1. The document discusses various methods of AC to AC power processing including on-off control, phase-angle control, and cycloconverters.
2. On-off control uses thyristors as switches to connect the load for a number of input cycles then disconnect it for a number of cycles to vary the output. Phase-angle control fires thyristors at a variable point in the AC cycle to control output.
3. Cycloconverters directly convert AC source frequency to meet load frequency requirements without converting to DC intermediate. They are used for applications requiring different frequencies than the source like 400Hz aircraft ground power.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
A silicon controlled rectifier or semiconductor controlled rectifier is a four-layer solid-state current-controlling device. The principle of four-layer p–n–p–n switching was developed by Moll, Tanenbaum, Goldey and Holonyak of Bell Laboratories in 1956.
For more notes on basics of electronics will see on https://www.slideshare.net/ATHEENAMILAGIPANDIAN/edit_my_uploads
Power Electronics - Phase Controlled Converters.pptxPoornima D
A detailed analysis of the Controlled Converters with SCR. it contains a single-phase Fully controlled- Half Wave and Full Wave Rectifier with R, RL and RLC loads., Three Phase Fully controlled- Half Wave and Full Wave Rectifier with R, RL and RLC loads. Dual Converters. It also explains the effect of source inductance on the performance of converters
There are numerous systems in use today that convert the fixed
voltage and fixed frequency a.c. supply into variable voltage or /and variable frequency supply using power semiconductor devices. The simplest forms of ac-to-ac converters are the a.c. voltage controllers that
convert fixed voltage fixed frequency into variable voltage fixed frequency. These voltage controllers are also called a.c. choppers or a.c. voltage regulators. Some of the applications are motor drive systems; electric furnaces heat control, light dimmers, HVAC systems, welding and other industrial applications. This chapter discusses the single phase and three-phase a.c. voltage controller (a.c. choppers) and their performance with resistive and resistive-inductive loads.
The ac-to-ac power converters available in industry today do not actually convert power directly from a.c. power of one frequency to a.c. power of another frequency. Instead, these converters first convert
electrical power to d.c. using a rectifier, and then convert power back into a.c. using an inverter.These are called two-stage converters. However,
a cycloconverter is a frequency changer that converts an a.c. supply of fixed input frequency directly to an a.c. output of another frequency.
Cycloconverters not only eliminate the problem of having multiple systems to perform a single function, they also limit the flow of power to a single switch at any one period in time. Therefore, there is no bus link,
d.c. or otherwise, included in a cycloconverter topology between power input and power output.
Part of Lecture series on EE321N, Power Electronics-I delivered by me during Fifth Semester of B.Tech. Electrical Engg., 2012
Z H College of Engg. & Technology, Aligarh Muslim University, Aligarh
Please comment and feel free to ask anything related. Thanks!
A silicon controlled rectifier or semiconductor controlled rectifier is a four-layer solid-state current-controlling device. The principle of four-layer p–n–p–n switching was developed by Moll, Tanenbaum, Goldey and Holonyak of Bell Laboratories in 1956.
For more notes on basics of electronics will see on https://www.slideshare.net/ATHEENAMILAGIPANDIAN/edit_my_uploads
Power Electronics - Phase Controlled Converters.pptxPoornima D
A detailed analysis of the Controlled Converters with SCR. it contains a single-phase Fully controlled- Half Wave and Full Wave Rectifier with R, RL and RLC loads., Three Phase Fully controlled- Half Wave and Full Wave Rectifier with R, RL and RLC loads. Dual Converters. It also explains the effect of source inductance on the performance of converters
There are numerous systems in use today that convert the fixed
voltage and fixed frequency a.c. supply into variable voltage or /and variable frequency supply using power semiconductor devices. The simplest forms of ac-to-ac converters are the a.c. voltage controllers that
convert fixed voltage fixed frequency into variable voltage fixed frequency. These voltage controllers are also called a.c. choppers or a.c. voltage regulators. Some of the applications are motor drive systems; electric furnaces heat control, light dimmers, HVAC systems, welding and other industrial applications. This chapter discusses the single phase and three-phase a.c. voltage controller (a.c. choppers) and their performance with resistive and resistive-inductive loads.
The ac-to-ac power converters available in industry today do not actually convert power directly from a.c. power of one frequency to a.c. power of another frequency. Instead, these converters first convert
electrical power to d.c. using a rectifier, and then convert power back into a.c. using an inverter.These are called two-stage converters. However,
a cycloconverter is a frequency changer that converts an a.c. supply of fixed input frequency directly to an a.c. output of another frequency.
Cycloconverters not only eliminate the problem of having multiple systems to perform a single function, they also limit the flow of power to a single switch at any one period in time. Therefore, there is no bus link,
d.c. or otherwise, included in a cycloconverter topology between power input and power output.
A survey on Single Phase to Three Phase Cyclo-Converter fed Induction MotorIJSRD
In various application of electrical energy especially in in industrial areas there are two type of current, Direct Current and Alternating Current are used. Generally fixed voltage, constant frequency Single-Phase or Three-Phase AC is easily available, yet for different applications various types of magnitudes and/or frequencies are essential. This paper presents a survey on 1-̉ۢ to 3-̉ۢ cycloconverter technique using thyristor with 3-̉ۢ induction motor along load frequency analysis. The cycloconverter is inspected in its utmost straight forward form without further output filters or elaborate control technique.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
1. AC to AC Power processing
AC Voltage Controllers
2. AC Voltage Controllers:
ON-OFF control.
Phase-angle control.
Single phase controllers with R and RL loads.
Single phase cyclo-converter
Topics
AC to Ac Power processing
5. A zero-crossing detector is used to generate a sync pulse as reference related to the AC voltage phase
angle often used in power control circuits.
Figure shows the relationship of a zero-crossing pulse to a sine wave. The pulse occurs at 0, 180, and
360 degrees.
Intro. zero-crossing pulse
7. AC to Ac Power processing
Technical Information- Silicon Carbide Heater Control
Characteristics of Silicon Carbide Heaters
Silicon carbide heaters are normally used in high temperature
furnaces and have a resistance that varies with time and also
with temperature.
Thyristor Firing Mode with Silicon Carbide Heaters
9. Non-Inverting Zero Crossing Detector
Inverting Zero Crossing DetectorInput and Output Waveforms of Schmitt Trigger
Zero Crossing Detector using OP-Am
10. The Schmitt trigger circuit has definite predefined upper
and lower input voltage levels that trigger the output to
switch from one saturation level to the other
Schmitt Trigger Circuit for AC
The input voltage, Vin, is applied to the inverting input
terminal .
voltage is connected as feedback to the non-inverting
input terminal, through a potential divider network.
The input voltage Vin triggers the output voltage Vout to
change from one saturation level to the other, every
time when the input voltage exceeds a certain
predefined voltage levels.
These voltage levels are called as upper threshold
voltage (VUT) and lower threshold voltage (VLT).
Schmitt trigger
13. AC-AC Converter: AC Voltage Controller
• ac–ac converters accepts electric power from one AC system and
converts it to another AC system with waveforms of different:
amplitude, frequency, and phase.
• The power may be single-phase or three-phase types depending on
their power ratings.
AC to Ac Power processing
14. Railroad trolleyBicycle
What is common for both of these machines to move ?
Power Electronic
AC-AC convertor
Power Stock
AC to Ac Power processing
Stokes are used to push the load slow/fast
16. Introduction
AC to Ac Power processing
If a thyristor is connected between ac supply and load, the power flow can be controlled by
varying the rms value of ac voltage applied to the load.
AC voltage controller
Types of control : 1) On-Off control
2) Phase-angle control
Common application : industrial heating, on-load transformer tap changing, light control,
induction motor speed control etc.
Fundamental output frequency remain the same as input
frequency.
17. 17
Principle of On-Off control
Voltage
across
thyristors2 2
1 1
T
T
AC to Ac Power processing
Voltages
across Load
On-Off Control (Integral Cycle
Control)
The load power can be controlled by
connecting the source to the load
for few complete cycles then
disconnecting the source from the
load for another number of cycles,
and repeating the switching cycle.
-Duty cycle, k = n/(m +n)
Average power to the load can be
varied from 0% through 100%
19. • In On-Off control technique Thyristors are used as switches to connect the load circuit to
the ac supply (source) for a few cycles of the input ac supply and then to disconnect it for
few input cycles.
• The Thyristors thus act as a high speed contactor (or high speed ac ON-OFF switch).
On-Off CONTROL
20. AC ON-OFF Control OR Burst Control
• For 25% of the power be present at the load, the thyristors should be completely ON for one full cycle and OFF
for three complete cycles.
• To provide 50% power to the load, the thyristor should be ON/OFF for every alternate cycle.
• To provide 75% power to the load, the thyristor should be on three cycle and OFF for one cycle
• To provide 100% power to the load, the thyristor should be ON for all input cycles.
AC Supply
21. PRINCIPLE OF ON-OFF CONTROL TECHNIQUE (INTEGRAL CYCLE
CONTROL)
Reference to the circuit shown below. The thyristor switches T1 and T2
are turned on by applying appropriate gate trigger pulses to connect the
input ac supply to the load for ‘n’ number of input cycles during the time
interval ON t .
The thyristor switches T1 and T2 are turned off by blocking the gate
trigger pulses for ‘m’ number of input cycles during the time interval
tOFF. The ac controller ON time tON usually consists of an integral number
of input cycles.
Waveforms
n = Two input cycles. Thyristors are turned ON during tON for two input cycles4
m =One input cycle. Thyristors are turned OFF during tOFF for one input cycle.
22. vs =Vm sinωt = 2VS sinωt
For a sine wave input supply voltage
V =RMS value of input ac supply = = RMS phase supply voltage
Analysis
Input ac supply is connected to load for ‘n’ number of cycles and
disconnected for ‘m’ number of input cycles
then tOFF = n×T tON = m×T
RMS Output (Load) Voltage
RMS Load Current
Output AC (Load) Power
Input Power Factor
RMS Current of Thyristor T (RMS )
23. A single phase full wave ac voltage controller working on ON-
OFF control technique has supply voltage of 230V, RMS 50Hz,
load = 50Ω. The controller is ON for 30 cycles and off for 40
cycles.
Example:
Calculate
• ON & OFF time intervals.
• RMS output voltage.
• Input P.F.
• Average and RMS thyristor currents.
26. PHASE CONTROL
• In phase control the Thyristors are used as switches to connect the load circuit to the input ac
supply, for a part of every input cycle.
• That is the ac supply voltage is chopped using Thyristors during a part of each input cycle. The
thyristor switch is turned on for a part of every half cycle, so that input supply voltage
appears across the load and then turned off during the remaining part of input half cycle to
disconnect the ac supply from the load.
• By controlling the phase angle or the trigger angle ‘α’ (delay angle), the output RMS voltage
across the load can be controlled. The trigger delay angle ‘α’ is defined as the phase angle
(the value of ωt) at which
• the thyristor turns on and the load current begins to flow.
27. AC Phase Control
• Phase angle control turns the thyristor on at a variable point in the AC cycle according to the control input of
the thyristor.
• Thyristor fired at 0 angle will let the 100%, AC sine waves of current pass through the load.
• At 50% input only half a sine wave will be seen by the load.
• Phase control thyristors give smooth and constantly variable control of the applied heater voltage and thus are
well suited for use with silicon carbide heaters
AC Supply
28. Single phase full wave ac
voltage controller using TRIAC
Triac Used for Full Wave AC Voltage Phase Control for Resistive Load.
Waveforms of single phase full wave ac voltage controller
30. PERFORMANCE PARAMETERS OF A SINGLE PHASE FULL WAVE
AC VOLTAGE CONTROLLER WITH RESISTIVE LOAD
for , α=0
31. A single phase full wave controller has an input voltage of 120 V
(RMS) and a load resistance of 6 ohm. The firing angle of thyristor is.
Find 2π
a. RMS output voltage
b. Power output
c. Input power factor
d. Average and RMS thyristor current.
Example
35. Frequency converter
Some load run at low frequency then the AC voltages generated by the Source (1500 KW 0-20HZ motor, 1kw=1.34Hp)
Some load run at low frequency then the AC voltages generated by the Source (400 Hz AC power
Aircraft ground power requirements)
Two method can be utilized to address this need
1. Convert AC source voltage to DC and then converter DC voltages to AC at required frequency
2. Direct conversion of AC source frequency to meet the load frequency requirements
Method one: AC to DC rectifier and Inverter circuits are required to implement.
Method two: Cycloconverter circuits are required for direct frequency conversion.
36. 20,000 HP
Synchronous Stator
Being Cleaned With
Dry Ice
Dry ice pellets are accelerated
through a blast system to the
surface being cleaned and upon
impact dissipate as a moisture free
gas.
The dry ice is non-abrasive and the
contaminate is removed from the
windings through a combination of
kinetic energy and gaseous
expansion.
38. WEG’s Net Revenues reached R$ 9.4 billion in 2016
The project scope was to repair the rotor and stator of
the 20,000 HP motor, 10 poles and 13.2 kV.
Scope of Work
Source: https://www.weg.net/institutional/US/en/news/products-and-solutions/weg-repairs-a-
critical-motor-supplying-water-to-sao-paulo
39. Variable Frequency Drives
Variable Frequency Drives (VFDs) control AC motor speed and torque by varying the frequency and
voltage of the motor. Reasons to consider a new VFD or an upgrade to your motor control system:
•Reduce electricity consumption and save on energy costs
• Improve process efficiency
• Provide greater longevity on equipment life
• Reduce maintenance and service costs
USE OF CYCLOCONVERTER
400HZ frequency converters for Aircraft ground power
42. Frequency Conversion from 60 Hz to 400 Hz, using
Horlick Motor-Generator Sets
60 Hz to 400 Hz Frequency Conversion
The single-module frequency converters
Cycloconverter inside???
43. • Cycloconverters are direct ac-to-ac. frequency changers
• AC input and AC output.
• The output frequency is lower/higher than the input frequency and is generally an integral
multiple of the input frequency.
Cycloconverters
Frequency converter
44. In simple words Cycloconvertere circuits are used to convert:
High input frequency to its lower integral frequency as output
OR
Low input frequency to its higher integral frequency as output
Two types of AC-AC frequency converters
Cyclo converters
Matrix converters
Frequency converter
(Step-down Cycloconverter)
(Step-up cycloconverter)
46. Frequency converter
Set of thrystor P1-P3, and P2-P4
as pair are used to develop the
positive half cycle of the out put
frequency
By firing these SCRs number of
time one can increase the width of
the +ve half cycle of output
frequency
Step-down frequency cycloconverter
To create +Ve Half Cycle of the output frequency
First fire P1-P3 for +ve half cycle of the input wave
then fire P2-P4 for +ve half cycle of the input wave
then fire P1-P3 for +ve half cycle of the input wave
That will keep the direction of current same in the Load
Single Phase Natural Commutated Cyclo-converter
47. Frequency converter
Set of thrystor N1-N3, and N2-N4
as pair are used to develop the
negative half cycle of the out put
frequency
By firing these SCRs number of
time one can increase the width of
the -ve half cycle of output
frequency
Step-down frequency cycloconverter
First fire N3-N1- for -ve half cycle of the input wave
then fire N4-N2- for -ve half cycle of the input wave
then fire N3-N1- for -ve half cycle of the input wave
To create -Ve Half Cycle of the output frequency
That will keep the direction of current same in the Load
Single Phase Natural Commutated Cyclo-converter
48. Frequency converter
• Three cycles of input frequency is used to make one cycle of the
output frequency
• Hence output frequency is one third of the input frequency.
• Therefore if input frequency was 60Hz the out frequency that was
created is 20Hz
Input (a) and output (b) voltage waveforms of a cyclo- converter with an
output frequency of 20 Hz for resistive (R) load
Input frequency 60Hz
Output frequency 1/3 of input frequency = 20Hz
Single Phase Natural Commutated Cyclo-converter
49. Frequency converter Single Phase Natural Commutated Cyclo-
converter
Natural Commutation is
used in Step down Cyclo
Converter
Step down for RL load
50. Frequency converter
Single Phase Forced Commutated Cyclo-converter
Step Up
Forced Commutation is
required to step-up the
frequency.
51. Step Up Cycloconverter
Fire P1-P2 at angle α
Forced commutation P1-P2 at wt1
(current direction change in the load)
To create +Ve half cycle of output
wt1
52. • Forced commutation N1-N2 at wt2
• Fire P1, P2 at wt2 (current direction change in
the load)
Repeat this procedure to create
three complete cycle of out put
frequency by using ½ cycle of
the input frequency.
Six complete cycles will be generate
by one full cycle of the input cycle.
Result: Step up 1:6
Step Up Cycloconverter
.
.
.
.
.
.
• Fire P1-P2 at angle α
• Forced commutation P1-P2 at wt1
• Fire N1-N2 angle α + wt1 (current
direction change in the load)
To create -Ve half cycle of the output
The principle of integral cycle control is explained by refering to single-phase voltage controller with resistive load. Gate pulses ig1,ig2 (applied at α-0°) turn on the thyristors T1, T2 respectively at zero-voltage crossing of the supply voltage. The source energises the load for n(=3) cycles. When gate pulses are withdrawn, load remains off for m(=2) cycles. In this manner, process of turn-on and turn-off is repeated for control of load power. By varying the number of n and m cycles, power delivered to the load can be regulated as desired. Power is delievered to load for n cycles. No power is delivered to load for m cycles. It is the average power in the load that is controlled.