In a traditional electric motor, the rotor rotating part spins inside the stator static part in a linear motor, the stator is unwrapped and laid out flat and the rotor moves. The lims 3phase coil assembly can be directly connected to the ac line for single speed applications or to an adjustable frequency drive for variable speed control. Ultrahigh frequency effects of power electronics tests on induction machines. Singlesided induction motor slims are used more because of their simple structure. Of course, this would introduce extra control problems, but it also. The result is a flat stator, or upper section, of iron laminations. By using variable frequency control, it is possible to adjust the speed of the motor either above or below base speed. Applications may require very precise speed or positional control, despite wide variations in vehicle total mass. Linear induction motors are quite an engineering marvel, to convert a general motor for a special purpose with more or less similar working.
Two types of the motor are found, singlesided and doublesided. P417 bechar 08000, algeria 2university of sciences and technology of oran, algeria abstract in this paper, an adaptive backstepping control system with a fuzzy integral action is. For many induction motors, the average torque drops a bit as it accelerates and then rises to a peak value of torque, known as the pullout or breakdown torque. This paper presents a field oriented control scheme of the linear induction motor lim in order to achieve high performance of the machine.
P417 bechar 08000, algeria 2university of sciences and technology of oran, algeria abstract in this paper, an adaptive backstepping control system. The speed control of induction motor is done at the cost of decrease in efficiency and low electrical power factor. Speed control of induction motor 7 ways to control induction. Even though the operating principle is exactly the same as a rotary motor, the linear motor has a finite length of the primary or secondary parts and it causes static and dynamic endeffect which is the discontinuous airgap flux phenomenon.
An induction motor is practically a constant speed motor, that means, for the entire loading range, change in speed of the motor is quite small. Speed of a dc shunt motor can be varied very easily with good efficiency, but in case of induction motors, speed reduction is accompanied by a corresponding loss of efficiency and poor power factor. The motor torque is here controlled by using the method indirect self control isc, and power oscillations between the inverter and the input filter. Design of a single sided linear induction motor slim using a user interactive computer program a thesis presented to the faculty of the graduate school university of missouricolumbia in partial fulfillment of the requirements for the degree master of science by sarveswara prasad bhamidi dr. Line voltage control the torque developed varies with the square of the applied voltage. Among these control techniques, the method of direct torque control dtc is considered one of the most efficient as techniques that can beused for induction motors, 9. Characteristics of linear induction motor considering. Speed control of a three phase induction motor using pwm. Speed control of threephase induction motor by stator. Nowadays, linear induction motors lims are widely used in a variety of applications like transportation, conveyor. Simultaneous propulsion and levitation control of linear. An843, speed control of 3phase induction motor using. I would just like to add some practical applications of lim. Linear induction motor, end effects, dolphin effect, finite element method, mosebach model, thrust.
Linear induction motors lims are used to control the propulsion of maglev transportation and carrier system. Thrust analysis and improvement of single sided linear. The invention relates to a speed control system for a linear induction motor. Normally lim is used to make a motion frictionless absolutely. Introduction linear electric motors lems belong to the group of special electrical machines. Figure 2 represents the configuration of a sp type linear induction motor. Vector control, also called fieldoriented control foc, is a variablefrequency drive vfd control method in which the stator currents of a threephase ac electric motor are identified as two orthogonal components that can be visualized with a vector. Approaches of vector control of a linear induction motor. The speed control of poly phase induction motor can be done through the different methods. Figure 3 shows the relation between the voltage and. They are capable of speeds up to 1800 insec 45 ms and are typically used in applications where accurate positioning is not required.
A three phase induction motor is mostly a constant speed motor so its fairly not easy to control its speed. So speed control of this motor is an important agenda. A theoretical background for the induction motor input current variation due to variation in speed is presented and the theoretical result is compared with the experimental observations, when the motor speed is varied by variation of input voltage. The simulation of speed control and thrust control is conducted to verify thecontrol syst em. It also illustrates the usage of dedicated motor control libraries that are included in the sdk. Nonlinear control for linear induction motor servo drive. The secondary of a slim consists of conducting plate backed by a ferromagnetic. Full form kit includes case, doublesided silkscreened pcb, heatsink, cooling fan, hardware and electronics including parts from revised article in august 20. Pdf construction of three phase linear induction motor.
A theoretical background on scalar motor control principle. Speed control of linear induction motor using sliding mode controller considering the end effects article pdf available in journal of electrical engineering and technology 71. In this control method, it is possible to apply the conventional vector control to the thrust force control of lim. Speed control of three phase induction motor electrical4u. The stator generally consists of a multi phase winding in a laminated iron core. Simplified steadystateequivalent circuit of induction motor.
Characteristically, linear induction motors have a finite primary or secondary length, which generates endeffects. Pdf adaptive backstepping controller design for linear. Speed tracking of a linear induction motor enumerative. In ac rotating machine speed of machine is govern by the equation n120fp. Speed control of linear induction motor using sliding mode controller considering the end effects article pdf available in journal of electrical. Selection of linear motor topology both linear permanent magnet synchronous motors lpmsms and linear induction motors lims have been manuscript received july 3, 2008. It has problem that the controls of the lim and of the levitation magnets interfere each other because the attractive. Characteristically, linear induction motors have a finite primary or secondary length, which generates endeffects, whereas a conventional induction motor. Synchronous speed of an induction motor is shown in equation 1. The role of cycloconverter in speed control of induction motor is to vary the supply frequency which in turn, changes the speed of motor.
Performance analysis of the linear induction motor for the. If a rotary induction motor is compared with the linear induction motor, the lim requires a larger air gap and hence, the magnetising current is greater and the power factor and efficiency of the motor are lower. A six thyristor balaced ciruit is proposed for speed control and its performance is compared with that of sine wave variac voltage control. The rotor speed of an induction motor is given by the equation shown below. Pdf programmable logic control based simultaneous speed. Speed tra cking of a linear induction motor enumerative. An induction motor can be defined as the ac electric motor device in which a power source fed by the alternating current with the help of a primary winding. The most commonly used controller for the speed control of. Abstract control of induction motor im is well known to be difficult owing to the fact the mathematical models of im are highly nonlinear and time variant. Here we will discuss about the speed control of wound rotor induction motor using variation of rotor resistance.
A linear induction motor lim is a specific type of alternating current ac, multiplephase machine that provides force and movement in a linear direction. Main applications of these machines are in high speed ground transportation, sliding doors, flexible manufacturing systems, robotic systems, etc. However, induction motors do not inherently have the capability of variable speed of operation. The user can quickly start evaluating the performance of the vhz system with this method. 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. An induction motor can therefore be made without electrical connections to the rotor. Index termslinear induction motor, equivalent circuit parameters, finite element method, vector control, material of reaction plate i. A linear induction motor provides linear force and motion rather than rotational torque.
However, linear motors are not necessarily straight. Induction motors are widely used electrical motors due to their reliability, low cost and robustness. A lim operates under the same principles as its ac rotary motor counterpart, typically powered by a threephase voltage scheme with a force that is produced by a moving magnetic field 1. Characteristically, a linear motor s active section has ends, whereas more conventional motors are arranged as a continuous loop.
Jun 08, 2019 nearly 80% of the worlds ac motors are poly phase induction motors. Design of high speed induction motors linear induction motors. In this paper, we propose the novel control method of the thrust force and the attractive force of lim driven by the power source with the frequency component synchronous with the motor speed. The simplest linear motor is the singlesided linear induction motor lim, which consists of a primary coil assembly and a secondary formed by a reaction plate. A linear induction motor lim is an alternating current ac, asynchronous linear motor that works by the same general principles as other induction motors but is typically designed to directly produce motion in a straight line. If the induction motor is operating in the linear magnetic region, the lm is constant.
In the present work, the simulation of speed control of motor at different. The performance of the proposed dtfc method is analyzed with considering endeffect. The characteristics of typical low speed linear induction motors are considerably different to the characteristics of typical squirrel cage induction motors. The basic characteristic of dtc is that the positions of the. Performance optimization of linear induction motor by eddy current 771 journal of engineering science and technology december 2011, vol. A properly designed variable frequency inductionmotor drive can be very flexible. In this post let us see what are the various methods to control the speed of induction motor. Control of traction and levitation of linear induction. Speed control of 3phase induction motor using pic18 microcontrollers. Mover position control of linear induction motor drive. In this type of motor, the stator and rotor are called primary and secondary respectively. This thesis considers robust control of an induction motor drive, consisting of an input filter, a voltage source inverter and one or several induction motors in parallel. Furthermore, the constant thrust control in switch areas is analyzed and the future research work is discussed. By matt johnson, industrial devices corp basically, linear induction motors are little more than a cut open and rolled flat version of rotary ac induction motors.
Induction motor seminar ppt, pdf report study mafia. Force engineering ltd how linear induction motors work. Numerous applications of lims can be found in industry today, one of the most interesting being high speed magnetic levitation railway systems. Performance analysis of the linear induction motor for the deepunderground highspeed gtx 202 maximum speed should be around 34. In the rotary induction motor the stator and the rotor area are same whereas in the lim the one of the two is shorter than the other. A linear motor is an electric motor that has had its stator and rotor unrolled thus instead of producing a torque it produces a linear force along its length. Request pdf speed control of doublesided linear induction motors for automated manufacturing systems the doublesided linear induction motor dlim is acquiring a significant relevance in the. Second order sliding mode control with mars speed estimation of. Several control techniques have been used to control the speed andor position of induction motor drives. The linear induction motor is designed for high speed operation. We know that t he speed of the induction motor is given by, from the above equation, the speed of the motor can be controlled by changing supply frequency and by changing number of poles in the stator. Model predictive control of linear induction motor drive. Figure 27 illustrates the peak magnitude of flux density in the. An843, speed control of 3phase induction motor using pic18 mcus.
Abstract this paper presents a novel sensorless second order sliding mode control sosmc scheme for linear induction motor lim. Rotor resistance control of induction motor electrical4u. Before discussing the methods to control the speed of three phase induction motor one should know the necessary formulas of speed. They contain no permanent magnets, so there are no attractive forces between motor components when power is removed from the system. The normal operating region for the induction motor is the nearly linear portion between rated speed and synchronous speed, shown by the heavy line. The motor design procedure consists of a system of non linear equations, which imposes induction motor characteristics and motor performance. Then, equation 1 can be shown in terms of magnitude as. Moreover, constraints over the flux and current could be imposed to keep them within permissible values. The advent of vector control techniques has solved induction motor control problems. Induction motor is configured in delta connection, with dc generator as load 6. Induction motors are the most widely used motors for appliances, industrial control, and automation. Introduction linear induction motor has been applied in urban transportation system widely, mainly because of its low. Speed control of vector controlled induction motors using.
Speed control of single phase induction motor using triac. What is a linear induction motor and how does it work. This makes constant vf the most common speed control of an induction motor. Speed control of doublesided linear induction motors for. Free download induction motor seminar ppt, pdf report. Linear induction motors are quite an engineering marvel, to convert a general motor for a special purpose with more or less similar working principle, thus enhancing its. Comparison of different motor control principles using. A three phase induction motor is basically a constant speed motor so its somewhat difficult to control its speed. It can control the speed of an induction motor over a range from as little as 5% of base speed up to about twice base speed.
The magnetic field now sweeps across the flat motor face instead of rotating. Introduction 1linear induction motor lim is widely used in places that requires linear motion since it produces thrust directly and has simple structure, easy maintenance and low cost. Direct current that excites magnetic field in dc generator is set so that, when rated speed is reached, electrical power amounts 4 kw. Adjustable squirrelcage linear induction motor for magnetic. Speed control of an induction motor there is a various method of speed control of an induction motor. Generally, it is known as the asynchronous motor because its running speed is less than its synchronous speed. Speed control of induction motor using cycloconverter. Speed control of induction motor 7 ways to control. A linear induction motor lim is an alternating current ac, asynchronous linear motor that. In this system, the scalar control vhz of induction motor experiments with and explores the use of speed control. The speed control of induction motor is done at the price of reduce in efficiency and low power factor. Before discussing the methods to control the speed of three phase induction motor one should know the basic formulas of speed and torque of three phase induction.
Energy harvesting with single sided linear induction machines featuring secondary conductive coating pdf. Optimalairgap control of a linear induction motor for korean. This study proposes a speed estimation scheme for the sensorlessvectorcontrolled linear induction motor lim drives for mediumlow speed maglev applications, which is composed of two parts. Thus it is obvious that to change speed of machine any one parameter either frequency or no of poles are to be changed.
Linear induction motor motion control h2w technologies. They can be used in control of motors used in conveyors and other machinery. The reference speed value for motor acceleration is linear ramp. An induction motor can be used as induction generator, or it can be unrolled to form the linear induction motor which can directly generate linear motion. Vivek brahmbhatt already has explained very nicely the construction of lim. A linear induction motor lim is a noncontacting, high speed, linear motor that operates on the same principal as a rotary, squirrel cage, induction motor.
Jun 30, 2015 a three phase induction motor is basically a constant speed motor. The application serves as an example of ac induction vector control drive design using a motorola dsp with sdk support. Nov 11, 2011 the linear induction motor is designed for high speed operation. From the equation 1 it is clear that the motor speed can be changed by a change in frequency f, a number of poles p, and slip s. These differences must be taken into account when choosing a control system. In this paper the speed control method of lim, which lead to optimal control characteristic of motor such as thrust, flux and current, is proposed. If the motor slip is known, the rotor speed can be expressed by the equation. Fuzzy logic control of linear induction motor emre ozkop adem sefa akp. The shape and operation of a linear induction motor can be visualized as depicted in the figure by making a radial cut in a rotating induction machine and flattening it out. Linear induction motor a linear induction motor lim is an advanced version of rotary induction motor which gives a linear translational motion instead of the rotational motion. Speed control kit for induction motors jaycar electronics. Effect of varying rotor resistance by adding external resistance to wound rotor motor speed control by variable frequency vfd. Simulation results have shown the algorithm had good performances. When power is supplied to an induction motor at the recommended specifications, it runs at its rated speed.
Linear induction motor lim is an asynchronous motor, working on the same principle an induction motor works, but is designed to produce the rectilinear motion, unlike the rotary movement produced by a motor. This paper present the speed control of single phase induction motor using arduino with the controlling objectives pwm and spwm. A linear induction motor lim is a specific type of alternating current ac motor designed to produce motion in a straight line. This paper deals with the indirect vector control of linear induction motor lim in order to control the speed and thrust output of the linear induction motor drive. Thus the leakage reactance of the linear motor is decreased and. Mover position control of linear induction motor drive using adaptive backstepping controller with integral action i. The article deals with linear induction motor lim with a squirrelcage.
Indirect vector control of a redundant linear induction motor. Pdf speed control of linear induction motor using sliding. Linear induction motor background alternating current ac electric motor powered by a three phase voltage scheme force and motion are produced by a linearly moving magnetic field used in industry for linear motion and to turn large diameter wheels 6 4. Accelerations of up to 1 g with speeds in excess of 1800 inches per second 45 ms are possible with lims. Modeling of linear induction machines for analysis and control institution.
Jan 09, 2017 speed control methods of induction motor. Electric motor electric motor linear induction motors. Pdf fuzzy logic control of linear induction motor emre ozkop. Chapter 3 induction motor and different speed control methods page no 3. The main goal of this controller is to provide the optimal 3phase primary voltages necessary fo r tracking a certain speed reference trajectory. The flat ac linear induction motor lim is typically run directly off of 3 phase line voltage, with an adjustable frequency, or vector drive if speed control is required. It is widely used in industry due to low cost and rugged construction. An induction motors rotor can be either wound type or squirrelcage. Linear induction motors can be manufactured in a wide range of force outputs, speeds, and footprints. Thrust control of traction linear induction motors in switch. Various induction motor speed control methods advantages. Generally, induction motors are categorized based on the number of stator windings.
Why is speed control in an induction motor, difficult. Lim is an advanced version of rotary induction motor which gives a linear translational motion instead of. Speed control induction motor pdf 8 speed control of induction machines. Previously, to control the relative speed of the primary and secondary members of a linear induction motor it has been necessary to control the supply of current to the primary member using complex and expensive electronic circuitry. In the usual maglev transportation system using lim, the levitation of the carrier are controlled by the levitation magnets. One component defines the magnetic flux of the motor, the other the torque. For singlesided assemblies, the reaction plate consists of 18in.