How to make BLDC work smoothly in low speed(400rpm) low temperature(-40DC) while use S912ZVML12F for controller?

[dannydeng]

Dears,

     Does anybody have any experiences in improving BLDC driving in low speed(about 400RPM) without hall sensor,especially in low temperature(about -40DC)?

     Please help me with this problem, my customer and me have blocked by such problem a lot.

     Thanks and Best Regards.

Ray Deng

[RadekS]

Hi Ray,

Unfortunately I do not have experience with such improving.

I am not sure what could be reason for unexpected behavior, but we have to take into account temperature dependency of components like transistors or capacitors.

Some problem could present also motor load. If motor load is significantly high (like for oil pump application) at -40°C or non linear, we have to more focus on alignment and startup (open loop) phases.

In fact, sensorless application could correctly work from some minimal shaft speed. For low speed, generated BEMF voltage is too low. From this point of view, some modification in analog filter or amplifier gain could help you.

I hope it helps you.

Have a great day,
RadekS

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[dannydeng]

Hi Radek,

     Thanks for your kindly response.

     I will do some experiment according to your advise, hope it can leading me to solve the problem.

     Best regards,

     Ray Deng