consequently the switching capability of individual power devices is generally under-utilized, and the control scheme produces high levels of ripple in the motor current and torque. This paper describes a new strategy for device switching and voltage vector selection in DTC. The basis of the strategy is an increase in the control update frequency, while limiting the switching rate of each inverter leg. Although the rate at which device switching events may occur is unchanged, the higher control update frequency leads to higher resolution timing of switching events. The advantages of the strategy, demonstrated by experimental results on a 3 kW induction motor drive, are a significant reduction in the steady-state torque ripple as well as a faster transient response     

基于Saber的异步电动机直接转矩控制系统仿真

为了验证基于三电平逆变器异步电动机直接转矩控制系统的可行性和有效性,利用Saber仿真软件优良的模块化和分级式的系统仿真能力,建立了异步电动机直接转矩控制系统中定子磁链与电磁转矩观测器、扇区判断、空间电压开关矢量表以及二极管箝位型三电平逆变器等子系统的仿真模型,并根据直接转矩控制原理最终构建了完整的系统仿真模型。利用所构建的系统仿真模型进行了仿真实验,仿真分析结果证明建立的系统模型是有效的,表明直接转矩控制系统具有良好的动态响应性能。     

Speed-sensorless sliding-mode torque control of an induction motor

Novel induction motor control optimizing both torque response and efficiency is proposed in the paper. The main contribution of the paper is a new structure of rotor flux observer aimed at the speed-sensorless operation of an induction machine servo drive at both low and high speed, where rapid speed changes can occur. The control differs from the conventional field-oriented control. Stator and rotor flux in stator fixed coordinates are controlled instead of the stator current components in rotor field coordinates i_sd and i_sq. In principle, the proposed method is based on driving the stator flux toward the reference stator flux vector defined by the input command, which are the reference torque and the reference rotor flux. The magnitude and orientation angle of the rotor flux of the induction motor are determined by the output of the closed-loop rotor flux observer based on sliding-mode control and Lyapunov theory. Simulations and experimental tests are provided to evaluate the consistency and performance of the proposed control technique     

Integrated starter generator for 42-V powernet using induction machine and direct torque control technique

This paper describes an integrated starter generator (ISG) for automobile applications with 42-V powernet. This system is based on an induction machine which is directly mounted on the engine crankshaft and controlled using the technique of direct torque control (DTC). The suitability of the technique for ISG application is explained. The control structure of DTC for ISG application is described. Detailed experimental results from a 1.4-1 diesel engine are presented demonstrating the performance of the system during cranking as well as generation. The ISG also incorporates the feature of "on the fly start" during generation mode. Details of a low voltage high current power converter developed for this application are also given.     

Probabilistic voltage harmonic analysis of direct torque controlled induction motor drives

In high frequency motor-drives such as direct torque controlled (DTC) induction motor drives, the motor harmonic loss, and electromagnetic interference are largely affected by the spectrum of the motor input voltage. Nonlinear elements in the control loop of DTC drive make harmonic analysis of the drive very complex compared to classical pulsewidth modulated controlled drives. In this paper, a probabilistic method to study the harmonic contents of voltage in DTC of induction motors is presented. The DTC voltage chain is simulated with a random process. Then, the autocorrelation function of voltage vectors is calculated and its power spectrum density is obtained. The effect of flux and torque hysteresis controller bands, machine parameters, and inverter dc-link voltage on the motor voltage spectrum is investigated. Major harmonics in the DTC voltage spectrum are specified and their behaviors are described. Simulation and experimental results are presented to justify the theoretical analysis.     

Nonlinear sliding-mode torque control with adaptive backsteppingapproach for induction motor drive

In this paper, the nonlinear sliding-mode torque and flux control combined with the adaptive backstepping approach for an induction motor drive is proposed. Based on the state-coordinates transformed model representing the torque and flux magnitude dynamics, the nonlinear sliding-mode control is designed to track a linear reference model. Furthermore, the adaptive backstepping control approach is utilized to obtain the robustness for mismatched parameter uncertainties. With the proposed control of torque and flux amplitude, the controlled induction motor drive possesses the advantages of good transient performance and robustness to parametric uncertainties, and the transient dynamics of the induction motor drive can be regulated through the design of a linear reference model which has the desired dynamic behaviors for the drive system. Finally, some experimental results are demonstrated to validate the proposed controllers     

Efficiency-optimized direct torque control of synchronousreluctance motor using feedback linearization

In this paper, a nonlinear controller capable of high dynamic torque regulation and efficiency optimization of the synchronous reluctance motor (SynRM) using input-output feedback linearization is proposed. The cross-coupling effects in the SynRM model and the torque nonlinearity due to the iron losses in torque-speed characteristics of the SynRM are discussed. The criterion for the efficiency optimization is also introduced and investigated. Since the proposed nonlinear controller directly regulates the torque by selecting the product of d- and q-axes torque currents as one of the output variables, the nonlinear and cross-coupling aspects between the d-and q-axes torque currents and the terminal currents can he eliminated. Hence, the linear torque-speed characteristic can be achieved. In addition, by controlling the power loss-minimizing criterion directly, the proposed controller can optimize the efficiency of the SynRM without deteriorating the dynamics performance     

A maximum torque control with a controlled capacitor for asingle-phase induction motor

This paper presents a new method to achieve a maximum torque for a single-phase induction motor. An AC adjustable capacitor using an electronic switch in parallel with a capacitor is proposed. The capacitor is short-circuited in a different period by an electronic switch during each cycle to vary the effective value of the AC capacitor. Two new optimization algorithms, which obtain a maximum starting torque by adjusting the effective capacitor, are proposed. No starting capacitor or centrifugal switch is used here. A theoretical analysis, and simulated and experimental results are presented in this paper     

交流电机直接转矩控制改进方案

从直接转矩控制的原理出发,介绍直接转矩控制减小脉动方法以及特点.虽然这些方法在一定程度上可改善直接转矩控制性能,但增加系统的复杂性.提出改善直接转矩控制性能而不增加系统复杂度,则是未来的研究重点.     

永磁同步电机直接转矩控制系统的仿真研究

文章分析了永磁同步电机直接转矩控制的原理,阐述传统直接转矩控制系统转矩脉动的缺点,本文将空间矢量脉宽调制技术引入永磁同步电机的直接转矩控制系统中,利用空间矢量的调制过程,可在相同的系统硬件条件下得到更多的、连续的电压空间矢量,进而得到对电机更准确的控制。仿真结果表明,该方案既保持了直接转矩控制快速动态响应,又减小了电机转矩的脉动。     

交流电机直接转矩控制改进方案

从直接转矩控制的原理出发．介绍直接转矩控制减小脉动方法以及特点。虽然这些方法在一定程度上可改善直接转矩控制性能,但增加系统的复杂性。提出改善直接转矩控制性能而不增加系统复杂度,则是未来的研究重点。     

开关磁阻电机的直接转矩控制系统的仿真研究

通过对开关磁阻电机的控制方法的介绍,引入了直接转矩控制技术,并对直接转矩控制进行了分析.并通过matlab搭建的仿真模型,验证了该控制系统的优良性能,取得了较好的控制效果,明显地减少了转矩脉动,提高了系统的调速性能.     

Simple direct torque control of induction machine using space vector modulation

A new method for direct torque control (DTC) based on load angle control is developed. The use of simple equations to obtain the control algorithm makes it easier to understand and implement. Fixed switching frequency and low torque ripple are obtained using space vector modulation, overcoming the most important drawbacks of classic DTC.     

Direct torque and frequency control of double-inverter-fed slip-ring induction motor drive

A novel sensorless scheme for direct torque and frequency control of a double-inverter-fed slip-ring induction motor is presented. The analysis of a double-inverter-fed induction motor is given to derive the proposed controller. Various frequency profiles are analyzed for a direct frequency controller. A novel frequency profile is suggested to make the sensorless drive operation reliable and machine parameter independent at any rotor speed. Simulation and experimental results are presented from a 50-hp drive, demonstrating that the drive can deliver full torque from 0 to 2-p.u. speed in either direction. Thus, double the rated power can be extracted from the motor without overloading it.