i need 12V DC to 220V AC inverter circuit

i know the tl494 is running at very high frequencies,

can i use ka3525 ONLY TO SWITCH THE H-BRIDGE MOSFETS @60HZ IN Order to gain this frequency.

so to refresh i am using both ics TL494 AS THE MAIN IC TO GENERATE PWM

AND KA3525 JUST TO DRIVE THE H-BRIDGE

Click to expand...

Yes. TL494 to drive the Push-Pull. KA3525 to drive the H-Bridge.

Another way to look at it is,

THE CIRCUIT IS RUNNING AT HIGH FREQUENCIES..... USING TL494

HOW DO I GET 50HZ,

hope u undertand where i am going wrong

Click to expand...

Using TL494 the circuit is running at high frequencies.
Using KA3525 to generate 50 Hz, you drive the bridge at 50Hz and so the bridge outputs an AC voltage with 50Hz frequency.
You also need to use a hi/lo side MOSFET driver for the H-bridge like IR2110/L6385. There are many others.

YES TAHMID i have finally got my understanding correct, thank you very much,

just wondering if u could know, the inverter i have opened up has 2 tl494 ics inside it, am wondering how caould this combination possible generate 50hz ?

AND

a different inverter has only 1 pwm ic, is it possible to go from high frequency such as 100khz to 50hz by just using a 2nd order lc filter ?

cos this inverter has a massive inductor inside it, am thinking its either using cut high frequencies, or to simply clean the end resulted signal, which do u think ?

thanks once again

Hi,
Sorry for the late reply.
I've also seen inverters using 2 TL494's. Although it's beyond its suggested parameter, they have been working at 50hz.
I don't think just using a 2nd order lc filter, it's possible. I think that pwm ic is a microcontroller, most common I've seen is a dsPIC.
Hope it helped.
Tahmid.

The Inverters that use 2 TL494S i tried to reverse engineer, but still wouldnt work, the 2nd tl494 works by using both outputs collector and emitter to control the h -bridge, respectively,

on my uf4oo4 diodes am geting an output of 650v ish volts is this correct ?, i have ordered ka3525, just waiting for it to arrive,

1 question i need to ask is, if a inverter is rated at 150w, how is this power determined ? i mean where do u look at the datasheet

mosfets used 05n03L *2

will i still need to use lc filter ? and am thinking of makin it in a sine wave, any long winded ideas ?

many thanks tahmid

Added after 43 minutes:

Ave seen ur circuitry using ka3525, can i used this direct to generate 50hz for h bridge drive, the IR2101 TEST CIRCUIT, umm is it at 83hz ?
or any specific may be use to me ?

to tahmid

hi

I am having difficutly understandin the ka3525 IC, i need to wire it up to give 50hz to control a h-bridge,

help anyone !

Hameeds,
The "500W" inverter you posted from Electronics-Lab has many errors. Its output might be only 100W, it has no protection diodes and its R and C in the CD4047 oscillator have completely wrong values.

It stupidly uses two LM324 quad opamps instead of a single LM358 dual opamp.

Its output is a simple square-wave with its voltage unregulated and many electronic products do not work from a square-wave.

check this this is from old elektor

To build an H-Bridged Inverter, you can use the TL494 or K3525 in a chopper circuit to get something in the neighborhood of of 350V @ high frequency. You rectify its output to get clean DC, this will be your DC bus.

Next, you will have another TL494 or K3525 circuit. This time, your frequency of oscillation will be 50Hz driving H-Bridge output of either mosfet or igbt powered by your DC bus, and your AC load is connected to the H-Bridge output directly.. with some filters .

Is any simple method to drive Full bridge without using mosfet driver IC's like Ir2110 , i have one ups using full bridge with 4 CET CEP83A3 ( I ball make ) but not using any drives or opto-coupler for driving

There is one very simple way which i have used. I made a small driver transformer with four drive windings, two windings in the same phase to drive two adjacent outputs in an H-Bridge, and the other two which are in anti-phase to drive the other two adjacent outputs.

thanks
there is no gate driver transformers in the circuit (PCB)

Hi guys i need some help.

I am using 2* IR2101 TO drive each side of the mosfets, i am putting pwm from sg3525 @50hz into both IR2101 ICs i have tested both high side and low side, (diagram from datasheet) working...and with 6us deadtime. now how do i link which source to which drain, i,ie high to low or high to high if u know what i mean

thanks guys

Ok, let us slow things down a little for easy understanding.
Check this out, hope it helps.

Enjoy.

THANK YOU VERY MUCH.......


NOW i have another question.......... how do i convert a square wave to sine wave

to pulse the h- bridge

KRYCHEK said:

how do i convert a square wave to sine wave to pulse the h- bridge?

Click to expand...

The 12V from the battery is converted to 345VDC with a power converter circuit.
The H-bridge operates from the 345VDC. The H-bridge is pulsed with PWM at about 25kHz. The PWM is modulated with a 50Hz sine-wave. The output of the H-bridge is filtered with an LC lowpass filter into a 50Hz 220VAC sine-wave. Since the carrier frequency is 25kHz then the filter's inductor and capacitor are small.

If you tried to filter a 50Hz square-wave into a sine-wave then the resistance of the huge expensive inductor will be so high that most the inverter's power will be wasted in it. Then the output power will be very low.

HI Audio guru

Currently i have designed a modified sinewave inverter

The H-Bridge is powered using 350V, and pulsed using 50Hz, using sg3525

Can you please explain to me, how can i generate 25kHz.....

Then if i pass this frequency through an LC filter, how will i get sine 50hz

Please correct me if I am wrong

Thnak you very much

Added after 1 hours 31 minutes:

i also need to know, how do i test my inverter,

I mean i need to test it using different load and draw up a graph

150w

230V

how many ohms do i start off and what value do i finish at

THANKS GUYS

KRYCHEK said:

HI Audio guru

Currently i have designed a modified sinewave inverter

The H-Bridge is powered using 350V, and pulsed using 50Hz, using sg3525

Can you please explain to me, how can i generate 25kHz.....

Then if i pass this frequency through an LC filter, how will i get sine 50hz

Click to expand...

A modified sine-wave inverter has a square-wave output with only two steps. Since its frequency is only 50Hz then its stepup transformer is huge and expensive and it is impossible to LC filter into a sine-wave without reducing its power output to almost nothing since the huge and expensive inductor would have a high resistance and will get hot.

Inexpensive sine-wave inverters use PWM at about 25kHz and the PWM is modulated with a 50hz sine-wave. Then the LC filter is small and inexpensive. the DC to DC converter can also use the 25kHz frequency and its transformer will be small and inexpensive with a ferrite core.
Any simple oscillator can generate 25kHz. The minimum oscillator frequency for an SG3525 is 100kHz so use 120kHz. The oscillator in a TL494 PWM controller IC (it is used in many sine-wave inverters) is from 1kHz to 300kHz.

how do i test my inverter?
I mean i need to test it using different load and draw up a graph

150W, 230V

how many ohms do i start off and what value do i finish at

Click to expand...

An inverter should be tested with an adjustable load resistance. Use the wire from an electric toaster or a heater. Light bulbs draw 10 times their rated power when cold so are a poor load for an inverter. Use Ohm's Law to calculate the resistance.

Different loads and different battery voltages will affect the output voltage of your inverter. You will want to add negative feedback for voltage regulation.

Hi Guru

I am using tl494 for high frequency to convert to 350V dc BUS

and sg3525 for 50Hz

SO if i step up my frequency for sg3525 to about 120Khz....feed it into H-Bridge.... and then use a filter.... should i then get a sine wave i mean does this seem reasonable,

the pulses from the sg3525 are about 5 v i think which feed into ir2101......

thanks

You need to use a 50Hz sine-wave to modulate the SG3525. The LC filter at the output removes most of the 120kHz switching frequency.