For example, the control of a rotary inverted pendulum requires a dc motor to drive the arm and the pendulum as shown in. Speed control of dc shunt motor by armature and field control. Direct current dc motors comprise one of the most common types of actuator designed into electro. Dc motor control forward, reverse, stop control by manual switch. Lab manual for ee380 control lab indian institute of.
The speed of dc servo motor is controlled by varying the armature voltage. The control can be archived either by controlling the field current or armature current. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Linear control systems laboratory manual systems engineering department revised september 2012. Lab manual for ee380 control lab department of electrical engineering, iit kanpur. In turn the motion of the lever arm is controlled by the dc brush motor through gear. What is the relation between torque and speed of dc servo motor. Control systems lab laboratory manual prepared by p. Dc motor control position control theory universidade do minho masters in mechatronics engineering teacher.
Dc motor speed control using chopper engineers garage. The purpose of this experiment is to design and implement a closeloop speed control of a dc motor drive. Its operation is based on the principle that when a current carrying conductor is placed in a. In this lab experiment, the dc motor speed control was studied. The transfer function is commonly used in the analysis of singleinput singleoutput electronic system, for instance. There are two types of controls which were made in order to control the speed as well as the current. Write the transfer function for an armature controlled dc motor. Speed control of dc shunt motor and 3ph induction motor. Industrial controls training systems labvolt series by. Electrical circuits and systems ii lab hbridge motor control objective.
Brushed dc motor theory and operation chris joyce, shane skikne, evan simpson, james nee january 8, 2014 abstract this study looked into the e ect of changing the material within the rotor of an electric motor. We shall use the same dc motor for which the parameters were calculated in the. Objective identify the components of an ac motor and explain their function. Module 6 dc motors this module describes the types of dc motors and includes discussions of speed control, applications, and load characteristics. Represent a mechanical load using a mathematical model. Separately excited dc servo motor dc servo motor theory. Do not close the switch until the faculty in charge checks. Using your ems power supply, dc motor generator, dc metering and electrodynamometer modules, connect the circuit shown in figure 2.
Motor control suppose we wish to use a microprocessor to control a motor or to control the load attached to the motor. It simply chops fixed dc and generates variable dc. To determine frequency response of a second order system and evaluation of frequency domain specifications. Speed control is achieved by adding an external resistance in the armature circuit.
It is mainly used in signal processing, communication theory, and control theory. A detailed information about the theory and tuning of pid controllers is given in 2. Module 5 dc generators this module describes the types of dc generators and their application in terms of voltage production and load characteristics. Qnet dc motor control laboratory manual ee labs home. The requirement of feeding back phasecurrent and speed of the motor will be studied in experiment4. Introduction to dc motors 1 ee 448 lab experiment no. This lab manual provides a platform to the students for understanding the. In many different applications it is required to control speed of dc motor. Like diode, it is also a unidirectional device and forward conduction is from anode to cathode. Why the speed torque characteristics of dc servo motor has large negative slope. C servomotors are series motors the shunt motors and the permanent magnet pm motor. C motor of the same size, but radio frequency interference is a problem in some applications. Ee 448 laboratory experiment 4 introduction to dc motors 6 c. Linear systems theory the superposition principle holds.
The motors which are utilized as dc servo motors, generally have separate dc source for field winding and armature winding. Apply a load to your dc motor by varying the dynamometer control knob until the scale marked on the dynamometer housing indicates 3. Modeling of dc motor the most common device used as an actuator in mechanical control is the dc motor. Permanent magnet dc motors are constructed out of a number of components. We send in a pulse width modulated signal from port t3 which will drive the motor.
Dc motor with speed and current closed loops, driven by. The mc3phac is a highperformance monolithic intelligent motor controller designed specifically to meet the requirements for lowcost, variablespeed, 3phase ac motor control systems. Electrical machines lab 1 griet eee 6 control the speed of a motor. In a brushed dc motor, the coils on the rotor utilize the motors magnetic eld to create torque on the axle. Field control has some specific advantages over armature control and on the other hand. The system for the speedcontrol of a dc motor is shown in fig 1. Learn motors and motor control circuits from university of colorado boulder.
Compoundwound dc motors basic drive circuits drive circuits are used in applications where a control ler of some kind is being used and speed control is required. Often we want to control the speed of a dc motor on demand. In particular, we will choose and tune the gains of a pi controller based on the effect of the gains on the systems closedloop poles while accounting for the inherent uncertainty in our model. The purpose of this experiment is to design and implement a closeloop speed control of a dcmotor drive. This method is used where a fixed voltage is available. Before you close a switch, think of the consequences. Conclusion in this lab experiment the dc motor speed. In experiment3 and 4, the speed of the dcmotor was controlled by using an openloop voltage control. Motor speed control laboratory equipment and software required.
Swinburnes test and speed control of dc shunt motor. In chopper controlled dc drive, the variable dc voltage which is fed to dc motor is controlled by chopping the constant or fixed input dc. Power electronics lab 2010 f f a silicon controlled rectifier scr is a four layer, three terminals and three junction device, which is basically a rectifier with a control terminal called gate. Simulate a dc position control system using matlab and. Et 438a automatic control systems technology 1 learning objectives 2 x after this presentation you will be able to. Another name for a coil or loop of wire inductors oppose the change in current.
This particular motor is of the permanent magnet type, with wire windings only on the armature. The term is often used exclusively to refer to linear timeinvariant systems lti. Chopper is a device that gives variable dc output from applied fixed dc input. Write a transfer function for a dc motor that relates input voltage to shaft position. Theory an ac servo motor is basically a two phase induction motor except for certain special design. See wikipedia for more information on electric motor, mathematical model, transfer function, and lti system theory. Power electronics lab manual vii sem ec set r1 and r2 to mid position and v1 and v2 to minimum.
The brushless dc bldc motor is becoming increasingly popular in sectors such as automotive particularly electric vehicles ev, hvac, white goods and industrial because it does away with the mechanical commutator used in traditional motors, replacing it with an electronic device that improves the reliability and durability of the unit. Write the necessary magnetic polarities n for north and s for south on the armatures electromagnet pole tips, in order to. Other members of the family are the direct current dc motor or generator, the induction motor or generator, and a number of derivatives of all these three. In this activity we will design and implement a speed controller for a simple dc motor. Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. Dc stepper motor control bipolar stepper motor control driver unipolar stepper motor control driver. This lab allowed us to further investigate the characteristics of the various dc motor speed control schemes. Simulate a dc position control system using matlab and obtain its step response.
That method is to change the terminal voltage of the motor. Induced voltage opposes applied voltage and limits current. You will be able to switch the motor on and off, and control its direction. This polyphase motor operates with a lag rather than at the synchronous speed. Dc motor speed control using pid controllers nikunj a. Brushed dc motor fundamentals microchip technology. Dc servo motors theory of dc servo motor electrical4u. The most common ac motor is the highly versatile threephase induction motor. To construct an hbridge using 6 enhancement mosfets. An introduction to brushless dc motor control digikey.
Compoundwound dc motors basic drive circuits drive circuits are used in applications where a controller of some kind is being used and speed control is required. The feedback voltage signal can be obtained as depicted in appendix a. Let us first understand how it generates variable dc. A dc motor may be thought of as a series of electromagnets, radially spaced around a common shaft. The ampl itude of the appl ied voltage is adjusted using the pwm technique. Speed control of a dc motor is either done manually by the operator or by means of an automatic control device. According to the cayleyhamilton theory, we know that. Notice that the motor is wired for shunt field operation and is connected to the variable dc output of the power supply. Pmdc motor modeling, identification, speed control 19. Control systems lab laboratory manual muffakham jah. The torque of dc servo motor decreases with increase in speed.
The industrial controls training systems are designed to teach the theory and techniques of electric motor controllers. The dc motor control experimental setup offers rich possibilities for learning the practical aspects of control systems design and implementation. Do not close the switch until the faculty in charge. Experiment 5 dc motor speed control walter scott, jr. Overview the acdc motor theory course was specifically developed for electricians and electronic technicians as well as for the multicraft training needs of process and manufacturing facilities. Electrical machines for mechatronics laboratory 7 4 speed control of series dc motors unlike with the shunt dc motor, there is only one efficient way to change the speed a series dc motor. Target motor theory dc motor with speed and current closed loops, driven by etpu on mcf523x, rev.
Using matlab for control systems cise 302 lab manual page 2 table of contents lab experiment 1. To study dc servo motor and plot its torque speed characteristics. One of the popular methods of speed control of dc motor is using chopper. Consider dc motor with no retarding torque or friction with constant voltage input, the steady state shaft speed. Electrical machinel dc laboratory manual grietelectrical and. To use this hbridge to control a motor using a qdrive and an inverted qdrive. The device is adaptable and configurable, based on its environment. To power the motor, the 2n2222 npn bjt was employed as a switch.
They allow students to select and mount control devices to form typical control circuits, and to troubleshoot them once a fault is inserted. The systems offer unique controls training possibilities, are modular, and include insertable faults. Quanser has a dc motor control kit with a user manual that lists at least 67 experiments1. Set the gate current ig ig1 such that forward break over voltage is between 15 to 20 v, by varying r2 and v2. We used the fact that the speed of a dc motor is directly proportional to the voltage applied across its windings. We shall use the same dcmotor for which the parameters were calculated in the. The student does not see the hardware innards of the control system.
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