Direct Field Orientation Research Articles

Comparison of incremental encoder digital signal processing techniques for theinduction motor flux-torque vector control systems

The articlepresents the results of a study on the effectiveness of varioustechniques forsynchronous reference frame angular position numerical calculation in flux-torque vector control system of induction motor.Investigation was caried out taking into account the discrete nature of the angular speedsignal obtained using an incremental encoder. In this workfor investigation by simulation useda direct torque vector control system, which, in the presence of an ideal rotor angular speedsignal, ensures direct asymptotic field orientation, asymptotic tracking of torque-flux referencetrajectories, as well as asymptotic decouplingtorque and flux subsystems. The parameters of the inductionmotor and encoder used in the study correspond to those existing in traction electromechanical systems of city trolleybuses. It is shown that the discrete nature of the angular speedsignal, which usedin synchronous reference frameposition equation of flux-torque vector control systems, introduces field orientation errors and leads to current and torque ripples, which in a real system increase acoustic noise and can cause mechanical vibrations and resonance phenomena. An analysis of possible ways to reduce the influence of the speed signal discreteness on flux-torque control is performed, and a method for practical implementation of the synchronous reference frame angular position numerical calculationis proposed. This method allows ensuring conditions for more precisefield orientation and, by using an additional filter for the angular speedsignal, reducing the level of current and torque ripplesto negligibly small values without affecting the field orientation processes. The proposed solution can be used in the development of high dynamicflux-torque vector control systems for inductionmotors using incremental encoders, including for electric vehicles.

Kajian Pengelolaan Limbah Bahan Berbahaya dan Beracun (B3) PT. X

PT.X is a branch of the industry engaged in agribusiness that provides agricultural products and services. The production process carried out by PT. X results in a product and other production process that can no longer be used or discarded. B3 waste is the residue of a company and/or activity which because of its nature and/or concentration and/or amount contains hazardous and/or toxic substances which directly or indirectly pollute the environment, human health and can endanger the survival of other living things. The purpose of this research is to know and understand the B3 waste management system and to implement an evaluation of the B3 waste operating system. Data collection through observation in the form of a general introduction to the location and direct field orientation by PT. X offline. Data processing and analysis was carried out by comparing the existing conditions of the B3 waste treatment carried out by PT. X with applicable regulations. Research variables include reduction, packaging and storage, as well as the use of B3 waste management. The results of the study show the compatibility between the application of B3 waste management at PT. X and the regulations in force largely comply with this.

Optimized Kalman filters for sensorless vector control induction motor drives

<span lang="EN-US">This paper presents the comparison between optimized unscented Kalman filter (UKF) and optimized extended Kalman filter (EKF) for sensorless direct field orientation control induction motor (DFOCIM) drive. The high performance of UKF and EKF depends on the accurate selection of state and noise covariance matrices. For this goal, multi objective function genetic algorithm is used to find the optimal values of state and noise covariance matrices. The main objectives of genetic algorithm to be minimized are the mean square errors (MSE) between actual and estimation of speed, current, and flux. Simulation results show the optimal state and noise covariance matrices can improve the estimation of speed, current, torque, and flux in sensorless DFOCIM drive. Furthermore, optimized UKF present higher performance of state estimation than optimized EKF under different motor operating conditions.</span>

Direct Field Orientation Control Based on H∞ Method of Wind Turbine Based on DFIG

This study aims to propose the direct field orientation control based on the H-infinity method (DFOC_ H∞) scheme for controlling the stator power (active/ reactive) of a direct drive vertical axis wind turbine power system based on a doubly fed induction generator (DFIG). the sensitivity to parameters uncertainty of the machine presents the major drawback of the PI controller, in order to cope with this problem; the H-infinity method was used to solve it. The proposed controller H∞ is evaluated with Matlab/Simulink. Simulation results showed that the suggested H∞ controller has a good performance in terms of enhancing the quality of energy provided to the power network. Even in the presence of DFIG parameter variation.

ROBUST DIRECT FIELD ORIENTED CONTROL OF INDUCTION GENERATOR

A novel and robust field oriented vector control method for standalone induction generators (IG) is presented. The proposed controller exploits the concept of direct field orientation and provides asymptotic rotor flux modulus and DC-link voltage regulations when a DC-load is constant or slowly varying. Flux subsystem, designed using Lyapunov’s second method, has, in contrast to standard structures, closed loop properties and therefore is robust with respect to rotor resistance variations. A decomposition approach on the base of the two-time scale separation of the voltage and torque current dynamics is used for design of the voltage subsystem. The feedback linearizing voltage controller is designed using a steady state IG power balance equation. The resulting quasi-linear dynamics of the voltage control loop allows use of simple controllers tuning procedure and provides an improved dynamic performance for variable speed and flux operation. Results of a comparative experimental study with standard indirect field oriented control are presented. In contrast to existing solutions, the designed controller provides system performances stabilization when speed and flux are varying. It is experimentally shown that a robust field oriented controller ensures robust flux regulation and robust stabilization of the torque current dynamics leading to improved energy efficiency of the electromechanical conversion process. The proposed controller is suitable for energy generation systems with variable speed operation. References 18, figures 8.

Penentuan Parameter Pemodelan Kecepatan Putar Motor Induksi 3 Phasa Menggunakan Jaringan Saraf Tiruan (JST)

Modeling speed control of induction machines 3 phase is very necessary, because will be make it more easier for used in mathematic analysis. In this book simulating modeling parameters is purposing give solution for made mode speed control induction machine 3 phase. And analysis using Universal Field Oriented (UFO) and Direct Field Oriented (DFO). Speed control machine 3 phase can be adapted with changing of load, so that using Neural Network. Result from analysis in this paper to give parameters mode adaptive control system in diagram block type.

Takagi-Sugeno Fuzzy Estimator Design for Adaptive Vector Control Systems

This paper presents an adaptive pseudo reduced-order Takagi-Sugeno (T-S) fuzzy flux estimator for the induction motor direct field orientation control system. The estimator gain can be obtained by solving a set of linear matrix inequalities (LMIs) to estimate the rotor flux accurately. It is well known that, because of changes in temperature, variations of stator and rotor resistances affect the accuracy of rotor flux estimation. To resolve this problem, a cerebellar model articulation proportional integral controller (CMAPIC) is proposed to estimate the stator and rotor resistances during temperature variations. These estimated quantities, including stator and rotor resistances, are taken as the T-S fuzzy flux estimator inputs, so that the flux estimation is uninfluenced by these parameter variations. Thus the estimators enhance the robustness of the system. Moreover, this work uses a cerebellar model articulation controller to estimate the rotor speed, which is fed back to the adaptive supervisory fuzzy cerebellar model articulation speed controller (ASFCMAC) to achieve the speed sensor-less control.

Sensorless observers with speed estimate for direct field orientation of induction motor and PMSM drives

The paper discusses the problem of sensorless rotor position/rotor flux angle estimation for the permanent magnet synchronous motor (PMSM) and for the induction motor (IM) and presents a family of sensorless observer designs that use a speed estimate. In sensorless field-oriented AC drive control, it is typical to measure the motor’s voltages and currents and to estimate the other quantities of interest: speed, fluxes (or EMFs) and the field orientation angle. The simultaneous estimation of these quantities is possible, however, the methods available are rather complicated and the accuracy is often questionable, especially under parameter variations. The paper proposes a sequential estimation approach which is much simpler: first, estimate the drive’s speed; then, use this speed estimate along with the measurements to estimate the states of the motor model and to obtain the field orientation angle. A family of observers for the IM and the PMSM is presented – these are constructed using the respective moto...

Sensorless field orientation of an induction motor drive using a time-varying observer

The study discusses the problem of state and rotor flux position estimation for the induction motor (IM) drive and presents a sensorless time-varying observer. The method treats the induction motor as a time-varying plant and uses non-linear techniques to develop a state observer based on the motor's model in the stationary reference frame. Initially, the observer is developed assuming that the speed of the motor is available through measurement – the resulting observer is asymptotically stable and some of its gains are time varying. To obtain a sensorless observer, the speed measurement is eliminated by replacing the speed signal with a speed estimate (assumed to be inaccurate but reasonably close to the real speed). The observer with improper speed is analysed – this is not asymptotically stable; however, the estimated fluxes are in phase with the real fluxes. This property allows estimation of the rotor flux angle of the IM. This is because the accuracy of the direct field orientation method that is based on the tan−1 function only depends on the phase of the flux components. The study shows that the observer yields fluxes with magnitude higher than real when the speed signal fed in the observer is smaller than real (and vice versa). The design of the observer under improper speed is analysed theoretically; it is then supported by simulations and is validated by experimental tests.

Maximum torque per ampere control of sensorless induction motor drives with dc offset and parameter compensation

Field orientation control of induction machine (IM) drives is a well-known strategy which has a fast dynamic response. In this paper, the direct rotor flux field orientation control of speed sensorless IM drive is presented. A two level space vector modulation inverter is employed to generate the command stator voltage. In proposed control scheme, a maximum torque per ampere strategy is achieved using a so-called fast flux search method. Based on this method, for a given load torque and rotor speed, the magnitude of rotor reference flux is adjusted step by step until the effective value of stator current becomes minimized finally. In addition, using the IM fifth order model in the stationary reference frame, a nonlinear rotor flux observer is developed which is also capable of motor resistances and rotor speed simultaneously estimation. Moreover, a useful method is introduced for dc offset compensation which is a major problem of ac drives especially at low speeds. The proposed control idea is experimentally implemented in real time using a CPLD board synchronized with a personal computer. Simulation and experimental results are finally presented to confirm the validity and effectiveness of the proposed method.

The Complex Controller Applied To The Induction Motor Control

This paper presents a design and tuning method of the complex gain controller, based on the three-phase induction motormathematicalmodel complex transfer function to be used in induction motor control when the machine operates at low speed which is a problem so far. The complex gain controller was applied in the direct rotor field orientation controlmethod and also on the direct torque control method. It was designed and tuned using the frequency-response function of the closed loop system. The complex gain controller presents low complexity in the inductionmotor control implementation. Experimental results were carried out for the controller validation.

A fuzzy learning—Sliding mode controller for direct field-oriented induction machines

This paper presents a direct field-oriented induction motor drive system with two distinct features: a sliding mode voltage mode flux observer (SMVMFO) and a fuzzy model reference learning controller (FMRLC). The speed of the induction motor is regulated using an FMRLC, which does not require rigorous tuning of the controller's parameters. The rotor flux estimation for the direct field orientation (DFO) is realized by a newly proposed SMVMFO, which is insensitive to the stator resistance variation. The complete drive system is shown to have very good speed tracking performance, accurate flux estimation and field orientation, and high robustness to stator resistance variation, which has been a long-standing problem in the area of motor drives. Extensive simulations are presented for performance evaluation and validation of the proposed control scheme.

A new scheme for sensorless induction motor control drives operating in low speed region

A novel simple stator resistance estimation technique for high-performance induction motor drives is proposed. It makes use of a synchronously revolving reference frame aligned with the stator current vector, so that the resistance can be straightforwardly derived from the mathematical model of the induction motor. A sensorless direct field orientation scheme is employed to validate the proposed solution, with the drive operating in the critical area of low speeds. A combination of two observers is used: a Kalman filter observer to estimate the rotor flux, and a MRAS observer for speed estimation. The stator resistance estimator alleviates the usual performance degradation of MRAS-based drives at low speeds, caused by the thermal drift of stator resistance. Computer simulations, including realistic disturbances, show high effectiveness of the described approach.

Elimination of the Stator Resistance Sensitivity and Voltage Sensor Requirement Problems for DFO Control of an Induction Machine

This paper focuses on a method for achieving robust direct field orientation control of an induction machine using a closed-loop voltage model flux observer that is insensitive to stator resistance variation and does not require voltage signal information, thereby eliminating the need for a voltage sensor. In contrast, the conventional voltage model observer topology requires voltage sensors and is highly sensitive to stator resistance variation, especially at low speed. The closed-loop sliding-mode voltage model flux observer presented here is based on current estimation error including a sliding-mode function which is a derivative of the stator flux. The newly designed sliding-mode function will not only drive the estimated current to the measured one, it will also directly give the estimation results for the terms (stator flux) replaced by the sliding-mode function. The constructed observer and chosen sliding-mode function also do not require information about parameters contained in the terms replaced by the sliding-mode function, i.e., voltage signal and stator resistance. The observer stability is verified in the paper. Simulation and experimental results are also used to illustrate features of the proposed observer.

A Novel Observer-Based Flux Estimation for Speed Sensorless DFO Control of Induction Machine

This article proposes a novel closed-loop rotor flux observer to estimate the rotor flux and velocity of induction motors. With the proposed algorithm, the accuracy of the estimated flux is guaranteed when the estimated stator current converges to its actual one. With the help of the estimated rotor flux magnitude and angle information, the direct rotor field orientation vector control can be implemented, and the rotor speed can be derived. Compared with the traditional Luenberger observer, the salient advantage of the proposed observer-based flux estimation is that the flux estimation is independent of either the estimated speed error or rotor time constant deviation. The validity of the proposed method is verified by intensive digital simulation results.

Stator-Core and Rotor-Core Losses Compensation for Direct-Field-Oriented Induction Motor

This paper focuses on a stator-core and rotor-core losses compensation technique devoted to a direct field-oriented control system of an induction motor incorporating parameter identification. The fundamental control algorithm is based on direct field orientation, which essentially requires rotor flux estimation using several motor parameters and detection of line currents and a rotor position. In order to suppress the flux estimation error caused by parameter mismatches, the magnetizing inductance and the rotor resistance are identified insensitively to the stator resistance by utilizing instantaneous reactive power. However, due to a model mismatch associated with the stator-core loss and rotor-core loss, neither the field orientation nor the parameter identification can be achieved as is expected, which mainly results in degradation of flux and torque control accuracy. This paper describes characteristics of the motor parameters precisely measured under various operating conditions, the influence of both stator-core loss resistance and rotor-core loss resistance on the field orientation and the parameter identification, and a compensation technique to obtain higher controllability than conventional field-oriented control techniques. Effectiveness of the proposed technique has been examined through experimental tests as well as computer simulations, and the absolute accuracy and linearity of the motor torque has been improved as a result.

A new sliding mode flux and current observer for direct field oriented induction motor drives

Abstract A direct field orientation (DFO) control for an induction machine is designed and implemented using a new sliding mode technique. The rotor flux is estimated using the current model flux observer. A close loop flux observer, based on the current estimate error, is then constructed. A unique feature of the proposed observer is that the flux and current observers include a sliding function, which is a derivative of the flux. Therefore, when the estimated current converges to the measured one, the sliding function itself is integrated to calculate the flux magnitude and angle. The observer stability is verified via Lyapunov stability analysis. Simulation and experimental results are presented to show the performance of sliding-mode based DFO control for an induction motor drive system.

An adaptive rotor flux observer for direct field oriented induction motor drives

At the present time the direct field oriented (DFO) control is the widely used control technique in high-performance induction motor (IM) drive. It requires the implementation of a state vector observer for the detection of rotor flux vector. The IM drive performance is strictly connected to that of the rotor flux observer. The motor parameter variations cause the observer mismatching and hence, the IM drive performance degradation. In the present paper an adaptive observer is proposed which allows the on-line rotor time-constant tuning. The identification of the rotor time constant is performed by an MRAS approach. The adaptive observer is synthesized using the Lyapunov stability theory. To improve the speed convergence of the identifier and the selectivity characteristic of the proposed adaptive observer, a time- varying gain has been introduced. The stability of the overall system has been verified using the Lyapunov stability theory. The simulation results evidence the good performance of the proposed observer and of the overall DFO controlled drive. In particular, the interactive effects between observer and identifier gains are evidenced and, thus, used for the selection of the identifier time-varying gain. Copyright © 2000 John Wiley & Sons, Ltd.

A novel stator resistance estimation method for speed-sensorless induction motor drives

A method for online estimation of the stator resistance of an induction machine is presented and a speed-sensorless field-oriented drive equipped with the proposed estimator is built. The drive is particularly suitable for low-speed operation. Resistance estimation is based on a two-time-scale approach, and the error between measured and observed current is used for parameter tuning. The simple full-order observer in use allows for direct field orientation in a wide range of operation. The system can drive active load and generate stall torque, as confirmed by numerical simulations and experimental tests on a general-purpose 7.5 kW induction machine.

Flux Tracking Methods for Direct Field Orientation

Numerous techniques have been reported in the literature to accomplish the task of locating the rotor flux axis for the purpose of direct field orientation. This paper first summarizes the existing sensorless techniques using high-frequency test signal injection to determine the flux spatial location in an induction machine. A novel approach employing balanced and unbalanced excitation is then investigated to track the flux. It is first demonstrated that the rotating flux vector in the machine causes saturation-induced saliency in the phases under normal operating conditions. By employing high-frequency test signals, this saliency is monitored and then used to track the flux in the machine under test. The feasibility of the proposed approach is verified with experimental results.