State/source dependence error when power module configured to 'sub-cycle average' instead of 'switched'

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1

Hi,

Attached is the primary-side of a typical Flyback converter, utilizing the chopper (low-side switch with reverse diode) power module with the series diode shorted as the working switch, and input gate signals captured via the PWM Capture block. The circuit works as expected when the power modules are configured in ‘switched configuration’.

However, error messages related to state/source dependence during switching between the transformer and power module (see attached pic.) occurs when sub-cycle average configuration is used in the power module. Adding parasitic capacitors and resistors in series between the transformer / power module does not seem to resolve the issue.

Would building the Flyback onto the RT Box using a discrete MOSFET device along with capturing the PWM capture output using the Data Type block be a viable approach?

Thank you so much.

plecs_flybacktrans.png
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plecs_error.png
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2

This is potentially an approach for you, but not one we generally recommend as you don’t get to benefit from the efficiency and high-frequency sampling of the power module/PWM Capture blocks, respectively. But if you are able to post your model here we can give feedback on how to deal with the state/source issue and still use the recommended approach.

3

Okay, thank you so much.

Just to double check, if the digital-out block was used to provide the PWM signal from the controller subsystem, it does not have to be received by a digital-in, a PWM capture block can also be used?

Best regards.

4

Yes, that’s correct. But of course, the PWM signal itself is then only updated and generated at the rate of the model step size (which may be acceptable for your application).