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

3.3 Coasting (Hi-Z)

Coasting allows motor to lose energy gradually with friction. This is especially useful if ISD is enabled and reverse drive is disabled but motor is spinning in opposite direction with speed that can cause high brake currents. Enabling coasting lets the motor reduce the speed before applying brake to bring the motor to stationary state before driving to set reference.

Table 3-4 Coasting Related Configurations
Configuration Sub-Feature Description Tuning Considerations
HIZ_EN Enable coasting to slow down the motor naturally with frictional losses Enable if braking to stop the motor is part of application use case to slow down the motor before braking to avoid high braking currents. Enable if ISD is enabled but reverse drive is disabled.
HIZ_TIME Coasting time based on the inertia of the motor to ramp down the motor. Take the time to coast from maximum speed to acceptable speed to apply brake with acceptable braking current. If motor spinning due to external factors like wind, then coasting can possibly not help.