Design and Simulation of a MOSFET-Based Inverter using Battery

Design and Simulation of a MOSFET-Based Inverter using Battery

Prachi Dhunde, Vinayak Zirmile, and Parth Shirsat

Dept of Electrical Engineering, AISSMS Institute of Information Technology

Project Guide: Prof.S.S Shingare

Abstract – The inverter functions as a vital power electronics component which transforms direct current (DC) electricity into alternating current (AC) electricity to power standard AC devices that operate on battery-powered systems. The paper presents the entire procedure which requires the development and evaluation and construction of a MOSFET inverter system that functions from a 12V battery. The system uses an H-bridge design which enables MOSFETs to operate as rapid switches that create an AC output waveform.

The engineers designed the inverter circuit and validated its performance through simulation testing which assessed crucial operational parameters that included output voltage and load current and switching characteristics and total efficiency. The report explains how the inverter operates while describing how MOSFETs achieve efficient switching operations. The simulation results show that the system successfully changed DC power into AC power while maintaining reliable switching operations and producing acceptable output results.

The proposed system connects with the ThingSpeak IoT platform which enables users to monitor inverter performance parameters in real time while displaying those metrics through visual tools. The cloud-based monitoring system allows tech- nicians to perform remote voltage and current monitoring which enhances system monitoring capabilities and voltage and current performance assessment.

The study shows that MOSFET-based inverters deliver energy-efficient low-power performance with minimal switching losses for use in portable power supplies and backup systems and renewable energy systems. The next phase of the project will focus on developing PWM-based sine wave generation methods and advanced filtering techniques which will decrease harmonic distortion and enhance output waveform quality.

1. INTRODUCTION

   These days theres a lot of talk about renewable energy and portable power sources, so converting between different types of energy is super important in electrical stuff. Batteries are key for storing energy, and they output direct current, DC, which feels pretty steady and reliable for a lot of uses.

   But most home appliances and machines in factories or wherever need alternating current, AC, to run properly. That creates a real issue, right, because you cannot just plug in a battery directly most of the time.

   Inverters helps fix that by converting DC supply into AC. They are in things like uninterruptible power supplies for computers, solar panel systems, electric cars, and even backup generators for emergencies. Without them, a bunch of modern tech wouldnt work so smoothly.

   The performance of an inverter depends a lot on its internal components, such as the switches and transistors inside. When this technology started, designers used bipolar junction

   transistors, or BJTs, which were okay but not the best one.Then MOSFETs took over, and that changed everything because they handle switching way better with less hassle. MOSFET is short for Metal Oxide Semiconductor Field Effect Transistor, I believe that is the full name. What stands out about MOSFETs is how they only require a small amount of current to turn on and off, which is great for battery powered inverters. Energy efficiency counts a lot in those setups, it seems like, especially when you are trying to make things last longer. This is basically about designing an inverter, looking at how it behaves under different conditions, and running some simulations to test it out. Some parts of the explanation might feel a bit off or not fully clear, but that is how it goes sometimes.

2. OBJECTIVE OF THE STUDY

   Converting DC power from a battery to AC power is a crucial process, and this study aims to achieve it in a simple and efficient manner. The focus is on designing and testing a MOSFET-based inverter, which is a type of converter that utilizes MOSFETs to switch on and off quickly, thereby min- imizing power losses. MOSFETs are ideal for this application due to their fast switching capabilities, making them a key component in creating an efficient converter. The primary objective is to take the DC power from the battery and convert it into AC power, which is the standard power format used in most homes and devices. This project has significant implications, particularly in situations where AC devices need to be powered using battery power. By developing an efficient MOSFET-based inverter, we can optimize the use of battery power and make it more practical for various applications. The converters efficiency and simplicity are critical factors, as they will directly impact its performance and usability. Overall, this study aims to provide a innovative solution for converting DC power to AC power, which can have a substantial impact on the way we utilize battery power in our daily lives.

   Another key objective is to understand the working princi- ple of the inverter, particularly the role of the H-bridge con- figuration in producing an alternating output waveform. The research also focuses on evaluating important performance parameters such as output voltage, load current, efficiency, and waveform characteristics.

   The goal of this project is to examine the limitations of a basic square wave inverter, specifically when it comes to

   harmonic distortion, and to identify potential solutions, such as utilizing Pulse Width Modulation (PWM) and filtering techniques. By leveraging simulation, we aim to test theo- retical concepts and ensure the inverter design functions as intended under various conditions. This approach will enable us to evaluate the inverters performance, pinpoint areas for improvement, and gain insight into its behavior. Furthermore, we will investigate how PWM and filtering can mitigate harmonic distortion and enhance the overall performance of the inverter. This knowledge will ultimately allow us to better design and optimize inverters for a range of applications. The simulation will be instrumental in helping us understand how the inverter operates and whether it meets our expectations, thereby providing a foundation for future improvements. As we explore the capabilities of PWM and filtering, we can develop more efficient and effective inverter designs.

3. METHODOLOGY

   The methodology adopted in this research involves a systematic approach that includes circuit design, component selection, simulation, and performance analysis.

   To start, we need to design the inverter circuit, and were going to use a full-bridge, also known as an H-bridge, topol- ogy. Weve chosen a 12V DC battery as our input source. Now, we arrange four MOSFETs in a bridge configuration, which allows us to reverse the current flowing through the load. When it comes to selecting the right MOSFETs, there are a few key things we need to consider. First, we need to think about the voltage rating – its got to be high enough to handle the job. Then theres the current handling capability

   – we dont want our MOSFETs to get overwhelmed. And finally, we want low ON-state resistance, so our circuit can operate efficiently. By choosing the right MOSFETs, we can make sure our inverter circuit works smoothly and does what its supposed to do.

   To regulate the MOSFETs, a switching system is created. This system utilizes a square wve oscillator, such as a 555 timer or signal generator, to produce gate pulses at a frequency of 50 Hz. These pulses are then applied to the MOSFET pairs in a complementary manner, resulting in the generation of alternating current at the output. It is also crucial to introduce a brief dead time between the switching signals, which prevents short-circuit conditions from occur- ring. This dead time is essential because it prevents the MOSFETs from being activated simultaneously, which could lead to a short circuit. By incorporating this dead time, the switching system can function correctly and safely, thus preventing potential damage to the circuit. The dead time serves as a safety mechanism, ensuring that the MOSFETs are not turned on at the same time, and it allows the switching system to operate efficiently and reliably.

   So youve got your circuit designed, now its time to see how it works. You use special programs like MAT- LAB/Simulink, Proteus, or LTspice to run a simulation. First, you build a model of your circuit in the program, and set all the important details, like the voltage going in, the resistance of the load, and how often the switch turns on and off. Then

   you do a thing called transient analysis, which shows you how the voltage and current change over time. This is really helpful for figuring out how your circuit will act in the real world. Its like a test run, before you actually build the circuit. You can see how it behaves, and make any changes you need to, before you start building. This way, you can be sure your circuit will work the way you want it to, and you wont have any surprises when you turn it on.

   Finally, the performance of the inverter is analyzed based on the simulation results. Parameters such as output wave- form, RMS voltage, load current, efficiency, and harmonic distortion are evaluated. The results are compared with theoretical expectations to validate the design. Based on the analysis, conclusions are drawn and possible improvements are suggested to enhance the performance of the inverter.

4. THEROTICAL BACKGROUND

   1. WORKING PRINCIPLE OF INVERTER AND MOSFET OPERATION

      An inverter flips DC into AC by constantly reversing the currents direction. So basically, it turns the straight, one way flow of DC into an alternating pattern like a heartbeat, always switching back and forth.

      If you look at a basic square wave inverter, it just swaps between the positive and negative side of your DC input. The math behind it. Maybe a bit tricky but you can picture it as the sign flipping every so often, kind of like a seesaw. Its definitely AC just not smooth there are lots of rough edges because extra frequencies sneak in.

      Now, about MOSFETs theyre the real stars of the show here. Since theyre voltage-controlled, you just apply a voltage to the gate, and if its high enough compared to the source, the gate opens up and lets current zip through. Take the voltage away and the gate slams shut no more flow.

      In inverters, MOSFETs act like lightning-fast switches, flipping on and off to craft that AC pattern. Theyre super efficient, too, thanks to their speed and the tiny resistance they have when on. Thats a huge deal for devices running on batteries because every bit of saved energy counts. Honestly, the way they keep things humming along without wasting power? Thats pretty impressive.

   2. MATHEMATICAL REPRESENTATION OF INVERTER OPERATION

   A square wave inverter is pretty straightforward. The output voltage just snaps between the positive and negative sides of the DC input. The basic formula is:

   Vout(t) = Vdc · sgn(sin(t))

   That breaks down like this: V dc is your DC input voltage. means 2 times the frequency, so if youre running at 50 Hz or 60 Hz, just plug those numbers in.

   As time ticks by, the output switches sharplyno gradual slope, just flipping from positive to negative. Its like fol- lowing the shape of a sine wave, but instead of smoothly rising and falling, its all or nothing. So the inverters output

   is always at full voltage, either positive or negative, never anything in between.

   RMS Value of Output Voltage

   With a square wave inverter, the RMS output voltage is the same as the DC input so VRMS is just Vdc. Thats pretty useful when you are trying to work on how much power goes to the load.

   Load Current Calculation

   Figuring out the load current is straightforward. Grab Ohms Law: I = V / R. Here, I stands for load current, V is your output voltage, and R is the resistance of the load.

   Fourier Series Representation (Harmonics)

   A square wave isnt just a simple toneits loaded with harmonics. If you break it down with a Fourier series, heres what you get:

   ” #

   V (t) = 4Vdc sin(t) + 1 sin(3t) + 1 sin(5t) + · · ·

   3 5

   So when you see a square wave, youre actually looking at a blend of all these odd harmonics: sin(t), sin(3t), sin(5t), and more. Thats what gives the wave its sharp edges and punchy sound, instead of the smooth look or tone of a pure sine wave.

   MOSFET Drain Current Equation

   When a MOSFETs in the active region, you can figure out its drain current with one simple equation:

   ID = k(VGS VT H )2

   Basically, the current shoots up as the gate-source voltage beats the thresholdall squared, and then scaled by the constant k. Engineers rely on this relation to tweak and control MOSFETs in their circuits. Its a handy way to predict how much juice is flowing.

5. INVERTER TOPOLOGY AND OPERATION

   This design uses an H-bridge configuration. Picture four MOSFETs laid out like a bridge, with your load connected right in the middle where the pairs meet.

   Heres the idea: To get a positive output, you switch on one pair of diagonally opposite MOSFETs. That sends current through the load one way. For the negative output, you turn on the other diagonal pair, so the current flows the other way. Switching between those pairs creates an AC waveform across your load. Youve gotta be careful though. If you accidentally turn on both MOSFETs on the same side, youre basically shorting out the batterythats called shoot- through. The fix? Add a bit of dead time between switching

   so theres no overlap. That keeps your circuit safe.

6. CIRCUIT DESIGN AND COMPONENT

   SELECTION

   This inverter runs off a 12V battery, so you start with a simple DC inputpretty standard for portable gadgets and DIY projects. It keeps everything straightforward and easy to work with.

   When it comes to MOSFETs, pick ones rated for higher voltages than your battery. You also want low ON resistance,

   Fig. 1. Components Selection

   so you dont end up losing energy as heat. The IRFZ44N works well hereits efficient, tough, and easy to find just about anywhere.

   To actually switch the MOSFETs, youll need an oscillator circuit. A 555 timer fits the bill and is sort of a go-to component for beginners and pros alike. It produces a square wave, which decides your AC output frequencyso, 50 Hz or 60 Hz, depending on where you live.

   That oscillator signal isnt strong enough on its own, so you need a driver circuit next. Its job is to boost the signal high enough to drive the MOSFET gates properly. Give them plenty of gate voltage, because if the signals too weak, the MOSFETs dont fully turn on. You lose power and risk them heating up for no good reason.

   Fig. 2. Circuit Diagram

7. SIMULATION METHODOLOGY

   Before you start building the inverter, its smart to run a simulation first. That way, youll know if the design actually works. Programs like MATLAB/Simulink, Proteus, or LTspice make the whole process pretty straightforward. You just build your circuit, press play, and see what happens. Start by putting together the H-bridge. Grab the MOSFET models that come with te software, connect your DC voltage source, and add a resistor for the load. The gate signals can

   get a bit tricky, so make sure the MOSFETs switch together in pairs but opposite from the other pair. Thats what makes the inverter function.

   When the circuits all ready, run a transient analysis. Youre looking for the output voltage to swing from positive to negativeif it does, your design works. Keep an eye on the current, power, and any losses from switching. This whole process gives you a clear idea of how well your inverter performs, long before you have to mess with real hardware.

   Fig. 3. MOSFET Based Inverter Circuit

8. RESULT AND DISCUSSION

   Fig. 4. MOSFET Based Inverter Circuit

   The simulation makes it clearthe inverter takes a 12V

   DC input and flips it into AC, bouncing between +12V and – 12V. You get a square wave, meaning the H-bridge is running just like its supposed to.

   The current going through the resistor depends on how big the resistance is. With a 100-ohm resistor, the current stays pretty low, so this setup is really only good for low-power jobs.

   Efficiency matters a lot with inverters, and here it mostly depends on the MOSFETs. Losses happen both while theyre conducting and while theyre switching. Most MOSFETs have low ON resistance and switch fast, so you can expect solid efficiencyusually somewhere between 85% and 95%. Still, square wave inverters have their ugly side. Harmonic distortion is the main problem. The output isnt just one frequencyits loaded with other, unwanted frequencies.

   Those harmonics can mess up sensitive electronics and drag down the overall power quality.

   A. ThingSpeak-Based IoT Monitoring

   The proposed MOSFET-based inverter system is integrated with the ThingSpeak IoT platform for real-time monitoring and visualization of inverter parameters. The system continu- ously uploads important electrical parameters such as battery voltage, inverter output voltage, and inverter current to the cloud platform for analysis.

   The graphical data obtained from ThingSpeak helps in evaluating inverter performance under different operating conditions. Real-time monitoring improves system reliability and enables easier fault analysis and performance optimiza- tion.

   Fig. 5. Thingspeak Dashboard

9. CONCLUSIONS

This paper presented the design, simulation, and imple- mentation of a MOSFET-based inverter powered by a 12V battery source. The inverter successfully converted DC power into AC output using an H-bridge configuration. The simu- lation results confirmed the proper operation of the inverter and showed satisfactory voltage and current characteristics. MOSFETs were chosen as switching devices because of their high switching speed, low power losses, and efficient performance in battery-powered applications. The simulation

Fig. 6. Thingspeak

and analysis showed that the proposed inverter offers reliable operation and good efficiency for low-power AC applica- tions.

Integrating the ThingSpeak IoT platform allowed for real- time monitoring and visualization of key inverter parameters such as output voltage and current. The cloud-based monitor- ing system improved performance analysis and highlighted how IoT technology can be used in modern power electronic systems.

Even though the generated square-wave output has har- monic distortion, the inverters performance can be improved by using Pulse Width Modulation (PWM) techniques and output filtering methods. Future work may include develop- ing a pure sine-wave inverter, better protection circuits, and improved IoT-based monitoring and control systems.

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