Ceramic capacitors for filtering after the H bridge circuit

[STHOTA]

Can I use ceramic/ Non polarized capacitors for filtering purpose after the H Bridge circuit?

 

[FvM]

Better than polarized capacitors in any case. You need to observe sufficient voltage rating.

 

[STHOTA]

I actually used some experimentally. Simulation works absolutely well. But, when comes to the practical scenario,it didn't work. I was thinking the use of my non polarized caps after the H bridge are causing some short circuit and providing a reverse current. This indeed created a spark and crashed my Arudino. The circuit is here. I'm so confused about the discharge path now.

 

[KlausST]

Hi,

By "filtering" I assumed low pass filtering...but you made a high pass filter.

And what's the use of the 1mH inductor? And what's the use of the 10k resistors? I assume this all is useless somehow..
And what is connected at the output? An inductance? Causing a resonance in combination with the capacitors? With high resonance voltage?

A lot of unknown things.

Klaus

 

[mtwieg]

For an equivalent capacitance/voltage rating, ceramics are going to be much larger and costlier. But will have a much lower ESR. Be aware that capacitance may change greatly as you get above half the rated voltage.

 

[STHOTA]

Hi,

By "filtering" I assumed low pass filtering...but you made a high pass filter.

And what's the use of the 1mH inductor? And what's the use of the 10k resistors? I assume this all is useless somehow..
And what is connected at the output? An inductance? Causing a resonance in combination with the capacitors? With high resonance voltage?

A lot of unknown things.

Klaus

Hi,
The capacitors after the H bridge are to convert the PWM squares into a sine wave. The inductor present above along with capacitor should work as a filter that gives a better sine wave. The resistors are used just for the discharge path. In simulation, that combination is giving a perfect sine wave, but experimentally it is not working.
I tried another Low pass filter after the H bridge, below attached the figure, but I'm getting a damped sine wave signal. . Could you recommend any other design of filter there or any other values to L & C that i can try to make it work both in simulation & in practical?
Thanks.

- - - Updated - - -

For an equivalent capacitance/voltage rating, ceramics are going to be much larger and costlier. But will have a much lower ESR. Be aware that capacitance may change greatly as you get above half the rated voltage.

Hello,
Yes, I understand. I managed to get them some how, but was considered about the charge and discharge paths of these non-polarized capacitors,( since polarized caps charges only in one direction and non-polarized caps can get charged in both the directions). I assume this may damage the circuit/ gate driver/ arduino. Is there any other way, I could protect my circuit by still using these ceramic capacitors?
Thanks.

 

[KlausST]

Hi,

Against your schematic of post#3 now you really have a low pass filter. But it has no damping component and therefore the voltage at resonace is indefinitely high. Connect some load and it will behave totally different.

Both filters are not useful. You need to read some documents on how to calculate such filters.

Klaus

 

[STHOTA]

Hi Klaus,

Yes it is working differently under load. I'm working on some concepts about filters now. I will sure update the design. Please let me know if you know any better links regarding this concept.
I appreciate your help.

Sri