AN3165 datasheet(16/31 Pages) STMICROELECTRONICS

16 / 31 page

STM32 dual motor field-oriented control

AN3165

16/31

Doc ID 17180 Rev 1

3.4

Timing

Figure 8.

ADC and FOC execution timing diagram

The two triangular-shaped signals represent the two synchronized timer counters. The

update points for each timer are indicated with a U. The update point is the moment at which

the computed values of the duty cycle registers become active.

To allow dual motor control, each timer is updated every two PWM periods (REP RATE = 3),

but not at the same time (each update is shifted by one PWM period).

The trigger point for the ADC conversion occurs during the ACD triggering interval, depicted

by a red bar in Figure 8.

The ADC’s triggering interval related to a specific timer does not overlap the other, so the

samplings can be performed using the same ADC peripheral (ADC3).

Space for both FOC instructions must be guaranteed and the routines completed before the

next corresponding update event.

3.5

CPU load and memory size

Figure 9.

Free MCU time vs PWM frequency in dual FOC MC

AN3165 Datasheet(PDF) 16 Page - STMicroelectronics