TMS329F28027 feedforward operation

paul kendle1

Using TMS320F28027 Piccolo in off-line 3-ph BLDC motor drive, approx. 25 Watts, Fsw = 20kHz. We want to use a passive valley fill rectifier front end at 50% ripple voltage. Is there a way to adjust the feed forward DC bus input to the Piccolo to reject the 120Hz DC bus ripple? Using the EVM we start getting appreciable 120hz feed through of the rectified mains when we have greater than 15% input voltage ripple.

over 9 years ago

0 Ramesh Ramamoorthy over 9 years ago

TI__Mastermind 27240 points

Lenio,

If V* is the preferred voltage to apply on the motor, at a known constant dc voltage Vdc*, this may result in a duty cycle of D*,

such that V* = Vdc* x D*

If Vdc has ripples, then the feed forward compensated duty cycle (D) will be

D = D* x Vdc* / Vdc.

Hope it helps,

ramesh

0 paul kendle1 over 9 years ago in reply to Ramesh Ramamoorthy

Prodigy 40 points

Hi Ramesh,

Thanks for the response. Do you have experience with the C2000 BLDC solution? If so do you think the feed forward compensation can be adjusted to compensate for close to 50% ripple on the DC bus?

Thanks,

Paul

0 Ramesh Ramamoorthy over 9 years ago in reply to paul kendle1

TI__Mastermind 27240 points

50% ripple may be ok, but you have to remember that the controller can output a max adj duty cycle of 100%. Within this, yes, it should be possible.

rgds,

ramesh

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TMS329F28027 feedforward operation