SPRUJF4A October   2024  – December 2024

 

  1.   1
  2.   Description
  3.   Features
  4.   Applications
  5.   5
  6. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
    5.     General Texas Instruments High Voltage Evaluation (TI HV EVM) User Safety Guidelines
  7. 2Hardware
    1. 2.1 Hardware Description
      1. 2.1.1 Auxiliary Power Supply
      2. 2.1.2 DC Link Voltage Sensing
      3. 2.1.3 Motor Phase Voltage Sensing
      4. 2.1.4 Motor Phase Current Sensing
        1. 2.1.4.1 Three-Shunt Current Sensing
        2. 2.1.4.2 Single-Shunt Current Sensing
      5. 2.1.5 External Overcurrent Protection
      6. 2.1.6 Internal Overcurrent Protection for TMS320F2800F137
    2. 2.2 Getting Started Hardware
      1. 2.2.1 Test Conditions and Equipment
      2. 2.2.2 Test Setup
  8. 3Motor Control Software
    1. 3.1 Three-Phase PMSM Drive System Design Theory
      1. 3.1.1 Field-Oriented Control of PMSM
        1. 3.1.1.1 Space Vector Definition and Projection
          1. 3.1.1.1.1 ( a ,   b ) ⇒ ( α , β ) Clarke Transformation
          2. 3.1.1.1.2 ( α , β ) ⇒ ( d ,   q ) Park Transformation
        2. 3.1.1.2 Basic Scheme of FOC for AC Motor
        3. 3.1.1.3 Rotor Flux Position
      2. 3.1.2 Sensorless Control of PM Synchronous Motor
        1. 3.1.2.1 Enhanced Sliding Mode Observer With Phase-Locked Loop
          1. 3.1.2.1.1 Mathematical Model and FOC Structure of an IPMSM
          2. 3.1.2.1.2 Design of ESMO for the IPMS
            1. 3.1.2.1.2.1 Rotor Position and Speed Estimation With PLL
      3. 3.1.3 Field Weakening (FW) and Maximum Torque Per Ampere (MTPA) Control
    2. 3.2 Getting Started Software
      1. 3.2.1 GUI
      2. 3.2.2 Download and Install C2000 Software
      3. 3.2.3 Using the Software
      4. 3.2.4 Project Structure
  9. 4Test Procedure and Results
    1. 4.1 Build Level 1: CPU and Board Setup
    2. 4.2 Build Level 2: Open-Loop Check With ADC Feedback
    3. 4.3 Build Level 3: Closed Current Loop Check
    4. 4.4 Build Level 4: Full Motor Drive Control
    5. 4.5 Test Procedure
      1. 4.5.1 Startup
      2. 4.5.2 Build and Load Project
      3. 4.5.3 Setup Debug Environment Windows
      4. 4.5.4 Run the Code
        1. 4.5.4.1 Build Level 1 Test Procedure
        2. 4.5.4.2 Build Level 2 Test Procedure
        3. 4.5.4.3 Build Level 3 Test Procedure
        4. 4.5.4.4 Build Level 4 Test Procedure
          1. 4.5.4.4.1 Tuning Motor Drive FOC Parameters
          2. 4.5.4.4.2 Tuning Field Weakening and MTPA Control Parameters
          3. 4.5.4.4.3 Tuning Current Sensing Parameters
    6. 4.6 Performance Data and Results
      1. 4.6.1 Load and Thermal Test
      2. 4.6.2 Overcurrent Protection by External Comparator
      3. 4.6.3 Overcurrent Protection by Internal CMPSS
  10. 5Hardware Design Files
    1. 5.1 Schematics
    2. 5.2 PCB Layouts
    3. 5.3 Bill of Materials (BOM)
  11. 6Additional Information
    1. 6.1 Known Hardware or Software Issues
    2. 6.2 Trademarks
    3. 6.3 Terminology
  12. 7References
  13. 8Revision History

2.1.3 Motor Phase Voltage Sensing

The software for the TIEVM-MTR-HVINV allows for both the enhanced Sliding Mode Observer (eSMO) and the Flux, Angle, Speed, and Torque (FAST™) sensorless observers. While the eSMO only requires the commonly used 3-phase motor current sensing, the FAST observer additionally requires requires 3-phase motor voltage sensing to improve low-speed performance and increase the precision of the motor speed estimation.

Note that the software parameter (USER_ADC_FULL_SCALE_VOLTAGE_V) depends on the circuit that senses the voltage feedback from the motor phases. Figure 2-4 shows how the motor voltage is filtered and scaled for the ADC input range using a voltage feedback circuit based on resistor dividers. The similar circuit is used to measure all three of both compressor and fan motors, and dc bus.

The maximum phase voltage feedback measurable by the microcontroller in this reference design can be calculated as given in Equation 1, considering the maximum voltage for the ADC input is 3.3 V.

Equation 1. VFS=VADC_FS×Gv=3.3V×122.46=404.13V

where

  • Gv is attenuation factor, Gv is calculated with Equation 2
Equation 2. GV=R62+R67+R70+R74R74=332kΩ+332kΩ+332kΩ+8.2kΩ8.2kΩ=122.46

With that voltage feedback circuit, the following setting is done in user_mtr1.h:

//! \brief Defines the maximum voltage at the AD converter
#define USER_M1_ADC_FULL_SCALE_VOLTAGE_V         (404.1292683f)

The voltage filter pole is needed by the FAST estimator to allow an accurate detection of the voltage feedback. Make the filter low enough to filter out the PWM signals, and at the same time allow a high-speed voltage feedback signal to pass through the filter. As a general guideline, a cutoff frequency of a few hundred Hz is enough to filter out a PWM frequency of 5 to 20 kHz. Change the hardware filter only when ultra-high-speed motors are run, which generate phase-voltage frequencies in the order of a few kHz.

In this reference design the filter pole setting can be calculated with Equation 3:

Equation 3. ffilter_pole=12×π×RParallel×C=405.15Hzwhere, C=47nF RParallel = 332kΩ+332kΩ+332kΩ×8.2kΩ332kΩ+332kΩ+332kΩ+8.2kΩ=8.133kΩ 

The following code example shows how this is defined in user_mtr1.h:

//! \brief Defines the analog voltage filter pole location, Hz
#define USER_M1_VOLTAGE_FILTER_POLE_Hz           (416.3602877f)
TIEVM-MTR-HVINV Motor Voltage Sensing CircuitFigure 2-4 Motor Voltage Sensing Circuit