TMS320F28069M: Move the motor CW and CCW before initialisation

Georgi Kolarov

Hello,

I'm implementing Instaspin-Motion for 3 phase BLDC motor but I'd like to make the motor move CW and CCW direction for a tiny fraction before calling the RS calibration procedure, zeroing the encoder and so on. Since the zero position of the encoder is depending on injecting current to the 3 phases simultaneous and I cannot control the direction of travel to the motor at this point of the initialisation process... is there a way I can make the motor move for 50-100ms CW and 50-100ms CCW just to unlatch a mechanical clutch attached to it? Should I look for solution by Instaspin FOC or something simpler like injecting DC current to a single phase out of the three available to force it move.

over 5 years ago

0 Yanming Luo over 5 years ago

TI__Guru** 117160 points

You have to do the offset calibration for the incremental encoder every power-on, so the motor will spin in an unknown direction.

You have to use the absolute encoder or the encoder with U/V/W hall sensor to know the initial position of the rotor if you want to spin the motor in the right direction from the first step.

0 Georgi Kolarov over 5 years ago in reply to Yanming Luo

Prodigy 195 points

Thanks for the suggestion. However neither of those is possible at the moment. Is there another way to achieve this? No smooth motion is required, just a jerky movement back and forth and then the initialisation procedure might begin.

0 Georgi Kolarov over 5 years ago in reply to Yanming Luo

Prodigy 195 points

0 Yanming Luo over 5 years ago in reply to Georgi Kolarov

TI__Guru** 117160 points

You might try to use the open-loop control (force angle running) to spin the motor and set the reference speed to position/negative value for CW/CCW rotation, but it's difficult to spin smoothly with a heavy load.

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TMS320F28069M: Move the motor CW and CCW before initialisation