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Field Oriented Control of PMSM by Using SI Units

This example implements the Field-Oriented Control (FOC) technique to control the speed of a three-phase Permanent Magnet Synchronous Motor (PMSM). However, instead of the per-unit representation of quantities(for details about the per-unit system, see Per-Unit System), the FOC algorithm in this example uses the SI units of signals to perform the computations. These are the signals and their SI units:

  • Rotor speed - Radians/ sec

  • Rotor position - Radians

  • Currents - Amperes

  • Voltages - Volts

Field-oriented control (FOC) needs a real time feedback of the rotor position. This example uses the quadrature encoder sensor to measure the rotor position. For details about FOC, see Field-Oriented Control (FOC).

Models

The example includes this model:

  • mcb_pmsm_foc_qep_f28379d_SIUnit

You can use this model for both simulation and code generation. You can use the open_system command to open the Simulink® model. For example, use this command for a F28379D based controller:

open_system('mcb_pmsm_foc_qep_f28379d_SIUnit.slx');

Required MathWorks® Products

To simulate model:

  • Motor Control Blockset™

To generate code and deploy model:

  • Motor Control Blockset™

  • Embedded Coder®

  • Embedded Coder® Support Package for Texas Instruments™ C2000™ Processors

  • Fixed-Point Designer™ (only needed for optimized code generation)

Prerequisites

1. Obtain the motor parameters. We provide default motor parameters with the Simulink® model that you can replace with the values from either the motor datasheet or other sources.

However, if you have the motor control hardware, you can estimate the parameters for the motor that you want to use, by using the Motor Control Blockset parameter estimation tool. For instructions, see Estimate Motor Parameters by Using Motor Control Blockset Parameter Estimation Tool.

The parameter estimation tool updates the motorParam variable (in the MATLAB® workspace) with the estimated motor parameters.

2. If you obtain the motor parameters from the datasheet or other sources, update the motor parameters and inverter parameters in the model initialization script associated with the Simulink® models. For instructions, see Estimate Control Gains from Motor Parameters.

If you use the parameter estimation tool, you can update the inverter parameters, but do not update the motor parameters in the model initialization script. The script automatically extracts motor parameters from the updated motorParam workspace variable.

Simulate Model

This example supports simulation. Follow these steps to simulate the model.

1. Open the model included with this example.

2. Click Run on the Simulation tab to simulate the model.

3. Click Data Inspector on the Simulation tab to view and analyze the simulation results.

Generate Code and Deploy Model to Target Hardware

This section instructs you to generate code and run the FOC algorithm on the target hardware.

The example uses a host and a target model. The host model is a user interface to the controller hardware board. You can run the host model on the host computer. The prerequisite to use the host model is to deploy the target model to the controller hardware board. The host model uses serial communication to command the target model and run the motor in a closed-loop control.

Required Hardware

This example supports this hardware configuration. Use the target model name (highlighted in bold) to open the model for the corresponding hardware configuration, from the MATLAB® command prompt.

  • LAUNCHXL-F28379D controller + BOOSTXL-DRV8305 inverter: mcb_pmsm_foc_qep_f28379d_SIUnit

For connections related to the preceding hardware configuration, see LAUNCHXL-F28069M and LAUNCHXL-F28379D Configurations.

Generate Code and Run Model on Target Hardware

1. Simulate the target model and observe the simulation results.

2. Complete the hardware connections.

3. The model automatically computes the ADC (or current) offset values. To disable this functionality (enabled by default), update the value 0 to the variable inverter.ADCOffsetCalibEnable in the model initialization script.

Alternatively, you can compute the ADC offset values and update it manually in the model initialization scripts. For instructions, see Run 3-Phase AC Motors in Open-Loop Control and Calibrate ADC Offset.

4. Compute the quadrature encoder index offset value and update it in the model initialization scripts associated with the target model. For instructions, see Quadrature Encoder Offset Calibration for PMSM Motor.

5. Open the target model. If you want to change the default hardware configuration settings for the model, see Model Configuration Parameters.

6. Load a sample program to CPU2 of LAUNCHXL-F28379D, for example, program that operates the CPU2 blue LED by using GPIO31 (c28379D_cpu2_blink.slx), to ensure that CPU2 is not mistakenly configured to use the board peripherals intended for CPU1.

7. Click Build, Deploy & Start on the Hardware tab to deploy the target model to the hardware.

8. Click the host model hyperlink in the target model to open the associated host model. You can also use the open_system command to open the host model. For example, use this command for a F28069M based controller:

open_system('mcb_pmsm_SIUnit_host_model.slx');

For details about the serial communication between the host and target models, see Host-Target Communication.

9. In the Host Serial Setup block mask of the host model, select a Port name.

10. Update the Reference Speed value in the host model.

11. Click Run on the Simulation tab to run the host model.

12. Change the position of the Start / Stop Motor switch to On, to start running the motor.

13. Observe the debug signals from the RX subsystem, in the Time Scope of host model.