How Can I Make a Pure Sine Wave Inverter with Limited Voltage and Current?

In summary, the conversation is about a student who is trying to make a pure sinewave inverter for a project. They initially had a specific specification, but their supervisor and lab manager have different limitations on voltage and current. The student is seeking advice and recommended resources for their project. The conversation also includes suggestions for using a microcontroller or other components to generate the desired sinewave output.
  • #1
dmaj
2
0
Hi i am a 3rd year electrical student, i have a limited knowledge about inverters. i am trying to make a pure sinewave inverter, my intial spec was to create a 1) boost converter dc to dc 2) 3 stage pwm using a bubba oscillator etc 3) using a filter.

my supervisor for the project said i could make this spec @ 220volts however the person in charge of the lab said we are limited to 0.5A or 1A and about 30volts.

I am now confused and don't know what to do any advice or recomended textbooks or links will be greatly appriciated

thank you
 
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  • #2
You can make an inverter from 12 v dc to ac, then use a transformer to increase the voltage to 220 V ac.
But the problem in the control signal of the switching devices(Mosfets, IGBTS..). In order to make a sine wave inverter you need to vary the duty cycle of the PWM signal applied to each switching device in a sinosiodal manner, so you can use a microcontroller like PIC 18f2331 to generate PWM signals, and you can test your program using a simulator which is Proteus, it is very good for simulating micro controllers.
After the generation of the control signal you have to make a driver circuit for the Mosfets, since the control signal voltage is about 5v and the Mosfet need a voltage greater than 5v to switch on, so you have to make a driver stage, you can use IR2110 integrated circuit for driving the mosfets, see the data sheet for more information about the connections.
The third stage is to filter the signal in order to get the 50 HZ output, LC filters are used for such applications.
 
  • #3
Oh wow thanks, I used a 555 timer to generate a pulse 2kHz but i am having problems getting the negative cycle of the squarewave. i tried inverting(not gate) the signal and putting into a H-bridge chip(L293), still no negative cycle. i got two pulses that are out of phase o_O. I designed and simulated a active filter which works perfectly using a 741 op-amp. I will looking into the microcontroller option thanks a lot ^_^
 

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  • #4
you don't really need a negative pulse to form the negative part of your AC output, what u should do is to get flip-flop chip (D-type) feed your control signal through the flip flop data input and take your complementary outputs from the the Q and ~Q pins. However, doing this will cut your output frequency in half, so you have to go back to the timing circuit, and increase the frequency(i.e if your ac frequency is f then the signal frequency input to the flip flop will be 2f i.e timing frequency of your 555 timer should be 2f) Note: I suggest that you try using sg3524, it has complementary outputs and the control circuitry is simplify. Refer to the datasheet to see details. see the attached file

Also, note that to have pure sine wave ac output, you need to use High frequency ferrite transformer because at high frequency iron core transformer will saturate easily and overheat causing damages to your circuit.
 

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  • #5
  • #6
Your problem is mainly political. Maybe you should mention to your supervisor the lab manager's objection to you producing voltages above 30 volts, presumably for safety reasons.

Then they could sort it out between them.

Depending on where you live, this may be a safety regulation that places your inverter into the same category as mains equipment, and for very good reasons. You could kill yourself and your relatives could sue the school.

You could contact the local Electrical authority and ask for the relevant regulations.

It seems strange to generate a square wave when you really want a sinewave. Why not use an opamp to generate a sinewave?

Or, use a binary counter to feed a digital to analog converter and generate an approximate sinewave like that.
 

What is a pure sine wave inverter?

A pure sine wave inverter is a type of power inverter that converts direct current (DC) electricity into alternating current (AC) electricity with a smooth and consistent sine wave output. This type of inverter is used to power sensitive electronic devices, such as laptops, TVs, and medical equipment, as it provides a cleaner and more stable power source compared to modified sine wave inverters.

How does a pure sine wave inverter work?

A pure sine wave inverter works by using a DC power source, such as a battery or solar panel, and converting it into AC power through a series of electronic components. These components, including transistors and capacitors, are used to manipulate the DC input waveform to produce a smooth and consistent AC output waveform that closely resembles the power provided by the electrical grid.

What are the benefits of a pure sine wave inverter?

The main benefit of a pure sine wave inverter is its ability to provide high-quality and stable power that is suitable for sensitive electronic devices. This can help prevent damage or malfunctions in these devices. Additionally, pure sine wave inverters are more energy-efficient and produce less electrical noise compared to modified sine wave inverters, which can extend the lifespan of electronic devices.

What are some common applications of pure sine wave inverters?

Pure sine wave inverters are commonly used in off-grid or backup power systems, such as in RVs, boats, and cabins, as they can convert DC power from batteries or solar panels into AC power. They are also used in medical equipment, telecommunications, and other sensitive electronic devices. In some cases, pure sine wave inverters may also be used in residential or commercial settings to provide backup power during power outages.

How do I choose the right pure sine wave inverter for my needs?

When choosing a pure sine wave inverter, it is important to consider the power rating, input voltage, and output voltage requirements of your electronic devices. You should also consider the type of battery or power source you will be using, as well as any additional features such as surge protection or remote monitoring. It is recommended to consult with a professional or read product specifications carefully to ensure you choose the right inverter for your specific needs.

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