high frequency full bridge inverters

[aumkota27]

high frequency inverters

HI everyone

hope ur all doing well..

I have a very fundamental question related to power electronic circuits.
if we use a high frequency full bridge inverter circuit, what will be the neutral to earth, line to earth voltage developed...

thanks very much..

 

[kabiru]

Re: high frequency inverters

Hi, you mention high freq inverter, note that when ever you drive high freq with bridge arrangment the out put will be AC and in what application are you using the inverter?

 

[aumkota27]

hi..
yes the output will be AC. the application is just a transformer less inverter.
pls throw some light on the neutral to earth voltage when we use the emi filter at the output and at the ac input.

thnx and bye

 

[kabiru]

I dont think their will be a problem when connecting you EMi filters cos their no any contunity btw nuetral and earth in your filters.

 

[aumkota27]

i am seeing a variable voltage of 90-200v between neutral and earth , as i used a Y- capacitor in the emi filter. Actually the ideal voltage should be less than 5v.

please explain me why am i getting this voltage.


thnx and bye

 

[kabiru]

Hi, what type of instrument do you used to measure you voltage? if you are using digital meter, it could be result of noise that why you are seeing variable voltage try to use analog meter and see what happen.

 

[FvM]

Are you talking about voltages at the inverter output? There is no "neutral" at all, both AC output lines should be simply considered L1 and L2.

 

[aumkota27]

hi kabiru..
i am measuring the voltage with digital multimeter as well as i am seeing it in oscilloscope also . clearly i can see the noised sine wave at neutal wrt earth i.e..90-250.


hi fvm..

ok ..if we consider there are only L1 and L2, then what will be the voltage between L1 to earth and L2 to earth. The topology i used is the full bridge with lc filter and emi filter at the output. My carrier frequency is 19KHz

 

[FvM]

You didn't tell, if or how the bus voltage is connected to protective ground. Also various filter topologies can be imagined.
But generally, there is no neutral in a full bridge output, and I don't see a reason to want it.

 

[aumkota27]

hi

the filter topology used is single stage differential and a two stage common mode sequentially. if we do not consider neutral and consider only L1 and L2 in the full bridge mode, what will be the voltage across L1 to earth and L2 to earth.

the DC bus ground is connected to the sources of the two lower mosfets. as you know the output voltage L1 and L2 are taken from the mid points of the two legs of the full bridge.

please throw some light on earth potential wrt L1 and L2.


thanks and bye

 

[kabiru]

Hi aumkota, L1andL2 are your output you are connecting you filter across the output so what is you problem with the ground, and what type of filter do you used with your inverter?