The "standard" motor control setup for FOC is to do the ADC measurement synchronously with the PWM, to sample the current while the low-side switch is closed.

The "standard" motor control setup for FOC is to do the ADC measurement synchronously with the PWM, to sample the current while the low-side switch is closed. Then the flux angles and voltages are computed immediately afterwards, and the PWM duty updated for the next cycle. This all happens in the interrupt, in a very hard real-time system -- start missing interrupts and all hell breaks loose. PWM is run as fast as you can get away with, 20 kHz minimum (human hearing). The controller spends maybe 80% of itw time in interrupt context, leaving main context for tasks that are not time-sensitive.