TIDUF42 January   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Terminology
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 EnDAT 2.2 Interface
      2. 2.3.2 SDFM Interface
      3. 2.3.3 EPWM Interface
      4. 2.3.4 ICSS-PRU IEP
      5. 2.3.5 EtherCAT CiA402 Velocity Control
  9. 3System Design
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
    4. 4.4 Test Results
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author

2.2 Design Considerations

The single-chip dual-axis servo motor drive implementation was architected around a central real-time path that is made up of the following:

  • ICSSG1 - EtherCAT client controller firmware
  • ICSSG0 - SDDF and EnDAT 2.2 decoding
    • Sigma-Delta filtering firmware with Load Sharing between RTU and PRU cores in PRU0 for phase current feed back from two directly connected motors
    • EnDat2.2 decoding firmware with Loading Sharing between RTU and PRU cores in PRU1 for angle, position, and speed feedback from two directly connected absolute encoders
  • R5FSS1_0 - EtherCAT client stack implementing CiA402 using FreeRTOS
  • R5FSS0_0 and R5FSS0_1 – Two independent closed-loop FOC capable of current, speed, or position closed-loop control for two directly connected motors with absolute encoders
  • IPC Notify in the MCU+ SDK provides low-latency inter-core synchronization and communication
  • EPWM – Six channels of enhanced PWM peripherals to generate waveforms based on the output of two FOC loops
GUID-20231023-SS0I-FX8F-D7MX-HTRWX7HV6RHG-low.svg Figure 2-3 Trigger FOC Timing – 50 kHz