Simcenter 3D Solutions FMU/FMI - Export a cosimulation FMU from the AMESim & Import it in the Simulink

• How to create the FMU in AMESim?
• How to export co-simulation FMU from AMESim?
• How to import this created FMU in Simulink?
• How to carry out co-simulation?

• At least AMESim base with FMU add on license
• Simulink with FMU license
• In addition to these other libraries as per your modeling requirements.

The electrical vehicle is gaining popularity and it is seeing as a technology of the future. Battery pack design is playing very important from the safety and performance point of view. Generally, a separate Battery management control unit is used to manage the performance of the battery. MIL, SIL, HIL, etc method is generally used to verify the algorithm and logic of the Battery management control unit. Simulink is generally used as a graphical language for coding of most of the electronic control units.  In this demo, a simplified BMC for battery cell balancing control algorithm is developed in Simulink; the model of the battery pack is implemented in Simcenter AMESim. By coupling between AMESim and Simulink, one can verify the effectiveness of code in the design stage. AMESim can be coupled with Simulink in several ways. In this demo, we will see “How AMESim can be coupled with Simulink to verify your control unit logic”. AMESim model is giving voltages of various cells as an output. This output is sent to the Simulink model. At every time step Simulink processes this output and give the optimum command to each cell so that cell balancing can be achieved.

• Simulink doesn’t comply with the so-called “structured variable naming” of FMUs (also known as “dotted convention” or “Modelica-like convention”). Apparently, Simulink mistakenly treats IO names as bus components. These issues do not arise with 3^rd party open-source toolboxes like DS’ FMI Kit for Simulink. Hence, you may face the issue while importing FMU.

• Right-click on “interface block” and click on the “Edit Interface”. This should open below the window. Change the “AME2SL” interface to the “FMI” interface.

        

• Connect all the ports and complete the model.
• If you wanted to change some of the parameters directly from the Simulink, then you can add them in the “watch parameter”. Similarly, you can also add the “Watch variable”. In this way, you can directly change these parameters from Simulink without opening AMESim

• Compile your model.
• Go to Interface >> FMU Export Assistant

• FMU type and version – Select the Co-simulation 2.0 option from here.
• Visibility level: Exposed elements – select the required option depending on “how many parameters and variables do you want to expose?
• Tick mark required option
• Select the output directory, where you wanted to save the .fmu file
• Click on the next.
• Select the targeted compiler. Please note, you should use the same compiler in Simulink.

• Click on Generate.

• It should generate the .fmu file in the targeted directory.

• Open existing .slx file and delete AME2SL block. This block needs to be replaced with FMU.
• Add FMU submodel into the Simulink sketch and double click on the FMU.
• It should open the below window. Browse the .fmu file here. It will load the co-simulation fmu.

• It will display only “1 input” and “1 output” ports instead of your expectation of “10 inputs” and “10 outputs” ports. Here you will have to create a bus in order to overcome this issue.
• Run below command to create a bus

• Connect all signals line properly. Your model is ready for co-simulation.

• Since it is a co-simulation example, hence, AMESim FMU will use a AMESim solver and the Simulink model will use a Simulink solver. Double click on FMU. It will open the “Block parameters” window.
• You can see here all run parameters from AMESim. AMESim run parameter setting can be directly controlled from here. If you scroll down in this window, then you can also see the parameters which you added in the “watch parameter” list before exporting FMU. You can directly change these parameters from here.

• Set the proper solver setting for the Simulink model.
• Run the model. You can see the results now

• We have tested this FMU in MATLAB 2019b version, hence this instruction may applicable till 2019b or higher version (If MATLAB will not improve on this). If MATLAB will do some improvement in the future version, then, you may not see this issue.

• Use Simulink bus extractor components to retrieve the individual signals
• Use the two MATLAB commands below:
  set_param('MyModel/FMU','FMUInputMapping','Flat')    set_param('MyModel/FMU','FMUOutputMapping','Flat')

• "Ame2slcosim" can provide better options compared to this option provided in this article.
• Till 2019b, Simulink doesn’t comply with the so-called “structured variable naming” of FMUs
• All process related to the FMU import and export is simple and more interactive in AMESim compare to Simulink.