TIDUBE5A January   2022  – October 2022

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TMS320F2800137
      2. 2.3.2 TMS320F280025C
      3. 2.3.3 TMS320F280039C
      4. 2.3.4 UCC28740
      5. 2.3.5 UCC27517
      6. 2.3.6 TLV9062
      7. 2.3.7 TLV76733
    4. 2.4 System Design Theory
      1. 2.4.1 Interleaved PFC
        1. 2.4.1.1 Full Bridge Diode Rectifier Rating
        2. 2.4.1.2 Inductor Ratings
        3. 2.4.1.3 AC Voltage Sensing
        4. 2.4.1.4 DC Link Voltage Sensing
        5. 2.4.1.5 Bus Current Sensing
        6. 2.4.1.6 DC Link Capacitor Rating
        7. 2.4.1.7 MOSFET Ratings
        8. 2.4.1.8 Diode Ratings
      2. 2.4.2 Three-Phase PMSM Drive
        1. 2.4.2.1 Field Oriented Control of PM Synchronous Motor
        2. 2.4.2.2 Sensorless Control of PM Synchronous Motor
          1. 2.4.2.2.1 Enhanced Sliding Mode Observer with Phase Locked Loop
            1. 2.4.2.2.1.1 Mathematical Model and FOC Structure of an IPMSM
            2. 2.4.2.2.1.2 Design of ESMO for the IPMSM
            3. 2.4.2.2.1.3 Rotor Position and Speed Estimation with PLL
        3. 2.4.2.3 Field Weakening (FW) and Maximum Torque Per Ampere (MTPA) Control
        4. 2.4.2.4 Compressor Drive with Automatic Vibration Compensation
        5. 2.4.2.5 Fan Drive with Flying Start
        6. 2.4.2.6 Hardware Prerequisites for Motor Drive
          1. 2.4.2.6.1 Motor Current Feedback
            1. 2.4.2.6.1.1 Current Sensing with Three-Shunt
            2. 2.4.2.6.1.2 Current Sensing with Single-Shunt
          2. 2.4.2.6.2 Motor Voltage Feedback
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Getting Started Hardware
      1. 3.1.1 Hardware Board Overview
      2. 3.1.2 Test Conditions
      3. 3.1.3 Test Equipment Required for Board Validation
      4. 3.1.4 Test Setup
    2. 3.2 Getting Started Firmware
      1. 3.2.1 Download and Install Software Required for Board Test
      2. 3.2.2 Opening Project Inside CCS
      3. 3.2.3 Project Structure
    3. 3.3 Test Procedure
      1. 3.3.1 Build Level 1: CPU and Board Setup
        1. 3.3.1.1 Start CCS and Open Project
        2. 3.3.1.2 Build and Load Project
        3. 3.3.1.3 Setup Debug Environment Windows
        4. 3.3.1.4 Run the Code
      2. 3.3.2 Build Level 2: Open Loop Check with ADC Feedback
        1. 3.3.2.1 Start CCS and Open Project
        2. 3.3.2.2 Build and Load Project
        3. 3.3.2.3 Setup Debug Environment Windows
        4. 3.3.2.4 Run the Code
      3. 3.3.3 Build Level 3: Closed Current Loop Check
        1. 3.3.3.1 Start CCS and Open Project
        2. 3.3.3.2 Build and Load Project
        3. 3.3.3.3 Setup Debug Environment Windows
        4. 3.3.3.4 Run the Code
      4. 3.3.4 Build Level 4: Full PFC and Motor Drive Control
        1. 3.3.4.1  Start CCS and Open Project
        2. 3.3.4.2  Build and Load Project
        3. 3.3.4.3  Setup Debug Environment Windows
        4. 3.3.4.4  Run the Code
        5. 3.3.4.5  Run the System
        6. 3.3.4.6  Tuning Motor Drive FOC Parameters
        7. 3.3.4.7  Tuning PFC Parameters
        8. 3.3.4.8  Tuning Field Weakening and MTPA Control Parameters
        9. 3.3.4.9  Tuning Flying Start Control Parameters
        10. 3.3.4.10 Tuning Vibration Compensation Parameters
        11. 3.3.4.11 Tuning Current Sensing Parameters
    4. 3.4 Test Results
      1. 3.4.1 Performance Data and Curves
      2. 3.4.2 Functional Waveforms
      3. 3.4.3 Transient Waveforms
      4. 3.4.4 MCU CPU Load, Memory and Peripherals Usage
        1. 3.4.4.1 CPU Load for Full Implementation
        2. 3.4.4.2 Memory Usage
        3. 3.4.4.3 Peripherals Usage
    5. 3.5 Migrate Firmware to a New Hardware Board
      1. 3.5.1 Configure the PWM, CMPSS, and ADC Modules
      2. 3.5.2 Setup Hardware Board Parameters
      3. 3.5.3 Configure Faults Protection Parameters
      4. 3.5.4 Setup Motor Electrical Parameters
      5. 3.5.5 Setup PFC Control Parameters
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 Bill of Materials
      3. 4.1.3 Altium Project
      4. 4.1.4 Gerber Files
      5. 4.1.5 PCB Layout Guidelines
    2. 4.2 Software Files
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  10. 5Terminology
  11. 6Revision History

2.4.2.5 Fan Drive with Flying Start

Flying start is a feature that allows the drive to determine the speed and direction of a spinning motor and begin the output voltage and frequency at that speed and direction. Without flying start, the drive will begin its output at zero volts and zero speed and attempt to ramp to the commanded speed. If the inertia or direction of rotation of a load requires the motor to produce a large amount of torque, excess current can result and overcurrent trips might occur on the drive. These problems can be eliminated with flying start.

Flying start is the capacity to start control at any speed other than ZERO, which is an important function in air-condition application for fan drive.

When a motor is started in its normal mode, the control initially applies a frequency of 0 Hz and ramps to the desired frequency. If the drive is started in this mode with the motor already spinning with non-zero frequency, large currents are generated. An over current trip can result if the current limiter cannot react quickly enough. Even if the current limiter is fast enough to prevent an over current trip, it can take an unacceptable amount of time for synchronization to occur and for the motor to reach its desired frequency. In addition, larger mechanical stress is placed on the application.

In flying start mode, the drive’s response to a start command is to synchronize with the motor’s speed (frequency and phase) and voltage. The motor then accelerates to the commanded frequency. This process prevents an over current trip and significantly reduces the time for the motor to reach its commanded frequency. Because the drive synchronizes with the motor at its rotating speed and ramps to the proper speed, little or no mechanical stress are present.

The flying start function implements an algorithm that searches for the rotor speed. The algorithm searches for a motor voltage that corresponds with the excitation current applied to the motor

When the motor is spinning, the speed and position information can be estimated from the BEMF voltages. Since the stator voltage is measured in InstaSPIN drive, the speed and position are easily obtained by switching the inverter. A zero torque current is applied to the motor and the generated current and stator voltage is measured, then InstaSPIN-FOC module uses these signals to estimate rotor position and speed.

The block diagram of FOC with flying start is shown in Figure 2-29, the flying start module outputs a flag to enable or disable speed close loop control. A zero reference torque current is set and the speed PI controller output is disabled while flying start is operating.

Figure 2-29 Flying Start Control Block Diagram

As shown in Figure 2-30, the module routine disables speed close loop control, sets the reference Iq to zero, and enables the FOC module during starting run the motor. After the phase currents and voltages are measured, the routine runs InstaSPIN-FOC and the real motor speed can be estimated. The program re-enables speed closed loop control and sets the speed reference value after flying start is completed. The current waveform during restart is as shown in Figure 3-32.

Figure 2-30 Flying Start Module Program Flowchart