Electrical circuits and systems ii lab hbridge motor control objective. You will be able to switch the motor on and off, and control its direction. Do not close the switch until the faculty in charge. According to the cayleyhamilton theory, we know that. C motor can be controlled by varying either the field current o the armature current. Electrical machinel dc laboratory manual grietelectrical and.
This lab manual provides a platform to the students for understanding the. C motor of the same size, but radio frequency interference is a problem in some applications. In this method, speed control is possible from rated speed to low speeds. An introduction to brushless dc motor control digikey. Consider dc motor with no retarding torque or friction with constant voltage input, the steady state shaft speed. To study dc servo motor and plot its torque speed characteristics. Qnet dc motor control laboratory manual ee labs home. Experiment 5 dc motor speed control walter scott, jr. One of the popular methods of speed control of dc motor is using chopper. Dc motor with speed and current closed loops, driven by. The student does not see the hardware innards of the control system.
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. Chopper is a device that gives variable dc output from applied fixed dc input. Separately excited dc servo motor dc servo motor theory. Target motor theory dc motor with speed and current closed loops, driven by etpu on mcf523x, rev. We shall use the same dcmotor for which the parameters were calculated in the.
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. 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. There are two types of controls which were made in order to control the speed as well as the current. Control systems lab laboratory manual muffakham jah. This course consists of 11 interactive, online lessons that address ac and dc motor theory. Dc servo motors theory of dc servo motor electrical4u. Module 6 dc motors this module describes the types of dc motors and includes discussions of speed control, applications, and load characteristics. Set the gate current ig ig1 such that forward break over voltage is between 15 to 20 v, by varying r2 and v2. In turn the motion of the lever arm is controlled by the dc brush motor through gear. We shall use the same dc motor for which the parameters were calculated in the. To construct an hbridge using 6 enhancement mosfets. Learn motors and motor control circuits from university of colorado boulder.
Theory an ac servo motor is basically a two phase induction motor except for certain special design. Modeling of dc motor the most common device used as an actuator in mechanical control is the dc motor. The industrial controls training systems are designed to teach the theory and techniques of electric motor controllers. The systems offer unique controls training possibilities, are modular, and include insertable faults. 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. This lab allowed us to further investigate the characteristics of the various dc motor speed control schemes. Dc motor control forward, reverse, stop control by manual switch. A dc motor may be thought of as a series of electromagnets, radially spaced around a common shaft. 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. This method is used where a fixed voltage is available. In experiment3 and 4, the speed of the dcmotor was controlled by using an openloop voltage control. The term is often used exclusively to refer to linear timeinvariant systems lti. Motor speed control laboratory equipment and software required. 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.
Often we want to control the speed of a dc motor on demand. Module 5 dc generators this module describes the types of dc generators and their application in terms of voltage production and load characteristics. Let us first understand how it generates variable dc. Industrial controls training systems labvolt series by. To use this hbridge to control a motor using a qdrive and an inverted qdrive. C servomotors are series motors the shunt motors and the permanent magnet pm motor. In this lab experiment, the dc motor speed control was studied. In this activity we will design and implement a speed controller for a simple dc motor. 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. It simply chops fixed dc and generates variable dc.
Why the speed torque characteristics of dc servo motor has large negative slope. Et 438a automatic control systems technology 1 learning objectives 2 x after this presentation you will be able to. 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. The device is adaptable and configurable, based on its environment. Quanser has a dc motor control kit with a user manual that lists at least 67 experiments1. They allow students to select and mount control devices to form typical control circuits, and to troubleshoot them once a fault is inserted. In a brushed dc motor, the coils on the rotor utilize the motors magnetic eld to create torque on the axle.
Dc motors although ac motors are used in most of the cases, dc motors have many applications and used for multipurpose applications. Field control has some specific advantages over armature control and on the other hand. Electrical machines lab 1 griet eee 6 control the speed of a motor. We used the fact that the speed of a dc motor is directly proportional to the voltage applied across its windings. Brushed dc motor fundamentals microchip technology. Dc motor control position control theory universidade do minho masters in mechatronics engineering teacher. Speed control is achieved by adding an external resistance in the armature circuit. Simulate a dc position control system using matlab and. To determine frequency response of a second order system and evaluation of frequency domain specifications. A detailed information about the theory and tuning of pid controllers is given in 2. Simulate a dc position control system using matlab and obtain its step response.
Dc motor speed control using pid controllers nikunj a. The motors which are utilized as dc servo motors, generally have separate dc source for field winding and armature winding. 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 torque of dc servo motor decreases with increase in speed. See wikipedia for more information on electric motor, mathematical model, transfer function, and lti system theory. Using matlab for control systems cise 302 lab manual page 2 table of contents lab experiment 1.
This particular motor is of the permanent magnet type, with wire windings only on the armature. The transfer function is commonly used in the analysis of singleinput singleoutput electronic system, for instance. Objective identify the components of an ac motor and explain their function. The term project develops a speed control system for a direct current dc motor. Dc stepper motor control bipolar stepper motor control driver unipolar stepper motor control driver. Like diode, it is also a unidirectional device and forward conduction is from anode to cathode. The purpose of this experiment is to design and implement a closeloop speed control of a dcmotor drive. Permanent magnet dc motors are constructed out of a number of components. Direct current dc motors comprise one of the most common types of actuator designed into electro.
Conclusion in this lab experiment the dc motor speed. The speed of dc servo motor is controlled by varying the armature voltage. Dc motor principle a machine that converts dc power into mechanical energy is known as dc motor. Speed control of dc shunt motor and 3ph induction motor.
The ampl itude of the appl ied voltage is adjusted using the pwm technique. Lab manual for ee380 control lab department of electrical engineering, iit kanpur. Its operation is based on the principle that when a current carrying conductor is placed in a. Using your ems power supply, dc motor generator, dc metering and electrodynamometer modules, connect the circuit shown in figure 2. Another name for a coil or loop of wire inductors oppose the change in current. Control systems lab laboratory manual prepared by p. This polyphase motor operates with a lag rather than at the synchronous speed. Linear control systems laboratory manual systems engineering department revised september 2012. Dc motor speed control using chopper engineers garage. That method is to change the terminal voltage of the motor. Notice that the motor is wired for shunt field operation and is connected to the variable dc output of the power supply. Write the necessary magnetic polarities n for north and s for south on the armatures electromagnet pole tips, in order to. The most common ac motor is the highly versatile threephase induction motor.
Do not close the switch until the faculty in charge checks. Motor control suppose we wish to use a microprocessor to control a motor or to control the load attached to the motor. Lab manual for ee380 control lab indian institute of. In many different applications it is required to control speed of dc motor. The system for the speedcontrol of a dc motor is shown in fig 1. The feedback voltage signal can be obtained as depicted in appendix a. This intentional change of drive speed is known as speed control of a dc motor.
Write the transfer function for an armature controlled dc motor. The requirement of feeding back phasecurrent and speed of the motor will be studied in experiment4. Represent a mechanical load using a mathematical model. This course can also be taken for academic credit as ecea 5341, part of cu boulders master of science in electrical engineering degree. Introduction to dc motors 1 ee 448 lab experiment no. Pmdc motor modeling, identification, speed control 19. Speed control of a dc motor is either done manually by the operator or by means of an automatic control device. Write a transfer function for a dc motor that relates input voltage to shaft position. Speed control of dc shunt motor by armature and field control. What is the relation between torque and speed of dc servo motor. To power the motor, the 2n2222 npn bjt was employed as a switch.
The dc motor control experimental setup offers rich possibilities for learning the practical aspects of control systems design and implementation. We send in a pulse width modulated signal from port t3 which will drive the motor. It is mainly used in signal processing, communication theory, and control theory. Ee 448 laboratory experiment 4 introduction to dc motors 6 c.
The mc3phac is a highperformance monolithic intelligent motor controller designed specifically to meet the requirements for lowcost, variablespeed, 3phase ac motor control systems. The control can be archived either by controlling the field current or armature current. For example, the control of a rotary inverted pendulum requires a dc motor to drive the arm and the pendulum as shown in. This is different to speed regulation where the speed is trying to be maintained or. Linear systems theory the superposition principle holds. Power electronics lab manual vii sem ec set r1 and r2 to mid position and v1 and v2 to minimum. Before you close a switch, think of the consequences.
Induced voltage opposes applied voltage and limits current. 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. Apply a load to your dc motor by varying the dynamometer control knob until the scale marked on the dynamometer housing indicates 3. The exact design and materials vary with each type of motor and depend on the application and constraints, but several elements are common to most. The purpose of this experiment is to design and implement a closeloop speed control of a dc motor drive. Motor property 1 torque is proportional to current question.
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