500VA sine wave inverter , problem in HBridge and filter designing

[--BawA--]

It was a small orange color ceramic capacitor
Aec104 PF ceramic capacitor.

 

[FvM]

How do you know that it has sufficient voltage rating? Even if the voltage rating is sufficient, the AC current may be still too high. But in this case, it won't "explode", rather overheat.

 

[ALERTLINKS]

Working voltage is less if it is small.
**broken link removed**

 

[--BawA--]

How do you know that it has sufficient voltage rating? Even if the voltage rating is sufficient, the AC current may be still too high. But in this case, it won't "explode", rather overheat

FvM ,i am not sure but i think these capaciror can handle 1000V ,
I have used 6 ceramic capacitors on DC bus . But only one or two exploded. I replaced them with new one but after some time of operation , the capacitor exploded again .all other components are safe.i have also used electrolytic and film capacitor.
Which ceramic capacitor must be used ? And what might be the reason for explosion..?

 

[FvM]

What's the capacitor's size? A 100 nF/1000 V capacitor from a major manufacturer looks like that:

Here's a respective SMD capacitor with some data like AC current capabilities.

 

[--BawA--]

What's the capacitor's size?

Its regular disc type ceramic capacitor of diameter 7mm.
Can i replace this capacitor with tantalum capacitor? If yes , what should be the required part no.?

 

[FvM]

Can i replace this capacitor with tantalum capacitor?

What's the operation voltage of the capacitor? I thought up to now, it's connected to the high voltage DC bus, there's no tantalum capacitor available for high voltage.

 

[--BawA--]

FvM, the only thing written on ceramic capacitor is AEC104. So m unable to find out its maximum operating voltage.and i am wondering 'why only two capacitors out of six got damage.
Do u know any ceramic capacitor on which the voltage rating is mentioned clearly?
Also one more thing i have to ask "when i tested the H-bridge at 12V,the output on the multimeter was
8.2V ac.and the waveform was clean sinusoidal.
And when i tested the bridge on 311V with 60w resistive load ,the output voltage on the multimeter was not constant ,its varying from 0 to 176 rapidly
I checked the waveform on oscilloscope and it was again sinusoidal (little distorted) and the V max was around 240..i am confused why multimeter is not showing constant volatge ?.

 

[--BawA--]

FvM , how to adjust the modulation index in code? I have used 32 values in sine table..

 

[FvM]

Sounds like a pure software problem that should be discussed close to the involved microprocessor features and performance. E.g. a processor with hardware multiplier can easily calculate duty cycles for each sine sample on the fly.

 

[--BawA--]

FvM , u meant that in order to increase the modulation index,i have to multiply each values of sine table with some constant number?

 

[--BawA--]

FvM. Please correct me if i am wrong in post #111

 

[FvM]

Yes, if it's a table of sine values, multiply each entry with a constant factor.

 

[arif01230]

Please post your 500VA sine wave inverter Code and Simulation