Frequently Asked Question

Yes. In addition to real-time simulation, Typhoon HIL software can be used for non-real-time “offline simulation”. Although real-time is not preserved, there are several advantages that such an approach provides:

• Much better simulation resolution (lower time step)
• A higher level of details (such as non-idealities in power converters)
• Possibility to build custom topologies

Currently, Typhoon offers the following approaches for offline simulation: TyphoonSim, the VHIL+ environment, and the Integration with Xyce simulator.

1. TyphoonSim is our new true offline simulator, featuring variable simulation step and iterative numerical solver capabilities. Check this collection of FAQs and the TyphoonSim webpage for additional information.

2. VHIL+ is a virtual "device" with relaxed hardware limitations. By using it, you can get closer to a typical offline simulator in terms of simulation step and modeling flexibility.

The main advantages of this approach:

• Ease of use - it can be used in the same way as any Virtual HIL device, so in case you have some models made for regular HIL devices, you can reuse them in the VHIL+ environment.
• Software integration - you can use all standard Typhoon tools - HIL SCADA, Typhoon API's, TyphoonTest IDE...
• You have more matrix memory available which allows you to build significantly larger models. The minimal simulation step is 10 ns, which allows you to model components at much higher switching frequencies.

However, there are some disadvantages of the VHIL+ device:

• As in the whole Typhoon toolchain, converter switches are modeled as ideal (zero on resistance, infinite off resistance, and instantaneous switching transition).
• If your model exceeds some level of complexity, the compilation process can take much more time.
• Building custom topologies is quite limited.

3. Integration with Xyce. Xyce is an open-source, SPICE-compatible, high-performance analog circuit simulator made by Sandia National Labs. The Xyce simulator can be used inside Typhoon HIL's Schematic Editor thanks to the Typhoon HIL/Xyce interface.

The Typhoon HIL - Xyce interface is an independent open-source project which is intended to equip Typhoon software with the power of the Xyce engine. This project is separate from the main Control Center application and we encourage our community of users to take part in its development. The complete project and Quick-start guide can be accessed on this link. If you have found some problem, or have some suggestion regarding this project, please open an issue on this page.

The main advantages of this approach:

• You have at your disposal ready-to-use SPICE libraries.
• It is possible to have more detailed models (high-fidelity switch models, analog control circuits).
• New topologies can easily be made from single switch components.

On the other hand, there are some disadvantages:

• Software integration - currently Xyce is not completely integrated into the Typhoon toolchain. You will not be able to use standard Typhoon tools (HIL SCADA, Typhoon API's, TyphoonTest IDE) with the Xyce engine.

• Model interoperability – as the Xyce engine is not using the Typhoon library, models that are built for HIL simulation can't run using Xyce.

It is important to remember that, the listed tools are intended to be used for offline simulations, so models that are specifically prepared for them generally require modifications for simulation on HIL devices in real-time.