Many direct torque control techniques were appeared to. Direct torque control dtc is known to produce the fastest torque response in ac drives. The block diagram of direct torque control for an induction motor is as shown in fig. Here, is the voltage space vector that may occupy any of the eight space positions as shown in figure 2.
Combining the principles of variable structure, direct. An induction motor can therefore be made without electrical connections to the rotor. The torque generated in the rotor of a 3phase induction motor is proportional to the flux generated by each stator pole, the rotor current and the power factor of the rotor. Direct torque control of three phase induction motor drive. During the recent 20 years, it has been developed rapidly for its concise system scheme, excellent dynamic and static performances. An induction motors rotor can be either wound type or squirrelcage type. In this control scheme the electromagnetic torque and stator flux. Direct power and flux control of induction motors e direct power control methods discussed in this paper bear certain similarity to the direct torque control dtc. Direct torque control is considered to be one of the best methods to drive induction motors, even better that the wellknown vector controls. Direct torque control, induction motor drive, space vector modulation, switching table. To control the torque and flux of the induction motor different strategies are available as per the literature.
A modified direct torque control with minimum torque. Despite its simplicity, dtc is able to produce very fast torque and flux control, if the torque and the flux are. Direct torque control dtc is one method used in variable frequency drives to control the torque and thus finally the speed of threephase ac electric motors. This scheme provides excellent properties of regulation without rotational speed feedback. This paper presents a modified direct torque control based on combination of hysteresis current control and space vector modulation for induction motor drives. In recent years, the commercial applications of the. A new method to control flux and torque of an induction motor is presented. The block diagram shows that dtc has two fundamental sections. Research on direct torque control of induction motor based on. An induction motor or asynchronous motor is an ac electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.
The block uses the threephase input voltages to regulate the individual phase currents, allowing control of the motor torque or speed. In this paper, we propose two approach intelligent techniques of improvement of direct torque control dtc of induction motor such as fuzzy logic fl and artificial neural network ann, applied in switching select voltage vector. The mc and the dtc advantages are combined together. These drives are also particularly suited to applications that must operate at very high speeds with a high level of field weakening, for example. The torque and flux references are tracked using hysteresis controllers and a switching table implemented with lut is used for selecting the optimum converters output. Pdf direct torque control strategy of induction motors. It offers a simple control structure, fast response, and robust operation 35. It allows the precise and quick control of the im flux and torque without calling. This paper presents a direct flux and torque control dtc of induction motor drive imd for speed regulator sr using fuzzy logic controller flc. The main goal of this technique is to control not only the torque and the magnitude of stator flux but also the stator currents. Therefore it is more suitable for the comparison to consider a direct field oriented control dfoc scheme, instead of a general foc scheme.
An efficient method of induction motor control is the direct torque control dtc. Fpgabased design and implementation of direct torque. This drive features closedloop speed control using hysteresisband torque and flux controllers. Space vector trajectory is also plotted to observe the performance. Pdf direct torque control of induction motor drives. Direct torque control of induction motor with fuzzy minimization torque ripple fatiha zidani. Jun 10, 20 this model simulates direct torque control of a three phase induction motor. Assessment of direct torque control for induction motor drives. Introduction in early days dc machine played an important role in variable speed drives applications since the magnetic flux and torque can be easily controlled independently by. A 6 kw three phase induction motor has been used in order to run and evaluate the developed model. The direct torque control dtc scheme has been widely used in induction motor drives which can provide the fast torque response, the simple control scheme without the coordinate transformation, and robustness against motor parameter variations 39.
Direct torque control, permanent magnet synchronous motor, space vector modulation 1 introduction direct torque control was introduced by i. Thus, their control techniques have received a lot of interest. Pdf direct torque control of induction motor with matrix. With this control structure, the drive performance can be significantly improved when compared to field oriented control. Introduction the history of electrical motors goes back as far as 1820, when hans christian oersted discovered the magnetic effect of. In foc, the principle of decoupled torque and flux control are applied and it relies on the instantaneous control of stator current space vectors. The control scheme gets the switch control signal of inverter with the space voltage vector modulation technology. Direct torque control dtc is a technique used in variable frequency drives.
The aim is to develop a lowcost highperformance im drive. Direct torque control of induction motor drive using fuzzy controller. The matrix converter mc with direct torque control dtc combination is efficient way to get better performance specifications in the industry. This involves calculating an estimate of the motor s magnetic flux and torque based on the measured voltage and current of the motor. Direct mean torque control dmtc combines the good dynamic performance of direct torque control dtc with the advantages of time equidistant control algorithms for digital implementation in signal processor based systems. Introduction the demand for high performance electric drives is steadily growing with the increasing emphasis for electri. The electromagnetic torque of a threephase induction motor can be written as 2, 4. Both foc and dtc are strategies allow torque and flux to be decoupled and controlled independently. Isncesr16 direct torque control of induction motor drive. The speed control loop outputs the reference electromagnetic torque and stator flux of the machine. Pdf induction motors are currently used in many industrial applications.
This paper presents a modified direct torque control based on variable hysteresis band current control for induction motor drives. Direct torque control dtc for motor drive applications has been well established in both academia and industry. Direct torque control an overview sciencedirect topics. The reduction of complexity and cost of dc link in. Indroduction advanced control of electrical machines requires an independent control of magnetic flux and torque. Pdf direct torque control of induction motor drives a study. The direct torque control of induction motor is one of the high performance control system, which was proposed after the vector control scheme. The direct torque control is one of the excellent control strategies available for torque control of induction machine. The rotor will constantly be turning to align its magnetic field with that of the stator field.
Direct torque control of induction motor copy free download as powerpoint presentation. But since dtc along with im is mostly nonlinear, fuzzy controller. Direct torque control of induction motor drive using pifuzzy. Chaudhari, performance improvement for direct torque control induction motor drives, international research journal of advanced engineering and science, volume 2, issue 2, pp. Pdf direct torque control dtc is an emerging technique for controlling pwm inverterfed induction motor im drives. For that reason it was not surprising, that the dcmachine played an important role in the early days. Pdf direct torque control of induction motor with stator. The dtc scheme comprises of flux and torque switching table. In scalar control, which is based on relationships valid in steady state, only the magnitude and frequency of voltage, current, and flux linkage space vectors are. Direct torque control of permanent magnet synchronous.
In scalar control, which is based on relationships valid in steady state, only the magnitude and frequency of. In conventional dtc pi controller is used in the speed controller. Direct torque control for induction motor without current. In this paper, a wind turbine emulation wte system using a squirrel cage induction motor scim working. Direct torque control, induction motor, fuzzy logic, torque ripple minimization, fuzzy logic controller i. Research on direct torque control of induction motor based. Index termsfpga, dspace, direct torque control dtc, induction motor. Induction motor drives with closedloop control are used in similar applications to d. Direct torque control of induction motor drive using pifuzzy logic controller venkatesh.
Direct the motor torque is proportional to the armture current. Direct torque control of induction motor using fuzzy logic. Three phase induction motor using direct torque control by. Finally the approach has been implemented on dsp in a 1. Introduction increment in induction motor im drives controlled with the vector control strategy is for the most part acknowledged in the business. Dtc was patented by manfred depen brock in the us and in germany, the latter patent having been filed on october 20, 1984, both patents having been termed direct self control dsc.
Stator flux and torque control the induction motor. The major problem that is usually associated with dtc drive is the high torque ripple. The stator flux locus should not consist any drift but incase if we find any. Its operation is based on the equation of the developed electromagnetic torque of the motor. It comes from estimating the magnetic flux from the voltage and. Design of direct torque controller of induction motor dtc.
Pdf direct torque control of induction motor drives a. Modified direct torque control of three phase induction motor drives with low ripple in flux and torque. Direct torque control of induction motor shodhganga. The efficiency of direct torque control for electric vehicle. Indicative of dtc performance with induction motors is torque response time to a 100% torque reference step that approaches the motors electrical time constant limit. However, dtc has some disadvantages, being one of the most important the torque ripple. Modern improvement techniques of direct torque control for. Comparison of the field oriented and direct torque control. Direct torque control of induction motor copy magnetic. S department of ece, skce, coimbatore, india department of ece, skce, coimbatore, india abstract direct torque control dtc of an induction motor fed by a voltage source inverter is a. Noguchi 1 as a new performant control strategy for induction motor drives fed by voltage source inverters vsi. In t, it is observed that the stator flux linkage will move. The efficiency of direct torque control for electric. Control of induction motor is complicated due to the control of decoupled.
These drives are also particularly suited to applications that must operate at very high speeds with a high level of field weakening, for example spindle motors. Pdf direct torque control of induction motor drives researchgate. In the dc machine, this decoupling is obtained in an electromagnetic way by orienting the. Direct torque control for induction motor without current sensors. The discretetime equations for stator fluxes in the frame are. Comparison between direct and indirect field oriented. Direct torque control of three phase induction motor drive using fuzzy logic controllers for low torque ripple a. The dtc scheme comprises torque and flux estimator, hysteresis controllers for flux and torque and a switching table. Modified direct torque control of three phase induction.
Different websites were used as a resource to develop the direct torque control. Implement direct torque and flux control dtc induction. Direct torque control of induction motor machines physics. Field oriented control foc and direct torque control dtc were chosen for simulation as they are standard induction motor control techniques 12. However, the low switching frequency of the dtc causes high ripples in the flux and torque that leads to an acoustic noise which degrades the control performances, especially at low speeds. The dtc induction motor drive ac4 block represents an improved scalar control drive for induction motors with direct torque and flux control. Pdf design of direct torque controller of induction motor dtc.
In this project, a dtc model has been developed and tested using a matlabsimulink package. Speed estimator is implemented to control of speed of motor along with the torque. Rachid nat sad this paper presents an improved direct torque control based on fuzzy logic technique. This paper describes direct torque control dtc scheme of induction motor im and its comparative study using intelligent techniques under varying dynamic conditions are discussed. Direct torque control of inverterfed induction machine allows high dynamic performance by means of very simple control schemes. Direct torque control of three phase induction motor using. Fpgabased design and implementation of direct torque control. Pdf direct torque control for induction motor using. Dtc system directly controls the electromagnetic torque and stator flux. The direct torque control scheme for an induction motor fed by a matrix converter was. Dtc was originally developed for ac induction motors because of their popularity in myriad industrial and commercial applications. Direct torque control of an induction motor file exchange. Direct torque control technique for voltage source. Direct torque control of induction motor drive using pi.
The basic idea of an electric motor is to generate two magnetic fields. Direct torque control of induction motor drives a study. Sensing circuitry and signal conditioning circuitry. A voltage source inverter vsi supplies the motor and it is possible to control directly the stator flux and the electromagnetic torque by the selection of. Conventional direct torque control dtc is one of the excellent control strategies available to control the torque of the induction machine im.
Block diagram of classical dtc scheme induction motor model the main objective of dtc is to control the induction motor. Pi controller is more suitable in steady state condition and for linear system. Direct torque control dtc, hysteresis current control hcc, space vector modulation svm, induction motor, switching losses. In any case, this control method requires complex organize change, internal. Since, dtc direct torque control introduced in 1985, the dtc was widely use for induction motor drives with fast dynamics. Optimised direct torque control of induction motor for. T s t 2 3 2 3 sa b sc e i a i b in principle thedtc method selects one of the six nonzero and two zero voltage vectors of the inverter on the basis of the instantaneous errors in torque and stator flux magnitude. Induction motor drive, modeling of induction motor, vector control, field orient control, direct torque control, and fuzzy applications. Research article sensorless direct power control of. To estimate the torque and flux, the induction machine direct torque control block discretizes the machine voltage equations in the stationary reference frame using the backward euler method.
Performance improvement for direct torque control induction. A direct torque control system for a variable speed induction motor drive consists of two hysteresis comparators, a selection table, a flux and torque estimator, and a pid speed controller. Simulation results have shown the validity and high accuracy of the. The 3phase set of currents, each of equal magnitude and with a phase. The induction motor block implements a threephase induction motor. The efficiency of direct torque control for electric vehicle behavior improvement 129 2 electric traction system elements modeling fig.
A new technique for the torque control of induction motors was developed and presented by i. Direct torque control dtc is an emerging technique for controlling pwm inverterfed induction motor im drives. Introduction the history of electrical motors goes back as far as 1820, when hans christian oersted discovered the magnetic effect of an electric current. For induction motors, direct torque control dtc 1, 2 and field oriented control foc. Solution to direct torque control of induction motor. Direct torque control of induction motor drives ieee conference. This involves calculating an estimate of the motors magnetic flux and torque based on the measured voltage and current of the motor. Direct torque control for induction motor drives main features of dtc decoupled control of torque and flux absence of mechanical transducers current regulator, pwm pulse generation, pi control of flux and torque and coordinate transformation are not required very simple control scheme and low computational time. Direct torque control of induction motor free download as powerpoint presentation. Direct torque control of induction motor fed from hybrid. Direct torque control direct torque control dtc method is used in variable frequency drives to control the torque and thus finally the speed of threephase ac electric motors. By default, the block sets the simulation type parameter to continuous to use a continuous sample time during simulation.
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