Documentation Home Page ◇ HYPERSIM Home Page
Pour la documentation en FRANÇAIS, utilisez l'outil de traduction de votre navigateur Chrome, Edge ou Safari. Voir un exemple.
Switches for EMT Studies
Types of Switch Models for EMT Studies
There are several types of switch models available to model the power electronic (PE) interfaces of distributed energy resources (DER) to perform studies related to DER integration to the power grid, and they all have their pros and cons. Thus proper selection requires knowledge of the test conditions and requirements, where tradeoffs can be made between the speed of simulation and the representation of details and achievable resolution, etc. A classification of the types of models available is shown in the figure below:
Knowing How/When to Reconcile Bandwidth (Computational Effort) with Resolution (Model Accuracy) for Best Simulation Results
The tradeoff between resolution (accuracy, coverage) and realtime performance (no skipped timesteps, throughput) is important to the strengths and limitations of simulation options. Users should know what they need from their simulation and what is best at providing it under the various circumstances under which they'll simulate. The figure below positions the available switch models on the model accuracy vs computational ease tradeoff spectrum.
See the second appearance of this graphic at the bottom of this topic to explore this very important strategic tradeoff in more detail.
Detailed Semiconductor
1 Source: https://ecee.colorado.edu/~bart/book/book/chapter7/ch7_5.htm#fig7_5_1
2 Source: A. Sokolov, “VariableSpeed Power Switch Gate Driver for Switching Loss Reduction in Automotive Inverters.”
Modeled Features
 Instantaneous turn on/off time representation
 Conduction and switching losses (Requires good tuning of parameters)
 Thermal model simulation with high accuracy
 Ripple representation with high accuracy
 Device transient characteristics (e.g. MOSFET, IGBT, etc.) can be modeled.
PROS  CONS 



Ideal Switch
Modeled Features
 Instantaneous turn on/off time representation
 Conduction and switching losses (Requires tuning of parameters)
 Ripple representation with high accuracy
PROS  CONS 



Constant Conductance
Also known as Pejovic Method  Associate Discrete Circuit.
Modeled Features
 Instantaneous turn on/off time representation
 Ripple representation with higher accuracy
PROS  CONS 



Switching Functions
Also known as Time Stamped Bridge (TSB)  Virtual FPGA Switching.
Modeled Features
 Suitable for voltagesource converters modeling
 Compensates for the adverse effects of pulsing from controllers (CHIL) occurring in between discretetime steps
 Accurately represents the voltage harmonic spectrum near the fundamental frequency of operation
 Allows effective modeling of switch deadtimes
PROS  CONS 



Average Models
Modeled Features
 Models the average signal produced by the converters
 Models the near fundamental dynamics of the system
 Effects of switching are neglected
PROS  CONS 



Types of Average Models
Voltage Source
 Implemented with the output filter
 Can include DC side dynamics
 Models the filter related dynamics of the system
Current Source
 Usually does not include DC side dynamics
 Filter dynamics are also neglected
 Systemlevel control dynamics can be modeled
Model Suitability for Microgrid/DER studies
This graphic depicts two continua, both along the Xaxis:
 Computational ease, i.e., the requirement of higher processing power and bandwidth, going from lowest required at the right to highest at the left.
 Model Exactitude, i.e., resolution or detail required, going from lowest requirements at the right to highest at the left.
 Also included on this graphic is realtime simulation to the right: realtime simulation makes very particular demands in terms of the processing power, such as no skipped time steps and higher speed of simulation.
 Conversely, offline simulation may be faster or slower than realtime, but it removes some factors from consideration: if one has more time, one can request more fidelity to models and less importance be assigned to the speed of simulation.
This graphic details the typical frequencies of interest that should concern users simulating various circumstances, from switching harmonics to controller interactions.
Similarly, it lays out the range of time step lengths, from nanoseconds to full seconds at which users may execute their models.
Example Available in HYPERSIM: 2 MW Connected PV Array
The following example is available for exploration and further understanding in HYPERSIM. Using the information outlined above, make changes and see how this affects the accuracy/bandwidth of your simulation.
References
S. Rosado, R. Burgos, S. Ahmed, F. Wang, and D. Boroyevich, “Modeling of Power Electronics for SimulationBased Analysis of Power Systems,” p. 8, 2007.
D. Maksimovic, A. M. Stankovic, V. J. Thottuvelil, and G. C. Verghese, “Modeling and simulation of power electronic converters,” Proc. IEEE, vol. 89, no. 6, pp. 898–912, Jun. 2001, doi: 10.1109/5.931486.
C. Dufour, “ArtEvents, a simplified and reliable eventbased block set for Simulink,” p. 7.
G. De Carne et al., “Which Deepness Class Is Suited for Modeling Power Electronics?: A Guide for Choosing the Right Model for GridIntegration Studies,” EEE Ind. Electron. Mag., vol. 13, no. 2, pp. 41–55, Jun. 2019, doi: 10.1109/MIE.2019.2909799.
A. M. . A. Amin, M. I. ElKorfolly, and S. A. Mohammed, “Exploring aliasing distortion effects on regularlysampled PWM signals,” in 2008 3rd IEEE Conference on Industrial Electronics and Applications, Singapore, Jun. 2008, pp. 2036–2041, doi: 10.1109/ICIEA.2008.4582878.
F. Gao, “RealTime Simulation Methods of Power Electronic Systems”, IEEE Power Electronics Society and Transportation Electrification Committee joint webinar, 2020. [Online]. Available: https://resourcecenter.ieeepels.org/webinars/PELSWEB011420v.html. [Accessed: 04 – Jun – 2020]
OPALRT TECHNOLOGIES, Inc.  1751, rue Richardson, bureau 1060  Montréal, Québec Canada H3K 1G6  opalrt.com  +1 5149352323