Different methods of speed control of threephase asynchronous. Induction motor speed control by stator voltage control ieee xplore. The speed control of poly phase induction motor can be done. Voltage frequency control with velocity feedback and pid control the pic18f4431 incorporates a set of innovative peripherals, designed especially for motor control applications. The basic idea of an electric motor is to generate two magnetic fields.
The steadystate and dynamic performance of a stator voltage controlled current source inverter csi induction motor drive are presented. It is an ac motor in which current is induced in the rotor winding by the magnetic field of the stator winding, by electromagnetic induction. It has been reported 4161 that an open loop voltageexcited csi induction motor drive has a torque speed characteristic that combines the properties of both culrrentand voltageexcited. Reducing the voltage is a common practice used to control the speed of induction motors that drive fans. The speed of a three phase induction motor can be varied by varying the supply voltage. In foc, the principle of decoupled torque and flux control are applied and it relies on the instantaneous control of stator current space vectors. Induction motor is a device which converts electrical energy into mechanical energy. Speed control of induction motor is possible in two sides. The rotor will constantly be turning to align its magnetic field with that of the stator field. This paper presents design and analysis of a three phase induction motor drive using igbt. The induction motor stators magnetic field is therefore changing or rotating relative to the rotor. The alternating current ac induction motor is one of the most rugged and most widely used machines in industry. Electrical motors, emerson motors abstract operation ofac.
In this model, speed of induction motor is controlled with proper firing angle of ac voltage controller. The circuit simulated above is one of the topologies of 3phase ac voltage controllers whose output is fed to im for drive applications a pdf file is attached to best explain the operation of. Control of induction motor is complicated due to the control of decoupled torque and flux producing components of the stator phase currents. The magnetization current im flowing in the motors equivalent circuit fig. 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 speed control of poly phase induction motor can be done through the different methods. Speed control of induction motor detailed explanation. Chapter 3 induction motor and different speed control methods page no 3. Threephase induction motor stator current optimization citeseerx. At motor terminal voltage v 3, the fan is operating with speed. The summation of all torques acting on the motor shaft comprises the mechanical model. Fundamentals of electric motors and transformers rajib mikail lecturer. Induction motor speed controlled by using thyrister based 3phase ac voltage controller.
Nov 18, 2015 induction motor torquespeed characteristics figure 6. The induction motor speed can be controlled by varying the stator voltage. With scalar control, only the magnitude and frequency of the supply voltage. It doesnt work well for ordinary mechanical losds, but because fan torque is proportional to speed squared or some higher power reducing voltage to allow the motor to slip more doesnt cause an overheat, because current also decreases. Both induction motor and transformer works under the principle of electromagnetic induction.
Speed control of wound rotor induction motor using rotor. It follows that any eycient method of speed control must be based on varying the. Analysis and control of dual stator winding induction motor. The stator consists of a series of wire windings of very low resistance permanently attached to the motor frame. Torque is directly proportional to stator voltage square. It gets damaged frequently due to wear and tear and needs rewinding. Whereas in induction motor, the stator and rotor are magnetically coupled. This paper establishes the fundamental laws relating to the speed control of induction motors by simple voltage control and emphasizes the problems. Speed control of three phase induction motor by stator voltage.
The stator is composed of laminations of highgrade sheet steel. While torque is proportional to voltage squared eq. Speed of a 3 phase induction motor can be controlled by these methods. Stator voltage control of three phase induction motor 2. This method of speed control is known as stator voltage control. It supplies an induction motor ich has a full load speed of 144wh 0. Three phase induction motor drive using igbts and constant v. Stator voltage control is basically a method to control the speed of an induction motor.
This method is only applicable for slip ring or wound rotor induction motor wrim. In this method of speed control, the rotor circuit resistance is varied by connecting a variable external resistance. The speed of a 3 phase induction motor can be varied by varying the supply. For variable speed drives, the source is normally an inverter that uses power. Generalities about control strategies of the cage induction motors. Torque is proportional to voltage squared and the current is proportional to the voltage. 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. This method is applicable to squirrel cage induction motor only. An induction motor or asynchronous motor is an ac electric motor in which the electric current. Find the percentage slip and number of poles of the induction motor. Stator voltage control of three phase induction motor fed by three. Problems and premature failures often indicate input power system troubles, poor or deteriorating mechanical installations, or malfunctions in the driven machinery. The stator frame consists of laminations of silicon steel, usually with a thickness of about 0. The circuit simulated above is one of the topologies of 3phase ac voltage controllers whose output is fed to im for drive applications.
Diagnostics of rotor and stator problems in industrial. It is logical that the least expensive, lowest maintenance type motor should be used most often. Problems and premature failures often indicate input power system troubles, poor or. An900, controlling 3phase ac induction motors using the. Stator voltage control is a method used to control the speed of an induction motor. Initially, when the motor is started, heavy current flows through the field winding of the stator because. Plc for controlling the operation of induction motor such as forward and reverse direction and speed is. As a voltage and a current is applied to the stator winding terminals, a magnetic field is developed in the windings.
There are two major components of an ac induction motor. Record all nameplate information for the induction motor. 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. Commutation effects are neglected and the analytical. The 3phase set of currents, each of equal magnitude and with a phase. Stator voltage control of induction motor drives is a cheaper and more reliable scheme of speed control and is widely used. It is a 16 bit highperformance digital signal controller dsc.
Stator voltage control of an induction motor circuit globe. Induction motor controlled by ac voltage controller file. Scalar control is the term used to describe a simpler form of motor control, using nonvectorcontrolled drive schemes. As we already know that the torque developed is proportional to the square of the supply voltage and the slip at the maximum torque is independent of the supply voltage. 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. Nearly 80% of the worlds ac motors are poly phase induction motors. Voltagefrequency control with velocity feedback and pid control the pic18f4431 incorporates a set. 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. Determine the impact of rewindingrepair on motor effi ciency. 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. The speed of the wound induction motor can be controlled by connecting an external resistance in the rotor circuit through slip rings. In the electrical model, the voltage, v, and the slip, s, determine the rotor current.
Stator voltagecontrolled current source induction motor drive. Rotor resistance control of induction motor electrical. In transformer, primary winding and secondary winding are magnetically. So, if the stator voltage is reduced the speed reduces and similarly if the stator. It has been reported 4161 that an open loop voltage excited csi induction motor drive has a torque speed characteristic that combines the properties of both culrrentand voltage excited. Initially, when the motor is started, heavy current flows through the field winding of the stator because back emf has not yet been induced.
Synchronous speed of the rotating magnetic field of an induction motor is given by, where, f frequency of the supply and p number of stator poles. Rotor resistance control of an induction motor rotor resistance control is also one of the methods by which we can control the speed of the induction motor. An induction motor can therefore be made without electrical connections to the rotor. The induction motor is made up of the stator, or stationary windings, and the rotor. The impactthatvoltage variations have on ac induction. Stator voltage is directly responsible for the rotating speed of the rotor. Stator voltage control of induction motor electrical concepts. Proposed system the block diagram of the system to be prepared for the proposed work is shown in fig. Motor analysis block diagram induction motor starting can be analyzed using electrical, mechanical, and thermal models which interact as diagrammed in figure 1. 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. May 26, 2018 rotor resistance control is one among the various methods for the speed control of induction motor.
Stator voltage control of three phase induction motor fed. Online estimation of stator resistance of an induction. Rotor resistance control of induction motor electrical4u. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Feb 15, 20 the circuit simulated above is one of the topologies of 3phase ac voltage controllers whose output is fed to im for drive applications a pdf file is attached to best explain the operation of the circuit.
In very simple words induction motors can be described as a threephase, self. The steadystate and dynamic performance of a stator voltagecontrolled current source inverter csi induction motor drive are presented. A three phase, 12 pole, salient pole alternator is coupled to a diesel engine running at 500 rpm. Nehrir, speed control of threephase induction motor by stator voltage control ieee transactions on industrial electronics and control instrumentatio n, may 1975. How to control the speed of 3 phase induction motor quora. Stator voltage control of an induction motor is used generally for three purposesa to control the speed of the motor b. In transformer, primary winding and secondary winding are magnetically coupled. By reducing stator voltage control of induction motor, speed of a highslip induction motor can be reduced by an amount which is sufficient for the speed control of some fan and pump drives fig. 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.
Electric motor construction of induction motors britannica. Stator voltage control of induction motor is a method for the speed control of induction motor by changing the stator terminal voltage. But the flux estimate, when estimated from the stator circuit variables, is dependent on the stator resistance of the induction motor. So speed control of this motor is an important agenda. He squirrel cage induction motor is basically a simple, cheap, and reliable machine which can. In this paper, various methods of speed control of induction asynchronous motors such as variable rotor resistance, variable stator voltage, constant voltshertz. Induction motor drives starting braking speed control of. Speed control of induction motors linkedin slideshare. Actual speed of an induction motor is given as n ns 1 s.
This means, increasing rotor resistance results in increase in. It doesnt work well for ordinary mechanical losds, but because fan torque is proportional to speed. Stator voltage control of induction motor electrical. Induction motor control by stator voltage control method. The torque developed in this method is proportional to the square of the supply voltage. Here we will discuss about the speed control of wound rotor induction motor using variation of rotor resistance. Electrical motors, emerson motors abstract operation ofac induction motors at voltage and frequencies other than the nominal value can affect significant changes in the motor operating costs, performance characteristics. 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. Dec 10, 2012 induction motor speed controlled by using thyrister based 3phase ac voltage controller. Speed control of induction motors requires the accurate estimation of the fluxes in the motor. Diagnostics of rotor and stator problems in industrial induction motors by fang duan b. A synchronous motor can also be used but it is more sensitive to keep a stable operation. Therefore, motor troubleshooting involves the entire system, not just the.
Rotor resistance control of induction motor electrical concepts. In networks where high voltage drops are likely to occur, an induction motor should generally be selected to ensure stable operation during the high voltage drops. Rotor resistance control of an induction motor circuit globe. Jun 08, 2019 another method of controlling the speed of induction motor drives is the stator voltage control. Online estimation of stator resistance of an induction motor.
Stator terminal voltage in this method is changed either by adding a series resistor, series inductor or auto transformer in stator circuit. Can someone explain stator voltage control of an induction. We can change the speed at the stator by, by changing the supply frequency. The speed of induction motor can be varied by changing supply voltage. Feb, 2015 stator voltage control is basically a method to control the speed of an induction motor.
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. A three phase induction motor is used to test the operations such as running the motor in forward or reverse direction and to run it on the desired speed command given by the user. The stator resistance is viewed as a function of the stator voltages, currents and stator flux magnitude, which is obtained using the react ive power of the motor. The threephase stator voltage at line frequency can be controlled by controlling the switches in the inverter. However, for both motor alternatives, comparison overview 9akk105465 en 062011. Electric motor electric motor construction of induction motors. Hence, the synchronous speed changes with change in supply frequency. Feed forward control of induction motor using ac voltage regulator.
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. Jan 09, 2017 this method is applicable to squirrel cage induction motor only. Telecommunication engineering, southwest jiaotong university, china, 2005 thesis submitted for. We can control the speed at stator side and at rotor side also. Stator voltage control of induction motor control by ac. Motor torque developed is proportional to the square of supply voltage and rotor current is proportional to the supply voltage in induction motors. Stator voltage control of three phase induction motor fed by. A survey of speed and flux control structures of squirrelcage. Jun 08, 2019 nearly 80% of the worlds ac motors are poly phase induction motors. Pdf on jan 1, 2017, arun kumar yadav and others published study of stator voltage control method for induction motor torque control. Pdf the stator voltagecontrolled current source inverter.
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