SLLU363 may   2023 MCF8315A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Hardware and GUI Setup
      1. 1.1.1 Jumper Configuration
      2. 1.1.2 External Connections
      3. 1.1.3 Connecting to the GUI
        1. 1.1.3.1 Connect to computer
        2. 1.1.3.2 Connect to the GUI
        3. 1.1.3.3 Verify Hardware Connection
  5. 2Essential Controls
    1. 2.1 Recommended Default Values
    2. 2.2 Device and Pin Configuration
      1. 2.2.1 Speed Input Mode
    3. 2.3 Control Configuration - Motor Parameters
      1. 2.3.1 Maximum Motor Electrical Speed (Hz)
    4. 2.4 Control configuration - Closed Loop
      1. 2.4.1 Current Limit for Torque PI Loop
    5. 2.5 Testing for Successful Startup into Closed Loop
    6. 2.6 Fault Handling
      1. 2.6.1 MPET IPD Fault [MPET_IPD_Fault]
      2. 2.6.2 MPET BEMF Fault [MPET_BEMF_Fault]
      3. 2.6.3 Abnormal BEMF Fault [ABN_BEMF]
      4. 2.6.4 Lock Current Limit [LOCK_LIMIT]
      5. 2.6.5 Hardware lock Current Limit [HW_LOCK_LIMIT]
      6. 2.6.6 No Motor Fault [NO_MTR]
  6. 3Basic Controls
    1. 3.1 Device and Pin Configuration
      1. 3.1.1 Power Saver or Sleep Mode for Battery Operated Applications
      2. 3.1.2 Direction and Brake Pin Override
    2. 3.2 System Level Configuration
      1. 3.2.1 Tracking Motor Speed Feedback in Real Time
      2. 3.2.2 Improving Acoustic Performance
      3. 3.2.3 Protecting the Power supply
      4. 3.2.4 Monitoring Power Supply Voltage Fluctuations for Normal Motor Operation
    3. 3.3 Control Configurations
      1. 3.3.1  Motor Parameter Estimation to Minimize Motor Parameter Variation Effects
      2. 3.3.2  Initial Speed Detection of the Motor for Reliable Motor Resynchronization
      3. 3.3.3  Unidirectional Motor Drive Detecting Backward Spin
      4. 3.3.4  Preventing Back Spin of Rotor During Startup
      5. 3.3.5  Faster Startup Timing
      6. 3.3.6  Gradual and Smooth Start up Motion
      7. 3.3.7  Improving Speed Regulation
      8. 3.3.8  Stopping Motor Quickly
      9. 3.3.9  Preventing Supply Voltage Overshoot During Motor Stop.
      10. 3.3.10 Protecting Against Rotor Lock or Stall Condition
      11. 3.3.11 Maximizing Thermal Efficiency and Increasing Thermal Performance
      12. 3.3.12 Mitigating Electromagnetic Interference (EMI)
      13. 3.3.13 Faster deceleration

3.3.7 Improving Speed Regulation

For applications that require better speed regulation, it is recommended to tune Speed loop PI controllers [SPD_LOOP_KP] and [SPD_LOOP_KI]. Kp coefficient of speed loop [SPD_LOOP_KP] controls the settling time and speed overshoots. Ki coefficient of Speed loop [SPD_LOOP_KI] controls speed overshoot and ensures regulation of speed at set value and drives the error to zero. Speed loop PI controller gains can either be auto-tuned by MCF8315A or tuned manually.

Auto Tuning: MCF8315A auto calculates Speed loop PI controller gains when [SPD_LOOP_KP] and [SPD_LOOP_KI] are set to zero.

Manual Tuning: Follow below steps to tune Speed loop PI controller gains manually

Step 1: Disable Speed loop [SPEED_LOOP_DIS]

Step 2: Disable closed loop [CLOSED_LOOP_DIS]

Step 3: Issue non-zero speed command to start the motor (refer to Section 2.5, step 1 on how to issue non-zero speed command). Motor will spin in open loop.

Step 4: Allow the open loop current to settle down and then measure the peak open loop current.

Step 5: Enter 110% of measured peak phase current as the Iq reference when speed loop is disabled [FORCE_IQ_REF_SPEED_LOOP_DIS]

Step 6: Enable closed loop [CLOSED_LOOP_DIS]. Now the motor will enter closed loop in torque mode.

Stp 7: Adjust the Iq reference [FORCE_IQ_REF_SPEED_LOOP_DIS] such that the motor speed reaches the maximum speed.

Step 8: Speed loop Kp [SPD_LOOP_KP] is calculated using Equation 6.

Equation 6. Speed loop Kp = Iq reference at maximum speedMaximum Electrical Speed in Hz 

Step 9: Speed loop Ki [SPD_LOOP_KI] is calculated using equationEquation 7.

Equation 7. Speed loop Ki=0.1 ×Speed loop Kp

Step 10: Enable speed loop [SPEED_LOOP_DIS]

Note:

Tuning speed loop Kp and Ki is experimental. If the above recommendation doesn’t work, then we recommend to manually tune Speed loop Kp and Ki till the desired results are achieved.