I am building a step up transformer for an output of 100 kV, 50 mA, at 50 kHz.

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For that I have planned to use a half bridge circuit with a ferrite transformer. However to test the circuit I am putting 30&nbsp;V DC across a half bridge input. I am using a TLP350 as a Gate driver. I am using 10&nbsp;&Omega; resistor as a *gate turn on* resistance, and a 1N5822 as a *turn off* diode for gate driver. 

[![Lower side IGBT gate voltage][1]][1]


This is my lower side IGBT gate voltage, the probe directly connected at IGBT legs. 15&nbsp;V. The probe is in 10X mode...

[![Half bridge output][2]][2]

This is my half bridge output, load is a 60 Watt 12 Volt car headlight. 

[![Voltage spike/overshoot at the leg of lower side IGBT][3]][3]

**This is my issue, a voltage spike/overshoot at the leg of lower side IGBT. Probe is connected in emitter and collector pin. Collector pin referenced to emitter**. This waveform taken without the snubber circuits. 

My question is how I can reduce the spike at the IGBT's collector emitter pin?

[![Test setup][4]][4]

This is my test setup for now. I have a **2&nbsp;µf, 2&nbsp;kV snubber** cap close to half bridge IGBTs. **10&nbsp;k&Omega;** resistor connected in gate and emitter at both IGBT to reduce accidental turn on. I am using **IHW40N65R5** IGBT with **DSEI60-12A** diode with each IGBT.
 
[![Lower side IGBT collector emitter voltage with snubber][5]][5]

After I put the snubber circuit my lower side IGBT collector emitter voltage look like this, spike reduced but little ringing happening now... Is that ok? Can I power up my circuit up to high voltage DC? Like 300 Volt DC?


  [1]: https://i.sstatic.net/U2Pna.jpg "Lower side IGBT gate voltage"
  [2]: https://i.sstatic.net/UF9PU.jpg "Half bridge output"
  [3]: https://i.sstatic.net/8bkWg.jpg "Voltage spike/overshoot at the leg of lower side IGBT"
  [4]: https://i.sstatic.net/qMOxA.jpg "Test setup"
  [5]: https://i.sstatic.net/imUBO.jpg "Lower side IGBT collector emitter voltage with snubber"