SLVAFF1 January   2023 DRV8452 , DRV8462

PRODUCTION DATA  

  1.   Abstract
  2.   Trademarks
  3. 1Power Efficiency of Stepper Motor Drivers
  4. 2Auto-Torque
    1. 2.1 Auto-Torque: Learning Principle
      1. 2.1.1 Configuring Auto-Torque Learning Routine
    2. 2.2 Current Control
      1. 2.2.1 Setting Current Control Parameters
    3. 2.3 PD Control Loop
    4. 2.4 Impact of Auto-Torque Tuning Parameters
      1. 2.4.1 Impact of Learning Parameters on Load Transient Response
      2. 2.4.2 Impact of ATQ_UL, ATQ_LL Hysteresis
      3. 2.4.3 Impact of Load Profile on Power Saving
      4. 2.4.4 Adaptive ATQ_UL, ATQ_LL
      5. 2.4.5 PD Parameter Dependency Curves
        1. 2.4.5.1 Dependency on KP
        2. 2.4.5.2 Dependency on KD and ATQ_D_THR
        3. 2.4.5.3 Dependency on ATQ_FRZ and ATQ_AVG
        4. 2.4.5.4 Dependency on ATQ_ERROR_TRUNCATE
      6. 2.4.6 ATQ_CNT at Different Motor Speeds
      7. 2.4.7 ATQ_CNT at Different Supply Voltages
      8. 2.4.8 Motor Temperature Estimation
    5. 2.5 Efficiency Improvement With Auto-Torque
  5. 3Case Studies
    1. 3.1 Application 1: ATM Machines
      1. 3.1.1 ATM Motor Operating Conditions
      2. 3.1.2 ATM Motor With Auto-Torque
    2. 3.2 Application 2: Textile Machines
      1. 3.2.1 Textile Motor Operating Conditions
      2. 3.2.2 Textile Motor With Auto-Torque
    3. 3.3 Application 3: Printer
      1. 3.3.1 Printer Motor With Auto-Torque
  6. 4Summary
  7. 5References

2.4.6 ATQ_CNT at Different Motor Speeds

Figure 2-29 ATQ_CNT as a Function of Motor Speed

Figure 2-29 shows how ATQ_CNT varies with motor speed with all other operating conditions remaining same. As is evident, there are two distinct segments with different slopes in the ATQ_CNT vs. speed plot.

  • The segment with lesser slope corresponds to sinusoidal current waveforms, as shown in Figure 2-30 and Figure 2-31.
  • At higher speeds, when the current waveform starts becoming triangular (as shown in Figure 2-31 and Figure 2-33), the ATQ_CNT vs. speed plot has a steeper slope.
  • For a given range of motor speed, firmware can adjust the ATQ_LRN parameters and ATQ_UL, ATQ_LL based on a curve like Figure 2-29.
    • To start with, user can vary the motor speed and plot this curve at maximum current.
    • During normal operation, at any speed, they can find the correction factor from the curve and apply it to the ATQ_LRN parameters, ATQ_UL and ATQ_LL.
GUID-20221117-SS0I-SBSL-JSK9-J8PWFPVBZ7JQ-low.pngFigure 2-30 3000 pps Step Frequency
GUID-20221117-SS0I-5ZZQ-DFHF-LDZHW8LS0WP6-low.pngFigure 2-32 6400 pps Step Frequency
GUID-20221117-SS0I-VH1J-4TRN-TF4F9R9LLFCF-low.pngFigure 2-31 4800 pps Step Frequency
GUID-20221117-SS0I-BCMP-LLFZ-PVKT2S1HWCDG-low.pngFigure 2-33 8000 pps Step Frequency