Quote:
Originally Posted by techhelpbb
A consistent load would be essential or it might poison your experiment.
I'm not sure what you mean by the Jaguar sourcing current to a Victor however.
Would it not be easier to just have a consistent load and a consistent source of power as static factors in your test?
I should think you'll need to monitor the load and source of power quite carefully and if that monitor is digital it'll have to have pretty high bandwidth for transients.
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The configuration I had in mind was a Jaguar running forward, bringing it's load node up high to +12V, and the Victor running reverse, bringing it's load node down to 0V, so that current flows:
Quote:
Jaguar M+ (at 12V) ---> Dynamic Load ---> Victor M+ (at 0V)
and
Jaguar M- (at 0V) <--- Dynamic Load <--- Victor M-(at 12V)
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In this configuration, both active legs see a stable constant current load, so both get a complete work out. Halfway through the test I'd flip the directions and work the other legs just as hard. Since the loss in the FETs are resistive and related to current, we'd only need constant current, not constant power, so the declining battery voltage is not necessarily a problem.
If my description still doesn't make sense, I can draw it up really quick and see if that makes more sense. The idea is the load current passes through both legs of both bridges while the FETs are monitored.
The problem with a consistent load is that resistors heat up and change resistance, and other components have similar temperature dependence. However I have not (yet) done the math to see if this variance is enough to warrant the trouble of a dynamic load. Perhaps it isn't necessary, though I agree I'd not want to use a digital controller to regulate the load, merely to program an analog feedback loop to regulate it due to bandwidth concerns.
Matt