It allows the precise and quick control of the im flux and torque without calling. Direct torque control of permanent magnet synchronous motors with nonsinusoidal backemf. Direct torque controlled drive train for electric vehicle. Delivering as minimum as possible ripple free torque with desired value to the wheels in various conditions, essentially increase safety and. This involves calculating an estimate of the motors magnetic flux and torque based on the measured voltage and current of the motor. Research on direct torque control of induction motor based on. The direct torque control and field oriented control are nowadays. Direct torque control dtc is one method used in variablefrequency drives to control the. Direct torque control electric motor control theory. Direct torque control dtc is another highperformance motor control method which may not be as popular or widely spread as foc. Project report on direct torque control of permanent magnet synchronous motor as without his constant motivation and support during my work, this would not have been possible. Direct torque control for induction motor without current sensors. Direct torque control electrical engineering portal. The proposed sensorless method is similar to the usual direct torque control method which is utilized for.
View test prep sensorless vector and direct torque control ocr p. Dtc direct torque control of induction motor drives has many outstanding performance and implementation properties. Using dtc or dsc it is possible to obtain a good dynamic control of the torque without any mechanical transducers on the machine shaft. Direct torque control, permanent magnet synchronous motor, space vector modulation 1 introduction direct torque control was introduced by i. Direct torque control and sensorless control of induction.
Torque control is one of important factors in drive train of electric vehicle. The main difference between direct torque control and the traditional ac drive control methods is that with dtc there is no separate voltage and frequency. The controllers for a direct torque control drive do not require complex coordinate transformation essential in all vector controlled drives. Digital signal processor, direct field oriented control,direct signal processor, direct torque control,pulsewidthmodulation.
Direct torque control of inverterfed induction machine allows high dynamic performance by means of very simple control schemes. It offers a simple control structure, fast response, and robust operation 35. Microcontrollerbased direct torque control servodrive. Direct torque control dtc, induction motorim, sensor count reduction, single current sensor.
Direct torque control design for three phase induction motor. In this technique by selecting optimum inverter switching modes the motor torque and. 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. This paper considers the application of direct torque control, to a threephase bldc drive operating in the 120 conduc. In direct torque control instantaneous values of torque and flux are calculated from primary variables and controlled independently by using an optimum switching table. Direct torque control of induction motor drives ieee conference. Design and simulation of field oriented control and direct. The direct torque control of induction motor is one of the high performance control system, which was proposed after the vector control scheme. Implement direct torque and flux controller dtfc or dtc. Pdf direct torque control of induction motor drives researchgate. I truly appreciate and value his esteemed guidance and encouragement from the beginning to the end of this report. Monographs in electrical and electronic engineering 25. The modeling of an im drive employing dtc with application of. Variable speed drives vsds control information from abb the flow of energy from the mains to the process.
This involves calculating an estimate of the motors magnetic flux and torque based. Pdf methods for direct torque control of induction machines. Direct torque control d tc is an improvised vc method. Direct the motor torque is proportional to the armature current. Because direct torque control is based on hysteresis controllers the inverter has a continuously variable switching frequency. Stator and rotor flux based deadbeat direct torque control of induction machines barbara h. Pdf evaluation of direct torque control using space vector. Direct torque control for induction motor without current. Design of direct torque controller of induction motor dtc. Comparison between direct and indirect field oriented. In this control scheme the electromagnetic torque and stator flux. This scheme provides excellent properties of regulation without rotational speed feedback. The performance of an induction motor under the classical direct torque control method and improved scheme have been studied and confirmed by simulation using matlab. To understand the answer to this question we have to understand that the basic function of a variable speed drive vsd is to control the flow of energy from the mains to the process.
Direct torque control technique for voltage source inverter. Direct torque control of permanent magnet synchronous. Direct torque control for doubly fed induction machinebased wind turbines under voltages dips and without crowbar protection international journal of electrical and electronics engineering ijeee, issn print. Conventional direct torque control dtc is one of the excellent control strategies available to control the torque of the induction machine im. Direct torque control of permanent magnet synchronous motor.
Direct torque control an overview sciencedirect topics. Direct torque control of brushless dc drives with reduced. Archived from the original pdf on october 18, 2011. Pdf direct torque control strategy of induction motors. Direct torque control dtc for motor drive applications has been well established in both academia and industry. Many direct torque control techniques were appeared to. Subsequent improvements in processor computational power, application programming, and communication interfaces have continually enabled higher dtc performance, providing premium motor control for a broad range of applications.
The efficiency of direct torque control for electric. With the dtc scheme employing a voltage source inverter, it is possible to control directly the stator flux linkage and the electromagnetic torque by the optimum selection of inverter switching vectors. Toliyat this work presents the direct torque control dtc techniques, implemented in. 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. Direct torque control dtc is one method used in variablefrequency drives to control the torque and thus finally the speed of threephase ac electric motors. Block diagram of the proposed drive system it relies on the principle that the torque and the magnitude of the stator flux are directly proportional with the ratio between the magnitude of the stator voltage and the stator frequency as given in 1 and 2 2. Comparison between direct and indirect field oriented control. This control results in quick torque response in the transient operation and improvement in the steady state. Reduction of torque ripples cause to deliver smoother power to the wheel. The direct torque and flux controller dtc directly controls the torque and stator flux of a machine, using inverter voltage vectors typically selected from an optimal switching table.
Although in these systems such variables as torque, flux modulus and flux sector are required, resulting dtc structure is particularly simplistic. The control scheme used and the test system that has been developed are explained. The foc aims to control the current vector and dtc aims to control the torque producing ux vector. Dtc system directly controls the electromagnetic torque and stator flux, using the analyzing method of space vector and stator flux orientation. 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. Kenny glenn research center, cleveland, ohio robert d. The control is quite different than the conventional fieldoriented or direct torque control. During a long time, permanent magnet synchronous motor pmsm were only reserved for some specific applications, however, recently, these machines are becoming more used due to the powerful magnetic characteristic of the rare earth. In dtc it is possible to control directly the stator flux and the torque by selecting the appropriate inverter state. The efficiency of direct torque control for electric vehicle.
Assessment of direct torque control for induction motor drives. Permanent magnet synchronous motor, direct torque control, pulse width modulation, fuzzy control. Using dtc or dsc it is possible to obtain a good dynamic control of the torque. Modeling and simulation of direct torque control induction. Pdf evaluation of direct torque control using space. Control and directtorque control of induction motors using an adaptive flux observer abdesselam chikhi1,a, mohamed djarallah1,b, khaled chikhi1,c abstract this paper presents a comparative study of fieldoriented control ifoc and directtorque control dtc of. 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. Pdf direct torque control of induction motor drives. The objective is to make a critical analysis of these methods in terms of ripples reduction.
Direct the motor torque is proportional to the armture current. It is function of the frontal area shape protrusion such as side, mirrors, ducts and air passages spoilers and any other factor. Pdf high performance drives with induction machines require use of vector control. Direct torque control dtc is an emerging technique for controlling pwm inverterfed induction motor im drives. Control loop of a dc motor drive evolution of direct torque control features advantages technical guide no. Direct torque control in ac drive technology what direct torque control dtc is, why and how it has evolved, the basic theory behind its success and the features and benefits of this new technology. Control and direct torque control of induction motors using an adaptive flux observer abdesselam chikhi1,a, mohamed djarallah1,b, khaled chikhi1,c abstract this paper presents a comparative study of fieldoriented control ifoc and direct torque control dtc of induction motors using an adaptive flux observer.
Modern improvement techniques of direct torque control for. A new technique for the torque control of induction motors was developed and presented by i. This paper presents the results of an investigation into the suitability of a direct torque control method for an electric vehicle application. This method therefore, results in highly simplified control structure compared to vector control. Stator and rotor flux based deadbeat direct torque control. Introduction dc direct torque control dtc of induction motors has gained popularity in industrial applications mainly due to its simple control structure from.
The direct torque control dtc is the main interest of this project and it will be described in the following sections. Noguchi 1 as a new performant control strategy for induction motor drives fed by voltage source inverters vsi. Most of the proposed techniques are complex and they does not take stator flux control in to account, so that high speed operations are not possible. In a direct torque control system introduced by takahashi and depenbrock independently in 1986, the first five components are replaced by two hysteresis comparators and a selection table 1. This paper presents an innovative direct torque controlled load generator based on space vector modulation suitable for the emerging applications such as electrical test benches that require extremely fast largesignal torque and dynamic responses. Pdf direct torque control strategy of induction motors toufouti riad academia. A comparative study of fieldoriented control and direct. Direct torque control cannot be used in these applications, and so a direct torque control drive must also be able to operate with space vector modulation for these applications.
Lorenz university of wisconsin, madison, madison, wisconsin prepared for the 2001 industry applications society annual meeting sponsored by the institute of electrical and electronics engineers. The direct torque control scheme is a simple technique compare to other techniques. Pdf direct torque control dtc is an emerging technique for controlling pwm inverterfed induction motor im drives. Dtc has been successfully applied to induction machines 10, 11, and, more recently, to blac machines 12. Direct torque control or dtc is the most advanced ac drive technology developed by any manufacturer in the world this manuals purpose. In dtfc, the motor torque and the flux are calculated from the primary variables, and they are controlled directly and independently by selecting optimum inverter switch modes 252. In this model, the on state of upper limb switches are represented by 1 and the lower limb switches are represented by 0 and the same has been defined by. Direct torque control technique for voltage source. When abb introduced its first direct torque control ac drive to the market in 1995, dtc was already a leading technology. A simpler alternative to the vector control is the direct torque control dtc. While dtc and vc have different concept of operation, they both provide an effective control of the flux and torque. Since the beginning, the new technique was characterized by simplicity, good performance and robustness. In this technique by selecting optimum inverter switching modes the motor torque and flux are controlled independent and also direct. The essential differences between the dtc of bldc and blac drives are in the torque calculation.
Direct torque control technique for voltage source inverter 631 controller imposes the time duration of the active voltage vectors, which move the stator flux along the reference trajectory, and the torque controller determinates the time duration of the zero voltage vectors which keep the motor torque in the predefined hysteresis tolerance band. The efficiency of direct torque control for electric vehicle behavior improvement 1 2. This paper considers the application of direct torque control, to a. Introduction dc direct torque control dtc of induction motors has gained popularity in industrial applications mainly due to its simple control structure from its first introduction in 1986 1.
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