TIDUES0E June   2019  – April 2024 TMS320F28P550SJ , TMS320F28P559SJ-Q1

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1  UCC21710
      2. 2.2.2  UCC14141-Q1
      3. 2.2.3  AMC1311
      4. 2.2.4  AMC1302
      5. 2.2.5  OPA320
      6. 2.2.6  AMC1306M05
      7. 2.2.7  AMC1336
      8. 2.2.8  TMCS1133
      9. 2.2.9  TMS320F280039C
      10. 2.2.10 TLVM13620
      11. 2.2.11 ISOW1044
      12. 2.2.12 TPS2640
    3. 2.3 System Design Theory
      1. 2.3.1 Dual Active Bridge Analogy With Power Systems
      2. 2.3.2 Dual-Active Bridge – Switching Sequence
      3. 2.3.3 Dual-Active Bridge – Zero Voltage Switching (ZVS)
      4. 2.3.4 Dual-Active Bridge - Design Considerations
        1. 2.3.4.1 Leakage Inductor
        2. 2.3.4.2 Soft Switching Range
        3. 2.3.4.3 Effect of Inductance on Current
        4. 2.3.4.4 Phase Shift
        5. 2.3.4.5 Capacitor Selection
          1. 2.3.4.5.1 DC-Blocking Capacitors
        6. 2.3.4.6 Switching Frequency
        7. 2.3.4.7 Transformer Selection
        8. 2.3.4.8 SiC MOSFET Selection
      5. 2.3.5 Loss Analysis
        1. 2.3.5.1 SiC MOSFET and Diode Losses
        2. 2.3.5.2 Transformer Losses
        3. 2.3.5.3 Inductor Losses
        4. 2.3.5.4 Gate Driver Losses
        5. 2.3.5.5 Efficiency
        6. 2.3.5.6 Thermal Considerations
  9. 3Circuit Description
    1. 3.1 Power Stage
    2. 3.2 DC Voltage Sensing
      1. 3.2.1 Primary DC Voltage Sensing
      2. 3.2.2 Secondary DC Voltage Sensing
        1. 3.2.2.1 Secondary Side Battery Voltage Sensing
    3. 3.3 Current Sensing
    4. 3.4 Power Architecture
      1. 3.4.1 Auxiliary Power Supply
      2. 3.4.2 Gate Driver Bias Power Supply
      3. 3.4.3 Isolated Power Supply for Sense Circuits
    5. 3.5 Gate Driver Circuit
    6. 3.6 Additional Circuitry
    7. 3.7 Simulation
      1. 3.7.1 Setup
      2. 3.7.2 Running Simulations
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Required Hardware and Software
      1. 4.1.1 Hardware
      2. 4.1.2 Software
        1. 4.1.2.1 Getting Started With Software
        2. 4.1.2.2 Pin Configuration
        3. 4.1.2.3 PWM Configuration
        4. 4.1.2.4 High-Resolution Phase Shift Configuration
        5. 4.1.2.5 ADC Configuration
        6. 4.1.2.6 ISR Structure
    2. 4.2 Test Setup
    3. 4.3 PowerSUITE GUI
    4. 4.4 LABs
      1. 4.4.1 Lab 1
      2. 4.4.2 Lab 2
      3. 4.4.3 Lab 3
      4. 4.4.4 Lab 4
      5. 4.4.5 Lab 5
      6. 4.4.6 Lab 6
      7. 4.4.7 Lab 7
    5. 4.5 Test Results
      1. 4.5.1 Closed-Loop Performance
  11. 5Design Files
    1. 5.1 Schematics
    2. 5.2 Bill of Materials
    3. 5.3 Altium Project
    4. 5.4 Gerber Files
    5. 5.5 Assembly Drawings
  12. 6Related Documentation
    1. 6.1 Trademarks
  13. 7Terminology
  14. 8About the Author
  15. 9Revision History

2.3.4.6 Switching Frequency

Switching frequency is an important design parameter which affects the efficiency and power density of the power converter. The input and output voltage levels primarily determine the type of switches used in the power stage. Usage of SiC MOSFETs in the power stage enables high switching frequencies. Operating at higher switching frequencies enables a reduced size of magnetics which improves thermal conditions, thereby improving the power density of the converter. Therefore, selection of switching frequency is primarily a tradeoff between the allowable heat sink design and the transformer size for a given efficiency target. Secondly, if the output capacitance (Ecoss) of MOSFET is very high, selection of high switching frequency leads to high switching losses at light load and hampers efficiency. Selection of switching frequency also affects the control-loop bandwidth implementation. Considering all of these parameters, 100 kHz was used as the switching frequency for this application.