TIDUE53I march   2018  – july 2023 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  UCC5320
      3. 2.2.3  TMS320F28379D
      4. 2.2.4  AMC1305M05
      5. 2.2.5  OPA4340
      6. 2.2.6  LM76003
      7. 2.2.7  PTH08080W
      8. 2.2.8  TLV1117
      9. 2.2.9  OPA350
      10. 2.2.10 UCC14240
    3. 2.3 System Design Theory
      1. 2.3.1 Three-Phase T-Type Inverter
        1. 2.3.1.1 Architecture Overview
        2. 2.3.1.2 LCL Filter Design
        3. 2.3.1.3 Inductor Design
        4. 2.3.1.4 SiC MOSFETs Selection
        5. 2.3.1.5 Loss Estimations
        6. 2.3.1.6 Thermal Considerations
      2. 2.3.2 Voltage Sensing
      3. 2.3.3 Current Sensing
      4. 2.3.4 System Power Supplies
        1. 2.3.4.1 Main Input Power Conditioning
        2. 2.3.4.2 Isolated Bias Supplies
      5. 2.3.5 Gate Drivers
        1. 2.3.5.1 1200-V SiC MOSFETs
        2. 2.3.5.2 650-V SiC MOSFETs
        3. 2.3.5.3 Gate Driver Bias Supply
      6. 2.3.6 Control Design
        1. 2.3.6.1 Current Loop Design
        2. 2.3.6.2 PFC DC Bus Voltage Regulation Loop Design
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. 3.1.1.1 Test Hardware Required
        2. 3.1.1.2 Microcontroller Resources Used on the Design (TMS320F28379D)
        3. 3.1.1.3 F28377D, F28379D Control-Card Settings
        4. 3.1.1.4 Microcontroller Resources Used on the Design (TMS320F280039C)
      2. 3.1.2 Software
        1. 3.1.2.1 Getting Started With Firmware
          1. 3.1.2.1.1 Opening the CCS project
          2. 3.1.2.1.2 Digital Power SDK Software Architecture
          3. 3.1.2.1.3 Interrupts and Lab Structure
          4. 3.1.2.1.4 Building, Loading and Debugging the Firmware
        2. 3.1.2.2 Protection Scheme
        3. 3.1.2.3 PWM Switching Scheme
        4. 3.1.2.4 ADC Loading
    2. 3.2 Testing and Results
      1. 3.2.1 Lab 1
      2. 3.2.2 Testing Inverter Operation
        1. 3.2.2.1 Lab 2
        2. 3.2.2.2 Lab 3
        3. 3.2.2.3 Lab 4
      3. 3.2.3 Testing PFC Operation
        1. 3.2.3.1 Lab 5
        2. 3.2.3.2 Lab 6
        3. 3.2.3.3 Lab 7
      4. 3.2.4 Test Setup for Efficiency
      5. 3.2.5 Test Results
        1. 3.2.5.1 PFC Mode - 230 VRMS, 400 V L-L
          1. 3.2.5.1.1 PFC Start-up – 230 VRMS, 400 L-L AC Voltage
          2. 3.2.5.1.2 Steady State Results at 230 VRMS, 400 V L-L - PFC Mode
          3. 3.2.5.1.3 Efficiency and THD Results at 220 VRMS, 50 Hz – PFC Mode
          4. 3.2.5.1.4 Transient Test With Step Load Change
        2. 3.2.5.2 PFC Mode - 120 VRMS, 208 V L-L
          1. 3.2.5.2.1 Steady State Results at 120 VRMS, 208 V-L-L - PFC Mode
          2. 3.2.5.2.2 Efficiency and THD Results at 120 VRMS - PFC Mode
        3. 3.2.5.3 Inverter Mode
          1. 3.2.5.3.1 Inverter Closed Loop Results
          2. 3.2.5.3.2 Efficiency and THD Results - Inverter Mode
          3. 3.2.5.3.3 Inverter - Transient Test
      6. 3.2.6 Open Loop Inverter Test Results
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  11. 5Trademarks
  12. 6About the Authors
  13. 7Revision History

2.3.2 Voltage Sensing

Voltage sensing happens at two points in the inverter signal path to aid in control: before and after the primary output relay. By enabling measurement on both sides of the relay, the control system can lock into the grid voltage and frequency before connecting, thus preventing any mismatch issues.

Both sensing topologies are similar. First, PGND is used as a virtual neutral using a resistor network. On the grid side of the relay, only neutral is used. The high voltage signal is attenuated using a series of large value resistances. An offset of 1.65 V is added to the attenuated neutral point to center the voltage signal in the middle of the input range of the OPA4350, and the attenuated value from the phase voltage is measured. Figure 2-36 shows this sensing arrangement.

GUID-DB07ADED-5E11-4CA0-9001-37B029C0FF89-low.gifFigure 2-36 High-Voltage Sensing Signal Path