Generally an induction motor operates at almost constant speed as the load is varied. Development of a variable frequency power electronics inverter to. State of the art of induction motor control request pdf. 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. Speed control of an induction motor by using indirect. Thus the speed of the motor can be changed by controlling the frequency, or number of poles or the slip. A variablefrequency drive vfd or adjustablefrequency drive afd, variablevoltagevariablefrequency vvvf drive, variable speed drive vsd, ac drive, micro drive or inverter drive is a type of adjustablespeed drive used in electromechanical drive systems to control ac motor speed and torque by. The multispeed operation and multipurpose operation are provided by controlling the speed of these motors. The amount of slip depends on the input power, the applied load, and the characteristics of the specific motor. Control of induction motors by using programmable logic controllers plc. Development of a variable frequency power electronics inverter to control the speed of a threephase induction motor. The difference between these two frequencies is called the slip. Stator frequency control speed control of three phase. Adjustable speed drive asd or variable speed drive vsd describes equipment used to control the speed of machinery.
More than 90% of motors used in industries are squirrel cage induction motor due to its rugged and maintenance free design. Speed control of 3phase induction motor using pic18 microcontrollers. This is why using vfd to control an induction motor was a good idea. The synchronous speed and therefore, the speed of the motor can be controlled by varying the supply frequency. This paper presents design and analysis of a three phase induction motor drive using igbt.
Design and control of the induction motor propulsion of an. The dspicdem mc motor control development system has electrical isolation and is fully selfprotected against faults. Jun 14, 2016 an induction motor works through the interaction between two electromagnetic fields one produced by the power applied to the motor windings, and one induced in the motor rotor by the lines of flux from the first field cutting through the conduct. Since, number of poles of a motor is fixed at the time of construction, special motors are required with provision of pole changing. Nov 26, 2015 this is a brief discussion about variable frequency drive of an induction motor. Typically, smaller vfds have no separate gate drive, but combine gating with logic power supplies to form a power board. Speed control of induction motor by variable frequency control. Speed control of induction motor by variable frequency control variable frequency control is a method which is used to control the speed of an induction motor. An843 ds00843apage 2 2002 microchip technology inc. Design and control of the induction motor propulsion of an electric vehicle b. This is a brief discussion about variable frequency drive of an induction motor. The abcs and 123s of variable frequency drives machine design. A fullwave power diode based solidstate rectifier converts threephase 50 hz power from a standard 220, 440 or higher utility supply to either fixed or adjustable dc voltage. Ac variable speed drive for 3 phase induction motors part number.
A majority of the existing variable speed drive systems with induction motors are. An introduction there are various methods for the speed control of an induction motor. Jan 09, 2017 speed control methods of induction motor. Mainly due to power electronics and digital control, the induction motor. The synchronous speed of an induction motor is given by the relation shown below. Aspalli department of electrical and electronics engineering, pdace, gulbarga, karnataka, india abstract there are several terms used to describe devices that control speed. Variable frequency drive uses power electronics vary the frequency of. Will variable frequency drives with standard induction. But producing goods and services is strongly related to the use of energy in an intelligent way. An induction motor works through the interaction between two electromagnetic fields one produced by the power applied to the motor windings, and one induced in the motor rotor by the lines of flux from the first field cutting through the conduct. Variable voltage variable frequency speed control of. Speed control of three phase induction motor by variable frequency drive 1madivalappa. Variable frequency control vf of induction motor drive.
The field orientation principle in control of induction motors. This paper seeks to carry out modeling, simulation and performance analysis of a variable frequency drive using matlabsimulink model. Variable speed drive of single phase induction motor using. Methods of speed control of induction motor electrical. Out of all the electrical machines, induction motor is the most used machine in industries. Vector control of induction motor drives springerlink. How to control the speed of 3 phase induction motor quora. Variable frequency drives or vfds are widely used throughout industry to provide adjustable speed control of ac motors. The discussion is based on the dspicdem mc motor control development system, but you can use your own hardware if you choose. It is capable of adjusting both speed and torque from an induction or synchronous motor. We already know that if we change the frequency of supply then we can easily change the speed of induction motor by the.
Vfds are not inherently positioning devices, so to make them control position would involve adding feedback to the induction motor and an additional layer of control, adding dollars and complexity, which ultimately take the form of added cost. The main motor has 6 poles and the other motor has 4 poles. Dec 17, 2019 any variable frequency drive or vfd incorporates following three stages for controlling a three phase induction motor rectifier stage. Speed of a 3 phase induction motor can be controlled by these methods. The expression for the synchronous speed indicates that by changing the stator frequency also it can be changed.
Voltagefrequency vf control of induction motor drives. Pdf induction motors do not run at synchronous speed, they are generally. In addition, electronics can reduce the systems average power consumption and noise generation of the motor. For our knowledge, in textbooks and literature, the unique description of designing slipregulator using analytical approach was described in. Firstly threephase induction motor drive system is simulated in various modes using matlabxilinx, then finally closed loop control of induction motor is. Ac and dc variable speed drives application considerations pdf. Induction motor drive has three distinct operating regions. Induction motor control is complex due to its nonlinear. This allows control of the steadystate speed or torque of the motor, while the magnetic field in the motor is kept at a constant, desired level. Induction ac motors are referred to as asynchronous motors or rotating transformers. An984, an introduction to ac induction motor control using. Todays sophisticated industrial drives are the result of the. The name itself suggests that vfd uses voltage and frequency to control the speed of induction motor.
Two induction motors are cascaded for the purpose of speed control. Induction motor is now called the racehorse of the industry 1. Why use variable frequency drive for induction motor. Variable frequency control vf of induction motor 1. When motoring the rotor frequency is always lower than the stator frequency. This can be achieved by using power electronic circuits called inverters which convert dc to ac of desired frequency. The pwm converter is merged with the inverter block.
The first industrial motors of this type were constructed at the end of the nineteenth century and soon gained the favor of users who appreciated their raggedness, simplicity and relatively low manufacturing cost compared to dc commutator motors. 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. The frequency and speed of the motor, with respect to the input supply, is called the synchronous frequency. Variable voltage variable frequency control of threephase induction motor in closed loop is the significant feature of the thesis work. The induction motor is operated at variable frequency and constant rated flux that is, e f. Various induction motor speed control methods advantages. Three phase induction motor drive using igbts and constant v. Optimal control of induction motor using high performance.
Motion and temperature heat control are paramount in energy. Methods of speed control of induction motor electrical concepts. A variable voltage, variable frequency drive is capable of operating over a wide speed range. Fall 2005 ee595s electric drive systems 2 overview of strategies voltsperhertz control constant slip control fieldoriented control. This research paper is variable speed drive of induction motor using frequency control. Vector control simplifies motor control using dq or. Selection of slip frequency control for maximum torque per amp. A modified approach to induction motor stator voltage and. Where f frequency of supply, p number of poles, and s slip. Variable frequency drive or vfd is the way that enables controlling of the speed of induction motor by applying varying frequency of ac supply voltage. The difference is that, in the case of the induction motor, the secondary windings can move due to the rotation of the rotor the secondary winding of the im, the induced voltage in it does not have the same frequency of the stator the primary voltage 3192014 emdii induction motor design. Analysis of variable frequency three phase induction motor.
Scalar control is the term used to describe a simpler form of motor control, using nonvectorcontrolled drive schemes. Variable speed and flow capability with standard induction motor. Until the advent of the ac variable frequency drive in the late 1950s, mechanical. Optimal control of induction motor using high performance frequency converter jerkovic vedrana, spoljaric zeljko and valter zdravko faculty of electrical engineering department of electromechanical engineering, osijek, croatia, email. Steady state equivalent circuit of a squirrel cage induction motor for constant flux control a. Variable frequency drive for induction motor elprocus.
Induction motor control is complex due to its nonlinear characteristics. Adjustable speed drive asd or variablespeed drive vsd describes equipment used to control the speed of machinery. Speed and frequency control of ac induction motor using variable frequency drive 273 other sensitive component and windings of the motor thus the life time of motor is reduced. This speed control method is known as volts per hz. Speed control of induction motor using variable frequency drive.
If frequency is increase than why speed and current of. An843, speed control of 3phase induction motor using pic18 mcus. Getting started guide model sizes 2 to 6 ac variable speed drive for 3 phase induction motors part number. This type of control is usually referred to as scalar control, since the controlled stator voltage or current are assumed sinusoidal, with only the magnitude and frequency adjusted, and with no. Motor speed control by variable frequency vfd determining motor circuit parameters. Speed control of induction motor using scalar control. The system may include transformers for high voltage system. Calculate the possible speed that can be obtained if the set is run on asupply of 50 hz frequency. In this post let us see what are the various methods to control the speed of induction motor. Squirrel cage induction motor an overview sciencedirect topics. A typical frequency converter with a special induction motor series are shown on. Ensure the motor is installed in accordance with the manufacturers recommendations.
Analysis of variable frequency three phase induction motor drive. Lets talk about two different load one is high load and other low load. Insidepenton com electronic design adobe pdf logo tiny. Induced current is what causes the magnetic field that envelops the rotor of these motors. Washing machine threephase acinduction direct vector control, rev. Scalar control of induction motor drives using dspace ds1104. At low load motor is delivering the load with some current and thereby torque is maintained.
The development of variable speed induction motor drives has a long history of more than four decades. Design of vfd drive for a 3phase induction motor ijirset. Any variable frequency drive or vfd incorporates following three stages for controlling a three phase induction motor rectifier stage. Speed and frequency control of ac induction motor using. Speed control of three phase induction motor by variable. Ac motors, controllers, and variable frequency drives. In the variable frequency drive itself are the most basic components present.
An843, speed control of 3phase induction motor using. Control of induction motors by using programmable logic. The speed of an induction motor can be easily controlled by varying the frequency of the 3phase supply. Aug 08, 2014 induction motor is constant speed motor at a particular frequency and consumes almost same power irrespective of load demand. Induction motor is constant speed motor at a particular frequency and consumes almost same power irrespective of load demand. Speed control of induction motor using variable frequency.
Limiting static and dynamic characteristics of an induction motor under frequency vector control 8 motor drive, which implement the assigned static values, was, at an early stage, a simple proportional law of voltage amplitude control of an induction motor s tator. The project is complete mathematical model of field orientation control foc induction motor is described and simulated in matlab for studies a 50 hp37kw, cage type induction motor has been considered. Comparison of different motor control principles using. The electric energy generated purchased by consumers for different needs.
Also the implementation of a hardware and software for speed control and. It gives the possibility to use it to show people about the control of an induction motor and the step towards electric cars is easily made. This principle is used in open loop volts per hertz control by frequency converter used in research. By controlling the output ac frequency, it is possible to drive the motor at different speed based on the requirements. It has been more than a century since the principle of the operation of induction motors was discovered. Ac variable speed drive for 3 phase induction motors. An3476, washing machine threephase acinduction direct. Variable frequency control vf of induction motor 1 youtube.
The rotor in induction ac motor products typically turns slower than the frequency that is supplied to it. Over the last four decades, power electronics technology has reduced vfd cost and size and has improved performance through advances in semiconductor switching devices, drive topologies. It is a 16 bit highperformance digital signal controller dsc. It is possible to combine a dahlander winding with a single. Different methods of speed control of threephase asynchronous motor. This may also apply to drives returned from a control techniques service. The other two observed control principles are based on vector control. Some problems encountered in the operation of this open loop drive are the following.