Vf speed control of 3 phase induction motor using space. Combining energy efficiency tax incentives, and utility rebates, returns on. This paper presents the design of a xilinx field programmable gate array fpga based sinusoidal pulse width modulation spwm for a threephase voltage source inverter vsi with variable voltage variable frequency vvvf for controlling the speed. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. The basic idea of an electric motor is to generate two magnetic fields. Model is developed for spwm inverter fed induction motor using xilinx. Some types of singlephase motors or synchronous motors can be. Different speed control methods of induction motor are explained below. Its are the most widely used motors for appliances, industrial control, and automation. The ac electric motor used in a vfd system is usually a three phase induction motor. We rely on support from people like you to provide free education. Rodel vincent andrada y corcuera of the university of the philippinesdiliman describes a novel and costeffective type of dctoac inverter circuit for induction motor speed control.
In ac rotating machine speed of machine is govern by the equation n120fp. Several various techniques are implemented to control the speed of three phase induction motor, namely vf speed control, rotor resistance control, frequency control, and stator voltage control 6. It is equally important to control the flux density in the motor to maintain torque producing capabilities throughout the speed range. Speed control of three phase induction motor by vvvf method using g7a drive gourambika, m. Vvvf speed control of induction motor electrical concepts. By changing the frequency ofthe ac wave fornl the speed ofthe ac motor is changed. N s 120fp 1 where f is frequency and p is number of poles. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. This is a brief discussion about variable frequency drive of an induction motor. Refer to user manual gs1m for additional specific wiring information. Experimental results of variable frequency drive for three. Lv variable frequency drives and soft starters full catalog power and controls products catalog.
In the first part of our presentation, we are going to discuss. Induction motors are the most widely used motors for appliances, industrial control, and automation. Induction motor or asynchronous motor is an ac electric motor in which the rotor torque produced is caused by electromagnetic induction from the stator winding of the magnetic field. The main aim of this modeling is to choose the appropriate rating of a motor so that the electric motor does not exceed its safe limit during operation. The motor side can have a different kva rating than mains power. Huge energy savings potential operating centrifugal fans, pumps and compressors vary frequency of electrical supply to an induction motor to vary the motor speed. The synchronous speed of an induction motor is controlled by the number of. Recent developments in control techniques and power electronics has made it possible for the induction motor im to be used in applications requiring fast dynamic response and decoupled control of torque and flux, like the brushed dc motor. Majority of industrial drives use ac induction motor because these motors are rugged, reliable, and relatively inexpensive.
Speed control of three phase induction motor by vvvf. Pdf the authors discuss the efficiency analysis and experimental data for an induction motor fed by a variablevoltage and variablefrequency vvvf. Using this approach, it is possible to accelerate a motor from zero speed to rated speed smoothly and without the high inrush currents normally associated with induction machine starting. This method cannot be used for squirrel cage induction motor. At time t, let the motor has following parameters p 1 heat developed, joulessec or watts. Variable frequency drives vfds popular speed control devices used in industrial, commercial and residential applications. Steady state response of speed, current and torque in induction motor are also obtained using this scheme. How to control the speed of an induction motor quora. The technique proposed gives leading input power factor.
To illustrate the behavior of the output voltage, let the modulation index a be equal to 1. In vf speed control technique vf ratio is to be kept constant so that flux remains constant. In afp elevator company, different invertors from different companies like lx, iastar. The ability of varying any one of the above three quantities will provide methods of speed control of an induction motor. Variable voltage variable frequency speed control of. Search weginductionmotorsfedbypwm50029350technical. So it is essential to test the health of speed sensor and a vvvf induction motor drive with field oriented control can be effectively used for that. Induction motors were invented by nikola tesla in 1888 while he was a college student. Speed of a 3 phase induction motor can be controlled by these methods. An843, speed control of 3phase induction motor using. Squirrel cage induction motor an overview sciencedirect topics. Abstract a novel topology of variable voltage control of induction motor has been designed and fabricated which uses only two high frequency pwm controllable switches. Vector control technique allows a squirrelcage induction motor to be driven with high dynamic performance, comparable to that of a dc motor.
Weg standard product catalog motors, enclosed motor controls, gears, and alternators weg automation catalog. When power is supplied to an induction motor at the recommended specifications, it runs at its rated speed. Fpga and fuzzy based speed control technique for three. So, a simple thermal model of any motor can be obtained assuming it to be a homogeneous body. How to control the speed of 3 phase induction motor quora. Induction motor drives electric vehicle machines and. Ac motor, main drive controller assembly, and driveoperator interface 210211 ac motor. There are three main types of control strategies for induction motor drives. As discussed, frequency is varied, therefore it is quite important to have a look at the maximum torque at variable frequency. Vvvf speed control method is widely used method for induction motor.
Thus it is obvious that to change speed of machine any one parameter either frequency or no of poles are to be changed. Basic construction and operating principle like most motors, an ac induction motor has a fixed outer portion, called the stator and a rotor that spins inside with a carefully engineered air gap between. Although ac induction motors are widely used, it is difficult to control the speed of these components. This control of voltage and frequency is required as it permits the user control the speed of an induction motor at different rates4,10.
The slip power frequency scheme is operates on 3phase induction motor using. From the equation 1 two primary methods for speed control of 3phase ac induction motor can be concluded. Rotor induction motor can either type of wound or squirrelcage. Let us first have a look at the relationship between the rotor speed and slip to arrive at various methods of speed control of induction motor. The analysis has been done in terms of thd in their line current. Pdf speed control of threephase induction motor based. Vvvf fed to the motor controls its speed and torque.
The ac induction motor is just about the simplest, mostrugged design in existence so it suits the application very well. Vvvf control variable voltage and variable feriquency in order to run, stop, motor direction definition, motor current consumption control and a lot of other geared or gearless elevator motors parameters, invertors or motor drivers are used. What is the difference between vfd and vvvf drive used for. A variable frequency drive vfd is a type of motor controller that drives an. A variablefrequency drive is a device used in a drive system consisting of the following three main subsystems. Induction motor speed control the speed of the rotating magnetic field developed in induction motor stator is given by. By comparison, given the fact that either an induction motor or a bldc motor would have sophisticated highpowered drive electronics, im not sure thered be any advantage to using the bldc over the induction motor. In the present day, induction motors consume between 90 to 95 percent of the motor energy used in industry. The vfd is used to create a controlled frequency ac wave form to the ac induction motor. A novel spwm vvvf ac drive using a discrete analog. Vvvf control principle of operation capacitors to accept power from the rectifier, stores it, and we will mention here only the salient points of vf control. Scalar control is the term used to describe a simpler form of motor control, using nonvectorcontrolled drive schemes.
Aspalli published 2014 one of the driving forces behind the industrial revolution was the invention. Firstly threephase induction motor drive system is simulated in various modes using matlabxilinx, then finally closed loop control of induction motor is. Vvvf control variable voltage and variable feriquency. The induction motors for electric propulsion is principally similar to that for industrial application. In vector control, machine dynamic model rather than steadystate model on which scalar controllers are based on, is. The induction motor is made up of the stator, or stationary windings, and the rotor. Implementation of close loop speed control with vvvf control fig. Based on the simulation results, when a 20 n load is applied at a low frequency to the lim based conveyor belt. One motor is the called the main motor, and another motor is called the auxiliary motor. Variable voltage variable frequency speed control of induction. As we know that, rotor of an induction motor rotates at a speed somewhat lower than the synchronous speed. Speed, thrust and air gap flux response at 5 hz frequency and 20 n applied at 15 sec with boost voltage of 20 volts. The 3phase set of currents, each of equal magnitude and with a phase. Implementation of close loop speed control with vvvf.
A variablefrequency drive vfd or adjustablefrequency drive afd. By combining them in parallel, 3c is available for the high speed. Waveforms of the output voltages vary by the modulation index and the phase angle. One popular method of speed control is using vvvf method. As you can see, the vfd dc bus has a dc voltage with an ac ripple. In vvvf speed control, motor stator supply as well as frequency is varied such that ratio vf is constant. Variable frequency control vf of induction motor 1. In this method of speed control of three phase induction motor, the two threephase induction motors are connected on a common shaft and hence called cascaded motor.
Vvvf techniques for speed control of induction motor dois. Speed control of three phase induction motor by vvvf method using g7a drive. There are more than one methods to control the speed of induction motor, you can choose one. In this control flux and torque can be controlled independently. Another method is to regulate the stator current frequency. Speed control of three phase induction motor electrical4u. Pdf optimal efficiency analysis of induction motors fed by variable. The ac electric motor used in a vfd system is usually a threephase induction motor. A vfd is an electrical device used to control the rotation speed of an alternating current ac electric motor by adjusting the frequency of the electrical power supplied to the motor. Aspalli abstract one of the driving forces behind the industrial revolution was the inventionmore than a century ago of the electric motor. Vvvf drives are popularly used for speed control of induction motor in many industrial applications.
As induction motors are widely being used, their speed control may be required in many applications. Methods of speed control of induction motor electrical. Variable voltage variable frequency control of threephase induction motor in closed loop is the significant feature of the thesis work. They can be used in control of motors used in conveyors and other machinery. Enhancing power factor with power saving in induction.
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