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Field-Oriented Control (FOC) of PMSM Using Hardware-In-The-Loop (HIL) Simulation

This example uses hardware-in-the-loop (HIL) simulation to implement the field-oriented control (FOC) algorithm to control the speed of a three-phase permanent magnet synchronous motor (PMSM). The FOC algorithm requires rotor position feedback, which is obtained by a quadrature encoder sensor. For more information on FOC, see Field-Oriented Control (FOC).

NOTE: This example runs only on Windows and Linux platforms. It is not supported on the Mac platform.

When the actual motor and inverter hardware are not available, you can use the HIL simulation workflow to validate the FOC algorithm in real-time by operating a realistic virtual plant. The HIL simulation setup consists of these elements:

  • Desktop computer or development hardware running Simulink®

  • Controller hardware running the code for the controller

  • Target hardware (FPGA) running the code for the physical plant

You need to deploy the controller code to the controller hardware and the HDL code for the plant to the FPGA target hardware. After deploying the controller code, the controller runs the FOC algorithm and outputs actual PWM signals. Whereas, after HDL code deployment, the FPGA hardware effectively emulates the actual inverter and motor by running the HDL code for the plant. Therefore, it replicates the actual plant by accepting the PWM signals and providing realistic current and rotor position feedback to the controller in real-time. The FPGA hardware runs in external mode and logs data in the Simulation Data Inspector of the Simulink Real-Time model.

The Simulink host model running on the desktop computer, interacts with the controller using serial communication protocol. You can use the host model to communicate with the controller, and therefore, control the motor operation.

You can also use this setup to effectively test scenarios like hardware failures, motor burn-out, and other faults. To know more about HIL simulation, see Basics of Hardware-In-The-Loop simulation (Simscape).

Open MATLAB Project

The example is packaged as a MATLAB® project. Use one of these methods to open the MATLAB project window:

1. Click Open Example.

2. Run the command mcb_foc_hil at the command prompt.

Model

The MATLAB project has a model folder that includes the following models:

  • mcb_pmsm_foc_f28379d.slx - This target model contains the FOC algorithm that you can deploy and run on the controller hardware. The model algorithm applies the Subcycle Averaging method for simulation and to run on the controller hardware to validate the controller FOC algorithm. You can use this model to generate the embedded C code for the controller hardware.

  • mcb_host_f28379d.slx - This is a host model to communicate with the embedded target hardware. Using this model, you can start the simulation and run the motor. You can then generate PWM signals and log data from controller hardware using this model.

Apart from these two models, you will need an FPGA plant model (a combination of inverter and motor equations), which you can deploy and run on the FPGA target hardware, and a Simulink® Real-Time™ application model, which you can use to choose the target hardware and deploy the FPGA plant model algorithms. This example uses the plant model slrt_ex_pmsm.slx. The plant model captures the PWM duty cycles provided by the controller and, in turn, runs the inverter and motor equations to generate and send back the actual ADC voltage and position signals to the controller hardware. You can use this plant model to generate the Simulink Real-Time (SLRT) model and the HDL code for the FPGA target hardware. For more information, see .

Required MathWorks® Products

To simulate model:

  • Motor Control Blockset™

To generate code and deploy model:

1. Motor Control Blockset™

2. Simulink Real-Time™

3. Embedded Coder®

4. Embedded Coder® Support Package for Texas Instruments™ C2000™ Processors

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

6. Stateflow®

7. HDL Coder™ (required only if you are changing the plant model)

8. Speedgoat I/O Blockset

Prerequisites

1. Obtain the motor and inverter parameters. The MATLAB project uses default motor and inverter parameters that you can replace with values from either the motor and inverter datasheets or from other sources.

Optionally, if you have the actual motor, you can estimate the parameters for the motor that you want to use with the motor control hardware by using the Motor Control Blockset parameter estimation tool. For instructions, see Estimate PMSM Parameters Using Recommended Hardware. The parameter estimation tool updates the motorParam variable (in the MATLAB workspace) with the estimated motor parameters.

2. Update the motor and inverter parameters in the mcb_pmsm_foc_f28379d_data.m parameter script associated with the target models available in the MATLAB project. This script automatically opens when you open the MATLAB project. You can also use the Project window to open this script from the scripts folder.

3. Click Run on the Editor tab to run the parameter script.

Simulate Model

Follow these steps to simulate the models included in the project:

1. Open target model mcb_pmsm_foc_f28379d.slx from the model folder included in the MATLAB project.

2. Click Run on the Simulation tab to validate the motor operation. You can increase the simulation speed by reducing the FPGA frequency f_base to 2MHz in pmsm_hil_data.m script. Observe the simulation results. Make sure to revert f_base to 200MHz before deploying to FPFA hardware.

3. Open plant model slrt_ex_pmsm.slx. If you want to change the plant model, update slrt_ex_pmsm.slx. Simulate mcb_pmsm_foc_f28379d.slx to verify the changes in simulation and proceed with HDL workflow to generate the new SLRT model.

Generate Code and Deploy Model to Target Hardware

This section shows you how to generate code and run the FOC and plant model algorithms on the controller and FPGA target hardware.

In addition to the target model, the MATLAB project uses a host model. The host model, which is a user interface to the controller hardware board, runs on the host desktop computer. To use the host model, you need to deploy the target model mcb_pmsm_foc_f28379d.slx to the controller hardware board. The host model uses serial communication to command and interface with the slrt_ex_pmsm_gm.slx model to run (and control) the inverter and motor equations (HDL code that emulates the actual plant) on the FPGA target hardware.

Generating the SLRT model is optional. You can use the slrt_ex_pmsm_gm.slx model to generate an SLRT model to run on the host desktop computer. The SLRT model uses the Simulation Data Inspector to collect and log the debugging data from the plant model HDL code (running on the FPGA hardware in external mode).

Required Hardware

The example supports this hardware configuration: LAUNCHXL-F28379D controller + Speedgoat IO-334 programmable FPGA card.

Prepare Hardware

1. Connect the Speedgoat board to the LAUNCHXL-F28379D controller board as shown in this table.

2. For encoder signals, connect the Speedgoat to controller board as shown in this table.

3. For analog signals, connect the Speedgoat to controller as shown in this table.

For more details on the Speedgoat board, see Speedgoat IO-334 and Speedgoat Connection box.

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

Generate Code and Run Model on Target Hardware

1. Complete the hardware connections.

2. Open the target model mcb_pmsm_foc_f28379d.slx. If you want to change the default hardware configuration settings for this model, see Model Configuration Parameters.

3. To ensure that CPU2 is not configured to use the board peripherals intended for CPU1, load a sample program to the CPU2 of the LAUNCHXL-F28379D. For example, you can load the program that operates the CPU2 blue LED by using GPIO31 (c28379D_cpu2_blink.slx).

4. Check that you have updated the correct motor and inverter parameters in the parameter script mcb_pmsm_foc_f28379d_data.m.

5. Click Build, Deploy & Start on the Hardware tab to deploy the target model mcb_pmsm_foc_f28379d.slx to the controller hardware.

6. Open the plant model slrt_ex_pmsm_gm.slx and build the model. Program the FPGA using this model and run it for 500 seconds by executing below lines in MATLAB command window.

tg = slrealtime;
tg.stop
mdl = 'slrt_ex_pmsm_gm';
tg.load(mdl);
tg.setStopTime(500)
tg.start;

NOTE: If you want to update the plant model, update slrt_ex_pmsm.slx and follow HDL workflow to generate the SLRT model slrt_ex_pmsm_gm.slx and program the FPGA.

7. Click the host model hyperlink in mcb_pmsm_foc_f28379d.slx target model to open the host model.

You can also use the MATLAB project window to open the host model mcb_host_f28379d.slx.

8. Turn the Stop-Start slider switch available in the Simulation Dashboard area to the Start position to allow the model to simulate and run the motor. Run the Open loop control first. Select Ia & Ib ADC counts from Debug signals and observe the ADC counts of the phase current.

9. Take the average value from peak to peak of the sinusoidal ADC count waveform for both Ia and Ib. This is the current offset. Update this current offset in mcb_pmsm_foc_f28379d_data.m for variables inverter.CtSensAOffset and inverter.CtSensBOffset. Build and flash the mcb_pmsm_foc_f28379d.slx model again to the controller hardware. Continue with the host model by running the motor in a closed loop operation.

During simulation, you can turn the switch to the Stop position anytime to immediately stop the motor.

10. In the host model, open the blocks Host Serial Setup, Host Serial Receive, and Host Serial Transmit, and select a Port.

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

12. Review the logged signals using the Simulation Data Inspector.