How to convert Square wave to sine wave in inverter output

Hi... guys..

i have a square wave inverter circuit for 1KVA.

I need to convert square wave to sine wave from that output.

Suggest me some circuits to get sine wave from square wave.

Thanks in Advance...

Re: How to convert Square wave to sine wave in inverter outp

There is no easy way to convert a “power” square wave to a “power” sine wave ..
It is low-frequency wave, so no reasonable filter can do it ..
If you try to filter the output of a square-wave inverter with a 50Hz filter (huge inductor + huge capacitor) then not only it will reduce the output power but if you remove the load you are in trouble (series-resonant circuit) ..
You are stuck, mate ..

IanP

Re: How to convert Square wave to sine wave in inverter outp

Thank you. Ianp...

then what is the solution for my square wave inverter to sine wave..

Tell me some other ideas..

Hello,

Only when you have access to lots of transformer cores, copper, capacitors, and space to leave everything, an LC series circuit followed by an LC parallel circuit will do the job.

This is a band pass filter where both circuits are tuned at the mains frequency EXACTLY. You also have to rewind the output transformer depending on the current output voltage as the BPF lowers the RMS output voltage. You will get 205Vrms with a 230V square wave. As the tuning circuits will be slightly off resonance (practically spoken), a minimal load may be required (this can be the losses in the inductors).

The parallel circuit is required to "catch" the inductive energy from the inductor in the series circuit. If this is an option I can give you some starting values.

When this is no option, you need to build or buy a true sine wave converter. These devices first convert the low voltage to an isolated DC high voltage. This DC high voltage feeds a PWM full bridge circuit that runs at 20kHz or above.

Please post the sinewave inverter circuit or send to my box.

In dc Frequency circuit it may easy to convert square to sine... The LC circuit is do the conversion work.. but you have to take huge L C values,
Go threw this attachment It may usefull to you...

@sentilkumer thank you ,i will try the post you sent

The way to convert a squarewave to a sine wave is to add other squarewaves to it.

This is often called a Walsh Generator and with just three basic harmonicaly related sqwarewaves a few XOR gates and a "summing circuit" will produce a sine wave with more purity than you are likley to need and the first harmonic spur being 16f away from the fundemental frequency.

Usually the summing device is resistors into the inverting input of an op-amp but that is not going to be man enough.

The solution is to sum squarewaves into independent windings on a transformer using a class D etc driver. The magnetic core summs the currents and delivers them out of the output winding as a sine wave.

I've used this arangment from UPS's to AM band transmitters.

Just google "walsh transform generator sinewave" to get the info.

Pls someone answer, is it possible to convert the 220v output of a square wave inverter to sine wave?

I'm also looking for this type of converter. Can anyone help on this regards?