An implementation of rotor speed observer for sensorless induction motor drive in case of machine parameter uncertainty

The paper describes observers using model reference adaptive system for sensorless induction motor drive with the pulse width modulator and the direct torque control under the circumstances of incorrect information of induction motor parameters. An approximation based on the definition of the Laplace transformation is used to obtain initial values of the parameters. These values are utilized to simulate sensorless control structures of the induction motor drive in Matlab-Simulink environment. Performance comparison of two typical observers is carried out at different speed areas and in presence of parameter uncertainty. A laboratory stand with the induction motor drive and load unit is set up to verify the properties of observers. Experimental results confirm the expected dynamic properties of selected observer

Comparative Analysis of Estimation Techniques of SFOC Induction Motor for Electric Vehicles

International audienceThis paper presents system analysis, modeling and simulation of an electric vehicle with different sensorless control techniques. Indeed, sensorless control is considered to be a lower cost alternative than the position or speed encoder-based control of induction motors for an electric vehicle. Two popular sensorless control methods, namely, the Luenberger observer and the Kalman filter methods are compared regarding speed and torque control characteristics. They are also compared against the well-known model reference adaptive system. Simulations on a test vehicle propelled by 37-kW induction motor lead to very interesting comparison results

GA-based tuning of nonlinear observers for sensorless control of IPMSMs

The paper considers two observer-based rotor position estimation schemes for sensorless control of interior permanent magnet synchronous machines (IPMSMs). Emphasis is given to techniques based on feedback linearisation followed by Luenberger observer design, and direct design of nonlinear observers. Genetic algorithms (GAs) based on the principles of evolution, natural selection and genetic mutation are employed to address difficulties in selecting correction gains for the observers, since no analytical tuning mechanisms yet exist, with results included to demonstrate the enhanced performance attributes offered by observers tuned in this way

Model reference adaptive backstepping control of double star induction machine with extended Kalman sensorless control

Introduction. Newly, the design of a controller for speed control of double star induction motor as a research focus. Consequently, backstepping technique is used to recursively construct a stable control law for speed and flux. Nevertheless, this control law coming from backstepping requires the knowledge of speed and flux values; in practice the measurement sensors are expensive and fragile. The novelty of this work consists to propose a control strategy which based on accurate Kalman filter observer that estimates speed, flux and torque. This extended Kalman filter is an optimal state estimator and is usually applied to a dynamic system that involves a random noise environment. Purpose. Apply a backstepping control of double star induction motor based on principle of rotor flux orientation. This approach consists in finding a Lyapunov function that allows deducing a control law and a modified adaptation rule is referred and sufficient conditions for the stability of the command-observer, in contrast to other techniques who use nonlinear principle. Results. The simulation results are shown to illustrate the performance of the proposed scheme under parametric uncertainties by simulation on MATLAB. The obtained results showed the robustness of the sensorless control in front of load and parameters variation of double stator induction motor. The research directions of the model were determined for the subsequent implementation of results with simulation samples.Вступ. Новітня розробка контролера для регулювання швидкості асинхронного двигуна з подвійною зіркою є предметом дослідження. Отже, метод відступу використовується для рекурсивної побудови стабільного закону керування швидкістю та потоком. Тим не менш, цей закон керування, що випливає з відступу, вимагає знання значення швидкості та потоку; на практиці вимірювальні датчики коштовні та недовговічні. Новизна даної роботи полягає в тому, щоб запропонувати стратегію управління на основі точного спостерігача за фільтром Калмана, який оцінює швидкість, потік і крутний момент. Цей розширений фільтр Калмана є оптимальним засобом оцінки стану і зазвичай застосовується до динамічної системи, яка включає середовище випадкових шумів. Мета. Застосування підходу відступу до керування асинхронним двигуном з подвійною зіркою на основі принципу орієнтації потоку ротора. Цей підхід полягає у знаходженні функції Ляпунова, яка дозволяє вивести закон керування та модифіковане правило адаптації, а також достатні умови для стабільності спостерігача команд, на відміну від інших методик, які використовують нелінійний принцип. Результати. Результати моделювання наведені для ілюстрації роботи запропонованої схеми за параметричних невизначеностей шляхом моделювання на MATLAB. Отримані результати показали надійність безсенсорного керування перед зміною навантаження та параметрів асинхронного двигуна з подвійним статором. Визначені напрямки дослідження моделі для подальшої реалізації результатів на прикладах моделювання

Sensorless Control of Two-Phase Induction Machine using MRAS Techniques

The paper presents most commonly usedcontrol techniques based on the Model Reference AdaptiveSystem (MRAS) for the Two-Phase Induction Machine(TPIM). The theoretical and experimental results areobtained using the Rotor Flux, Back EMF, and Reactivepower estimators. The main characteristic of this research istheir performance during start-up and reverse conditions.The experimental results were obtained at the no loadoperation. The estimated values of the angular speed arecompared with the data from the incremental encoder. TheMatlab/Simulink simulation software was utilized toperform the simulation results. The control techniquesimplementation and data acquisition were done by thetechnical computing device Dspace DS1103

GA-tuning of nonlinear observers for sensorless control of automotive power steering IPMSMs

The paper considers two observer-based rotor position estimation schemes for sensorless control of interior permanent magnet synchronous motors (IPMSMs) for use in future automotive power steering systems. Specifically, emphasis is given to techniques based on feedback-linearisation followed by classical Luenberger observer design, and direct design of non-linear observers. Genetic algorithms (GAs), using the principles of evolution, natural selection and genetic mutation, are introduced to address difficulties in selecting correction gains for the observers, since no analytical tuning mechanisms yet exist. Experimental measurements from an automotive power steering test-facility are included, to demonstrate the enhanced performance attributes offered by tuning the proposed observer schemes, online, in this manner

Differential-Algebraic Approach to Speed and Parameter Estimation of the Induction Motor

This thesis considers a differential-algebraic approach to estimating the speed and rotor time constant of an induction motor using only the measured terminal voltages and currents. It is shown that the induction motor speed satisfies both a second-order and a third-order polynomial equation whose coefficients depend the stator voltages, stator currents, and their derivatives. Further, it is shown that as long as the stator electrical frequency is nonzero, the speed is uniquely determined by these polynomials. The speed so determined is then used to stabilize a dynamic (Luenberger type) observer to obtain a smoothed speed estimate. With full knowledge of the machine parameters and filtering of the sensor noise, simulations and experiments indicate that this estimator has the potential to provide low speed (including zero speed) control of an induction motor under full load. A differential-algebraic approach is also used to obtain an estimate of the rotor time constant of an induction motor, again using only the measured stator voltages and currents. Experimental results are presented to demonstrate the practical use of the identification method

DFIG Based Wind Turbine System For Clemson Micro-grid

As an important part of the smart grid, the micro-grid interfaces with distributed energy sources, loads and control devices. A doubly fed induction generator (DFIG) based wind turbine (WT) is the main power source of the presented project. The DFIG system is connected to the three phase AC grid via back-to-back power converter and an LCL filter. Decoupled q-d control strategies are investigated for the DFIG system. Matlab/Simulink results will show the performance of the proposed system. Hardware validation results are also presented and discussed. As a rapidly increasing research interest area the dc micro-grid has been extensively investigated. A topology is proposed to connect the DFIG based WT system to a dc link using a diode bridge and a three phase power converter. The rotor side of the DFIG is connected to the dc link through a converter while the stator is connecting to a three phase diode bridge with the dc side connected to a dc link. The control method is developed to regulate the stator frequency and the d-q axis voltage of the diode bridge to operate the DFIG at a desired stator frequency and generate the required power. Undesired harmonics in the three phase system will lead to excessive THD, a decrease the power quality and an increase the power loss of the system. An novel methods to compensate the current harmonics by controlling the power converter of the DFIG system is also proposed. With the DFIG connected to the three phase AC gird, the focus has been put into a scenario: a nonlinear load connected to the same node of the DFIG point of common coupling (PCC) to the gird, to draw the harmonics to the system. In the proposed dc link system, the diode bridge will introduce harmonics to the stator current of the DFIG. In both cases, the selected low-order harmonics are detected and calculated by a multiple reference frame estimator. The control methods of how to regulate the harmonics are developed for both the grid-side converter and the rotor-side converter based on multiple reference frame theory. A hybrid state observer for speed-sensorless motor drives of induction machines is also proposed. The hybrid observer comprises of a Luenberger observer and a sliding mode observer. For a conventional induction motor with shorted rotor, the stator currents and rotor flux linkages are estimating following a Luenberger observer. While, for a DFIG the similar approach will apply to the stator currents and rotor currents. The rotor speed is estimated using a sliding mode observer. The combination of two observers takes advantage of both approaches. The Luenberger observer is easy to realize and the computational burden is small. The sliding mode observer is known for its robustness with respect to model parameter errors and it will also provide a fast convergence rate. The chattering of the sliding mode observer is addressed by applying a boundary layer

Sensorless Direct Field-Oriented Control of Three-Phase Induction Motor Drives for Low-Cost Applications

A sensorless direct rotor field-oriented control (SDRFOC) scheme of three-phase induction motors for low-cost applications is presented in this paper. The SDRFOC algorithm is based on a sensorless closed-loop rotor flux observer whose main advantages are simplicity and robustness to motor parameter detuning. The whole algorithm has been developed and implemented on a low-cost fixed-point digital signal processor controller. Experimental results are presented for a 0.5-kW induction motor drive for a primary vacuum pump used in industry applications