Field oriented control of induction motors

Induction motors have always been known for their simple rugged construction, but until lately were not suitable for variable speed or servo drives due to the inherent complexity of the controls. With the advent of field oriented control (FOC), however, the induction motor has become an attractive option for these types of drive systems. An FOC system which utilizes the pulse population modulation method to synthesize the motor drive frequencies is examined. This system allows for a variable voltage to frequency ratio and enables the user to have independent control of both the speed and torque of an induction motor. A second generation of the control boards were developed and tested with the next point of focus being the minimization of the size and complexity of these controls. Many options were considered with the best approach being the use of a digital signal processor (DSP) due to its inherent ability to quickly evaluate control algorithms. The present test results of the system and the status of the optimization process using a DSP are discussed

Indirect Field Oriented Control of Induction Motors is Robustly Globally Stable

Field orientation, in one of its many forms, is an established control method for high dynamic performance AC drives. In particular, for induction motors, indirect fieldoriented control is a simple and highly reliable scheme which has become the de facto industry standard. In spite of its widespread popularity no rigorous stability proof for this controller was available in the literature. In a recent paper (Ortega et al, 1995) [Ortega, R., D. Taoutaou, R. Rabinovici and J. P. Vilain (1995). On field oriented and passivity-based control of induction motors: downward compatibility. In Proc. IFAC NOLCOS Conf., Tahoe City, CA.] we have shown that, in speed regulation tasks with constant load torque and current-fed machines, indirect field-oriented control is globally asymptotically stable provided the motor rotor resistance is exactly known. It is well known that this parameter is subject to significant changes during the machine operation, hence the question of the robustness of this stability result remained to be established. In this paper we provide some answers to this question. First, we use basic input-output theory to derive sufficient conditions on the motor and controller parameters for global boundedness of all solutions. Then, we give necessary and sufficient conditions for the uniqueness of the equilibrium point of the (nonlinear) closed loop, which interestingly enough allows for a 200% error in the rotor resistance estimate. Finally, we give conditions on the motor and controller parameters, and the speed and rotor flux norm reference values that insure (global or local) asymptotic stability or instability of the equilibrium. This analysis is based on a nonlinear change of coordinates and classical Lyapunov stability theory

Implementation of Field Oriented Control in Simulink

Indukční stroje jsou jedním z nejpoužívanějších elektrických strojů v mnoha průmyslových a dopravních aplikacích. Je proto důležité mít zařízení pro jejich ovládání. Naproti tomu, DC stroje je možné řídit pomocí mnohem jednodušších schémat, ale kvůli jejich technickým nevýhodám se v současnosti nejeví jako nejlepší volba pro průmyslové použití. Pro řízení rychlosti a točivého momentu indukčních strojů bylo vyvinuto mnoho řídicích strategií a stále probíhá další výzkum pomocí modernějších technik, jako například „Fuzzy logic“ nebo neuronové sítě. Tématem práce je polem orientované vektorové řízení, které je jedním z nejpoužívanějších způsobů řízení. Implementovali jsme schéma s polem orientovaným řízením v softwaru Simulink na indukční stroj se skutečnými parametry. Pro zkoumaný řadič jsme vyzkoušeli různé scénáře s cílem zjistit jeho fungovaní a možná vylepšení. Rovněž jsme implementovali bezsenzorové řízení stroje s odhadem otáček.Induction machines are one of the most widely used electric machines on many industrial and transportation applications. It is, therefore, important to have a facility to control these machines for the wide range of applications. On the other hand, it is possible to control DC machines with much simpler control schemes, but their technical drawbacks do not make them the preferable choice for the industry nowadays. Many control strategies have been developed for the speed and torque control of induction machines and more research is still ongoing using more modern techniques, such as “fuzzy logic” and “neural networks”. One of the most widely used control techniques is the “field-oriented control”, which is the topic of this thesis. With the parameters of a real induction machine, we implemented a control scheme based on the field-oriented control in the Simulink software. Various scenarios were applied to the controller in order to study its functioning and possible improvements. Furthermore, a speed estimation part was implemented for a sensorless control of the machine

Speed sensorless field oriented control of ac induction motor using model reference adaptive system

In order implement the vector control technique, the motor speed information is required. Incremental encoder, resolvers and tachogenerator, are used to reveal the speed. These sensors require careful mounting and alignment and special attention is required with electrical noises. Sensorless speed vector control is greatly used and applied in induction machine drives instead of scalar control and vector control for their robustness and reliability, and very low maintenance cost. In this project MRAS based techniques are used to estimate the rotor speed based on rotor flux estimation, the estimated speed in the MRAS algorithm is used as a feedback for the vector control system. The model reference adaptive control system is predicated on the comparison between the outputs of adjustable model and reference model. The error between them is employed to drive a suitable adaptation mechanism which generates the estimated rotor speed for the adjustable model. And indirect vector control scheme controls the flux and torque by restricting the torque and flux errors with respective hysteresis bands, and motor flux and torque are controlled by the stator voltage space vectors using optimum inverter switching table. Modeling and simulation of the induction machine and the vector control drives implemented in MATLAB/SIMULINK. Simulation results of proposed MRAS and indirect vector control technique are presented

Takagi-Sugeno fuzzy perpose as speed controller in indirect field oriented control of induction motor drive

This paper deal with the problem in speed controller for Indirect Field Oriented Control of Induction Motor. The problem cause decrease performance of Induction Motor where it widely used in high-performance applications. In order decrease the fault of speed induction motor, Takagi- Sugeno type Fuzzy logic control is used as the speed controller. For this, a model of indirect field oriented control of induction motor is built and simulating using MATLAB simulink. Secondly, error of speed and derivative error as the input and change of torque command as the output for speed control is applied in simulation. Lastly, from the simulation result overshoot is zero persent, rise time is 0.4s and settling time is 0.4s. The important data is steady state error is 0.01 percent show that the speed can follow reference speed. From that simulation result illustrate the effectiveness of the proposed approach

Robust indirect field oriented control of induction generator

The paper presents a novel robust field oriented vector control for induction generators. The proposed controller exploits the concept of indirect field orientation and guarantees asymptotic DC-link voltage regulations when DC-load is constant or slowly varying. An output-feedback linearizing Lyapunov’s based technique is employed for the voltage controller design. Flux subsystem design provides robustness with respect to rotor resistance variations. Decomposition of the voltage and current-flux subsystems, based on the two-time scale separation, allows to use a simple controllers tuning procedure. Results of comparative experimental study with standard indirect field oriented control are presented. It is shown that in contrast to existing solutions designed controller provides system performances stabilization when speed and flux are varying. Experimentally shown that 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. Proposed controller is suitable for energy generation systems with variable speed operation

The field oriented control of a permanent magnet synchrounous motor (PMSM) by using fuzzy logic

This project presents the comprehensive performance analysis on the principle of operation, design considerations and control algorithms of the field oriented control (FOC) for a permanent magnet synchronous motor (PMSM) drive system of Fuzzy Logic Controller (FLC) and proportional-integral PI for speed control in closed loop operation. To perform speed control of typical PMSM drives, PI controllers and FOC method are classically used. PI Controller controller suffers from the drawback that for its proper performance, the limits of the controller gains and the rate at which they would change have to be appropriately chosen. Fuzzy based gain scheduling of PI controller has been proposed in which uses in order to overcome the PI speed controller problem. The simulation results show that the proposed FLC speed controller produce significant improvement control performance compare to the PI controller. FLC speed controller produced a better performance than PI speed controller where the overshoot is totally removed and the settling time faster than PI speed controller in achieving desired output speed. The fuzzy algorithm is based on human intuition and experience and can be regarded as a set of heuristic decision rules. It is possible to obtain very good performance in the presence of varying load conditions changes of mechanical parameters and inaccuracy in the process modelling. Research and application of fuzzy logic are developing very rapidly, with promising impacts on electric drives and power electronics in future. Keywords: FOC, PMSM, FLC, PI and for Speed Control

Linear Model Predictive Control of Induction Machine

This article presents new control algorithm for induction machine based on linear model predictive control (MPC). Controller works in similar manners as field oriented control (FOC), but control is performed in stator coordinates. This reduces computational demands as Park’s transformation is absent and induction machine mathematical model in stator coordinates contains less nonlinear elements. Another aim of proposed controller was to achieve fast torque response

Field Oriented Control of PMSM Supplied by Photovoltaic Source

The Permanent magnet synchronous motor (PMSM) is suitable for so much application, such as traction, aeronautics and generally in industrial automated processes. In our work, we will study the application of PMSM in renewable energies especially solar pumping. Our objective is to model the complete system, including the photovoltaic inverter, PMSM and the centrifugal pump under Matlab/Simulink environment. Solar panels generate electrical energy as direct current by direct conversion of solar radiation using semiconductor materials made of monocrystalline, polycrystalline or amorphous silicon. The energy received depends on radiation and on ambient temperature. The permanent magnet synchronous motor (PMSM) is not stable in open loop. To control the PMSM in terms of speed, torque or position, we need to implement vector control.We will establish the field oriented control of a PMSM supplied by photovoltaic source with a focus on their applications in variable speed domain