CCS/UCD3138: XN after PID calculate , we get YN . Can we limte the YN value before get YN value ?

user5006419

Part Number: UCD3138

Tool/software: Code Composer Studio

XN after PID calculate , we get YN . Can we limte the YN value before get YN value ?

Because in fast interrupt of HSFB :

vloop_filter = (signed int) (Filter0Regs.FILTERYNREAD.bit.YN);
iloop_filter = (signed int) (Filter1Regs.FILTERYNREAD.bit.YN);

I find YN0 value is higher than YN1 value , so I want to limte the max of YN .Is that right ？

over 7 years ago

0 Sean Xu over 7 years ago

TI__Genius 14580 points

Hi,

The better way to limit YN is to set the limit for FilterxRegs.FILTERKICLPHI.bit.KI_CLAMP_HIGH. After this clamping, YN should be clamped.

Regards,
Sean

0 user5006419 over 7 years ago in reply to Sean Xu

Expert 1795 points

Can we calculate the result of YN value ？

0 Cormac Harrington over 6 years ago in reply to user5006419

TI__Intellectual 1245 points

hello

The YN value can also be clamped using the register FilterxRegs.FILTERYNCLPHI.all, where x = 0, 1 or 2

As Sean mentioned, you can also clamp the output of the I stage using the register FilterxRegs.FILTERKICLPHI.bit.KI_CLAMP_HIGH. It is important that if you clamp YN using FilterxRegs.FILTERYNCLPHI.all, that you also clamp I appropriately so you don't get integral windup when YN is saturated high.

If you want more information on how YN is computed from the outputs of the P, I and D stages, see the technical reference manual www.ti.com/.../sniu028a.pdf, section 4.1.5 (page 146).

Best Regards
Cormac

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CCS/UCD3138: XN after PID calculate , we get YN . Can we limte the YN value before get YN value ?