SLLU364 may   2023 MCT8315A

 

  1.   1
  2.   Abstract
  3. 1Revision History
  4.   Trademarks
  5. 2Introduction
    1. 2.1 Hardware and GUI setup
      1. 2.1.1 Jumper Configuration
      2. 2.1.2 External Connections
      3. 2.1.3 Connecting to the GUI
        1. 2.1.3.1 Connect to computer
        2. 2.1.3.2 Connect to the GUI
        3. 2.1.3.3 Verify Hardware Connection
  6. 3Essential Controls
    1. 3.1 Recommended Default Values based on application
    2. 3.2 Device and Pin Configuration
      1. 3.2.1 Speed input mode
    3. 3.3 Algorithm configuration – Motor speed
      1. 3.3.1 Maximum motor electrical speed (Hz)
    4. 3.4 Control Configuration
      1. 3.4.1 Cycle by cycle current limit (ILIMIT)
    5. 3.5 Testing for successful startup into closed loop
    6. 3.6 Fault handling
      1. 3.6.1 Abnormal Speed [ABN_SPEED]
      2. 3.6.2 Loss of Sync [LOSS_OF_SYNC]
      3. 3.6.3 No Motor Fault [NO_MTR]
      4. 3.6.4 Cycle by cycle current limit [CBC_ILIMIT]
  7. 4Basic Controls
    1. 4.1 Device and pin configuration
      1. 4.1.1 Power saver or sleep mode for battery operated applications
      2. 4.1.2 Direction and Brake pin override
    2. 4.2 System level configuration
      1. 4.2.1 Tracking motor speed feedback in real time
      2. 4.2.2 Monitoring power supply voltage fluctuations for normal motor operation
    3. 4.3 Control configurations
      1. 4.3.1  Initial speed detection of the motor for reliable motor resynchronization
      2. 4.3.2  Unidirectional motor drive detecting backward spin
      3. 4.3.3  Preventing back spin of rotor during startup
      4. 4.3.4  Faster startup timing
      5. 4.3.5  Improving speed regulation
      6. 4.3.6  Stopping motor quickly
      7. 4.3.7  Faster deceleration
      8. 4.3.8  Preventing supply voltage overshoot during motor stop and deceleration
      9. 4.3.9  Protecting against rotor lock or stall condition
      10. 4.3.10 Maximizing thermal efficiency and increasing thermal performance
      11. 4.3.11 Mitigating Electromagnetic Interference (EMI)
      12. 4.3.12 Improving Motor efficiency
      13. 4.3.13 Limiting and regulating supply power

4.2.2 Monitoring power supply voltage fluctuations for normal motor operation

In applications where the power supply may fluctuate, it is recommended to specify the minimum and maximum power supply voltage range. During an undervoltage condition, the motor might operate at lower speeds. During an overvoltage condition, the MOSFETs, MCT8315A and motor may be stressed with continued operation in high voltage.

Step 1: Keep decreasing the supply voltage until we see a drop in the speed. Measure the bus voltage at which the speed drops and set MIN_VM_MOTOR to that value. The range of minimum bus voltage that can be configured is between 6V and 15V.

Step 2: Keep increasing the bus voltage to a point where the motor phase voltage reaches the maximum rated voltage of the motor. MAX_VM_MOTOR will be the bus voltage at which motor phase voltage reaches the maximum rated voltage of the motor. Range of maximum bus voltage that can be configured is between 20V and 40V.

Note:

MCT8315A provides an undervoltage recovery mode [MIN_VM_MODE] and Overvoltage recovery mode [MAX_VM_MODE]. Undervoltage recovery mode can be configured to either automatically clear Undervoltage fault [MTR_UNDER_VOLTAGE] or latch on Undervoltage fault. Overvoltage recovery mode can be configured to either automatically clear Overvoltage fault [MTR_OVER_VOLTAGE] or latch on Overvoltage fault.