 14th January 2010, 08:55 #61
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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 HBRIDGE 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 HBRIDGE
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
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 Hbridge like IR2110/L6385. There are many others.
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 14th January 2010, 19:04 #62
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Re: i need 12V DC to 220V AC inverter circuit
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
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 20th January 2010, 17:36 #63
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i need 12V DC to 220V AC inverter circuit
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.
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 20th January 2010, 22:21 #64
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Re: i need 12V DC to 220V AC inverter circuit
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
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 21st January 2010, 18:57 #65
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Re: i need 12V DC to 220V AC inverter circuit
hi
I am having difficutly understandin the ka3525 IC, i need to wire it up to give 50hz to control a hbridge,
help anyone !
 22nd January 2010, 07:42 #66
 22nd January 2010, 18:31 #67
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i need 12V DC to 220V AC inverter circuit
Hameeds,
The "500W" inverter you posted from ElectronicsLab 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 squarewave with its voltage unregulated and many electronic products do not work from a squarewave.
 24th January 2010, 03:30 #68
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Re: i need 12V DC to 220V AC inverter circuit
check this this is from old elektor
 26th January 2010, 16:29 #69
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Re: i need 12V DC to 220V AC inverter circuit
To build an HBridged 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 HBridge output of either mosfet or igbt powered by your DC bus, and your AC load is connected to the HBridge output directly.. with some filters .
 31st January 2010, 03:26 #70
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i need 12V DC to 220V AC inverter circuit
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 optocoupler for driving
 1st February 2010, 11:27 #71
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Re: i need 12V DC to 220V AC inverter circuit
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 HBridge, and the other two which are in antiphase to drive the other two adjacent outputs.
 1st February 2010, 20:52 #72
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i need 12V DC to 220V AC inverter circuit
thanks
there is no gate driver transformers in the circuit (PCB)
 2nd February 2010, 19:06 #73
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Re: i need 12V DC to 220V AC inverter circuit
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
 7th February 2010, 20:55 #74
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Re: i need 12V DC to 220V AC inverter circuit
Ok, let us slow things down a little for easy understanding.
Check this out, hope it helps.
Enjoy.
 7th February 2010, 22:00 #75
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Re: i need 12V DC to 220V AC inverter circuit
THANK YOU VERY MUCH.......
NOW i have another question.......... how do i convert a square wave to sine wave
to pulse the h bridge
 7th February 2010, 22:27 #76
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Re: i need 12V DC to 220V AC inverter circuit
Originally Posted by KRYCHEK
The Hbridge operates from the 345VDC. The Hbridge is pulsed with PWM at about 25kHz. The PWM is modulated with a 50Hz sinewave. The output of the Hbridge is filtered with an LC lowpass filter into a 50Hz 220VAC sinewave. Since the carrier frequency is 25kHz then the filter's inductor and capacitor are small.
If you tried to filter a 50Hz squarewave into a sinewave 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.
 8th February 2010, 03:54 #77
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Re: i need 12V DC to 220V AC inverter circuit
HI Audio guru
Currently i have designed a modified sinewave inverter
The HBridge 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
 8th February 2010, 16:00 #78
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Re: i need 12V DC to 220V AC inverter circuit
Originally Posted by KRYCHEK
Inexpensive sinewave inverters use PWM at about 25kHz and the PWM is modulated with a 50hz sinewave. 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 sinewave 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
Different loads and different battery voltages will affect the output voltage of your inverter. You will want to add negative feedback for voltage regulation.
 8th February 2010, 16:10 #79
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Re: i need 12V DC to 220V AC inverter circuit
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 HBridge.... 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
 8th February 2010, 16:10
 8th February 2010, 19:41 #80
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i need 12V DC to 220V AC inverter circuit
You need to use a 50Hz sinewave to modulate the SG3525. The LC filter at the output removes most of the 120kHz switching frequency.
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