Project Id :- 68640 Table of contents
TABLE OF CONTENTS
CHAPTER PAGE NO.
TABLE OF CONTENTS i
FIGURES LIST iv
ABBREVIATION v
ABSTRACT vi
CHAPTER 1. Introduction 1
1.1 Problem Summary 1
1.2 Aim & objective of the project 1
1.3 Problem specification 1
1.3.1 Harmonics contain in inverter 1
1.3.2 Switching loss 2
1.4 Literature review 2
1.4.1 Introduction of TLI technology 2
1.5 Plan of work 4
1.6 Material & tools require 4
1.6.1 Capacitor 4
Electrical Engineering i
Project Id :- 68640 Table of contents
1.6.2 Diode 4
1.6.3 Power switches 4
1.6.4 Micro controller 4
1.6.5 Transformer 4
1.6.6 Photovoltaic cell 5
1.6.7 Other tools 5
CHAPTER 2. Design Methodology 6
2.1 Design method 6
2.1.1 Neutral point clamped 6
2.1.2 Flying capacitor 7
2.1.3 Cascaded H-bridge 8
2.2 Working of inverter 8
2.3 Canvas 9
2.3.1 Empathy canvas 9
2.3.2 Ideation canvas 11
2.3.3 Product development canvas 12
2.3.4 AEIOU canvas 13
CHAPTER 3. Project Adv. Disadv. Application 15
3.1 Project Advantages 15
3.2 Project Disadvantages 15
3.3 Project Application 15
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Project Id :- 68640 Table of contents
3.3.1 Energy conversion 15
3.3.2 In Three Phase machine 16
3.3.3 Train Traction 16
CHAPTER 4. Work plan & Future Work 18
4.1 Work Plan 18
4.2 Future Work 18
CONCLUSION 19
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Project Id :- 68640 Figures List
FIGURES LIST
FIGURE NO. & CONTENT PAGE NO.
1.3.1 Harmonics contain in inverter 2
1.4.1 Introduction to TLI technology 3
2.1 Design Method 6
2.1.1 Neutral point clamped 7
2.1.2 Flying capacitor 7
2.1.3 Cascaded H-bridge 8
2.3.1 Empathy canvas 10
2.3.2 Ideation canvas 11
2.3.3 Product development canvas 13
2.3.4 AEIOU canvas 14
3.3.1 Energy conversion 15
3.3.2 In Three phase machine 16
3.3.3 Train traction 17
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Project Id :- 68640Abbreviation
ABBREVIATION
1. DC :- Direct Current
2. AC :- Alternating Current
3. NPC :- Neutral Point Clamped
4. MCU :- Micro Controller
5. PWM :- Pulse Width Modulation
6. IGBT :- Insulated Gate Bipolar Transistor
7. PCB :- Printed circuit board
8. FC :- Flying Capacitor
9. CHB :- Cascaded H-Bridge
10. Ex. :- Example
11. TLI :- Three Level Inverter
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Project Id :- 68640 Abstract
ABSTRACT
Now a days 3-level inverter has many applications in medium voltage, high voltage power application such as variable speed drive, power compensation, rolling mills and renewable energy. The close loop control modelling and prototype implementation of conventional 3-level neutral point clamped (NPC) controller is done. This project focuses on hardware implementation of 3-level inverter using controller and balancing the neutral point potential (NPP), here by reducing the output voltage distortion. It has capability to handle high power with less total harmonics distortion, reduce switching losses and good power quality.
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Project Id :- 68640 Introduction
CHAPETER 1INTRODUCTION
It is an Electronic device that change direct current (DC) to alternating current (AC).The input voltage of the inverter depends on the design and purposed of inverter. In our project we use photovoltaic Cell as a green energy source as an input of inverter.
INPUT VOLTAGE: A power inverter device or circuit requires a relatively stable DC power source capable of supplying sufficient current for the intended power demands of the system. The input voltage depends on the design and purpose of the inverter.
OUTPUT WAVEFORM: When input voltage given to inverter it can produce square wave, modified sine wave, pulse sine wave, PWM wave or sine wave as per design consideration.
1.1 Problem Summary
In this project we havetry to make inverter output pure sine wave, reduced harmonics,operate in any weather condition, portable power supply, low costing,reduce switching loss, high operating frequency.
1.2 Aim and Objective of the project
To make low cost inverter by using cheap microcontroller and mobile power supply.
1.3 Problem Specifications
Usually the inverter output contains a harmonic and switching losses which reduces the efficiency of inverter which result in more costly operation.
1.3.1 Harmonics contain in Inverter
A harmonics referred to power quality in ideal world means how pure the voltage is how pure the current wave form is in its sinusoidal form.
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Project Id :- 68640 Introduction
Power quality is very importantto commercial and industrial power system design. It shouldbe present dueto many reasons like external disturbance and switching.
FIGURE 1.3.1
1.3.2 Switching Loss
As switching frequency increase, it becomes of Paramount importance to reduce the switching losses in the converter. It is loss associated with transition of switch from its on state to off state and vice versa.
1.4 Literature Review
1.4.1 Introduction to Three Level Inverter (TLI) Technology
The 3-level inverter offers several advantages over the more common two level inverter. As compared to two level inverters, three level inverters have smaller output voltage steps that minimize motor issues due to long power cables between the inverter and the motor. These issues consist surge voltages and rate of voltage rise at the motor terminals and motor shaft bearing currents. In addition, the clean output waveform provides an effective switching frequency twice of the actual switching frequency. Should an output filter be required, the components will be smaller and less costly than for an equivalent rated two level inverter.
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Project Id :- 68640 Introduction
Most often the NPC inverter is used for high voltage inverters. Because the IGBTs are only subjected to half of the bus voltage, lower voltage IGBT modules can be used.
Basic Circuit Configuration and Its Behaviour:
Figure 1.4.1 shows the circuit configuration of the NPC inverter. Each leg has four IGBT switches connected in series. The applied voltage on the IGBT is one-half that of the conventional two level inverter. The bus voltage is dividing in two by the connection of equal series connected bus capacitors. Each leg is completed by using the addition of two clamp diodes. This topology traditionally has been used for medium voltage drives both in industrial and other applications. In addition to the ability of handling higher voltages, the NPC inverter has several favourable features like lower line-to-line and common-mode voltage steps and lower output current ripple for the same switching frequency as that used in a two level inverter.
FIGURE 1.4.1
Summary :
The TLI series IGBT modules, specifically designed for low & medium voltage NPC or three level inverters, provide a cost effective approach for the design of an inverter with the following desirable characteristics:
• High quality output voltage and current waveforms result in less motor stress even for long power cables.
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Project Id :- 68640 Introduction
• High efficiency design due to decrease switching losses
• Reduced output filter component size and cost as compared to a two level inverter
•IGBT module reliability
1.5 Plan Of Work
To use microcontroller for switching control of power switches(IGBT) to increase operating frequency.
1.6 Material and Tools Required
1.6.1 Capacitor
It is a passive two-terminal electrical component used to temporarily store electrical energy in an electric field. It measure in FARADAY.
1.6.2 Diode
It is a two-terminal electronic component that conducts primarily in one direction (asymmetric conductance).
1.6.3 Power Switches
It is an electrical switch that switches a load between two sources. Some transfer switches are manual, in that an operator effects the transfer by throwing a switch, while others are automatic and trigger when they sense one of the sources has lost or gained power.
1.6.4 Micro Controller
MCU is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals.
1.6.5 Transformer It is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction.
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Project Id :- 68640 Introduction
1.6.6 Photovoltaic Cell
It is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect.
1.6.7 Other Tools
• PCB
• Soldering Machine
• Connecting Wire
• Multimeter
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Project Id :- 68640 Design Methodology
CHAPTER 2 Design Methodology
2.1 Designing Method
FIGURE 2.1
2.1.1 Neutral Point Clamped(NPC) :
A NPC converter is basically composed of two traditional two-level VSCs
stacked one over the other with some minor modifications. It can be seen in
Fig. 2.1.1, the negative bar of the upper converter and the positive bar of the
lower one are joined together to form the new phase output, while the original
phase outputs are connected through two clamping diodes to form the neutral
point N, dividing the dc-link voltage in two. Now each power device has to
block only half of the total converter voltage; hence with the same
Semiconductor technology,the power rating of the converter can be doubled.
In addition, the neutral point enables the generation of a zero voltage level,
obtaining a total of three different voltage levels.This method has some
Advantages so we refer this method.
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Project Id :- 68640 Design Methodology
FIGURE 2.1.1
2.1.2 Flying Capacitor
The FC topology is in some way similar to the NPC, with the main difference being that the clamping diodes are replaced by flying capacitors, as can be seen in Fig. 2.1.2. Here the load cannot be directly connected to the neutral of the converter to generate the zero voltage level. Instead, the zero level is obtained by connecting the load to the positive or negative bar through the flying capacitor with opposite polarity respect the dc-link. Like with the NPC, only two gating signals are necessary per phase to avoid dclink and flying capacitor short-circuit. However, in the FC, the inverted gating signals are related to different switching devices, as shown in Fig. 2.1.2.
FIGURE 2.1.2
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Project Id :- 68640 Design Methodology
2.1.3 Cascaded H-Bridge
CHB are multilevel converters formed by the seriesconnection of two or more single-phase H-bridge inverters, hence the name. Each H-bridge corresponds to two voltage source phase legs, where the line–line voltage is the converter output. Therefore, a single H-bridge converter is able to generate three different voltage levels. Each one leg has only two possible switching state, to avoid dc-link capacitor short-circuit. Since there are two legs, four different switching states are possible, although two of them have redundant output voltage. Fig. 2.1.3 shows the three different output voltage levels and their corresponding equivalent circuits. The zero level can be generated connecting the phase outputs to the positive or the negative bars of the inverter.
FIGURE 2.1.3
2.2 Working of inverter
3-level is indicate that its output will change three times (+Vdc/2, 0, -Vdc/2).Here Vdc is a supplying DC voltage. We use a solar cell to generate a dc & it will store in battery and then give to input of inverter. NPC is also called as Diode Clamped.The voltage Vdc is split into three levels by two connected bulk capacitors C1& C2. The middle point of the two capacitors n can be
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Project Id :- 68640 Design Methodology
defined as the neutral point. The output voltage Van has three states: +Vdc/2, 0 -Vdc/2.
For voltage level +Vdc/2,switches S1 and S2 need to be turned on;for Voltage level -Vdc/2, switches S1’ and S2’ need to be turned on;for the 0 , S1’ and S2 need to be turned on. Refer Figure 2.1.1.
2.3 Canvas
2.3.1 Empathy canvas
From the empathy canvas we can know about users and stakeholder who are invest there amount in project. Activities around the project also include in it.
Users : Family member, Business men, Bank person, Office worker, Hospital worker, College admin etc.
Stakeholders : Director of Industry, Hospital, Railway, Family member, Bank, School/College trustee etc.
Activities : Worker work in industry, Operation of Patient, Student Study,Older person reading newspaper, Employee work on the PC, Running appliance in car etc.
Story Boarding : The Story Boarding is an activity where it is needed to incorporate emotions related with activities, user, stakeholders identified. The story made up here tells about emotional attachment including historical aspect connected (maybe) however it is lacking of on hand experience or a user at present.
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Project Id :- 68640 Design Methodology
FIGURE : 2.3.1
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Project Id :- 68640 Design Methodology
2.3.2 Ideation Canvas
People : The project can be used by persons are include in it. Ex. Business men, Bank person, office worker, Railways etc.
Activities : With thought on people involved in different activities, an attempt was made to think up on possibilities or various activity. Ex. Worker work in industry, Operation of Patient, Student Study, Older person reading newspaper, Employee work on the PC, Running appliance in car etc.
Situation/context/Location : We attempted to identify different location that are involved in performing such activities that was relevant to activities. Ex. Power cut, Summer/winter/rainy, Industries, Bank, Railway etc.
Props/Possible Solution : This is section ideation canvas help in carving out different in line with attempting/looking forward to have an idea about addressing a problem.
FIGURE : 2.3.2
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Project Id :- 68640 Design Methodology
2.3.3 Product Development Canvas
The canvas begins with mention of purpose and people. By this, it has brought down to a very limited set off people that are thought to be directly involved in major of the activities. The Product Experience was to be mentioned as the product is giving experience to the users.
Purpose : Comfort, Time saving, Increase efficiency, Low cost etc.
People : The project can be used by persons are include in it. Ex. Business men, Bank person, office worker, Railways etc.
Product Experience : Comfortable, Time saving, Low cost, Good efficiency etc.
Product Function : Continuous Power supply, Useful in traction system, DC to AC conversion.
Product Feature : Low cost Controller, Solar base input, Economical, Near by sinusoidal output.
Component : IGBT, Diode, Controller, Connecting Wire, Battery, Solar plate, PCB, Soldering Machine.
Customer Revalidation : Comfortable, Working good, Less battery charge during rainy season, Very useful for hospital, individual supply to ach switch.
Reject, Redesign, Retain : Weight> use parallel battery supply, Less Battery charge during rainy season> Use back-up DC source during rainy season.
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Project Id :- 68640 Design Methodology
FIGURE 2.3.3
2.3.4 AEIOU Canvas :
In this Canvas we can about Activities, Environment, Interactions, Object, and Users.
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Project Id :- 68640 Design Methodology
FIGURE 2.3.4
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Project Id :- 68640 Project Adv. Disadv. Application
CHAPTER 3Project Adv. Disadv. Application
3.1 Project Advantages
1) It can generate output voltages with extremely low distortion and lower dv/dt .
2) It can operate with a lower switching frequency.
3) High efficiency.
4) Economical cost.
3.2 Project Disadvantages
1) Complimentary circuit.
2) External DC supply require to each insulated gate bipolar transistor (IGBT) switches.
3) Harmonics affecting the output signal.
3.3 Project Applications
3.3.1 Energy Conversion
In energy Conversion inverter mostly used. In DC generation like wind plant or solar plant for conversion of DC to AC inverter is used. It is also be possible to convert DC into AC for small appliance like car auxiliary.
FIGURE 3.3.1
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Project Id :- 68640 Project Adv. Disadv. Application
3.3.2 In 3-phase Machine
Generally motors has starter for speed control and Protection purpose. We can use inverter as speed control of machine. A combination of rectifier and inverter is used in industry for speed control.
FIGURE 3.3.2
3.3.3 Train Traction
In traction system to control the speed of wheels can be possible by inverter. The voltage from the line is given to the rectifier through pantograph and circuit breaker. Rectifier converts it in DC then 3-level inverter with NPC topology convert into AC. Speed can be control through firing angle.
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Project Id :- 68640 Project Adv. Disadv. Application
FIGURE 3.3.3
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Project Id :- 68640 Work plan & Future work
CHAPTER 4 Work plan & Future work
4.1 Work Plan
In the starting stages of this phase study about the research topic was carried out & this topic, Design and simulation of 3-level inverter by using solar cell were found the potential one. There were many problem found the for selecting this topic. After it we take knowledge about it and do project work.
Table:4.1 Work plan details
June – July Project Search/ Finalized Project
July – August Canvas Activity
August – September Research about Project theory
September – October Report and preparation of Presentation
4.2 Future Work
In the 8th semester we will collect the components of the project and with help of internal guide we implementing the hardware of this project.
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Project Id :- 68640 Conclusion
CONCLUSION
The project that was undertaken by us was the unique one with few applications followed by few drawbacks also. It is used in industry, railway for RPM control. The 3-level inverter is a novel design which can be easily operates when supply given to it. It simply convert the DC to AC, it has some advantages compare to simple inverter. The output is more sinusoidal and harmonics are reduced. It can be uses for both domestic and industrial purpose. However yet some issue are present such as weight and size, but it is less affect to working. Considering the financial aspect in designing the 3-level inverter initial cost is high as the parts purchased are genuine, but if we manufacture this in mass production cost can be minimized based on the type of application.
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