pure sine wave inverter

[Vladmir]

i want to design a pure sine wave inverter, using a quadrature oscillator to serve as the sine wave gen. and a 555 timer and 2n3906 as the triangular wave gen. please how do i go about it.

 

[Audioguru]

The sinewave and triangle wave feed the inputs of a comparator IC. The output of the comparator will have the Pulse-Width-Modulation waveform that drives output Mosfets that drive a stepup transformer.
Your circuit should use output voltage regulation.

It is difficult to make a symmetrical triangle waveform with a 555. Usually a dual opamp is used, the first one is a Schmitt trigger and the second one is an integrator. They oscillate to make a perfect triangle wave.

 

[m.mokhtar]

Using XR2206 will give you the sine wave directly and a mains transformer will step up you voltage to the required voltage

 

[Audioguru]

Using XR2206 will give you the sine wave directly and a mains transformer will step up you voltage to the required voltage

1) The Exar XR2206 IC is not made anymore.
2) The output power of the XR2206 is extremely low. If a linear amplifier boosts its power then the amplifier will waste a lot of battery power making heat.

 

[lw1ecp]

Just an idea: I once thougt of making a sinewave inverter this way: a quick-and-dirty unregulated DC-to-DC, suplying high voltage DC to a switching power stage, driven by a PWM created from sine values. An inductor in series with the output smooths the pulses into a continuous sine.

 

[Audioguru]

Just an idea: I once thougt of making a sinewave inverter this way: a quick-and-dirty unregulated DC-to-DC, suplying high voltage DC to a switching power stage, driven by a PWM created from sine values. An inductor in series with the output smooths the pulses into a continuous sine.

Yes, some inverters use a DC to DC converter at a high frequency so the transformer is small with a ferrite core. Then they use high voltage Mosfets to switch the output with Pulse-Width-Modulation. The output filter is usually an LC, not just an inductor.

 

[Vladmir]

i got circuit online, but i'm having problems getting the calculations for the values of the resistor and capacitors used. i tried making use of the f=1/2*pi*RC formula but i don't seem to be getting a result.

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i though the waveform from the PWM is fed into two mosfet drivers and then used to drive the mosfet. i only have the output from the transformer in the dc to dc converter section being fed into the mosfet.

and you were right about the 555 timer, it gave me a sawtooth waveform instead.