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TMS320F280039C: BuckBoost open/closed loop control issue

Cherry Zhou
Mastermind 22235 points
Part Number: TMS320F280039C
Other Parts Discussed in Thread: SFRA

Hi Team,

The customer from Cincon is currently setting up open and closed loop controls for the BuckBoost circuit.

The error in the Buck mode is small without load while the error in Boost mode is large, especially when the Ref is higher. Also, increasing the input voltage causes the output voltage to rise, deviating from the set Ref value. There will also be an error after loading, which will be greater during heavy loads, making it impossible to adjust to a stable condition.

So they would like to make sure if PI is appropriate for control of the BuckBoost circuit. Could you help take a look? Thanks.

Best Regards,

Cherry

  • 0
    TI__Mastermind 29721 points

    Hello Cherry,

    Cherry Zhou said:
    The error in the Buck mode is small without load while the error in Boost mode is large, especially when the Ref is higher. Also, increasing the input voltage causes the output voltage to rise, deviating from the set Ref value. There will also be an error after loading, which will be greater during heavy loads, making it impossible to adjust to a stable condition.

    The compensator needs to be tuned for the customer system (aka plant). Please have the customer run the code in open loop at a given test condition (e.g. boost) and run SFRA to gather the plant data. Then use compensation designer to tune the compensator accordingly. Once the compensator coefficients are calculated, then can be loaded on the firmware. 

    www.ti.com/.../SFRA