báo cáo chuyên đề tiếng anh chuyên ngành

Concept A synchronous electric motor is an AC electric motor in which, at steady state, the rotation of the shaft 1s synchronized with the frequency of the supply current; the rotation p

Trang 1

KHOA DIEU KHIEN & TU DONG HOA

£

ĐúI HỌC ĐIỆT LỰC

ELECTRIC POWER UNIYERSITY

BAO CAO CHUYEN DE

NGÀNH: Công nghệ kỹ thuật điều khiến và tự động hóa

CHUYÊN NGÀNH: Tự động hóa và điều khiển thiết bị công nghiệp

HỌC PHẢN: Tiếng Anh chuyên ngành

Giảng viên hướng dẫn: Nguyễn Ngọc Khoát

Nhóm sinh viên/ sinh viên thực hiện — Mã sinh viên:

Nhóm 3 : Nguyễn Khánh Hùng Khôi - 19810430152 Trần Lâm Hải Long - 19810430211

Lê Hoàng Minh - 19810430138 Trần Anh Thắng - 19810430273

Lop : DI4ATDH&DKTBCN3

HA NOL, 2/2022

Trang 2

Chuong 1: Introduction to power sources (DC and AC power) 1.1 Definition

1.2 How to use power sources in an electrical circuit? 1.3 How to produce power sources?

1.4 How internal resistance of power sources affects operation of an electrical circuit? 1.5 Ohm’s law of an electrical circuit regarding power sources

1.6 Applications of power sources

Chuong 2: Synchronous AC motors 2.1 Concept 2.2 Classification 2.3 Structure 2.4 Working principle 2.5 Speed control methods for the synchronous AC motors 2.6 Applications Chwong 3: Introduction to PLC Mitsubishi 3.1 What is PLC?

3.2 What are differences between PLC and traditional relay circuits? 3.3 Select and present briefly a PLC of Mitsubishi

Trang 3

LOI CAM ON

Trong thời gian làm báo cáo chuyên dé, em đã nhận được nhiéu sự giúp đỡ,

đóng góp ý kiến và chỉ bảo nhiệt tình của thầy cô và bạn bè Em xin gửi lời cảm ơn

chân thành đến thầy Nguyễn Ngọc Khoát, giảng vên người đã tận tình hướng dẫn, chỉ bảo em trong suốt quá trình làm chuyên dé điều khiến số Em cũng xin chân

thành cảm ơn thây cô giáo trường Đại học Điện Lực nói chung, các thây cô bộ môn

điện tử công suất nói riêng đã hướng dẫn cho em kiến thức về cách trình bày và nội dung đồ án, giúp em có được cơ sở lý thuyêt và tạo điều kiện gúp đỡ em trong quá

trình làm báo cáo chuyên đề Tuy vậy, với kinh nghiệm và kiến thức còn thiếu sót

nên bản báo cáo chuyên dé của em còn chưa được hoàn thiện lắm, em mong được sử

chỉ dẫn chân thành của các thây cô

Cuối cùng, em xin chân thành cảm ơn thầy cô và bạn bè đã luôn tạo đều kiện,

Trang 4

Chuong 1: Introduction to power sources (DC and AC power) 1.1 Definition

Alternating current power is the standard electricity that comes out of power outlets and is defined as a flow of charge that exhibits a periodic change in direction

AC's current flow changes between positive and negative because of electrons- electrical currents come from the flow of these electrons, which can move in either a positive (upward) or negative (downward) direction This is known as the sinusoidal AC wave, and this wave is caused when alternators at power plants create AC power Alternators create AC power by spinning a wire loop inside a magnetic field Waves of

alternating current are made when the wire moves into areas of different magnetic

polarity—for example, the current changes direction when the wire spins from one of the magnetic field's poles to the other This wave-like motion means that AC power can travel farther than DC power, a huge advantage when it comes to delivering power to consumers via power outlets

Direct current (DC) power, as you may guess from the name, is a linear electrical current—it moves in a straight line

Direct current can come from multiple sources, including batteries, solar cells, fuel

cells, and some modified alternators DC power can also be "made" from AC power by

using a rectifier that converts AC to DC DC power is far more consistent in terms of

voltage delivery, meaning that most electronics rely on it and use DC power sources such as batteries Electronic devices can also convert AC power from outlets to DC

power by using a rectifier, often built into a device's power supply A transformer will

also be used to raise or lower the voltage to a level appropriate for the device in

question

1.2 How to use power sources in an electrical circuit? Power sources do two important things:

+) They supply energy to the circuit in the form of an electric potential difference +) They provide a source and sink for electrons in a circuit

As a simple analogy, you can think of a power source as the heart of a circuit; just as our heart circulates blood to enable our bodies to function, electric power

sources pump or circulate electrons, enabling electric circuits to function

You can think of a power source as a ‘pump’ that keeps electrons flowing in a circuit Without a power source, a circuit will quickly lose energy due to the electrical resistance of its components

Power sources are known as active components because they supply energy to the electric circuit

Power sources supply electric power by pushing and pulling the electrons in a circuit Without a power source, circuits quickly stop working due to energy losses Think about the battery in your phone or tablet When the battery runs out of charge, it stops functioning as a power source and your device quickly shuts down Power sources are really important because every circuit and component relies on them in order to function We start our discussion on circuits with power sources because they are the beating heart of every circuit

Trang 5

1.3 How to produce power sources?

The three major categories of energy for electricity generation are fossil fuels (coal, natural gas, and petroleum), nuclear energy, and renewable energy sources Most electricity 1s generated with steam turbines using fossil fuels, nuclear, biomass, geothermal, and solar thermal energy Other major electricity generation technologies

include gas turbines, hydro turbines, wind turbines, and solar photovoltaics

1.4 How internal resistance of power sources affects operation of an electrical circuit?

In the case of circuits, the equivalent of ‘friction’ 1s something called electric

resistance Every electric component has some amount of electric resistance Even conductors like wires have some resistance to the movement of electrons That’s because conductors don’t conduct electricity perfectly, and they lose some energy as heat as a result The energy loss quickly causes all the electrons in the circuit to stop

moving when disconnected from the power source, even if the circuit remains closed

In AC circuits, resistance is called impedance That’s because the total ‘resistance’ to current flow in an AC circuit doesn’t just come from electric resistance Capacitance and inductance also contribute to the overall opposition to current flow in

an AC circuit The total opposition to current flow, caused by resistance, capacitance

and inductance is called impedance

1.5 Ohm’s law of an electrical circuit regarding power sources

The current through a resistor is in direct proportion to the voltage across the resistor's terminals This relationship is represented by Ohm's law:

Where I is the current through the conductor in units of amperes, V is the

potential difference measured across the conductor in units of volts, and R is the

resistance of the conductor in units of ohms (symbol: Q)

1.6 Applications of power sources For DC

e DC current limited by a resistor causes light-emitting diodes (LEDs) to produce

light

e Mechanical and electronic switches can deliver large amounts of DC control current to motors, solenoids, and resistive heaters

e DC currents and voltages establish the electrical conditions that allow transistors to amplify AC signals

For AC

e Cell phones Flashlights\

The Lilypad-based D&D Dice Gauntlet

Trang 6

Chuong 2: Synchronous AC motors

2.1 Concept

A synchronous electric motor is an AC electric motor in which, at steady state,

the rotation of the shaft 1s synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles Synchronous motors contain multiphase AC electromagnets on the stator of the motor that create a magnetic field which rotates in time with the oscillations of the line current The rotor with permanent magnets or electromagnets turns in step with the stator field at the same rate and as a result, provides the second synchronized rotating magnet field of

any AC motor A synchronous motor is termed doubly fed if it is supplied with

independently excited multiphase AC electromagnets on both the rotor and stator What are Synchronous Motors? St, hy, ‹5 3 DC Supply Synchronous Motor _ @® Electrical 4 U Qed

The synchronous motor and the induction motor are the most widely used types of AC motors The difference between the two types is that the synchronous motor rotates at a rate locked to the line frequency since it does not rely on current induction to produce the rotor's magnetic field By contrast, the induction motor requires slip: the rotor must rotate slightly slower than the AC alternations in order to induce current in

the rotor winding Small synchronous motors are used in timing applications such as in

synchronous clocks, timers in appliances, tape recorders and precision

servomechanisms in which the motor must operate at a precise speed; speed accuracy is that of the power line frequency, which is carefully controlled in large

interconnected grid systems

Synchronous motors are available in self-excited sub-fractional horsepower sizes to high power industrial sizes In the fractional horsepower range, most

synchronous motors are used where precise constant speed is required These

Trang 7

machines are commonly used in analog electric clocks, timers and other devices where correct time is required In higher power industrial sizes, the synchronous motor provides two important functions First, it is a highly efficient means of converting AC

energy to work Second, it can operate at leading or unity power factor and thereby

provide power-factor correction

2.2 Classification

Synchronous motors are classified according to their speed They are either high-speed or low-speed machines Those operating over 500 RPM are designated high-speed motors

Beside speed, synchronous motors can be classified by type There are different

types of synchronous motors based on the way they are excited

e Non Excited Synchronous Motors e Current Excited Synchronous Motors Non Excited Synchronous Motor

The rotor is made up of steel The external magnetic field magnetizes the rotor, and it rotates in synchronism with it The rotor is generally made of high retentivity steel such as cobalt steel

Non-excited motors are available in three designs:

+) Hysteresis Motor

Hysteresis motors are single phase motors in which the rotor is made up of ferromagnetic material The rotors are cylindrical in shape and have high hysteresis

loss property They are generally made up of chrome, cobalt steel or alnico The stator

is fed by single phase AC supply The stator has two windings: 1 main windings and

2 auxiliary windings

The combination of the two produces a revolving magnetic field from a single phase supply They are self-starting and do not need additional windings When single phase AC supply is given, a rotating magnetic field is produced This rotating

magnetic field induces eddy currents in the rotor The rotor starts to move initially with a slip When the rotor reaches synchronous speed, the stator pulls the rotor into

synchronism So initially the motor starts as an induction motor and later runs as a

synchronous motor

+) Reluctance Motor

The reluctance motor is based on the principle that an unrestrained piece of iron will move to complete a magnetic flux path where the reluctance is minimum The

stator has the main winding and the auxiliary windings just like the hysteresis motor

Trang 8

poles The reluctance becomes minimum when the rotor is aligned with the magnetic

field of the stator

When single phase AC supply is given, the motor starts as an induction motor

The rotor tries to align itself with the magnetic field of the stator and experiences

reluctance torque But due to inertia, it exceeds the position and again tries to align itself during the next revolution In this manner, it starts to rotate Once it reaches 75%

of synchronous speed, the auxiliary windings are cut off When the speed reaches synchronous speed, the reluctance torque pulls it into synchronism The motor remains in synchronism due to synchronous reluctance torque

+) Permanent Magnet Synchronous Motors

The rotor is made up of permanent magnets They create a constant magnetic flux The rotor locks in synchronism when the speed is near synchronous speed They are not self-starting and need electronically controlled variable frequency stator drive

Direct Current Excited Motor

Direct current excited synchronous motors need a DC supply to the rotor to generate rotor magnetic field A direct current excited motor has both stator windings

as well as rotor windings They can either have cylindrical rotors or salient pole rotors

They are not self-starting and need damper windings to start Initially, they start as an induction motor and later attains synchronous speed

Trang 9

2.3 Structure

The construction of synchronous motor is similar to that of a synchronous alternator Most of the synchronous motors construction uses the stationary armature

Trang 10

3 Phase supply St, to, DC Supply Synchronous Motor 2.4 Working principle

The principle of operation of a synchronous motor can be understood by

considering the stator windings to be connected to a three-phase alternating-current

supply The effect of the stator current is to establish a magnetic field rotating at

120 f/p revolutions per minute for a frequency of fhertz and for p poles A direct

current in a p-pole field winding on the rotor will also produce a magnetic field rotating at rotor speed If the rotor speed 1s made equal to that of the stator field and

there is no load torque, these two magnetic fields will tend to align with each other As mechanical load is applied, the rotor slips back a number of degrees with respect to the rotating field of the stator, developing torque and continuing to be drawn around by

this rotating field The angle between the fields increases as load torque 1s increased

The maximum available torque is achieved when the angle by which the rotor field

lags the stator field is 90° Application of more load torque will stall the motor

10

Trang 11

TOPE LIOF

One advantage of the synchronous motor is that the magnetic field of the

machine can be produced by the direct current in the field winding, so that the stator windings need to provide only a power component of current in phase with the applied

stator voltage—.e., the motor can operate at unity power factor This condition minimizes the losses and heating in the stator windings

The power factor of the stator electrical input can be directly controlled by adjustment of the field current If the field current is increased beyond

the value required to provide the magnetic field, the stator current changes to include a

component to compensate for this overmagnetization The result will be a total stator

current that leads the stator voltage in phase, thus providing to the power system

reactive volt-amperes needed to magnetize other apparatuses connected to the system

such as transformers and induction motors Operation of a large synchronous motor at

such a leading power factor may be an effective way of improving the overall power factor of the electrical loads in a manufacturing plant to avoid additional electric supply rates that may otherwise be charged for low power-factor loads

2.5 Speed control methods for the synchronous AC motors

Synchronous motors are constant speed motors They run at the synchronous speed of the supply They are generally used for constant speed operation under no load conditions such as to improve the power factor Synchronous motors have fewer

losses than induction motors at a given rating

The speed of a synchronous motor is given by

_ 120ƒ Pp

N

Trang 12

do not use that method However, with the invention of solid-state devices, the

frequency of the current fed to the synchronous motor can be varied We can control the speed of the synchronous motor by changing the frequency of the supply to the

motor

We can use a combination of rectifiers and inverters to control the speed of

synchronous motors They can be used in two ways:

e Inverter Fed Open Loop Synchronous Motor Drive: In this method, the

synchronous motor is supplied by variable frequency inverter in an open loop By open loop, we mean that there is no feedback given to the supply The inverter has no information about the current position of the rotor This method is preferable when highly accurate speed control is not required Supply from the mains is fed into the rectifier inverter set where desired frequency can be attained Depending on the frequency, the synchronous speed of the motor can be varied

e Self Synchronous (Closed — Loop) Operation: We use self-synchronous (closed-loop) operation when highly accurate speed control is required In this method, the inverter output frequency is determined by the speed of the rotor

The speed of the rotor is fed back to the differentiator The difference between

the preset speed and the actual speed is fed to the rectifier Accordingly, the inverter changes the frequency and adjusts the speed of the motor We get more accurate control over the motor speed with the closed loop operation For example, if speed gets reduced (due to increase in load), the stator supply

frequency gets reduced so that the rotor stays in synchronism with the stator magnetic field No spontaneous oscillation or hunting occurs in this method

2.6 Applications

Synchronous motors can be used toraise overall the power factor of the installation When a synchronous motor is run without load with over-excitation for improving the power factor of an installation, it is called as the synchronous capacitor or synchronous condenser

Synchronous motors are also used to regulate the voltage at the end of transmission lines

Because of the higher efficiency possible with synchronous motors, they can be used for loads where constant speed is required

Synchronous motors can be built for speeds as low as 120 RPM They are well-

suited for direct connection to reciprocating compressors

12

Trang 13

Chuong 3: Introduction to PLC Mitsubishi

3.1 What is PLC? 3.1.1 Definition

Programmable Logic Controller, PLC, or Programmable Controller is a digital

computer used for automation of industrial processes, such as control of machinery on factory assembly lines Unlike general-purpose computers, the PLC is designed for multiple inputs and outputs arrangements, extended temperature ranges, immunity to

electrical noise, and resistance to vibration and impact Programs to control machine

operation are typically stored in battery-backed or non-volatile memory A PLC is an example of a real time system since output results must be produced in response to

input conditions within a bounded time, otherwise unintended operation will result

3.1.2 Features

The PLC engineering environment has undergone outstanding innovation and growth We are now entering the era of MELSEC Engineering Software! MELSEC's

many different software products provide solutions for TCO reduction in an engineering environment, using methods such as improving design efficiency,

shortening debugging time, reducing downtime, and data holding

e iQ Works: This integrated software suite includes various programming software for PLC, motion control, and GOT

e GX Works3: The next-generation engineering software contributes to development cost reduction with its intuitive programming environments e GX Works2: This sequence programming software uses the program assets

cultivated by GX Developer to pursue a more comfortable level of operability e PX Developer: This software enables easy loop control programming with

simple drag & drop operations

e MX Component: This Active X controller library enables easy communication

processing from the PC and tablet to PLC, without the need for communication protocol awareness

e MX Sheet: Software which uses Excel to easily monitor, log, collect alarm information and change configurations for the PLC

e iQ AppPortal: MELSOFT iQ AppPortal 1s software used to manage assets integrated for each purpose, such as project files of MELSOFT products or design drawings/documents

e FieldDeviceConfigurator: A Field Device managing/setting software which is MITSUBISHI ELECTRIC products and it is corresponding to FDT/DTM open specification And it can be used as a FDT frame application to set the

Trang 14

e Other engineering softwares: Lineup of various software to support the MELSEC Series engineering environment

e Peripheral equipment support tools: Lineup of various free tools that further simplify development of the MELSEC Series

e e-Manual: e-Manual for the Mitsubishi FA product users for quick search of

necessary information 3.1.3 Applications

Automotive: Improve productivity and realize flexibility in different automotive

assembly lines with high-accuracy motion control, including linear/circular

interpolation and electric cam profile

Ta

Automated warehouse: Realize advanced logistics coordination and eliminate errors in repetitive processes Servo-based high-speed material handling and highly accurate

positioning 1m sử Tm=c and reduce energy consumption

` os " : AI Xã -

Í

Food and beverage, CPG: Realize improvements in various packaging applications

such as high-speed filling, which requires a highly accurate, continuous feed rate and recision

Semiconductor: Reduce maintenance costs using the high-durability MELSEC Series Having the compact, robust design desired for semiconductor manufacturing,

MELSEC products solve the small footprint, high-performance requirements

14

Trang 15

-

` `

Pick-and-place: Achieve highly precise, fast and accurate placement of components in various sizes and shapes such as that required by SMT pick-and-place equipment, further improving productivity

Flat panel display (FPD): Improve the large data bandwidth and high-performance

requirements common in FPD manufacturing processes using MELSEC's integrated

control platform The integrated controller and network solution offer increased

flexibility and enhanced performance >

Renewable energy Easily integrate renewable energy plant management utilizing plant-wide data acquisition and extensive real-time control, thereby reducing overall investment and maintenance costs

3.1.4 What 1s timing diagram

Timer accumulative timers of four types: low-speed timer, high-speed timer, low- speed integrator, and high-speed integrator

The PLC takes a certain amount of time to react to changes The total response time of

the PLC 1s a fact that has to be considered while selecting a PLC for some application

where speed is a concern

Hence, Input Response Time + Program Execution Time + Output Response Time = Total Response Time Having understood the concept behind the response

15

Trang 16

time, let us see what happens in a typical PLC Applications The PLC can only see an input turn ON/OFF when its looking In other words, it only looks at its inputs during the check input status part of the scan

3.1.5 Advantages and disadvantages of PLCs

Advantages:

e Small physical size & shorter project time

Disadvantages:

e Fixed circuit operation

e PLCs manufacturers offer only closed loop architecture

e PLCs are propitiatory, which means software and parts one manufacturer can’t be easily used in combination with part of another manufacturer

e Number of optional modules must be added to maximize flexibility and performance Cost effective for controlling complex system Reliability Less and simple wiring Faster response Remote control capability More flexibility

Ease of maintenance / troubleshooting

3.2 What are differences between PLC and traditional relay circuits? PROGRAMMABLE LOGIC CONTROLLERS (PLC) DISTRIBUTED CONTROL SYSTEMS (DCS) Speed of response 10 capacity Logic development Redundancy Architecture

PLCs are can respond to a

change within one-tenth of a

second

A PLC 1s capable of handling

few hundred IOs When it comes to analog IOs, it can handle tens of them

PLC can programmed be programmed based on our

application

PLCs can be made redundant with additional hardwares which makes them expensive than DCS

PLCs have a simple and flexible architecture A PLC system consists of controllers, IO modules, HMIs and an

Nguyễn Khánh Hùng Khôi 19810430152

DCS are slower than PLCs

Typical respond time of DCS is

30ms

A DCS can handle thousands of IOs It can handle hundreds or

even thousands of analogs IOs

and PID functions

DCS comes with built-in control functions that need to be

configured based on the application

Redundancy is a default feature

of distributed control systems DCS systems are less flexible

They come with controllers, IO

systems, database servers,

engineering and operating