12v DC to 220v AC Portable Inverter

This project's goal is to create an inverter circuit that will convert the DC power produced by the solar panels into AC power at 220V, making it possible to power a variety of electrical devices

For this tutorial we need:

• 1 x NE555 IC
• 4 x 1N4007 diode
• General value resistors
• soldering iron
• Capasitor
• Resistors
• BC547 transistors
• Led
• IRFZ44N mosfets x8
• Transformer 12-0-12 2A
• Insulation pads to insulate transformer base and high voltage side from touching each other
• 10A fuse
• A Long Ribbon Cable, and 
• A Breadboard or a Custom Built PCB 
• Don't worry I will share the nessary files at the end

In an era where mobile and off-grid power solutions are increasingly vital, the need for efficient, compact, and portable inverters cannot be overstated. These devices are essential for providing AC power from 0C sources, making them invaluable for camping, emergency backups, and mobile workstations. This article delves into the design and construction of a compact and portable 12V DC to 220V AC 50Hz inverter, highlighting its key features, components, and applications.

And yes this will also improves your electronics basics and trust me it will improve your self confidence and encourage you to make new things

DISCLAIMER

Try this only if you know how to save yourself from high AC voltages ⚡️

The inverter's design incorporates several critical components to achieve its performance goals. At its core are high-efficiency power MOSFETs used for switching, providing reliable and efficient operation. A high-frequency transformer is employed to step up the voltage from 12V DC to 220V AC. The oscillator circuit, based on the NE555 timer IC, generates a stable 50Hz signal to control the MOSFET switching. A dual integrator circuit is used to convert the square wave output to a sine wave, ensuring smooth and clean AC power. The control circuit, often microcontroller-based, manages the inverter’s operations precisely. To handle thermal management, heat sinks and cooling fans are incorporated, preventing overheating during high load conditions.

WORKING of refrence signal

here we are converting 12v dc to 220v ac at 50 hz

So first we need a refrence ocillator to give us a stable 50hz ocillation to begin with so we employ one of the most common ic ie NE 555 at astable ocillator mode

So how to do that?

Astable

The continuous output signal in Astable mode allows you to determine both the frequency in Hertz (Hz), how long it takes the signal to repeat and the duration of time the signal is in the high and low states. All three values that would define the output signal can be found using the values of R1 and R2 measured in ohms (Ω) and the capacitance value C1 measured in Farads (F).

Th= 0.693(R1+R2)C1

Tl= 0.693*R2*C1

f = 1.44 / (R1+2R2)*C1

So, for example a circuit with resistors of 10,000 (10k) and 15,000 (15k) ohms (Ω) of a resistance and a capacitance value of 10 microfarads (10 µF), the output signal would have the following characteristics

Time High

Th = 0.693(10, 00022 + 15, 00022)0.00001F = 0.1732s

Time Low

Ti = 0.693(15, 00022 x 0.00001 F) = 0.1039s

Frequency

f = 1.44/(10, 0009 + 2 x 15, 0002)0.00001 F) = 3.6Hz

Similarly we calculate our required frequency for 50Hz and hence we found the values for R1 R2 AND C1 as 4.7k 120k and 100nf respectively

So as we all know ne555 offeres one output that is from the pin number 3 but we need 2 similar signals to trigger our mosfets but at the same time the signal should be inverted to each other or in other words when one signal is high other should be low

So how can we do that , simple we use a bjt to solve that issue preferably an npn and I've used BC547

WHY we need 2 signal is that because we are using a transformer with a center tap and between the other two inputs the transformer must get same signal equal frequency amplitude and with one inverse of other so that transformer gets Powe at both cycles of ocillation

Above circuit gives us the expected result , only downside is that it can cause small voltage drop but that's not an issue since the signal is just used to trigger the main mosfets

Now we transform square wave to sine wave why ? Because our appliances are all running on 50hz 220v sine wave so running them on square wave can cause damages

How to convert ? Simple.... we use second order integrator to do that refer above image for the circuit

And yes it will give you the result at a cost of some voltage drop again that doesn't matter because this signal is just to trigger mosfets

We use 4 mosfets for each cycle in parrell configration why you may ask it's because we can reduce heat decipation and load on a single mosfet as total load gets divided amoung 4

And the output of mosfet is connected to transformer where the center tap is directly connected to 12v vcc and mosfet is set to switch ground sounds complex but it's actually simple

And there you go ur inverter is ready

Don't worry this is 100% working because we have tested it

And don't be fooled by the simplicity this is actually a winner : best project at keraleeyam 2023

: silver prize at IIT PALAKKAD for best hardware project hosted by KSCSTE

Project link : https://nithinmathewjoji.github.io/A-GN-web-page/

Amal Kumar A

Ashwin S Nair

Govind M Nair

Nithin Mathew Joji