TIDA-00364: Conduction loss calculation

GANESH BHALERAO

Prodigy 20 points

Part Number: TIDA-00364

Hello Team,

Could you please let me know why does motor phase rms current is divided by 1.414 while calculating conduction loss?

Regards,

Ganesh B

over 5 years ago

0 Pawan Nayak over 5 years ago

TI__Expert 4695 points

Hi Ganesh,

Assuming symmetrical PWM operation in both the positive and negative half cycles of motor phase current, the current through the top and bottom FET can be estimated to be equal to the RMS value of one half cycle of motor phase current waveform.

This is why you have a divide by 2 factor.

Regards,

Pawan

0 GANESH BHALERAO over 5 years ago in reply to Pawan Nayak

Prodigy 20 points

Hi Pawan,

Please see the formula mentioned in TIDA-00364

Motor RMS current is divided by 1.414 factor

Regards,

Ganesh

0 Pawan Nayak over 5 years ago in reply to GANESH BHALERAO

TI__Expert 4695 points

Hi Ganesh,

The 1.414 is squared, so the formula should look like 0.5 * Irms^2 * rdson

Regards,

Pawan

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TIDA-00364: Conduction loss calculation