Below are the questions asked during the live event, along with their respective answers.
Q: How do I import my PCB data into my simulation tool?
A: You can import files from all common layout tool. Typically we use the ODB++ format to import.
Q: What commercial simulators are available for this application?
A: This simulation is run with CST Studio. A tool from Dassault Systems, Simulia.
Q: Do you have any suggestions in designing a harmonic tag on CST microwave? Especially in diode and electrical circuit section?
A: This is quite a general question. The methods shown in this webinar can also be applied to the design of components. They are not exclusive to EMC.
Q: How long did it take to create the powertrain model and how long did it take to run the simulation?
A: Creating the simulation model out of existing CAD data takes about 3 days. The simulation time is 3D model – about 5 hours. Circuit frequency domain about a few minutes. If the whole switching in time domain on the circuit needs to be considered then the circuit task takes about one day.
Q: How is simulation time required for the IGBT module?
A: The simulation time is: 3D model – about 5 hours. Circuit frequency domain about a few minutes. If the whole switching in time domain on the circuit needs to be considered then the circuit task takes about one day.
Q: Thanks for your nice presentation. I wonder how to model the motor controller generating PWM signals in CST Design Studio.
A: There is a macro in CST Design Studio that creates PWM signals. Macros -> Construct -> Create PWM Signals
Q: Is CATIA different than SIMULIA ?
A: Both are brands of Dassault Systems. Catia is a design tool for the creation of CAD models. Simulia is the brand for physics-based simulation.
Q: You showed CE simulation result. Is RE simulation also possible? How do set the antenna for typical automotive RE test with Bicon, or Log or Horn antenna?
A: Yes RE is also possible because the 3D solver calculates fields. In a first step, you should use field probes, that record the field (H, E) at a certain point in space. In the second step, you can also add the antenna into the model.
Q: Circuital part, as you explain, is a key part of the simulation. So fundamental is to have a precise spice model of all the components. When we simulate a flyback SMPS for example, the switching component is the critical component to evaluate, but usually, suppliers are not sharing this model, because it contains their key knowledge. How to solve this impasse?
A: In the first step, you can use a voltage controlled switch. In EMC simulation you typically start to simulate one mode of operations (one switching frequency, one load). Control loops are typically not included. Check for example this presentation. (This will download a PDF.)
Q: What level of ferrite permeability & permittivity detail is needed for accurate common mode choke modeling, i.e. does the type of ferrite affect the results much?
A: First you need to check if there is a need to include the CMC in 3D. This is the case if the choke interacts by stray fields. If the choke does not interact by fields you can use spice/touchstone files to model its behavior. If you need the 3D model, you can build it on your own: Choose right geometry and windings, adapt the ferrite material to obtain the differential/common mode impedance and inductance stated in the datasheet.
Q: What are the challenges if we simulate to high frequency such as 74-108MHz compared 0.53MHz-1.7MHz?
A: The model is typically the same. Your simulation time for the 3D simulation would, however, increase because you now have a broader frequency range.
Q: What type of model of the IGBT is enough for your simulation?
A: We use a 3d representation for the geometry and connect them to simple circuit elements in a first step. What you need to make sure is that you model the current flow correctly.
Q: At what point are SPICE blocks necessary to replace ideal parasitic elements? What are the differences between the two cases?
A: In many cases, elements with 1st order parasitic values are sufficient to model the EMC behavior. Replacing them with spice blocks is a late step that is typically a cross-check to ensure that the system behavior is not changed by these models.
Q: How can you verify your simulation accuracy?
A: The best validation is always to compare to measurements. It can be a lengthy process but it gives you a lot of insight because once you understood deviations, you have also understood a lot about your model.
Q: Could you give more details of your company software you mentioned in the presentation?
A: The company is Dassault Systems Simulia. https://www.3ds.com/products-services/simulia/
Q: Could you run a simulation for a certain real PCB having components already mounted? PCB file available.
A: Please contact your local Dassault Systems representative at https://www.3ds.com/products-services/simulia/. We can discuss different ways of collaboration.