Model Partitioning Components
This section describes the general properties of circuit properties components in Typhoon HIL's Schematic Editor, such as core couplings, device couplings, core markers, device markers, etc.
In real-time/VHIL simulation, there are two different types of coupling elements, Ideal Transformer based (IT) and Transmission Line Model based (TLM). IT coupling components are ideal transformers with a transfer ratio of one. They are used to partition the complete emulated power electronics circuit into multiple sub-circuits. Consequently, each sub-circuit is assigned and executed on a separate processing core and/or separate device. In addition, this ideal transformer block introduces a time delay (0.5 µs, 1 µs or 2 µs) between measured variables and corresponding controlled sources, which is negligible for most practical systems.
In TyphoonSim, the fixed timestep constraint is absent.
Offline (non-real-time) simulators, like TyphoonSim, use variable simulation step in
their simulations, so real-time constraints are not a concern. As a result, model
partitioning is not required for offline simulations because there is no need to split
the model to improve computational performance within a fixed time frame.
In real-time/VHIL simulation, when IT coupling components are added to the circuit, topological conflicts can occur (described in Topological Conflicts). These conflicts are solved by adding snubber circuits in parallel with a coupling's current source and/or in series with a coupling's voltage source. Snubbers are embedded in coupling components. Check Core couplings - Ideal Transformer for more informations about snubbers and their usage.
IT coupling can make a model unstable, so coupling stability analysis routine is available. Coupling stability analysis checks the stability of all core coupling components in the model. If core coupling stability analysis is enabled, then during compilation, a stability report is printed for all couplings in the circuit. For each coupling, there can be three messages: coupling element is stable, coupling element is unstable and coupling element is around stability border. For more information about stability analysis check Core couplings - Ideal Transformer.
Core couplings - Ideal Transformer are ignored in TyphoonSim.
In real-time/VHIL simulations, TLM (Transmission Line Model) core coupling components are based on transmission-line links. Similar to IT coupling components, they are used to partition the complete emulated power electronics circuit into multiple sub-circuits. A coupling component can be either capacitive or inductive.
The main advantage of TLM couplings, compared to the ideal transformer based coupling components, is that TLM couplings are symmetrical components. Both sides of the TLM couplings are voltage sources behind an impedance. Because of this property, TLM coupling rotation is not important and they will not introduce any topological conflict in the circuit. The main disadvantage is that they will add some additional inductance or capacitance to the circuit. However, it is better to replace an existing inductor/capacitor with a TLM coupling in order to get better results. For more details about TLM coupling placement please refer to Coupling component placement and parametrization - TLM based couplings.
The bilinear discretization method is recommended since TLM coupling is based on this approach. But, if the TLM inductance(capacitance) is relatively small, trapezoidal discretization can be used. TLM coupling is in general more robust than Ideal Transformer coupling. TLM coupling in combination with bilinear or trapezoidal discretization method guarantees stability in most practical use cases, so there is no need for an additional stability analysis.
TLM core coupling
components are partially ignored in TyphoonSim. Please check Core couplings - TLM for more information about TLM coupling
components.
In addition to the Ideal Transformer and Transmission Line Model coupling components, a Bergeron transmission line can be used for circuit decoupling in real-time/VHIL simulations. Check Single Phase Bergeron Model and Three Phase Bergeron Model for more information about Bergeron models.
The current version of Schematic Editor offers a selection of the following types of circuit coupling components:
Core couplings - Ideal Transformer