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Switch Mode Invertor Designing 5000watts RMS.

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Junior Member level 2
Sep 23, 2009
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Hi all i am Designing a Invertor that uses High Freq's to drive a High Freq Transformer that will be converted back to DC then using a Pure sinewave Circuit to drive High voltage Mosfets to switch the DC voltage of 240volt the output would be a nice puresinewave 240volt 15amp
The DC volts in would be about 24volt DC from 2 car batts in series this will be regulated for the High Freq controler and the Pure Sinewave Controler.
The high Freq controler is based on the SG3524 wich will drive Transistors or mosfets that will then supply a 24volt Center Tap High Freq Transformer that will be bridge rectified back to 240VDC this will supply power for the High Voltage Fets that will switch 240volt @ 50hz the gate on the fets will be controlled by the Pure sinewave controller.
the invertor will a rating of 5000watts RMS.
any input will help Thanks.

I guess in a way this would be a Switch mode invertor.

here is the first part of the PCB it has the 10voltage warning this PCB is for the last stage it generates 50hz/60hz square wave the emittor and collector connects to another PCB that has two LM386 that make it into a sinewave and that will switch the power Transistors. (240volt) the selection of the Transistors will be the hard part the transistors i have in mind is mj11028G they can handle 300watts RMS and 120volt that is the part i am worried about that it would be the voltage exactly from what i know its always better to be some volts higher for protection especialy with invertors.

This will be a very inefficient inverter.More than half of total power consumed from the battery will
be dissipated in the inverter.

lol.. that will never survive at 5kw.

check out this thread for much better examples of real products in the power range you desire.


this is just a driver circuit the Transistors are not shown. this is the diagram of most of it but i am trying to get rid of the bulky transformer.

PS its funny how most people just leave a message on this website like oh that not work or something like that and leave nothing else the point of this website is to share idea's i guess many people have forgoten that thank you at leased you given some input but as for it does not work at 5kw it does.

PS i forgot to mention i will expaned on the Filter section when i make it and i will upload photos of the finished product with it working in the photos.
Plus with Meter and Scope connected and a nice load.

i had a look at the link and the 3773npn Transistor you would need alot of them like 19 on each side to get about 5200Watts as they are 150watts each.
THE MJ11028 TO-3 is a nice 300watts each.
but thank you MR cool but i have seen the CD4047 used the SG3524 is better as it can have voltage adjust and voltage sence and freq control.

Added after 25 minutes:

so using the MJ11028 you will need about 9 on each side clearly you would connect them in parra to the 3055 and then get a Massive Transformer that is custom made to handle this hence i wanted help to make some changes but it does not look so good. but anyway i have all the stuff to finish mine as for someone else attempting this you will face 2 problems Heatsink's for the T0-3 its hard work drilling all those holes and finding a nice long heatsink Second is the Transformer will be another pain if you want 5000watts.
Recomended to get a Transformer with this Specs.
Primary 48Volt Center Tapped (200amps) Secondary 300Volt 20amps no keep in mind that the sensing Transformer will clamp the Voltage at 240Volt so the Extra windings on the 300volt is for when the batt's start to drop voltage to give some head room also Transformers or really anything will drop some volts with LOAD so remember this too.

Are you trying to do something like create a 5kW, 240V sinusoidal power supply by using mosfets configured like a class-B amplifier?

right now i have a invertor based on the designs that are shown i am trying to get idea's from people here into making this easyer for anyone to build.
the current design shown works well yes its a Mod wave right now but i wish to make changes to get a sinewave and also to use high freq transformers thus making it flexable to different batt configs right now this design can take different batt configs just change the transfomer for example if you start out with a 12volt batt system and have a 12volt Center Tap Transformer @ 1000watts changing the batt config to 24volt would mean you have to change the transformer and second i am not using mosfets because they are very very clumbs when it comes to dealing with sudden load changes hence i used Solid transistors.

the only two mosfets Style Transitors TIP120 are for amplifing for when i add a filter network for the base of the transistors there will be a signal drop as any Freq Filter gets hence they are there, i have tested with out them and this works fine.

Added after 42 minutes:

Here are some Random photos to show yes i am in the finishing Stages And YES this is nearly working but i want better i want to improve it.

I'm really curious to see what Wire Gauge you will use to your Battery, that will handle the 200 AMPS or MORE.
Also Curious to see the Primary winding of the Transformer.

And what High Frequency Diodes at these current ratings?

First of all a 5kW switcher is not something to take lightly. Looking at your test setup:

Those long wires will result in leakage inductance. That together with switching 200A is going to give you many headaches. Remember L(di/dt)? A inverter of this size needs careful planning and layout to minimize stray components, and adequate protection systems unless you like the smell of burnt semiconductor devices.

Sit back and do a few calculations ( sanity check 8O ) and get a picture of the task at hand. Push pull topology at this power using bipolar's will be a challenge to say the least. There are much more to this than you think.

BTW I'm not just talking, but from experience designing high power inverters.

Good luck!

yes the wires where a mess and yes i know that for the final i would use shorter and thicker wire as i said i am just testing so far.
and if you really think you know what your talking about then you would see by the pictures this is just switching 600Watts and is not switching 5000watts in those photos it was just a Concept there would need to be alot more Transistors and YES Bigger Cable.

if you really think you know what your talking about then you would see by the pictures this is just switching 600Watts

The attitude shown in this post may be understand as a pretty strong hint to better ignore this thread for the time being...

The text posted with the said photo was actually talking of 1000W@12V input. It's o.k. to say it's meant for 600W or even less,
but you didn't mention this. My impression, is, that the other contributors knew very well, what they are talking about. Your posts
didn't prove yet the same.

Over this topic;
Sorry, its only an inkorrekte Spinnerei or Zeitvertrieb, but we dont need it_I think...

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