表面永久磁石形同期電動機のトルクセンサレス高精度トルク制御に関する研究

福井大学博士(工学)doctoral thesi

Using sensorless direct torque with fuzzy proportional-integral controller to control three phase induction motor

Induction motors (IM) attracted many researchers in the last few decades. In this field, various applications are implemented, such as servo motor drives and electric vehicles. This work applies a sensorless direct torque controller (DTC) to control a three-phase IM. System dynamics of the IM were derived. A nonlinear dynamic model had introduced with white noise. Given the complexity of the dynamics, the Jacobean Linearization technique has been used to obtain the linear model for a control task. A DTC technique is employed to control the motor speed of the system with a combination of two controllers. The fuzzy proportional-integral (PI) controllers are applied to obtain the reference torque based on an optimization process against the speed error raise. The optimizer is called grey wolf optimizer (GWO) and is implemented to achieve the centre values of the two output memberships for the fuzzy PI controllers. Then the extended Kalman filter (EKF) is used to evaluate the direct and quadratic components of the rotor flux and rotor speed from the observation of stator voltages and currents. The system is tested employing MATLAB simulation software and determines the targeted results. The outcomes are evaluated to improve the control performance

Формирование сигналов задания системы тягового асинхронного электропривода

The purpose of this work is to build the analytical improved (with resistances estimation) real time computation of the reference inputs for rotor flux and torque in the vector control system of an induction motor of a traction electric drive. The reference inputs must maximize electromagnetic torque in conditions of voltage source instability, particularly in magnetic field weakening mode. The conventional way to control the field weakening mode is to form flux coupling task inversely proportional to the speed or inversely proportional to the square of the speed in second and third zones respectively. Such reference input signals are not able to provide the maximum torque capability over the entire speed range, and the improved torque capability is achieved in different ways. For instance, voltage feedback is useful for the torque capability enhancement in conditions of internal and external perturbations. A wide change in speed with the weakening of the flux reveals the nonlinear properties of an induction electric motor. However, in vector control systems, proportional-integrating (PI) regulators are usually used. Therefore, firstly, linear PI controllers must be robust, and secondly, the reference input signals for flux and torque must guaranty linear, not saturated state of each PI controller. The proposed expressions for calculating reference inputs for induction motor rotor flux and electromagnetic torque as functions of actual rotor speed are the approximate expressions. The estimation of the possible error shows that the error is acceptable. Simulation is performed for the vector control system of an induction motor and taking into account the calculation of the control signal by the microcontroller and the dynamics of the frequency invertor. The simulation of the resulting system validates the effectiveness of the control system using the proposed expressions for the formation of real-time reference input signals for setting the flux and torque.Цель данной работы – формирование в реальном времени сигналов задания потокосцепления и момента в системе векторного управления асинхронным электродвигателем тягового электропривода. Сигналы задания должны максимизировать момент в условиях нестабильности напряжения источника питания, в частности в режиме ослабления магнитного поля. Обычный способ управления режимом ослабления поля заключается в формировании задания потокосцепления обратно пропорционально скорости либо квадрату скорости. Так формируемые сигналы задания не способны обеспечить максимум располагаемого момента во всем диапазоне изменения скорости, и увеличение располагаемого момента достигается различными путями. Например, обратная связь по напряжению используется для увеличения располагаемого момента в условиях внутренних и внешних возмущений. Широкое изменение скорости при ослаблении потокосцепления выявляет нелинейные свойства асинхронного электродвигателя. Однако в системах векторного управления обычно применяются пропорционально-интегрирующие (ПИ) регуляторы. Следовательно, во-первых, линейные ПИ-регуляторы должны быть робастными, во-вторых, сигналы задания для потокосцепления и момента должны гарантировать линейное без насыщения функционирование каждого ПИ-регулятора системы управления. Предложенные выражения для расчета входных сигналов задания для потокосцепления ротора и электромагнитного момента как функции текущего значения скорости ротора являются приближенными выражениями. Оценка возможной погрешности показывает, что погрешность допустима. Имитационное моделирование выполнено для системы векторного управления асинхронным электродвигателем и с учетом вычисления сигнала управления микроконтроллером и динамики преобразователя частоты. Имитационное моделирование системы подтверждает эффективность управления с применением предложенных выражений для формирования в реальном времени сигналов задания потокосцепления и момента

Closed-Loop Drive Detection and Diagnosis of Multiple Combined Faults in Induction Motor Through Model-Based and Neuro-Fuzzy Network Techniques

In this paper, a fault detection and diagnosis approach adopted for an input-output feedback linearization (IOFL) control of induction motor (IM) drive is proposed. This approach has been employed to detect and identify the simple and mixed broken rotor bars and static air-gap eccentricity faults right from the start its operation by utilizing advanced techniques. Therefore, two techniques are applied: the model-based strategy, which is an online method used to generate residual stator current signal in order to indicate the presence of possible failures by means of the sliding mode observer (SMO) in the closed-loop drive. However, this strategy is not able to recognise the fault types and it can be affected by the other disturbances. Therefore, the offline method using the multi-adaptive neuro-fuzzy inference system (MANAFIS) technique is proposed to identify the faults and distinguish them. However, the MANAFIS required a relevant database to achieve satisfactory results. Hence, the stator current analysis based on the HFFT combination of the Hilbert transform (HT) and Fast Fourier transform (FFT) is applied to extract the amplitude of harmonics due to defects occur and used them as an input data set for the MANFIS under different loads and fault severities. The simulation results show the efficiency of the proposed techniques and its ability to detect and diagnose any minor faults in a closed-loop drive of IM

Adaptive Non-Linear High Gain Observer Based Sensorless Speed Estimation of an Induction Motor

International audienc

Robust Speed-Sensorless Vector Control of Doubly Fed Induction Motor Drive Using Sliding Mode Rotor Flux Observer

This paper presents a robust observer for sensorless speed control of doubly fed induction motor (DFIM), based on the slidin mode. In the first step, a model of the doubly fed induction motor fed by two PWM inverters with separate DC bus link is developed. In the second step and in order to provide a robust separate control between flux and motor speed a vector control by field oriented strategy applying a sliding mode regulator was implemented. Finally, speed estimation of a doubly fed induction motor based on sliding mode observer is presented. The simulation tests schow the effectiveness of the proposed method especially in the load disturbances, the change of the refrence speed and low speed. Also the influence of parameter variations will be studied by simulatio

Nonlinear Dynamics of Asynchronous Electric Drive: Engineering Interpretation and Correction Techniques

The results of theoretical and practical research studies most widely used in the industry of variable frequency drives (VFD) are presented in this manuscript. Such objects are characterized by dynamic nonlinearities that are difficult to take into account in the mathematical description for the development of control algorithms. Accounting for these nonlinearities leads to equations that are very problematic to solve. Therefore, the equations of the mathematical model on which the vector control system is based are compiled with the assumption of the sinusoidality of the processes occurring in the control object. Comparative results of the analysis of dynamic of VFD with two types of sensorless control, vector and scalar, show the problems that these assumptions lead to.. For identification of nonlinearities, dynamic formulas of transfer functions of torque generator in VFD are proposed, taking into account slip and stator voltage frequency The nonlinear transfer functions obtained in this work made it possible to substantiate structural solutions that linearize the VFD and substantially increase their efficiency. The use of dynamic feedback on the stator current allowed to significantly increase the dynamics and efficiency of a more stable scalar control

Robust Control

The need to be tolerant to changes in the control systems or in the operational environment of systems subject to unknown disturbances has generated new control methods that are able to deal with the non-parametrized disturbances of systems, without adapting itself to the system uncertainty but rather providing stability in the presence of errors bound in a model. With this approach in mind and with the intention to exemplify robust control applications, this book includes selected chapters that describe models of H-infinity loop, robust stability and uncertainty, among others. Each robust control method and model discussed in this book is illustrated by a relevant example that serves as an overview of the theoretical and practical method in robust control

PV Array Driven Adjustable Speed Drive for a Lunar Base Heat Pump

A study of various aspects of Adjustable Speed Drives (ASD) is presented. A summary of the relative merits of different ASD systems presently in vogue is discussed. The advantages of using microcomputer based ASDs is now widely understood and accepted. Of the three most popular drive systems, namely the Induction Motor Drive, Switched Reluctance Motor Drive and Brushless DC Motor Drive, any one may be chosen. The choice would depend on the nature of the application and its requirements. The suitability of the above mentioned drive systems for a photovoltaic array driven ASD for an aerospace application are discussed. The discussion is based on the experience of the authors, various researchers and industry. In chapter 2 a PV array power supply scheme has been proposed, this scheme will have an enhanced reliability in addition to the other known advantages of the case where a stand alone PV array is feeding the heat pump. In chapter 3 the results of computer simulation of PV array driven induction motor drive system have been included. A discussion on these preliminary simulation results have also been included in this chapter. Chapter 4 includes a brief discussion on various control techniques for three phase induction motors. A discussion on different power devices and their various performance characteristics is given in Chapter 5

Robust fault tolerant control of induction motor system

Research into fault tolerant control (FTC, a set of techniques that are developed to increase plant availability and reduce the risk of safety hazards) for induction motors is motivated by practical concerns including the need for enhanced reliability, improved maintenance operations and reduced cost. Its aim is to prevent that simple faults develop into serious failure. Although, the subject of induction motor control is well known, the main topics in the literature are concerned with scalar and vector control and structural stability. However, induction machines experience various fault scenarios and to meet the above requirements FTC strategies based on existing or more advanced control methods become desirable. Some earlier studies on FTC have addressed particular problems of 3-phase sensor current/voltage FTC, torque FTC, etc. However, the development of these methods lacks a more general understanding of the overall problem of FTC for an induction motor based on a true fault classification of possible fault types.In order to develop a more general approach to FTC for induction motors, i.e. not just designing specific control approaches for individual induction motor fault scenarios, this thesis has carried out a systematic research on induction motor systems considering the various faults that can typically be present, having either “additive” fault or “multiplicative” effects on the system dynamics, according to whether the faults are sensor or actuator (additive fault) types or component or motor faults (multiplicative fault) types.To achieve the required objectives, an active approach to FTC is used, making use of fault estimation (FE, an approach that determine the magnitude of a fault signal online) and fault compensation. This approach of FTC/FE considers an integration of the electrical and mechanical dynamics, initially using adaptive and/or sliding mode observers, Linear Parameter Varying (LPV, in which nonlinear systems are locally decomposed into several linear systems scheduled by varying parameters) and then using back-stepping control combined with observer/estimation methods for handling certain forms of nonlinearity.In conclusion, the thesis proposed an integrated research of induction motor FTC/FE with the consideration of different types of faults and different types of uncertainties, and validated the approaches through simulations and experiments