Posted on August 19, 2017 at 13:34debugging motor in open loop mode#define OPEN_LOOP_VOLTAGE_d 6000 /*! < Three Phase voltage amplitude in s16 format */ What is the formula for the value of If I want to output a fixed voltage value, how to determine the S16 value? PhaseVoltage(V) = [PhaseVoltage(s16V) * Vbus(V)] /[sqrt(3)*32767].If I want to output a fixed voltage value, how to determine the S16 valueï¼Ÿ

Associate III

Question

OPEN_LOOP_VOLTAGE_d parameter

Posted on August 19, 2017 at 13:34

debugging motor in open loop mode

#define OPEN_LOOP_VOLTAGE_d 6000 /*! < Three Phase voltage amplitude in s16 format */

What is the formula for the value of
If I want to output a fixed voltage value, how to determine the S16 value
?

PhaseVoltage(V) = [PhaseVoltage(s16V) * Vbus(V)] /[sqrt(3)*32767].

If I want to output a fixed voltage value, how to determine the S16 valueï¼Ÿ

This topic has been closed for replies.

ST Employee

Posted on August 24, 2017 at 15:50

Hi,

I think the value is defined as duty-cycle of the PWM applied to the motor in a 16 bit format.

0 --> 0 % of duty-cycle --> no voltage applied

65535 --> 100 % of duty-cycle --> 100% of the bus voltage applied to the motor

6000 --> 6000/65535 = 0.0915 = 9.15 % of duty-cycle --> about 9% of the bus voltage is applied to the motor

You can easily check it with an oscilloscope

Associate III

Posted on August 24, 2017 at 16:47

I tested, S16V maximum is 32767, but how can not calculate

ST Employee

Posted on August 25, 2017 at 15:43

Ok, so you already have the answer.

Vphase = Vbus*OPEN_LOOP_VOLTAGE_d/32767

This will be the peak value of the the sinusoidal voltage applied to the motor.