Stator voltage control of induction motor electrical concepts. Each pair of the thyristor controls the voltage of the phase to which it is connected. The speed of a three phase induction motor can be varied by varying the supply voltage. Induction motor 1 chapter 3 induction motor bee23 electrical machine power system 2 learning outcomes. Dec 23, 2017 the speed control of induction motor by considering to control on stator side can also subdivide into several speed controlling methods such as. If the induction motor is operating in the linear magnetic region, the lm is constant. Available voltage control methods include control by a transformer or by phase control. Motor torque developed is proportional to the square of supply voltage and rotor current is proportional to the supply voltage in induction motors. Telecommunication engineering, southwest jiaotong university, china, 2005 thesis submitted for the degree of masters of engineering science in school of electrical and electronic engineering the university of adelaide, australia august 2010. The proposed solution is based on a voltage frequency vf control approach and a pi antiwindup regulator. Nehrir, speed control of threephase induction motor by stator voltage control ieee transactions on industrial electronics and control instrumentatio n, may 1975. The first commutatorfree single phase ac induction motor was invented by. The rotor will constantly be turning to align its magnetic field with that of the stator field. The thevenin voltage is the voltage applied to the rotor assuming that the rotor current is zero.
May 29, 2019 understanding the scalar speed control theory. Induction motor drives starting braking speed control of. The diagram below shows the stator voltage control of the three phase induction motors by thyristor voltage controller. Torque is proportional to voltage squared and the current is proportional to the voltage. Stator fluxoriented vector control with neuralnetworkbased svm and flux estimation. These strategies are known as extinction angle control eac, modified phase angle control mpac, and symmetrical angle control sac.
We can change the speed at the stator by, changing the supply frequency, changing the supply voltage and changing the number of stator poles. The 3phase set of currents, each of equal magnitude and with a phase. The basic idea of an electric motor is to generate two magnetic fields. Speed control of induction motor is possible in two sides. Speed control of induction motor is achieved by controlling the stator terminal voltage. Enter your email below to receive free informative articles on. The magnetic field in the air gap from the voltage applied to the stator. It is logical that the least expensive, lowest maintenance type motor should be used most often. Hii, i am trying to implement the stator voltage control of 3 phase induction motor with thyristor as a switching device. Can someone explain stator voltage control of an induction. It is not desirable to start large motors direct on line giving full voltage to the stator. Perform an analysis on induction machines which is the most rugged and the most.
Simulation and speed control of induction motor drives ethesis. Pdf study of stator voltage control method for induction motor. For detail of this method, please read stator voltage control of induction motor. Typically, they consist of 1 a stator with laminations and turns of copper wire and 2 a rotor, constructed of steel laminations with large slots on the periphery, stacked together to form a squirrel cage rotor. The singlephase induction motor is more subtle and less efficient.
This stator flux should be sinusoidal to obtain ripple free torque. This can be achieved by using power electronic circuits called inverters which convert dc to ac of desired frequency. This method of speed control is known as stator voltage control. The speed of induction motor is changed from both stator and rotor side. The field orientation principle in control of induction motors. It is based on freescales 56f800e microcontrollers. Alternately, the ac voltage can be adjusted by setting. Torque is directly proportional to stator voltage square. The paper presents a new torque control algorithm for induction motor, based on the stator flux vector control. The squirrel cage induction motor rotor is shorted and so there is no rotor excitation, the rotor voltage equals zero.
In variable stator voltage control method, since the voltage cannot be varied above the rated voltage, the speed control is possible only below the rated speed. A statorfluxoriented vectorcontrolled induction motor. In stardelta starting induction motor stator is connected in star connection for starting after picking up speed it is connected to delta connection. Nov 30, 2016 speed of a 3 phase induction motor can be controlled by these methods. Analysis and control of dual stator winding induction motor. Stator frequency control speed control of three phase. Stator voltage control is a method used to control the speed of an induction motor. Simplified steadystateequivalent circuit of induction motor. Speed control of wound rotor induction motor using rotor. Various methods for speed control of induction motor include pole changing, stator voltage control, supply frequency control, rotor resistance control, scalar control and vector control.
Out of the several methods of speed control of an induction such as pole changing, frequency variation, variable rotor resistance, variable stator voltage. Analysis and control of dual stator winding induction motor article pdf available in archiwum elektrotechniki 6 january 2012 with 637 reads how we measure reads. This video explains the working principle, salient features, merits and drawbacks of stator terminal voltage control of an induction motor. The stator consists of a series of wire windings of very low resistance permanently attached to the motor frame. Control strategies for induction motors in railway traction. Speed control of wound rotor induction motor using rotor resistance control aim to use variable resistance in the rotor circuit to control wound rotor induction motor speed theory polyphase induction motors are mainly of two types by construction, squirrel cage and woundrotorwith sliprings.
At each sampling period, the value of stator voltage is calculated to keep the stator flux equal to the reference vector, while the stator flux. For example, an ac controller can be used to adjust the stator voltage of an induction motor running under variable load in order to maintain better efficiency. If anyone has already implimented please revert back as. So, if the stator voltage is reduced the speed reduces and similarly if the stator. Stator terminal voltage in this method is changed either by adding a series resistor, series inductor, auto transformer, ac controller or ac chopper in stator circuit. Diagnostics of rotor and stator problems in industrial.
Thevenin impedance is the impedance of the stator part of the circuit, seen from the rotor, assuming that the stator supply is short circuited. An induction motor can therefore be made without electrical connections to the rotor. Induction motor control by stator voltage control method. The speed control of induction motor is done at the cost of decrease in efficiency. Initially, when the motor is started, heavy current flows through the field winding of the stator because back emf has not yet been induced. You should also make a dc measurement of stator winding linetoline resistance using a dmm. The induction motor is made up of the stator, or stationary windings, and the rotor. The singlephase motor stator has a laminated iron core with two windings arranged perpendicularly. The speed control of induction motor by considering to control on stator side can also subdivide into several speed controlling methods such as.
Pdf on jan 1, 2017, arun kumar yadav and others published study of stator voltage control method for. This method is not so easy to do with an ac speed control motor. A stator fluxoriented vectorcontrolled induction motor drive 9 fig. Stator voltage is directly responsible for the rotating speed of the rotor. The threephase induction motor is the easiest motor of this type to understand so these notes start with that type. Jun 08, 2019 another method of controlling the speed of induction motor drives is the stator voltage control. The induction motor stator resembles the stator of. Methods of speed control of induction motor electrical concepts. Pdf analysis and control of dual stator winding induction motor. The induction motor speed can be controlled by varying the stator voltage.
Speed control is obtained by varying the conduction period of the thyristor. As a voltage and a current is applied to the stator winding terminals, a magnetic field is developed in the windings. 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. But the recent developments in speed control methods of the induction motor have led to. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. Torque versus slip speed of an induction motor with constant stator flux. How an induction motor works by equations and physics. Stator voltage control of an induction motor circuit globe. Exprimental investigation of effects of voltage unbalance on three phase induction motor free download as powerpoint presentation.
Understanding scalar vf control for induction motors. How to control the speed of 3 phase induction motor quora. This method is useful for loads requiring less starting torque but the torque requirement increases with the load. Stator voltage control of three phase induction motor 2. Introduction this application note describes the design of a 3phase ac induction motor drive with volts per hertz control in closedloop vhz cl. Jun 02, 2018 stator voltage control of induction motor is a method for the speed control of induction motor by changing the stator terminal voltage.
Disadvantages of stardelta starting of induction motor. Full voltage is only applied when the motor picks up speed. Understand the principle and the nature of single phase and 3 phase induction machines. The speed control of three phase induction motor from stator side are further classified as. In induction motor control concepts where vhz technique is employed, the speed control is implemented by adjusting the stator voltage with respect to frequency such that the air gap flux is never able to deviate beyond the expected range of the steadystate, in other words it is maintained within. Normally with motors beyond 5 hp, starters are provided. Ac induction motors are also the most common motors used in main powered home appliances. Dec 17, 2019 the speed of induction motor is changed from both stator and rotor side. A 3 phase induction motor can be used for different applications with various speed and load requirements. Speed control of induction motor ac motor speed control. For reduction in the starting current, a lower voltage is applied to the stator, especially for the squirrel cage induction motors. Study of stator voltage control method for induction motor torque control using matlab simulation. Dc motor drive since ac motors were not capable of smoothly varying speed. The threephase induction motor is the extensively used for various kinds of industrial drives.
When induction motor is connected in star connection stator phase voltage reduced by 12 times the line voltage. In this paper, a new design of a realtime lowcost speed monitoring and closedloop control of the threephase induction motor im is proposed. The motor is mounted in a test rig that allows one to control the torque applied to the motor shaft and to measure both rpm and torque. Feb, 2015 stator voltage control is basically a method to control the speed of an induction motor. Record all nameplate information for the induction motor. Single phase induction motor the singlephase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. Speed control methods of various types of speed control. The speed of a 3 phase induction motor can be varied by varying the supply. Stator voltage control of an induction motor stator voltage control is a method used to control the speed of an induction motor. Then, equation 1 can be shown in terms of magnitude as. At the end of the lecture, student should be able to.
Realtime lowcost speed monitoring and control of three. If the induction motor is viewed as a type of transformer, it becomes easy to understand. The expression for the synchronous speed indicates that by changing the stator frequency also it can be changed. With the present semiconductor technology mosfets, igbts, gtos and. Exprimental investigation of effects of voltage unbalance. Induction motors are the most widely used electrical motors.
These techniques depend on varying the stator ac voltage to control the speed of threephase induction motor. Lec 03 stator terminal voltage control of induction motor. An induction motor or asynchronous motor is an ac electric motor in which the electric current. Singlephase induction motor threephase induction motor singlephase induction motor there are probably more singlephase ac induction motors in use today than the total of all the other types put together. Speed control of induction motor detailed explanation.
Advantages of 3 phase induction motor generally easy to build and cheaper than corresponding dc or synchronous motors induction motor is robust. Speed control of three phase induction motor electrical4u. Methods of speed control of induction motor electrical. Speed control at the rotor side we can change the speed at the rotor by,by adding some external resistance in the rotor circuitby cascade connection of the motor.
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