Accurate current sensing is important to estimate
the rotor angle and speed, and also have the best
dynamic motor control. The current sensing
parameters must match the hardware by setting the
following related parameters:
- Dead-band time, the rising edge delay time must
be greater than (high-side turn on time) + (low
side turn-off time) of the power module, and the
falling edge delay time must be greater than
(high-side turn-off time) + (low-side turn-on
time) of the power module as shown in the
following setting for a power module used in the
reference design.
//! \brief Defines the PWM deadband falling edge delay count (system clocks)
#define MTR1_PWM_DBFED_CNT (uint16_t)(2.5f * 120.0f) // 2.5us, (>2.0us)
//! \brief Defines the PWM deadband rising edge delay count (system clocks)
#define MTR1_PWM_DBRED_CNT (uint16_t)(2.5f * 120.0f) // 2.50us, (>2.0us)
- Minimum duration of pulse width PWM, specifies to
be greater than (Hardware delay time + Dead band
time + Ringing duration + ADC sampling time).
//! \brief Defines the minimum duration, Clock Cycle
#define USER_M1_DCLINKSS_MIN_DURATION (450U)
- Sample and hold delay time, specifies the time
delay from PWM output to ADC sample time for
current sensing. The delay time is dependent on
the hardware and includes the propagation delay of
the gate driver circuit and turn on and turn off
delay of the power FET, and is less than or equal
to (Minimum duration – ADC sampling time).
//! \brief Defines the sample delay, Clock Cycle
#define USER_M1_DCLINKSS_SAMPLE_DELAY (430U)