High Power SCR Driver Design for Plasma Compression Coil Activation

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SUMMARY

This discussion focuses on the design of a high power SCR driver for activating a plasma compression coil using two high power hokeypuck SCRs. The user inquires about the necessity of inserting diodes between the optoisolated drivers (U1 and U2) and the limiting current resistors (R1 and R2) to manage the cathode voltage falling below 0V. The circuit design includes a 6mF capacitor charged via resistor R5, which discharges through the superconducting inductor L1, with a control signal triggering the discharge process.

PREREQUISITES
  • Understanding of SCR (Silicon Controlled Rectifier) operation and applications
  • Knowledge of plasma physics and plasma compression techniques
  • Familiarity with circuit design involving optoisolators and high power components
  • Experience with inductive load management and energy discharge systems
NEXT STEPS
  • Research SCR gate drive circuit design best practices
  • Learn about the role of diodes in SCR circuits and their placement
  • Study the characteristics of superconducting inductors in high power applications
  • Explore methods for managing inductive kickback in SCR circuits
USEFUL FOR

Electrical engineers, power electronics designers, and researchers in plasma technology will benefit from this discussion, particularly those involved in high power SCR applications and plasma compression systems.

Javier Lopez
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I have made following design to drive two high power hokeypuck SCRs to activate a Plasma compression coil. As long as catode falls below 0V, I do not know if it is needed to insert diodes from the optoisolated driver A1 (and A2) and the limiting current resistor R1 (and R2):
 

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Where exactly would you insert those diodes? And can you show the full circuit for the gate drive circuits?
 
Here is the complete drawing. U1 and U2 are isolated drivers. I ask if I have to insert a diode between U1 and R1 and another between U2 and R2 (in the forward resistor direction). (The R3 and R4 are set to drain the inducted voltage due high dV/dt at SCR due >10kAmps are drain).
My idea is to charge the 6mF capacitor using R5, then drain the capacitor energy through the coil sorrounding the plasma that is L1 by using a trigger signal named "control". As long as L1 is a superconducting inductor, most of the current will come back to the capacitor then I will switch off the device :)
30m6beg.png
 

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