TIDUF64A December   2023  – August 2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
    2. 1.2 PV Input with Boost Converter
    3. 1.3 Bidirectional DC/DC Converter
    4. 1.4 DC/AC Converter
  8. 2System Design Theory
    1. 2.1 Boost Converter
      1. 2.1.1 Inductor Design
      2. 2.1.2 Rectifier Diode Selection
      3. 2.1.3 MPPT Operation
    2. 2.2 Bidirectional DC/DC Converter
      1. 2.2.1 Inductor Design
      2. 2.2.2 Low-Voltage Side Capacitor
      3. 2.2.3 High-Voltage Side Capacitor
    3. 2.3 DC/AC Converter
      1. 2.3.1 Boost Inductor Design
      2. 2.3.2 DC-Link Capacitor
  9. 3System Overview
    1. 3.1 Block Diagram
    2. 3.2 Design Considerations
      1. 3.2.1 Boost Converter
        1. 3.2.1.1 High-Frequency FETs
        2. 3.2.1.2 Input Voltage and Current Sense
      2. 3.2.2 Bidirectional DC/DC Converter
        1. 3.2.2.1 High-Frequency FETs
        2. 3.2.2.2 Current and Voltage Measurement
        3. 3.2.2.3 Input Relay
      3. 3.2.3 DC/AC Converter
        1. 3.2.3.1 High-Frequency FETs
        2. 3.2.3.2 Current Measurements
        3. 3.2.3.3 Voltage Measurements
        4. 3.2.3.4 Auxiliary Power Supply
        5. 3.2.3.5 Passive Components Selection
    3. 3.3 Highlighted Products
      1. 3.3.1  TMDSCNCD280039C - TMS320F280039C Evaluation Module C2000™ MCU controlCARD™
      2. 3.3.2  LMG3522R030 650-V 30-mΩ GaN FET With Integrated Driver, Protection and Temperature Reporting
      3. 3.3.3  TMCS1123 - Precision Hall-Effect Current Sensor
      4. 3.3.4  AMC1302 - Precision, ±50-mV Input, Reinforced Isolated Amplifier
      5. 3.3.5  ISO7741 Robust EMC, Quad-channel, 3 Forward, 1 Reverse, Reinforced Digital Isolator
      6. 3.3.6  ISO7762 Robust EMC, Six-Channel, 4 Forward, 2 Reverse, Reinforced Digital Isolator
      7. 3.3.7  UCC14131-Q1 Automotive, 1.5-W, 12-V to 15-V VIN, 12-V to 15-V VOUT, High-Density > 5-kVRMS Isolated DC/DC Module
      8. 3.3.8  ISOW1044 Low-Emissions, 5-kVRMS Isolated CAN FD Transceiver With Integrated DC/DC Power
      9. 3.3.9  ISOW1412 Low-Emissions, 500kbps, Reinforced Isolated RS-485, RS-422 Transceiver With Integrated Power
      10. 3.3.10 OPA4388 Quad, 10-MHz, CMOS, Zero-Drift, Zero-Crossover, True RRIO Precision Operational Amplifier
      11. 3.3.11 OPA2388 Dual, 10-MHz, CMOS, Zero-Drift, Zero-Crossover, True RRIO Precision Operational Amplifier
      12. 3.3.12 INA181 26-V Bidirectional 350-kHz Current-Sense Amplifier
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Note
    3. 4.3 Test Setup
      1. 4.3.1 Boost Stage
      2. 4.3.2 Bidirectional DC/DC Stage - Buck-Mode
      3. 4.3.3 DC/AC Stage
    4. 4.4 Test Results
      1. 4.4.1 Boost Converter
      2. 4.4.2 Bidirectional DC/DC Converter
        1. 4.4.2.1 Buck Mode
        2. 4.4.2.2 Boost Mode
      3. 4.4.3 DC/AC Converter
  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 Authors
  13. 7Revision History

4.4.1 Boost Converter

The voltage of the switching node was measured as shown in Figure 4-5. From the picture, observe the sharp switching edges without overshoot and ringing. A rise-time of around 25ns can be observed.

C4 - Switching node voltage

TIDA-010938 Boost Switching Node Figure 4-5 Boost Switching Node

Figure 4-6 and Table 4-4 show the efficiency of input DC/DC Boost converter at 400V DC-link output. The input string voltages considered are 50V, 150V, 200V, 250V and 350V. For 200V input, the peak efficiency achieved is 98.9%, where the boost converter demonstrates the worst-case ripple conditions for a duty cycle of 50%. The table shows that the converter achieves both peak and full load efficiency of 99.3% for 350V input.

TIDA-010938 Boost Converter Efficiency Figure 4-6 Boost Converter Efficiency
Table 4-1 Boost Converter Efficiency
OUTPUT POWEREFFICIENCY AT VPV=50VOUTPUT POWEREFFICIENCY AT VPV=150VOUTPUT POWEREFFICIENCY AT VIN=200VOUTPUT POWEREFFICIENCY AT VIN=250VOUTPUT POWEREFFICIENCY AT VIN=350V
0.2kW95.6%0.6kW98.3%0.8kW98.7%

1.0kW

98.9%

1.4kW

99.2%

0.3kW96.2%0.9kW98.5%1.2kW98.9%

1.5kW

99.0%

2.1kW

99.3%

0.4kW96.3%1.2kW99.5%1.6kW98.9%

2.0kW

99.0%

2.8kW

99.3%

0.5kW96.2%1.5kW98.5%2.0kW98.8%

2.5kW

99.1%

3.5kW

99.3%

0.5kW96.0%1.6kW98.5%2.2kW98.8%

2.7kW

99.0%

3.8kW

99.3%

0.6kW95.8%1.8kW98.4%2.4kW98.8%

3.0kW

99.0%

4.2kW

99.3%

0.6kW95.6%1.9kW98.3%2.6kW98.7%

3.2kW

98.9%

4.5kW

99.2%

0.7kW

95.4%

2.1kW

98.4%

2.8kW

98.8%

3.5kW

99.0%

4.9kW

99.3%

0.7kW

95.7%

The GaN junction temperature for the worst-case duty-cycle for the GaN operation (for example, from conversion of PV string input of 50V to the DC-link voltage of 400V can be seen in Figure 4-7. The temperature does not go higher than 68°C.

TIDA-010938 GaN v/s Heatsink Temperature for Boost Converter Figure 4-7 GaN v/s Heatsink Temperature for Boost Converter