Transformerless Inverter

I gave that a GA.

I have this LINK in my favourites. I have also previously run it under a simulation and it does work. Also, lower right on the schematic is the 470uF capacitor...connect a few of these suckers together and you get some nice results with increasing voltage and some workable current. The guy says it is not a charge pump, but sure behaves like one when you tinker with the schematic a bit as I mentioned.

Tinker with the lower left 22uF capacitor on the schematic and the 9.1V zener diode does change things slightly

To make this circuit workable, I would beef up the transistors.

Down side is using an inductor as opposed to a transformer.

Need to state your current / power requirements. A charge pump, especially anything over 3 stages, only works for low-current / low-power designs.

Why no transformer?

If you are concerned about size and weight, a high frequency converter/inverter design (with a small ferrite core transformer) might be a better choice.

Quite.

Link.

When there is an easy and efficient way to do it (transformer) and that in return puts an inductor in series (thereby helping in filtering the harmonics) why one should not do it except in case specifically asked not to do it (by the professor) ?

It would certainly work, but I think it's "cheating". Although you don't have a transformer (i.e. two windings, magnetically coupled), you do still have a "primary winding" (in the 24Vdc motor) and a "secondary winding", mechanically coupled.

Accepted,but ultimately it depends on how OP see It.

No, it would certainly not work, remember that OP needs 50 Hz. on the 400-volt side.

Yahlasit

"... so I have to boost 24V DC to 400V DC ..."

That is a quotation from the OP. Try reading it.

One more way to do it is, sell 24Volts source and buy 10 new sources of 1/10th AH rating of 24VDC and connect them in series.

No electronics, no transformers.

How much power do you need?

That determines practicality.

500 watts power

IMHO you need a switch mode inverter design which will use a ferrite core transformer. Good efficiency and small size can be obtained if your operating frequency is about 50kHz or higher. With proper design techniques, very small and efficient converters can be built up to 1MHz switching. However, for the average electronics project builder, anything above 100kHz gets pretty difficult.

Fisrt you need to boost 24V DC. use DC-DC converters available in the market or you can design your own: www.powerint.com/ ; good luck

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Fairly standard 200Vdc bus to 60Hz 120V PWM Sine wave inverter. Basically the 2nd half of what the OP needed. The 1st half would be a DC-DC step-up from 24V to 200V.