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

4.3.2 DC-DC Tests

Figure 4-2 shows the board connections.

TIDA-010954 Board Connections for DC-DC Tests Figure 4-2 Board Connections for DC-DC Tests

The test sequence for lab 3 follows:

  1. Connect the negative terminal of the differential probe to TP13 and the positive terminal to TP10.
  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 DC load.
  5. Set CYCLO_LAB define in cinv_settings.h to 3.
  6. Configure the DC source to 7V with 10A limit, and DC load to 50V in constant voltage mode
  7. Build and download firmware to the controller and run.
  8. Import <DPSDK>\solutions\tida_010954\source\debug\lab3.txt file to expressions view.
  9. Set the following variables cyclo_iref_g = 0.0, cyclo_polarity = 1, cyclo_d1 = 0.47, cyclo_d2 = 0.0.
  10. Set cyclo_run = 1, observe that cyclo_started becomes 1.
  11. In 0.05 steps, decrease cyclo_d1 to 0.25, observe that the primary side voltage pulse becomes wider.
  12. Make sure the DC power source current limit still has enough margin before applying change.
  13. In 0.02 steps, change cyclo_d2 to 0.1, observe that the center primary side pulse becomes the leading secondary pulse center. The output current increased. The input current increased too.
  14. Observe measurements in variables cyclo_v_dc_V, cyclo_v_ac_V, cyclo_i_dc_A, and cyclo_i_ac_A

The test sequence for lab 4 follows:

  1. Connect the negative terminal of differential probe to TP13 and the positive terminal to TP10.
  2. Connect the second differential probe to TP27 and TP12, respectively.
  3. Connect the Rogowski coil around transformer T1 secondary side wire.
  4. Connect current probe to wire going to DC load.
  5. Set CYCLO_LAB define in cinv_settings.h to 4.
  6. Configure DC source to 7V with 10A limit, and DC load to 50V in constant voltage mode.
  7. Build and download firmware to the controller and run.
  8. Import the <DPSDK>\solutions\tida_010954\source\debug\lab4.txt file to expressions view.
  9. Set the following variables cyclo_iref_g = 0.0, cyclo_polarity = 1.
  10. Set cyclo_run = 1, observe that cyclo_started becomes 1.
  11. Change cyclo_iref_g = 0.0 to 0.5A with 0.1 steps.
  12. Observe that the output current changed corresponding to the reference setting with some calculation error.

The test sequence for lab 5 follows:

  1. Connect the negative terminal of the differential probe to TP13 and the positive terminal to TP10.
  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 DC load.
  5. Set CYCLO_LAB define in cinv_settings.h to 5.
  6. Configure the DC source to 7V with 10A limit, and the DC load to 50V in constant voltage mode.
  7. Build and download firmware to the controller and run.
  8. Import the <DPSDK>\solutions\tida_010954\source\debug\lab5.txt file to expressions view.
  9. Set the following variables cyclo_iref_g = 0.0, cyclo_polarity = 1, cyclo_pi_enabled = 1.
  10. Set cyclo_run = 1, observe that cyclo_started becomes 1.
  11. Change cyclo_iref_g = 0.0 to 0.5A with 0.1 steps.
  12. Observe that the output current changed corresponding to the setting with error compensation with the PI controller.

Check the DC-DC negative polarity operation by swapping polarity on the AC side (eload polarity swap) and repeating all the steps with cyclo_polarity = –1 and positive cyclo_iref_g. This is still pushing power from primary side to secondary side. An easier test load would be a power resistor since it is an AC load and there is no need to switch the connection polarity.

Check the DC-DC operation with backward current flow by connecting the DC load (7V) on the DC side and the DC source (50V) on the AC side and doing negative cyclo_d2 or negative cyclo_iref_g. For this test, TI recommends setting cyclo_polarity = –1 and use cyclo_d2 or negative cyclo_iref_g to push power in reverse while keeping the power supply and eload polarity the same.

Check high-voltage operation by slowly increasing the voltage on the DC side up to 40V and the secondary side voltage up to 325V.

Note: For DC to AC labs, the user does not need to manually set cyclo_polaritythe for either forward or reverse power flow. The user will only need to set the cyclo_iref_g +/- sign and magnitude value.