SLLA663 March   2025 MCF8315A , MCF8315C , MCF8315C-Q1 , MCF8315D , MCF8316A , MCF8316C-Q1 , MCF8316D , MCF8329A , MCT8315A , MCT8316A , MCT8329A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2End Application Configuration Recommendation
    1. 2.1 Resynchronization
    2. 2.2 Reverse Drive
    3. 2.3 Coasting (Hi-Z)
    4. 2.4 Startup Brake
    5. 2.5 Direction Change Mode
  6. 3Tuning Guidance
    1. 3.1 Initial Speed Detection Module
      1. 3.1.1 Initial Speed Detection
      2. 3.1.2 ISD Times
      3. 3.1.3 Stationary Detect Threshold
    2. 3.2 Resynchronization
      1. 3.2.1 Forward Drive Resync Threshold
      2. 3.2.2 Reverse Drive
      3. 3.2.3 Reverse Acceleration Parameters
      4. 3.2.4 Reverse Drive Current Limits
      5. 3.2.5 Reverse Drive Handoff Threshold
      6. 3.2.6 Reverse Drive Open Loop Deceleration (REV_DRV_OPEN_LOOP _DEC)
    3. 3.3 Coasting (Hi-Z)
    4. 3.4 Brake
      1. 3.4.1 Brake Config (BRK_CONFIG)
  7. 4Feature Availability of MCx Devices
    1. 4.1 FOC Family (MCF83xx devices)
    2. 4.2 TRAP Family (MCT83xx devices)
  8. 5Summary
  9. 6References

3.1.1 Initial Speed Detection

Initial Speed Detection (ISD_EN) decides if speed detection is required to resynchronize if the motor is spinning or to stop the motor irrespective of speed and restart from stationary state. In high inertia applications, ISD helps optimize the startup by reducing startup time significantly.

ISD_EN = 0bFigure 3-1 ISD_EN = 0b
ISD_EN = 1bFigure 3-2 ISD_EN = 1b

In Figure 3-1, the motor was forced to brake and start from stationary even with sufficient BEMF available for direct pass-off to closed loop as ISD is disabled. In Figure 3-2, Motor resyncs with the drive and ramps up to commanded speed due to ISD being enabled.