TIDUFD2A May   2025  – October 2026

 

  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
      1. 2.2.1 Input Capacitors Selection
      2. 2.2.2 DC Side
      3. 2.2.3 AC Side
    3. 2.3 Highlighted Products
      1. 2.3.1 TMDSCNCD28P55X - controlCARD Evaluation Module
        1. 2.3.1.1 Hardware Features
        2. 2.3.1.2 Software Features
      2. 2.3.2 LMG2104R022
      3. 2.3.3 AMC3302
      4. 2.3.4 UCC21550A
      5. 2.3.5 TMCS1133 - Precision 1MHz Hall-Effect Current Sensor With Reinforced Isolation
      6. 2.3.6 INA185 - 26V, 350kHz, Bidirectional, High-Precision Current Sense Amplifier
      7. 2.3.7 LM5164 – 100V Input, 1A Synchronous Buck DC-DC Converter With Ultra-Low IQ
      8. 2.3.8 UCC34141-Q1
  9. 3System Design Theory
    1. 3.1 Isolation for Solar Inverters
    2. 3.2 Topology Overview
    3. 3.3 Control Theory
      1. 3.3.1 Single and Extended Phase Shift Modulation Technique
      2. 3.3.2 Zero Voltage Switching and Circulating Current
      3. 3.3.3 Optimized Control Method
      4. 3.3.4 Dead-Time Compensation
      5. 3.3.5 Frequency Modulation
      6. 3.3.6 Controller Block Diagram
    4. 3.4 MPPT and Input Voltage Ripple
  10. 4Hardware, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
      1. 4.3.1 Board Check
      2. 4.3.2 DC-DC Tests
      3. 4.3.3 DC-AC Tests
      4. 4.3.4 AC-DC Tests
      5. 4.3.5 DC-AC Offgrid Tests
    4. 4.4 Test Results
      1. 4.4.1 Efficiency and iTHD
      2. 4.4.2 Operating Waveforms for Various Loads
  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
  13. 7Revision History

4.3.3 DC-AC Tests

Figure 4-3 shows the board connections for DC-AC tests. If the AC source does not allow backward current flow, connect power resistors in parallel to AC lines.

TIDA-010954 Board Connections for DC-AC TestsFigure 4-3 Board Connections for DC-AC Tests

The test sequence for lab 6 follows:

  1. Connect the differential probe to AC connectors, J4 and J2.
  2. Connect the second differential probe to TP27 and TP12, respectively.
  3. Connect the Rogowski coil around transformer T1 secondary side wire.
  4. Connect the current probe to the wire going to the AC line.
  5. Set CYCLO_LAB define in cinv_settings.h to 6.
  6. Configure the DC source to 40V with 16A limit in parallel with the DC load settled to 42V in constant voltage mode (DC load only needed if testing in reverse power flow).
  7. Configure the AC source to 25VAC with 5A limit.
  8. Connect the resistors in parallel, if needed.
  9. Build and download firmware to controller and run.
  10. Import <DPSDK>\solutions\tida_010954\source\debug\lab6.txt file to expressions view.
  11. Set the following variables cyclo_iref_g = 0.2.
  12. Set cyclo_run = 1, observe that cyclo_started becomes 1, cyclo_polarity is changing the sign.
  13. Change cyclo_iref_g = 0.5A with 0.1 steps.
  14. Observe the AC voltage and current waveforms. On high output voltage, current spikes can be observed due to the mode change.

The test sequence for lab 7 follows:

  1. Connect the differential probe to AC connectors J4 and J2.
  2. Connect the second differential probe to TP27 and TP12, respectively.
  3. Connect the Rogowski coil around transformer T1 secondary side wire.
  4. Connect the current probe to the wire going to the AC line.
  5. Set CYCLO_LAB define in cinv_settings.h to 7.
  6. Configure the DC source to 40V with a 16A limit in parallel with the DC load settled to 42V in constant voltage mode.
  7. Configure the AC source to 25VAC with 5A limit.
  8. Connect the resistors in parallel, if needed.
  9. Build and download the firmware to the controller and run.
  10. Import the <DPSDK>\solutions\tida_010954\source\debug\lab7.txt file to expressions view.
  11. Set the following variables cyclo_iref_g = 0.2, cyclo_pi_enabled = 1, cyclo_dt_comp_enabled = 1
  12. Set cyclo_run = 1, observe that cyclo_started becomes 1, cyclo_polarity is changing the sign.
  13. Change cyclo_iref_g to 3.6A with 0.1 steps.
  14. Observe the AC voltage and current waveforms. On high output voltage, current spikes is significantly lower, but THD is still high.

The test sequence for lab 8 follows:

  1. Connect the differential probe to the AC connectors, J4 and J2.
  2. Connect the second differential probe to TP27 and TP12, respectively.
  3. Connect the Rogowski coil around the transformer T1 secondary side wire.
  4. Connect the current probe to the wire going to the AC line.
  5. Set CYCLO_LAB define in cinv_settings.h to 8.
  6. Configure the DC source to 40V with a 16A limit in parallel with the DC load settled to 42V in the constant voltage mode.
  7. Configure the AC source to 25VAC with a 5A limit.
  8. Connect the resistors in parallel, if needed.
  9. Build and download the firmware to the controller and run.
  10. Import the <DPSDK>\solutions\tida_010954\source\debug\lab8.txt file to the expressions view.
  11. Set the following variables cyclo_iref_g = 0.2, cyclo_pi_enabled = 1, cyclo_dt_comp_enabled = 1, cyclo_pr_enabled = 1.
  12. Set cyclo_run = 1, observe that cyclo_started becomes 1, cyclo_polarity is changing the sign.
  13. Change cyclo_iref_g = 3.6A with 0.1 steps.
  14. Observe AC voltage and current waveforms. THD is significantly reduced.