Sensored and sensorless speed control methods for brushless doubly fed reluctance motors

The study considers aspects of scalar V/f control, vector control and direct torque (and flux) control (DTC) of the brushless doubly fed reluctance machine (BDFRM) as a promising cost-effective alternative to the existing technological solutions for applications with restricted variable speed capability such as large pumps and wind turbine generators. Apart from providing a comprehensive literature review and analysis of these control methods, the development and results of experimental verification, of an angular velocity observerbased DTC scheme for sensorless speed control of the BDFRM which, unlike most of the other DTC-concept applications, can perform well down to zero supply frequency of the inverter-fed winding, have also been presented in the study

A Comparative Analysis of Field Oriented Control and Direct Torque Control of Induction Motor Drive

Electric Motor Drive System is employed in the various industrial applications such as pumping, air blowing, cooling and compression refrigeration. The motor drive speed control can be achieved by variety of techniques, but an emerging one is Variable Frequency Drive System (VFDS). The motor driven equipment on a typical industrial site accounts for approximately two thirds of the electricity consumption. Now-a-days induction motor is the main work-horse of the industries. So controlling of performance of induction motor is most precisely required in many high performance applications. Scalar control method gives good steady state response but poor dynamic response. While vector control method gives good steady state as well as dynamic response. But it is complicated in structure so to overcome this difficulty, direct torque control introduced. This paper discusses the comparative analysis of Field Oriented Control (FOC) and Direct Torque Control (DTC) methods of Polyphase Induction Motor (PIM) according to their working principle, structure complexity, performance, merits and demerits

Performance Comparison of Different Speed Estimation Techniques in Sensorless Vector Controlled Induction Motor Drives

Field-oriented control and direct torque control are fast becoming necessities of modern industrial setups for induction motor drive control. Induction motors are considered as the beginning part to create any electrical drive system to be subsequently utilized for several industrial requirements. So now a day due to its high application the need to control the performance of the induction motor is gaining importance. In modern control system, IM is analyzed by different mathematical models mainly depending on its applications. Vector control method is suitably applied to induction machine in 3-phase symmetrical or in 2-phase unsymmetrical version. For vector control IM is realized as DC motor having its characteristics. This dissertation work is aimed to give a detailed idea about the speed control and variations in an induction motor through vector control technique thereby showing its advantage over the conventional scalar method of speed control. It also focusses on the speed estimation techniques for sensorless closed loop speed control of an IM relying on the direct field-oriented control technique. The study is completed through simulations with use of MATLAB/Simulink block sets allowing overall representation of the whole control system arrangement of the Induction motor. The performance of different sensorless schemes and comparison between them on several parameters like at low speed, high speed etc. is also provided emphasizing its advantages and disadvantages. The analysis has been carried out on the results obtained by simulations, where secondary effects introduced by the hardware implementations have not been considered. The simulations and the evaluations of different control techniques are executed using parameters of a 50 HP, 60 Hz induction motor which is fed by an inverter

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

Comparative Analys is of Direct Torque Control in Three Phase and Five Phase Induction Motor Drives

The Direct Torque Control(DTC)is a type of vector control technique which is used to regulate the torque and hence speed of an induction motor drive.This method is very efficient,cheap and is very easy to execute.The absence of mechanical speed estimators along with the ease of processing and computations make it the most preferred option among all vector control techniques.In this method, only the voltage and current are sensed and they are used to estimate the torque,flux and the angle between the rotor and stator flux.Depending on the torque and flux errors,a suitable voltage vector is selected to keep the errors within the desired tolerance region.At present times,three phase induction motors have become the backbone of industries.Lifts,agricultural pumps,conveyor belts,lathes, cranes,drilling machine,etc.are some of the prominent areas where induction motors have been very effective. These motors can be controlled using the scalar V/F control techniques.However,for applications requiring quick response vector control techniques like DTC are preferred. But the problem lies in the presence of torque ripples in case of DTC of three phase induction motor drive.Recently it has been seen that multiphase induction machines have the inherent feature of low torque pulsations.Hence they have replaced their three phase counterparts in areas like ship propulsions and aerospace industries where higher accuracy is required.This feature along with many other advantages of multiphase induction machines make them a strong competitor to their three phase counterparts in the field of industrial drives.This project aims to study and simulate the conventional DTC technique in a five phase induction machine with the help of MATLAB & Simulink and compare the results with its three phase counterpart to verify the effectiveness of the multiphase machine

A Fault-Tolerant Control Architecture for Induction Motor Drives in Automotive Applications

International audienceThis paper describes a fault-tolerant control system for a high-performance induction motor drive that propels an electrical vehicle (EV) or hybrid electric vehicle (HEV). In the proposed control scheme, the developed system takes into account the controller transition smoothness in the event of sensor failure. Moreover, due to the EV or HEV requirements for sensorless operations, a practical sensorless control scheme is developed and used within the proposed fault-tolerant control system. This requires the presence of an adaptive flux observer. The speed estimator is based on the approximation of the magnetic characteristic slope of the induction motor to the mutual inductance value. Simulation results, in terms of speed and torque responses, show the effectiveness of the proposed approach

A comprehensive review on brushless doubly-fed reluctance machine

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

Electromechanics of an Ocean Current Turbine

The development of a numeric simulation for predicting the performance of an Ocean Current Energy Conversion System is presented in this thesis along with a control system development using a PID controller for the achievement of specified rotational velocity set-points. In the beginning, this numeric model is implemented in MATLAB/Simulink® and it is used to predict the performance of a three phase squirrel single-cage type induction motor/generator in two different cases. The first case is a small 3 meter rotor diameter, 20 kW ocean current turbine with fixed pitch blades, and the second case a 20 meter, 720 kW ocean current turbine with variable pitch blades. Furthermore, the second case is also used for the development of a Voltage Source Variable Frequency Drive for the induction motor/generator. Comparison among the Variable Frequency Drive and a simplified model is applied. Finally, the simulation is also used to estimate the average electric power generation from the 720 kW Ocean Current Energy Conversion System which consists of an induction generator and an ocean current turbine connected with a shaft which modeled as a mechanical vibration system

Electromechanics of an Ocean Current Turbine

The development of a numeric simulation for predicting the performance of an Ocean Current Energy Conversion System is presented in this thesis along with a control system development using a PID controller for the achievement of specified rotational velocity set-points. In the beginning, this numeric model is implemented in MATLAB/Simulink® and it is used to predict the performance of a three phase squirrel single-cage type induction motor/generator in two different cases. The first case is a small 3 meter rotor diameter, 20 kW ocean current turbine with fixed pitch blades, and the second case a 20 meter, 720 kW ocean current turbine with variable pitch blades. Furthermore, the second case is also used for the development of a Voltage Source Variable Frequency Drive for the induction motor/generator. Comparison among the Variable Frequency Drive and a simplified model is applied. Finally, the simulation is also used to estimate the average electric power generation from the 720 kW Ocean Current Energy Conversion System which consists of an induction generator and an ocean current turbine connected with a shaft which modeled as a mechanical vibration system