About half bridge converter.

Happy sundays.
Im currently working on half bridge transformer converter and have a question for you guys.
The circuit scheme is here ;

The circuit based on design handbook. It ready front of me but before energies the circuit i desided to ask you guys something.
A and B is trigger signal. Here it is ;

Deadtime is 2us. The driver circuit is made by ir2110. And based on Tahmids.blog. Ch1 is LO and CH2 is HO output pins.

the first question is as you can see on scope ,HO have spikes and im wondering can those spikes turn on my first igbt at turn off position ?
The second question is when i pulsing igbts without connecting to main supply , on +DC and -DC are acting like short circuit. Im saing that cause when i take my multimeter to connectivity tester and check those point of my circuit.

Because of those issues im confussing ! Cause those igbt s are last ones and i really dont want to ruin those.

I hope you can answer my question with urgent cause i cant wait to see its working
Thanks.

Edit.: Also forget to mention another issue. The primery side of the transformer has nearly equal to zero resistance. The transformer wounded by me.

The noise on HO is ground noise and is mostly a function of scope grounding. It is ok.
You are not applying 230Vac yet. When you plug into the power line you can not have a scope probe on the IGBTs. Grounding your scope probe will cause sparks. Please add a fuse & or breaker.
I use a isolation transformer to be more save and to allow me to connect a scope probe.
Some times I use a 220V to 24V transformer to give isolation and to reduce the voltage to a safer level. This makes the 310vdc 30vdc. This is a good place to start.

qwertyqwq said:

The primery side of the transformer has nearly equal to zero resistance.

Click to expand...

The DC resistance is just the resistance of the wire. At 100khz (switching frequency) the current is a function of the inductance of the primary and the resistance has little to no effect.

ronsimpson said:

The noise on HO is ground noise and is mostly a function of scope grounding. It is ok.
You are not applying 230Vac yet. When you plug into the power line you can not have a scope probe on the IGBTs. Grounding your scope probe will cause sparks. Please add a fuse & or breaker.
I use a isolation transformer to be more save and to allow me to connect a scope probe.
Some times I use a 220V to 24V transformer to give isolation and to reduce the voltage to a safer level. This makes the 310vdc 30vdc. This is a good place to start.


The DC resistance is just the resistance of the wire. At 100khz (switching frequency) the current is a function of the inductance of the primary and the resistance has little to no effect.

Click to expand...

Thanks
First like you mentioned scope grounfing issue i have already isolated from ground of my oscilloscope. The power bar ‘s ground cable disconnected and circuit energy cable has not ground cable also.
And second i was thinking of using a isolated variac transformer for my main supply project but didnd found on my country yet. Every isolated variacs are in unfortunately UK and China. UK is expensive (also hard to tracking) and China has virus. But i will use a transformer as you told like 230Vac/24Vac voltage ratio.

ronsimpson said:

The noise on HO is ground noise and is mostly a function of scope grounding. It is ok.

Click to expand...

Actually my scope isnt connected to ground because i dont want to burn my scope when i m working on nonisolated power supplies. If i forget to remove probes from circuit especially when im keeping my mind how to hard to buy a scope here , this will not good for me.

Anyway i will get a transformer before try this circuit on main supply.

At total so you are saying it looking good right ?
Thanks again.

ronsimpson said:

The noise on HO is ground noise and is mostly a function of scope grounding. It is ok.
You are not applying 230Vac yet. When you plug into the power line you can not have a scope probe on the IGBTs. Grounding your scope probe will cause sparks. Please add a fuse & or breaker.
I use a isolation transformer to be more save and to allow me to connect a scope probe.
Some times I use a 220V to 24V transformer to give isolation and to reduce the voltage to a safer level. This makes the 310vdc 30vdc. This is a good place to start.


The DC resistance is just the resistance of the wire. At 100khz (switching frequency) the current is a function of the inductance of the primary and the resistance has little to no effect.

Click to expand...

And i forgot to ask you Ron.
What do you think about my second question ?