Pulsing high current into capacitive load?

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Discussion Overview

The discussion revolves around the challenge of pulsing high current into a capacitive load, specifically addressing issues related to the RC time constant and the inability to start pulses from zero amps. Participants explore potential solutions to improve the efficiency of the setup.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant describes the issue of delivering 80 Amps at 1 KHz into a capacitive load, noting that the high RC constant prevents the pulse generator from starting at 0 amps.
  • Another participant suggests providing more context about the purpose of the setup to better understand the problem.
  • A different participant proposes using a higher resistor value to achieve a faster decay rate, calculating a suggested resistance of 200 ohms based on a desired decay time of 0.2 ms.
  • One participant recommends using a variable square wave generator and a MOSFET as a potential solution.
  • A later reply indicates that the original problem was resolved by generating a second low-powered pulse that is 180 degrees out of phase to discharge the capacitor.

Areas of Agreement / Disagreement

The discussion includes multiple competing views and proposed solutions, but there is no consensus on the best approach to the problem. Some participants suggest alternative methods while one indicates a solution has already been found.

Contextual Notes

Participants do not clarify the specific characteristics of the capacitive load or the implications of the chosen resistor values, leaving some assumptions and dependencies unresolved.

waht
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I have to pulse 80 Amps @ 1 KHz into a capacitive load of a few uF. Unfortunately the RC constant is high enough that it prevents the next pulse to start from 0 amps. So in a sense the pulse generator delivers about 70 to 80 amps per cycle instead of 0 to 80 amps like it would in a non-capacitive load.

I fixed this temporarily by hooking up a 0.75 ohm high current resistor in parallel so it could discharge the load when the pulse is off. However I'm wasting a lot of power this way.

So I'm wondering if there is another solution?
 
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You might try being more specific about the purpose of your setup and what it is intended to accomplish.
 
put a higher resistor instead of a such small one.

your decay rate should be faster than 1msec, let's say it is about 0.2msec, so RC = 0.2msec => R = 200ohms?
 
Have you tried using a variable square wave generator and a mosfet?
 
Farlander said:
Have you tried using a variable square wave generator and a mosfet?

Thanks for replying, but the problem has been solved two months ago. We basically generated a second low powered 180 degree out of phase pulse to discharge the cap.
 

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