high frequency inverter - sinewave ?

Thread Starter

youdontknowme

Joined May 30, 2017
15
Hi,

I'm planning on making a high frequency inverter that is able to produce sine wave. This is for wireless power transfer with a load of 12vdc at the receiver side.

Transmitter side :
Input of the inverter will be 12VDC. Then 555 timer will be used to create 100khz squarewave.

How do i make it to sine wave ??

ScottWang

Joined Aug 23, 2012
7,065
Square wave through two stages of RC filters will be become sine wave, but the amplitude will be smaller, so you need to amplifying the sine wave to the amplitude you want.

Papabravo

Joined Feb 24, 2006
16,833
What is your goal for power output in watts versus power in, also in watts?

BobTPH

Joined Jun 5, 2013
3,690
You can feed the square wave directly into a series LC tuned circuit where the L is the coil used for transmitting the power. It will turn into a sine wave.

Bob

Thread Starter

youdontknowme

Joined May 30, 2017
15
Square wave through two stages of RC filters will be become sine wave, but the amplitude will be smaller, so you need to amplifying the sine wave to the amplitude you want.
say 150khz squarewave output from the 555 timer, what
What is your goal for power output in watts versus power in, also in watts?
around 10W

Thread Starter

youdontknowme

Joined May 30, 2017
15
Square wave through two stages of RC filters will be become sine wave, but the amplitude will be smaller, so you need to amplifying the sine wave to the amplitude you want.
how do i calculate the values of the RC needed in the 2 stages ?? say for 150khz square wave

You can feed the square wave directly into a series LC circuit where the L is the coil used for transmitting the power. It will turn into a sine wave.

Bob
how do i calculate the values of LC needed for 150khz square wave ?

BobTPH

Joined Jun 5, 2013
3,690
If you want to design circuits, you should know how to do that. Look up the formula on Google.

Bob

Papabravo

Joined Feb 24, 2006
16,833
...

around 10W
Didn't you read my question? You gave one answer, and I was expecting two. Is 10W the input power or the output power?

ScottWang

Joined Aug 23, 2012
7,065
You can feed the square wave directly into a series LC tuned circuit where the L is the coil used for transmitting the power. It will turn into a sine wave.

Bob
I tried the LC filter before, but the output amplitude of positive and negative is unbalance, so it needs to through op amp to adjust, maybe you have a better solution.

ScottWang

Joined Aug 23, 2012
7,065
I just doing a random test below, if you want the Vout2 more like the sine wave then the amplitude will be smaller, and you will need an op amp level shifter.

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DickCappels

Joined Aug 21, 2008
7,743

This is a keyed 187 kHz transmitter. You can leave out the 1N4148 and the related 4.7k resistor. It makes beautiful sine wave currents at the carrier frequency.

Use your own tank circuit and get rid of the LED and 100 ohm resistor.

Scaling will be needed to get up to 10 watts.

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