RC Snubber Design Hint for 3 phase AC-AC PWM Chopper

[ow19m]

Hello ,
 Im trying to design a 3 phase Ac-Ac Pwm Chopper, I'm having difficulty designing the snubber network for the mentioned topology.

 Now I tried testing this circuit on bench , with my IGBT snubber values being 10Ω10W and 0.47uF Resistance and Capacitance Respectively, Highlighted in red .While my Output RC network Highlighted in Blue had values 10Ω10W and 2.2uF Resistance and Capacitance Respectively. This was strictly a hit and trial without any type of short-circuit overload protection circuitry. For trials firstly I ran my circuit on 3 100W lamps. When I ran my circuit , all the freewheeling diode network along with the IGBT's blew off. This had to happen probably because I wasn't thinking clearly and I believe I made a huge mistake of putting 2.2uF caps on the output without any kind of choke in series . How can I optimize my 2 RC networks so that it doesn't blow off at least because of the hardware ,Also For now I have no input Filter on my Circuit.I've Also given the Rated Motor Parameters below for the current Motor I was going to run my Circuit on in future.

Circuit Parameters  :
IGBT : FGA25N120 , 25Amp
Supply Voltage : 220V
Line Frequency : 50Hz
Switching Freq : 1KHz

Motor Parameters :
Rated Power      : 4Kw
Line to Line Voltage : 380v
Frequency         : 50Hz
Stator Resistance  : 1.43Ω
Stator Leakage Inductance : 0.00523H

Citation Link : https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8675728

[jonpaul]

1/ Check IGBT reccomended snubber placement and values. . Ask mfg and see specs and app notes.

2/ Resistors should be metal oxide or WW,  but flameproof for safety and safety compliance.

3/ Caps should be AC rated and specific for snubber application! Some VDE X caps may be used if the VAC is within  rating   250 VAC

RC snubbers as a single part are available 


4/ Design, components, proto and debug of a 4 kW power electronic requires special experience and test equipment. Do you have it?

Bon Chance


Jon

[Terry Bites]

Heres the thing....

[johansen]

380 volts into a 10 ohm 2.2uf rc is 38 amps.

The R part of the rc snubber should match the load.

A diode pumped capacitor with a resistor on the capacitor is a better choice here. Start small and debug your circuit at low voltag. Its likely you blew it up because the igbts didnt turn off (lack of dead time or lack of gate drive).