Power Inverter

Eso, Michael C.Gomeseria, Roniele J.Nual, Jerson G.Pagilagan, Rashleigh Rhon V.

Technological Institute of the Philippines Manila

ACKNOWLEDGEMENT

The Researchers expressed their highest gratitude to all generous persons who helped them made possible the completion of the project.To Engr. Cayetano Hiwatig for being the adviser of the researchers and for his meaningful comments and valuable suggestion for the improvement of the projectTo Engr. Mabanta for being patient and sharing his expertise to the researchers on conducting the experiments.To the section of EE51FB1 for being supportive and helping the researchers in every inch of the way.The most important of all, the Almighty God, His love and blessings gave strength and guidance to the researchers as they finish the project.

The Researchers

DEDICATION

The researchers fondly dedicated this research work as appreciation of their deep gratitude to the following:To their parents Mr. Eso, Mr. Gomeseria, Mr. Nual, Mr. Pagilagan, for the moral support, love, and care to them as well as the financial support that they are always ready to give in order to make this project possible.To our Almighty God for all the blessings that He gave to the researchers and for His words that uplift our spirits during the lowest point in this project.

The Researchers

TABLE OF CONTENTSPagesTitle PageApproval SheetAcknowledgementDedicationAbstractTable of ContentsList of TablesList of Figures

CHAPTER I PROJECT AND ITS BACKGROUNDIntroductionObjective of the StudyStatement of the ProblemSignificance of the StudyScope and Delimitations

CHAPTER II THEORETICAL FRAMEWORK AND RELATED LITERATURERelated LiteratureRelated StudiesConceptual Framework / Research ParadigmDefinition of Terms

CHAPTER III - METHODOLOGYMethods of ResearchData GatheringResearch SettingRespondents of the StudyStatistical AnalysisQuestionnaireTechnical ApproachBlock Diagram Budgetary Outlay

CHAPTER IV PRESENTATION, INTERPRETATION, AND ANALYSIS OF DATA

CHAPTER V - FINDINGS OF THE STUDY, CONCLUSION, RECOMMENDATIONFindings of the StudyConclusionRecommendation

APPENDIX 1 THE PROJECT

APPENDIX 2 THE CLIENT

APPENDIX 3 OTHER PICTURES

APPENDIX 4 - DATASHEETS

APPENDIX 5 CURRICULUMN VITAE

BIBLIOGRAPHY

LIST OF TABLESTable TitlePages 2.1Summary Table of Related Literature

3.1Point Scale System

3.2Budgetary Outlay

4.1Statistical Treatment of Questionnaire

4.2Maximum Speed

4.3Average Speed

4.4 Minimum Soeed

LIST OF FIGURES

FIGURETITLE PAGES 3.1Structural Diagram

3.2Simulation

3.3Test Output Voltage

CHAPTER 1PROJECT AND ITS BACKGROUNDIntroductionNowadays, generation of electric power comes in different ways. These provide essential contributions to the world who is constantly in dire need of power. A lot of methods of power generation are now being developed and still on the process of improving to solve the energy crisis that the world might experience in the coming years. Utilization of equipment and available resources like car batteries could also be a way to solve these existing problems. However, these methods can only get raw energy which are not readily useable for the appliances. This is where significance of power inverters take place. Existing power inverters in the market has the capability to convert the DC power into AC power which are useful for generating equipment and household appliances such as computers, refrigerators, televisions and etc. However, all of these are not efficient way in running these products since it draws high current and usually requires battery utilization. As a result, power inverters comes into large sizes that can consume large spaces especially in households. The tablet-size power inverter provides specifications to correct the existing problems in using it in industry and personal uses. This inverter exhibits major development in terms of its portability. This could be essential characteristic that would give flexibility to the product thus, increasing its significance to the society. Despite of miniaturization, efficiency of the power inverter was still considered. Retaining the important characteristics of power generation such as power factor and output power needed by the appliances remained to be the focal point of the inverter. Furthermore, the project will be beneficial to continuous development of existing inverters.Statement of the ProblemThe purpose of the project is to create a tablet-size power inverter that can provide power to household appliances. It seeks to answer the following questions:1. How can the inverter be miniaturized?2. Can it provide safety while generating power for household appliances?3. Can the inverter provide an efficient power needed by household appliances?ObjectivesThe general objective of this project is to create a tablet-size power inverter that can provide power to household appliances. In the focus of the project are the following problems: To provide a maximum load of 2kVA To have a power density not less than 25W/in3 To create power inverter with a volume of not greater than 80in3 To have a voltage input of 380V DC To provide an output of 220V AC To have a frequency of 60Hz To have a power factor ranging from 0.7-1 To have an efficiency not less than 95% To have an input ripple current not greater than 20% To have an input ripple voltage not greater than 3%Scope and DelimitationsThe project limits its function as an inverter that can provide a sinusoidal output waveform. The project would only provide a 2kVA output for household appliances. The voltage source of the project is 380V DC that will be converted to 220V AC. The size of the project will have a power factor ranging from 0.7 to 1 only and have a power density of at least 25W/in3.

Chapter 2REVIEW OF RELATED LITERATURE AND STUDIES The global electrical demand now a days is steadily increases to meet the needs of the people in using electricity in their everyday lives. The cost of renewable energy technologies is on a falling trend and is expected to fall further as demand and production increases. As we see the fast growing availability of renewable energy around us, the problem is how this energy can be harness to use in our household demand. Electrical power transmission is classified into two methods: alternating current and direct current. Alternating current can be found in AC motor drives and long distance power transmission. The cyclic nature of alternating current enables the use of transformers, which use magnetic principles to alter voltage levels. By stepping up an AC voltage, a large amount of power can be transferred over a long distance with less energy lost in heating up a conductor due to a lower current requirement, since P=I2 R. As such, AC power is more conventional than high voltage DC systems due to the ease of stepping up voltage for transmission and stepping voltage down to household outlet levels. DC voltage also has a place in powering devices. Wherever there is a changing electrical current, a changing magnetic field accompanies it. In a device-level electrical circuit, the magnetic variations introduced by AC current manifest themselves as electrical noise. The effects of this can range from audible line hum in an audio system to inaccurate measurements in an electronic instrument. Thus, it is commonplace for a device such as an MP3 player to employ DC voltages that have been rectified and filtered from an AC wall outlet. An MP3 player also proves one other benefit of DC power transmission: it can be done with a compact form factor. Without a need for transformers or switching circuitry, battery-powered MP3 players, or any other portable device, can be made small enough to fit into a pocket. However, there may come a time when household AC power is cut off due to a power outage. The multitude of devices that are designed around AC/DC power conversion (computers, for example) would then no longer be able to operate. One solution to this problem is an auxiliary AC power generator, like those powered by gasoline engines, or DC/AC power inverters which use energy stored in batteries (a DC source) and emulate a wall outlet AC output through voltage boosting and switching to create a changing voltage with the proper amplitude across a load. In practice, DC/AC conversion is done with topologies of varying precision. It can be as simple as applying voltages of equal amplitude in opposite directions across a load to generate a square wave. This method achieves the AC voltage requisite of a changing voltage across a load, but this rough approximation has consequences discussed later in this paper. 11 Figure 1:Square, Modified Sine, and Sine Waves Comparison2 A more precise method of DC/AC conversion is the modified sine wave, which introduces a dead time in a normal square wave output so that higher peak voltages can be used to produce the same average voltage as a sinusoidal wall-outlet output. This method produces fewer harmonics than square wave generation, but it still is not quite the same as the AC power that comes from an AC outlet. The harmonics that are still present in a modified sine wave make modified sine-wave inverters unsuitable for use while electrical noise is a concern, such as in medical devices which monitor the vital signs of a human. Pure sine wave DC/AC conversion will introduce the least amount of harmonics into an electrical device, but are also the most expensive method. Since the AC sine wave must come from a DC source, switching must still take place. However, switching takes place with logic so that the energy delivered to a load approaches that of a pure sine wave. This means that extra components and design considerations are involved in the control circuitry of a pure sine wave inverter, driving up cost.The switched-capacitor (SC) power converter has received more and more attention because it has only semiconductor switches and capacitors. Thus, this kind of SC converters is one of the good solutions for low-power DC-DC/DC-AC conversion. Unlike the traditional converter, the SC converter needs no magnetic element, so they always have the small volume and light weight. The SC converter is usually designed for an output higher than supply voltage or a reverse-polarity voltage. This function fits many applications, e.g. drivers of electromagnetic luminescent (EL) lamp, white light emitting diode (WLED), op-amp, and LCD drivers. Up to now, the various SC types have been suggested for power conversion. In 1990, the first SC step-down converters were proposed by Japan researchers, and their idea is to switch MOSFETS cyclically according to 4 periods of capacitors charging/discharging for step-down conversion. In 1993, Cheong et al. suggested a modified SC converter with two symmetrical SC cells working in the two periods. In 1995, Chung and Ioinovici suggested a current-mode SC for improving current waveforms. In 1998, Mak and Ioinovici suggested an SC inverter with high power densit. In 2004, Chang proposed design and analysis of power-CMOS-gate-based SC boost DC-AC inverter. The advantage of this SC inverter is to reduce the electromagnetic interference (EMI) problem. In 2007, Chang proposed CPLD-based closed-loop implementation of SC step-down DC-DC converter for multiple output choices. In 2010, Hinago and Koizumi proposed a single-phase multilevel inverter using switched series/parallel DC voltage sources based on multiple independent voltage sources in order to reach the higher number of levels so as to reduce the THD value. In 2011, Chang proposed an integrated SC step-up/down DC-DC/DC-AC converter/inverter. In this paper, by using the 2-stage 4-phase SC boost and SPFM control, the boost DC-AC inverter is proposed not only to enhance full-wave output regulation via SPFM technique, but also to improve the THD value and provide the maximum gain proportional to the number of pumping capacitors.

Conceptual FrameworkInvert Direct CurrentStep Down Direct Current

Invert Direct CurrentPWM, Digital Signal ProcessingHeat Sink utilizationBridge ConverterTemperature MaintenanceMOSFET switchingEfficiency MaintenanceAlternating Current

The basic function of the inverter is converting the DC input to AC output. The procedure to attain this function is through inversion of DC to AC peak amplitude. DC can be stepped down through DC-DC converter. The MOSFETs on and off using pulse width modulation will make the current alternating delivered from the microcontroller through a gate driver. Temperature maintenance would be significant in achieving high efficiency.

Chapter 3Research Design and MethodologyIn this chapter, the different methods to quantify the needed data for the experiments are discussed. The different designs for the prototype are also presented to conduct several trials and achieve different results but in line with the objectives of the study.The approach used in this study includes Technical approach to focus on both gathering data and testing procedures.Types of ResearchThe type of research that will be used in this study are basic research, applied research and quantitative research. Basic research provided knowledge enhancement for the researchers, which is needed for the further study to be conducted. This type of research laid down the foundation for the applied research. Since applied research is considered as problem solving research, it will be a help to the researchers to meet the different specifications of the project. Lastly, the quantitative research is based on numeric figures or numbers. By quantitative research, it will measure the quantity or values and compares it with the past records and tries to project for future period. Also, experiments, testing procedures and calculations are most needed in this study. These show the attainment of the specifications and objectives of the study.Experimental Design1. Study the structure of the inverter2. Identify the functions of each component3. Create an inverter4. Apply microelectronics to miniaturize the inverter5. Create again the mini inverter6. Run some test to check if specifications are attainedResearch SettingThe research is conducted in a work place which can provide the different components needed for the creation of prototype. Since in running test procedures can cause failure or damage to component, it is necessary to work on a work place where there is an easy access to these components. Moreover, protective devices such as fuses are included in the circuitry of the design. Budgetary OutlayItemQuantityCost

Inductor1 pcPhp 1,500.00

Power MOSFET 47N60C34 pcsPhp 120.00

6A diode4 pcPhp 300.00

Capacitor1 sheetPhp 350.00

Fuse10pcsPhp 150.00

PWM Microcontroller1 kiloPhp 20.00

12V Rechargeable Lead Acid Battery1 pcPhp 495.00

Voltage Regulator (LM7805 & LM7812)12 pcPhp 136.00

Clamp3 pcPhp 60.00

Electronic Parts1 setPhp 160.00

Wires5 mPhp 60.00

Aquarium1 pcPhp 750.00

Electrica006C Tape1 pcPhp 20.00

Mighty Bond1 pcPhp 75.00

Light Receptacle1 pcPhp 25.00

PVC 1 1 tubePhp 190.00

90 Angle Connector2 pcPhp 70.00

Aluminum1 sheetPhp 120.00

Total CostPhp 4601.00

Data Gathering Procedure and Instrument UsedThe set-up for the instruments would be established first before conducting the actual gathering of the data. Figure 3.1 and figure 3.2 illustrates the two set-ups of the project to conduct the actual gathering of the data.

Figure 3.1: 240V Split Phase Configuration

Figure 3.2: 240V to Ground Configuration

The data will vary according to the load. The design will consider the power factor ranging from 0.7 to 1 leading or lagging. The testing procedures will only be focused on the load side of the configuration, load bank. Industry softwares like Multisim, Matlab and PSpice. These softwares will be responsible for determining the following parameters to be considered in the design:1. Total Harmonic Distortion plus Noise2. Input Ripple Current and VoltageOther parameters will be measured through DMM and multitester. These include the following: output voltage, frequency output. The efficiency of the device will be determined by taking the measurement at 6 different load levels as shown in the table 3.1.Table 3.1: Weighting Factors for CEC Efficiency Calculation

CHAPTER IVPRESENTATION, INTERPRATATION, AND ANALYSIS OF DATAThis chapter shows the interpretation and analysis of data obtained from the several trials conducted by the researchers. The data are analyzed and tabulated to interpret the results from each designs.CALCULATEDMEASURED% DIFFERENCE

TrialILOAD (A)Ripple Voltage (V)ILOAD (A)Ripple Voltage (V)

10.3231 A10.1270 V0.3231 A10 V1.2541 %

20.3334 A10.4499 V0.3334 A10 V4.3053 %

30.3236 A10.1427 V0.3236 A10 V1.4069 %

40.3335 A10.4530 V0.3335 A10 V4.3337 %

50.3233 A10.1331 V0.3233 A10 V1.3135 %

60.3234 A10.1365 V0.3234 A10 V1.3466 %

70.3299 A10.3402 V0.3299 A10 V3.2900 %

80.3287 A10.3026 V0.3287 A10 V2.9371 %

90.3298 A10.3370 V0.3298 A10 V3.2601 %

100.3334 A10.4499 V0.3334 A10 V4.3053 %

110.3731 A11.6042 V0.3731 A10 V13.8243 %

120.3256 A10.2054 V0.3256 A10 V2.0127 %

130.3540 A11.0956 V0.3540 A10 V9.8742 %

140.3371 A10.5659 V0.3371 A10 V5.3559 %

150.3256 A10.2054 V0.3256 A10 V

Table 4.1 Ripple VoltageCALCULATEDMEASURED% DIFFERENCE

TrialRipple Voltage ()Dc Voltage ()Ripple Factor %Ripple Voltage ()Ripple Voltage (V)Ripple Factor %

110.1270 V381.8377 V2.6521 %10 V380 V 2.6316 %0.7790 %

210.4499 V381.8377 V2.7367 %10 V381 V2.6247 %4.2711 %

310.1427 V381.8377 V2.6563 %10 V379 V2.6385%0.6367 %

410.4530 V381.8377 V2.7376 %10 V379 V2.6385%3.7559 %

510.1331 V381.8377 V2.6538 %10 V380 V2.6316 %0.8436 %

610.1365 V381.8377 V2.6547 %10 V379 V2.6385%0.6140 %

710.3402 V381.8377 V2.7080 %10 V379 V2.6385%2.6341 %

810.3026 V381.8377 V2.6982 %10 V380 V2.6316 %2.5308 %

910.3370 V381.8377 V2.7072 %10 V380V2.6316 %2.8738 %

1010.4499 V381.8377 V2.7367 %10 V380 V2.6316 %2.8738 %

1111.6042 V381.8377 V3.0390 %10 V382 V2.6178 %16.0898 %

1210.2054 V381.8377 V2.6727 %10 V380 V2.6316 %1.5618 %

1311.0956 V381.8377 V2.9058 %10 V382 V2.6178 %11.0016 %

1410.5659 V381.8377 V2.7671 %10 V379 V2.6385%4.8740 %

1510.2054 V381.8377 V2.6727 %10 V378 V2.7455 %2.6516 %

Table 4.2 Ripple Voltage Factor

CALCULATEDMEASURED% DIFFERENCE

TrialILOAD (A)Ripple Voltage (V)ILOAD (A)Ripple Voltage (V)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Table 4.2 Ripple Current

= = 10.1270 V = = 10.4499 V = = 10.1427 V = = 10.4530 V = = 10.1331 V = = 10.1365 V = = 10.3402 V = = 10.3026 V = = 10.3370 V = = 10.4499 V = = 11.6042 V = = 10.2054 V = = 11.0956 V = = 10.5659 V = = 10.2054 V

Ripple Factor % = x 100 % = x 100 % = 2.6521 %Ripple Factor % = x 100 % = x 100 % = 2.7367 %Ripple Factor % = x 100 % = x 100 % = 2.6563 %Ripple Factor % = x 100 % = x 100 % = 2.7376 %Ripple Factor % = x 100 % = x 100 % = 2.6538 %Ripple Factor % = x 100 % = x 100 % = 2.6547 %Ripple Factor % = x 100 % = x 100 % = 2.7080 %Ripple Factor % = x 100 % = x 100 % = 2.6982 %Ripple Factor % = x 100 % = x 100 % = 2.7072 %Ripple Factor % = x 100 % = x 100 % = 2.7367 %Ripple Factor % = x 100 % = x 100 % = 3.0390 %Ripple Factor % = x 100 % = x 100 % = 2.6727 %Ripple Factor % = x 100 % = x 100 % = 2.9058 %Ripple Factor % = x 100 % = x 100 % = 2.7671 %Ripple Factor % = x 100 % = x 100 % = 2.6727 %

CHAPTER VFINDINGS OF THE STUDY, CONCLUSION AND RECOMMENDATIONSThis chapter includes the summary and interpretation of the data gathered from the experiment. The recommendations for further improvement of the study are also discussed. The different suggested solutions to avoid the recurring problems during testing procedures are also explained.Findings of the StudyDuring the conduct of testing procedures, multiple problems arose. Several trials are made and during each of these trials, different problems occurred. In the first design, short circuit happened in the AC output current feedback input of the PWM microcontroller. The problem occurred largely because of the timing in the switching of the microcontroller and the voltage input DC of the circuit. During the second trial, the first voltage induced in the circuit is the 380V DC input and then followed by the 16V AC after stabilizing the first input voltage. In just split seconds after putting the 16V AC, the protective devices included in the circuit suddenly tripped as well as the VARIAC. Short circuit in the input side happened that caused tremendous amount of current that tripped all the adjacent fuses. Timing of the switching of the drivers caused the problem and the gradual increase of the DC voltage input as time varies. Another possible cause is the grounded voltage input that can put up noises that would eventually trigger the switching process of the pulse-width modulator. The last design tried to resolve the problems regarding the grounded voltage input. Through the use of an isolation transformer, it removed the ground noise of the 16 V VARICAC to be supplied in inverter. Setting the VARIAC in 240 V AC and tapping it in the step down transformer, output voltage get from the 24 V AC output, adjusting the VARIAC to get the value of 16 V AC. As supplied in the inverter itself, short circuit happens still in the supply from 380 V DC. Problem of the fault in the inverter still unknown, depending on the use of higher voltage input of 380 V dc, the discussed input in the inverter itself was based on the input voltage indicated in the Google Little Box Challenge, the proponents of the input voltage was to be supplied in their laboratory, given the available resource the only option of the researcher was the available VARIAC to be full in the laboratory equipment in the school.

ConclusionTherefore conclude that the inverter of this project was not possible given the resource have in the school to supply the inverter of the needed 380 V Dc and 16 V Dc. Due to the fact that the grounded noise was present in this VARIAC that affects the switching timing of the driver of the inverter. Affected by that noise the ability of the inverter to switch accordingly in it operation, that would lead in fault as 380 V Dc and 16 V AC was present in the inverter. As the moment that the 16 V AC was supplied in the inverter, the two gate of the H bridge of the inverter, open that cause the fault in the inverter the reason the fault was present or the fuse in the 380 V dc was open. The reason only the could lead to its explanation as the noise in the ground knowingly that the VARIAC was externally supplied the inverter, also with the use of the isolating transformer it didnt answer the problem. Another conclusion that the researcher came up that cause this project to not feasible in our case was the supply of 380 V DC, the supply must comform with the pure DC supply, given that the use 380 V dc in the inverter was came from the full wave rectified voltage comes in the VARIAC.

Power Inverter

Eso, Michael C.Gomeseria, Roniele J.Nual, Jerson G.Pagilagan, Rashleigh Rhon V.

Technological Institute of the Philippines Manila

ACKNOWLEDGEMENT

The Researchers expressed their highest gratitude to all generous persons who helped them made possible the completion of the project.To Engr. Cayetano Hiwatig for being the adviser of the researchers and for his meaningful comments and valuable suggestion for the improvement of the projectTo Engr. Mabanta for being patient and sharing his expertise to the researchers on conducting the experiments.To the section of EE51FB1 for being supportive and helping the researchers in every inch of the way.The most important of all, the Almighty God, His love and blessings gave strength and guidance to the researchers as they finish the project.

The Researchers

DEDICATION

The researchers fondly dedicated this research work as appreciation of their deep gratitude to the following:To their parents Mr. Eso, Mr. Gomeseria, Mr. Nual, Mr. Pagilagan, for the moral support, love, and care to them as well as the financial support that they are always ready to give in order to make this project possible.To our Almighty God for all the blessings that He gave to the researchers and for His words that uplift our spirits during the lowest point in this project.

The Researchers

TABLE OF CONTENTSPagesTitle PageApproval SheetAcknowledgementDedicationAbstractTable of ContentsList of TablesList of Figures

CHAPTER I PROJECT AND ITS BACKGROUNDIntroductionObjective of the StudyStatement of the ProblemSignificance of the StudyScope and Delimitations

CHAPTER II THEORETICAL FRAMEWORK AND RELATED LITERATURERelated LiteratureRelated StudiesConceptual Framework / Research ParadigmDefinition of Terms

CHAPTER III - METHODOLOGYMethods of ResearchData GatheringResearch SettingRespondents of the StudyStatistical AnalysisQuestionnaireTechnical ApproachBlock Diagram Budgetary Outlay

CHAPTER IV PRESENTATION, INTERPRETATION, AND ANALYSIS OF DATA

CHAPTER V - FINDINGS OF THE STUDY, CONCLUSION, RECOMMENDATIONFindings of the StudyConclusionRecommendation

APPENDIX 1 THE PROJECT

APPENDIX 2 THE CLIENT

APPENDIX 3 OTHER PICTURES

APPENDIX 4 - DATASHEETS

APPENDIX 5 CURRICULUMN VITAE

BIBLIOGRAPHY

LIST OF TABLESTable TitlePages 2.1Summary Table of Related Literature

3.1Point Scale System

3.2Budgetary Outlay

4.1Statistical Treatment of Questionnaire

4.2Maximum Speed

4.3Average Speed

4.4 Minimum Soeed

LIST OF FIGURES

FIGURETITLE PAGES 3.1Structural Diagram

3.2Simulation

3.3Test Output Voltage

CHAPTER 1PROJECT AND ITS BACKGROUNDIntroductionNowadays, generation of electric power comes in different ways. These provide essential contributions to the world who is constantly in dire need of power. A lot of methods of power generation are now being developed and still on the process of improving to solve the energy crisis that the world might experience in the coming years. Utilization of equipment and available resources like car batteries could also be a way to solve these existing problems. However, these methods can only get raw energy which are not readily useable for the appliances. This is where significance of power inverters take place. Existing power inverters in the market has the capability to convert the DC power into AC power which are useful for generating equipment and household appliances such as computers, refrigerators, televisions and etc. However, all of these are not efficient way in running these products since it draws high current and usually requires battery utilization. As a result, power inverters comes into large sizes that can consume large spaces especially in households. The tablet-size power inverter provides specifications to correct the existing problems in using it in industry and personal uses. This inverter exhibits major development in terms of its portability. This could be essential characteristic that would give flexibility to the product thus, increasing its significance to the society. Despite of miniaturization, efficiency of the power inverter was still considered. Retaining the important characteristics of power generation such as power factor and output power needed by the appliances remained to be the focal point of the inverter. Furthermore, the project will be beneficial to continuous development of existing inverters.Statement of the ProblemThe purpose of the project is to create a tablet-size power inverter that can provide power to household appliances. It seeks to answer the following questions:1. How can the inverter be miniaturized?2. Can it provide safety while generating power for household appliances?3. Can the inverter provide an efficient power needed by household appliances?ObjectivesThe general objective of this project is to create a tablet-size power inverter that can provide power to household appliances. In the focus of the project are the following problems: To provide a maximum load of 2kVA To have a power density not less than 25W/in3 To create power inverter with a volume of not greater than 80in3 To have a voltage input of 380V DC To provide an output of 220V AC To have a frequency of 60Hz To have a power factor ranging from 0.7-1 To have an efficiency not less than 95% To have an input ripple current not greater than 20% To have an input ripple voltage not greater than 3%Scope and DelimitationsThe project limits its function as an inverter that can provide a sinusoidal output waveform. The project would only provide a 2kVA output for household appliances. The voltage source of the project is 380V DC that will be converted to 220V AC. The size of the project will have a power factor ranging from 0.7 to 1 only and have a power density of at least 25W/in3.

Chapter 2REVIEW OF RELATED LITERATURE AND STUDIES The global electrical demand now a days is steadily increases to meet the needs of the people in using electricity in their everyday lives. The cost of renewable energy technologies is on a falling trend and is expected to fall further as demand and production increases. As we see the fast growing availability of renewable energy around us, the problem is how this energy can be harness to use in our household demand. Electrical power transmission is classified into two methods: alternating current and direct current. Alternating current can be found in AC motor drives and long distance power transmission. The cyclic nature of alternating current enables the use of transformers, which use magnetic principles to alter voltage levels. By stepping up an AC voltage, a large amount of power can be transferred over a long distance with less energy lost in heating up a conductor due to a lower current requirement, since P=I2 R. As such, AC power is more conventional than high voltage DC systems due to the ease of stepping up voltage for transmission and stepping voltage down to household outlet levels. DC voltage also has a place in powering devices. Wherever there is a changing electrical current, a changing magnetic field accompanies it. In a device-level electrical circuit, the magnetic variations introduced by AC current manifest themselves as electrical noise. The effects of this can range from audible line hum in an audio system to inaccurate measurements in an electronic instrument. Thus, it is commonplace for a device such as an MP3 player to employ DC voltages that have been rectified and filtered from an AC wall outlet. An MP3 player also proves one other benefit of DC power transmission: it can be done with a compact form factor. Without a need for transformers or switching circuitry, battery-powered MP3 players, or any other portable device, can be made small enough to fit into a pocket. However, there may come a time when household AC power is cut off due to a power outage. The multitude of devices that are designed around AC/DC power conversion (computers, for example) would then no longer be able to operate. One solution to this problem is an auxiliary AC power generator, like those powered by gasoline engines, or DC/AC power inverters which use energy stored in batteries (a DC source) and emulate a wall outlet AC output through voltage boosting and switching to create a changing voltage with the proper amplitude across a load. In practice, DC/AC conversion is done with topologies of varying precision. It can be as simple as applying voltages of equal amplitude in opposite directions across a load to generate a square wave. This method achieves the AC voltage requisite of a changing voltage across a load, but this rough approximation has consequences discussed later in this paper. 11 Figure 1:Square, Modified Sine, and Sine Waves Comparison2 A more precise method of DC/AC conversion is the modified sine wave, which introduces a dead time in a normal square wave output so that higher peak voltages can be used to produce the same average voltage as a sinusoidal wall-outlet output. This method produces fewer harmonics than square wave generation, but it still is not quite the same as the AC power that comes from an AC outlet. The harmonics that are still present in a modified sine wave make modified sine-wave inverters unsuitable for use while electrical noise is a concern, such as in medical devices which monitor the vital signs of a human. Pure sine wave DC/AC conversion will introduce the least amount of harmonics into an electrical device, but are also the most expensive method. Since the AC sine wave must come from a DC source, switching must still take place. However, switching takes place with logic so that the energy delivered to a load approaches that of a pure sine wave. This means that extra components and design considerations are involved in the control circuitry of a pure sine wave inverter, driving up cost.The switched-capacitor (SC) power converter has received more and more attention because it has only semiconductor switches and capacitors. Thus, this kind of SC converters is one of the good solutions for low-power DC-DC/DC-AC conversion. Unlike the traditional converter, the SC converter needs no magnetic element, so they always have the small volume and light weight. The SC converter is usually designed for an output higher than supply voltage or a reverse-polarity voltage. This function fits many applications, e.g. drivers of electromagnetic luminescent (EL) lamp, white light emitting diode (WLED), op-amp, and LCD drivers. Up to now, the various SC types have been suggested for power conversion. In 1990, the first SC step-down converters were proposed by Japan researchers, and their idea is to switch MOSFETS cyclically according to 4 periods of capacitors charging/discharging for step-down conversion. In 1993, Cheong et al. suggested a modified SC converter with two symmetrical SC cells working in the two periods. In 1995, Chung and Ioinovici suggested a current-mode SC for improving current waveforms. In 1998, Mak and Ioinovici suggested an SC inverter with high power densit. In 2004, Chang proposed design and analysis of power-CMOS-gate-based SC boost DC-AC inverter. The advantage of this SC inverter is to reduce the electromagnetic interference (EMI) problem. In 2007, Chang proposed CPLD-based closed-loop implementation of SC step-down DC-DC converter for multiple output choices. In 2010, Hinago and Koizumi proposed a single-phase multilevel inverter using switched series/parallel DC voltage sources based on multiple independent voltage sources in order to reach the higher number of levels so as to reduce the THD value. In 2011, Chang proposed an integrated SC step-up/down DC-DC/DC-AC converter/inverter. In this paper, by using the 2-stage 4-phase SC boost and SPFM control, the boost DC-AC inverter is proposed not only to enhance full-wave output regulation via SPFM technique, but also to improve the THD value and provide the maximum gain proportional to the number of pumping capacitors.

Conceptual Framework

Invert Direct CurrentStep Down Direct Current

Invert Direct CurrentPWM, Digital Signal ProcessingHeat Sink utilizationBridge ConverterTemperature MaintenanceMOSFET switchingEfficiency MaintenanceAlternating Current

The basic function of the inverter is converting the DC input to AC output. The procedure to attain this function is through inversion of DC to AC peak amplitude. DC can be stepped down through DC-DC converter. The MOSFETs on and off using pulse width modulation will make the current alternating delivered from the microcontroller through a gate driver. Temperature maintenance would be significant in achieving high efficiency.

Chapter 3Research Design and MethodologyIn this chapter, the different methods to quantify the needed data for the experiments are discussed. The different designs for the prototype are also presented to conduct several trials and achieve different results but in line with the objectives of the study.The approach used in this study includes Technical approach to focus on both gathering data and testing procedures.Types of ResearchThe type of research that will be used in this study are basic research, applied research and quantitative research. Basic research provided knowledge enhancement for the researchers, which is needed for the further study to be conducted. This type of research laid down the foundation for the applied research. Since applied research is considered as problem solving research, it will be a help to the researchers to meet the different specifications of the project. Lastly, the quantitative research is based on numeric figures or numbers. By quantitative research, it will measure the quantity or values and compares it with the past records and tries to project for future period. Also, experiments, testing procedures and calculations are most needed in this study. These show the attainment of the specifications and objectives of the study.Experimental Design1. Study the structure of the inverter2. Identify the functions of each component3. Create an inverter4. Apply microelectronics to miniaturize the inverter5. Create again the mini inverter6. Run some test to check if specifications are attainedResearch SettingThe research is conducted in a work place which can provide the different components needed for the creation of prototype. Since in running test procedures can cause failure or damage to component, it is necessary to work on a work place where there is an easy access to these components. Moreover, protective devices such as fuses are included in the circuitry of the design. Budgetary OutlayItemQuantityCost

Inductor1 pcPhp 1,500.00

Power MOSFET 47N60C34 pcsPhp 120.00

6A diode4 pcPhp 300.00

Capacitor1 sheetPhp 350.00

Fuse10pcsPhp 150.00

PWM Microcontroller1 kiloPhp 20.00

12V Rechargeable Lead Acid Battery1 pcPhp 495.00

Voltage Regulator (LM7805 & LM7812)12 pcPhp 136.00

Clamp3 pcPhp 60.00

Electronic Parts1 setPhp 160.00

Wires5 mPhp 60.00

Aquarium1 pcPhp 750.00

Electrica006C Tape1 pcPhp 20.00

Mighty Bond1 pcPhp 75.00

Light Receptacle1 pcPhp 25.00

PVC 1 1 tubePhp 190.00

90 Angle Connector2 pcPhp 70.00

Aluminum1 sheetPhp 120.00

Total CostPhp 4601.00

Data Gathering Procedure and Instrument UsedThe set-up for the instruments would be established first before conducting the actual gathering of the data. Figure 3.1 and figure 3.2 illustrates the two set-ups of the project to conduct the actual gathering of the data.

Figure 3.1: 240V Split Phase Configuration

Figure 3.2: 240V to Ground Configuration

The data will vary according to the load. The design will consider the power factor ranging from 0.7 to 1 leading or lagging. The testing procedures will only be focused on the load side of the configuration, load bank. Industry softwares like Multisim, Matlab and PSpice. These softwares will be responsible for determining the following parameters to be considered in the design:1. Total Harmonic Distortion plus Noise2. Input Ripple Current and VoltageOther parameters will be measured through DMM and multitester. These include the following: output voltage, frequency output. The efficiency of the device will be determined by taking the measurement at 6 different load levels as shown in the table 3.1.Table 3.1: Weighting Factors for CEC Efficiency Calculation

CHAPTER IVPRESENTATION, INTERPRATATION, AND ANALYSIS OF DATAThis chapter shows the interpretation and analysis of data obtained from the several trials conducted by the researchers. The data are analyzed and tabulated to interpret the results from each designs.CALCULATEDMEASURED% DIFFERENCE

TrialILOAD (A)Ripple Voltage (V)ILOAD (A)Ripple Voltage (V)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Table 4.1 Ripple VoltageCALCULATEDMEASURED% DIFFERENCE

TrialILOAD (A)Ripple Voltage (V)ILOAD (A)Ripple Voltage (V)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Table 4.2 Ripple Current

CHAPTER VFINDINGS OF THE STUDY, CONCLUSION AND RECOMMENDATIONSThis chapter includes the summary and interpretation of the data gathered from the experiment. The recommendations for further improvement of the study are also discussed. The different suggested solutions to avoid the recurring problems during testing procedures are also explained.Findings of the StudyDuring the conduct of testing procedures, multiple problems arose. Several trials are made and during each of these trials, different problems occurred. In the first design, short circuit happened in the AC output current feedback input of the PWM microcontroller. The problem occurred largely because of the timing in the switching of the microcontroller and the voltage input DC of the circuit. During the second trial, the first voltage induced in the circuit is the 380V DC input and then followed by the 16V AC after stabilizing the first input voltage. In just split seconds after putting the 16V AC, the protective devices included in the circuit suddenly tripped as well as the VARIAC. Short circuit in the input side happened that caused tremendous amount of current that tripped all the adjacent fuses. Timing of the switching of the drivers caused the problem and the gradual increase of the DC voltage input as time varies. Another possible cause is the grounded voltage input that can put up noises that would eventually trigger the switching process of the pulse-width modulator. The last design tried to resolve the problems regarding the grounded voltage input. Through the use of an isolation transformer, it removed the grounded configuration of the DC source