Thus in this paper, ac chopper is implemented to control the speed of single phase induction motor by using 3 asymmetrical pwm method. The strategy used is a modified field oriented control to control. Various methods are 3 magnetizing flux oriented control used to control the. There are three method to control the speed of induction motor by the stator end. Speed control of three phase squirrel cage induction motor. Adding an external resistant into rotor side circuit. Controlling number of stator poles to control n s c. To improve speed control performance of the scalar control method, an encoder or speed tachometer is required to feedback the rotor angle or rotor speed signal and compensate the slip frequency. Jun 05, 2018 in this method, the slip power of induction motor is utilized for speed control. But the recent developments in speed control methods of the asynchronous motor have led.
However, asynchronous motors do not inherently have the capability of variable speed operation. The rotor speed of an induction motor is given by the equation shown below. Conventional methods for starting and speed control of singlephase induction motor need often quite expensive external electrical equipment. 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. The speed control of the induction motor can be done by the stator as well as rotor end. The main challenge is based on robustness and low cost. Ac induction motor speed control so what can we do to control the speed of an ac induction motor. This will cause excessive stator current and distortion of the stator flux wave. The performance of the motor speed control required in. The analysis has been done in terms of thd in their line current. Variable frequency speed control is a way to change the power frequency of motor stator and then change its synchronous speed. Changing the frequency of power supply is a economical speed regulation method, and it is also one of most popular ways of induction motor speed control.
Pdf speed control of induction motor using foc method. There are following methods of speed control of three phase induction motor. 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. Matlab simulation of the proposed speed control method for 1hp induction motor was done to verify the performance of the proposed method. In pole changing method, the number of pole pairs is changed by changing the field connection. Three phase induction motor induction is one of the widest spread motor due to its robustness, simple construction, no need for complex circuits for starting.
Rotorresistance speed control similar to rotorresistance starting, this method consists of varying the effective resistance in the rotor of a woundrotor induction motor to vary the speed. As vf method of speed control of induction motor is one of the mostly used methods for speed control. So for varying the speed of the 3 phase induction motor we have to vary the ns. A digital phase locked loop speed control of three phase. Speed control of induction motor using vector control. Microcontroller based control of three phase induction motor using pwm technique. Speed control of a three phase induction motor using pwm. Ahuja speed control of induction motor using vector or field oriented control international journal. Speed control of an induction motor by using indirect vector. Variants of this method include rotor power recovery systems using a second machine or an auxiliary solidstate rectifier and converter. Stator voltage is directly responsible for the rotating speed of the rotor.
The speed control of induction motor by considering to control on rotor side can subdivide into several speed controlling methods such as. In ac rotating machine speed of machine is govern by the equation n120fp. Speed control methods of the various speed control motors. The motor in which the provision of changing the number of poles is present, they are called pole changing motor or multi speed motor. The synchronous speed of an induction motor is given by the relation shown below. 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. The three phase induction motor or synchronous motor is used as ac drive. As we know the speed of induction motor, torque of induction motor, so, the speed of induction motor can be changed by changing synchronous speed or by changing the slip of induction motor and then parameter r2 and x2 are changed then torque remain constant and change in slip is affected in speed control.
Why is speed control in an induction motor, difficult. Speed control of three phase induction motor electrical. Pdf the applications of induction motors in various fields are increasing day by day because of the robustness and low maintenance cost. Methods of speed control of induction motor electrical. There are two ways of speed control for a dc motor, field control in this method, the eld current or current through stator is varied to control the speed of. The output control method of a speed control circuit can be divided roughly into two groups. Speed control of three phase squirrel cage induction motor using vf method is implemented. In this paper, various methods of speed control of induction asynchronous motors such as variable rotor resistance, variable stator voltage, constant voltshertz. 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. Therefore the efficiency of three phase induction motor is reduced by this method of speed control. Speed control methods of various types of speed control. Methods of speed control of induction motor electrical concepts. Speed control of single phase induction motor using ac.
An introduction there are various methods for the speed control of an induction motor. Speed control methods of dc motor shunt, series motors. Speed control of an induction motor by using indirect. Various induction motor speed control methods advantages. A theoretical background on scalar motor control principle. Digital phase locked loop dpll, induction motor, scalar strategy, speed drives and load appliance. The speed control method of our inverter units is divided into the two types. Matlab simulation for speed control of three phase. A three phase induction motor is basically a constant speed motor so its somewhat difficult to control its speed. Speed control of wound rotor induction motor using rotor. Pdf speed control of induction motors kamakhya basumatary. Jun 08, 2019 the motor in which the provision of changing the number of poles is present, they are called pole changing motor or multi speed motor.
Speed control of induction motor using pwm technique. A 3 phase induction motor can be used for different applications with various speed and load requirements. Jul 12, 2017 in ac rotating machine speed of machine is govern by the equation n120fp. Paper open access speed control of 3phase induction. Ims are used in many industry sectors as the leading element to convert electrical energy into mechanical one. 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. Since motor parameters are required to estimate speed and sometimes it is impractical to do noload and locked rotor tests, it is necessary to estimate motor parameters from motor label or by simple measurements. The pmdc consists of rotor or armature and a stator, which is a permanent magnet. 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.
The different methods of speed control of induction motor can be broadly classified in to scalar and vector control methods. Jan 09, 2017 this method is applicable to squirrel cage induction motor only. Different methods of speed control of threephase asynchronous. While researching on the internet i came across this one circuit that proposes a model that uses a microcontroller and a triac circuit and a. Pdf speed control of induction motor using pi and vf. This method is also called the tandem control and obsolete now.
Hi all, so im working on a project titled controlling the speed of a single phase induction motor. The synchronous speed and therefore, the speed of the motor can be controlled by varying the supply frequency. However, it is expensive and destroys the mechanical robustness of the induction motor. Variants of this method include rotor power recovery systems using a second machine or.
Speed control of an induction motor there is a various method of speed control of an induction motor. As we know that, air gap power p g is sum of mechanical power output and power loss in rotor winding assuming rotor winding to be shorted. The most popular type is the 3phase, squirrelcage ac induction motor. Speed control of induction motor using vf technique phase i a thesis submitted in partial fulfillment of the requirements for the degree of bachelor of. 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. Slip power in induction motor is the power dissipated in the rotor winding as ohmic loss. Steady state response of speed, current and torque in induction motor are also obtained using this scheme. Speed control of three phase induction motor electrical4u. Model is developed for spwm inverter fed induction motor using xilinx. Constant vf control of induction motor this is the most popular method for controlling the speed of an induction motor. Dec 17, 2019 when the speed control of three phase induction motor is done by adding resistance in rotor circuit, some part of power called, the slip power is lost as i 2 r losses.
Since the number of pole pairs can only be changed in steps like from 2 to 4, this scheme provides stepped speed control of induction motor. Another method of controlling the speed of induction motor drives is the stator voltage control. Dec 23, 2017 the speed control of induction motor by considering to control on rotor side can subdivide into several speed controlling methods such as. Speed control in three phase induction motor mcqs with. Pole changing method speed control of induction motor.
It is widely used in industry due to low cost and rugged construction. Speed control of single phase ac induction motor possible. Induction motor, mathematical model, voltperhertz controller, control, matlab simulink. Different method of speed control a three phase induction motor is mostly a constant speed motor so its fairly not easy to control its speed. New method for speed control of single phase induction motor. Low cost, low maintenance, simple construction, reliability and high efficiency.
In this method, the slip power of induction motor is utilized for speed control. In this paper, a new method of speed control for the single phase induction motor is introduced to overcome the disadvantages of the conventional methods. This enables to analyze and calculate the different parameters like voltage and current in different parts of the converter and performance of. Jun 30, 2015 a three phase induction motor is basically a constant speed motor. Induction motor drives starting braking speed control of. There are more than one methods to control the speed of induction motor, you can choose one depending on your resources, efficiency required etc. Induction motor is now called the racehorse of the industry 1. The ac speed control motor unit that uses the most popular singlephase capacitorrun induction motor, the small and highly efficient brushless dc motor unit. Pdf induction motors do not run at synchronous speed, they are generally fixed speed motors. The torque developed in this method is proportional to the square of the supply voltage. Speed control of a three phase induction motor using.
Ns can be varied by varying the factor on which it depends upon i. While control of the induction machine is considerably more complicated than its dc motor counterpart, with continual advancement of microelectronics, these control complexities have essentially been. An increasing number of applications in high performing electrical drive systems use nowadays, squirrelcage induction motors. Asynchronous motors are the most widely used electrical motors due to their reliability, low cost, ruggedness and robustness. Speed control in three phase induction motor mcqs with answers q1. This paper describes a simplified method for the speed control of a three phase ac drive using proportionalintegral controller. The implementation is done using a rectifier and an inverter, where the pwm triggering pulses were generated by using pic micro controller for switching the igbts of the inverter. The method which can be used for the speed control of induction motor from stator side is a. Speed control of induction motor by variable frequency control. A three phase induction motor is basically a constant speed motor. Speed control of three induction motor by vf method for batching motion system. The three phase induction motor has following advantages. Pdf speed control of three phase induction motor using.
A sliding mode control smc with integral surface is employed to control the speed of threephase induction motor in this paper. As we know that, air gap power p g is sum of mechanical power output and power. Open loop control of induction motor im is used in this inverter scheme. Other methods use ac chopper with pulse width modulation pwm technique to control the applied voltage of the motor 24. With several available speed control techniques, this paper presents a new. However, present trends and increase of speed control methods of an induction motor have improved the use of induction motors in electrical drives broadly. How to control the speed of an induction motor quora.
Currently the use of threephase induction machines has been increased tremendously in industrial applications due to several methods available to control the speed and torque of the motor. In this method, the magnitude of the main winding current and its angle are controlled to control the motor speed, as well as to increase the starting torque at all speed settings. Speed control methods of various types of speed control motors. You should also make a dc measurement of stator winding linetoline resistance using a dmm. Induction motor is a fixed speed motor and its fixed speed is nearly equal to the synchronous speed that is the speed of rotating magnetic field. The simulation results show that the step response of the model is very fast, steady and able to work in four quadrants, and robustness and. Speed control of induction motor detailed explanation. Record all nameplate information for the induction motor. This slip power loss can be recovered and supplied back to improve the overall. In this system, the scalar control vhz of induction motor experiments with and explores the use of speed control. A common method of controlling the stator voltage is by use phase angle control of thyristor circuit inserted in series between the supply and motor. As in above method, if the supply frequency is reduced keeping the rated supply voltage, the air gap flux will tend to saturate. Due to this reason, earlier dc motors were applied in most of the electrical drives.
Variable voltage variable frequency speed control of. The speed control of induction motor is done at the cost of decrease in efficiency and low electrical power factor. The user can quickly start evaluating the performance of the vhz system with this method. New method for speed control of single phase induction. The speed of induction motor can be varied by changing supply voltage. 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. Thus it is obvious that to change speed of machine any one parameter either frequency or no of poles are to be changed. Before discussing the methods to control the speed of three phase induction motor one should know the basic formulas of speed and torque of. In the simulation all realistic components of the drive system has been included. February 5, 2002 have been shown to be more than a match for dc drives in highperformance applications.
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