Half bridge power supply

gb_R said:

GDT voltage and signals are same on both side.

Click to expand...

KlausST said:

Hi,

A half bridge is made to run from DC ... I am not surprised that it does not work on AC.


I would be very suprised if this is true.

***
We don´t know what "perfect" means in your case.
We don´t have a schematic to check correctness.
We don´t have datasheets of the used parts.
We don´t have scope pictures to see signals and their timing.
We don´t even know what´s the power supply specification regarding output and input.
We even don´t know what the HIGH side and what the LOW side IGBT is on the given picture.
We don´t see the PCB layout ... like GND plane and low inductance wiring, current loops sizes and so on.

Without knowing anything about your power supply ... it´s impossible to help.

Klaus

Click to expand...

cupoftea said:

hi,
you do half bridge but remember they go out of balance when done in
current mode.

This has been discussed many times on this forum before....try a google search of "edaboard easy peasy half bridge"
Easy Peasy has good info on this.

Current mode Half Bridge converter.

Hi, We all knew that Half Bridge shouldnt be done in Current Mode. But with software to guide it, Current mode becomes possible. You simply repeatedly measure the voltage on each of the series stacked capacitors....(by using two potential dividers)...and then you slightly adjust the alternate...

www.edaboard.com

Voltage Mode Half Bridge made easier.

We are doing a 3kW Half bridge converter. Vin 600V, vout = 24v. Done in voltage mode for obvious reasons. (Split cap balancing etc) Cant we just find the output LC resonant frequency....(which is also the frequency of the troublesome output double poles). So then all we do is find the Output...

www.edaboard.com

It always used to be said that a dc blocking cap was needed
when in voltage mode. Then the voltage build up on the blocker will oppose the
off balancing factor. But be sure your cap blocker is not too big. You need it
to show some voltage change during the cycle on time.
Anyway, current mode with slope compensation also can be workable with
half bridge.
Also, some people do extra circuits to detect the imbalance, and then reduce
one of the gate drives minutely, so as to even things back up again...but generally
, nobody bothers with that and just does a 2 tran forward instead.

Click to expand...

cupoftea said:

hi,
you do half bridge but remember they go out of balance when done in
current mode.

This has been discussed many times on this forum before....try a google search of "edaboard easy peasy half bridge"
Easy Peasy has good info on this.

Current mode Half Bridge converter.

Hi, We all knew that Half Bridge shouldnt be done in Current Mode. But with software to guide it, Current mode becomes possible. You simply repeatedly measure the voltage on each of the series stacked capacitors....(by using two potential dividers)...and then you slightly adjust the alternate...

www.edaboard.com

Voltage Mode Half Bridge made easier.

We are doing a 3kW Half bridge converter. Vin 600V, vout = 24v. Done in voltage mode for obvious reasons. (Split cap balancing etc) Cant we just find the output LC resonant frequency....(which is also the frequency of the troublesome output double poles). So then all we do is find the Output...

www.edaboard.com

It always used to be said that a dc blocking cap was needed
when in voltage mode. Then the voltage build up on the blocker will oppose the
off balancing factor. But be sure your cap blocker is not too big. You need it
to show some voltage change during the cycle on time.
Anyway, current mode with slope compensation also can be workable with
half bridge.
Also, some people do extra circuits to detect the imbalance, and then reduce
one of the gate drives minutely, so as to even things back up again...but generally
, nobody bothers with that and just does a 2 tran forward instead.

Click to expand...