The modelling language Modelica and libraries based upon it are excellently suited for model-based design of future aircraft systems, e.g. more electric aircraft or sustainable air-conditioning systems. To enable those design tasks, Modelica Libraries for media models, electromagnetic devices such as transformers and electrical machines and for wavelet analysis were developed or extended by a consortium of three partners.
XRG Simulation provided two fluid property models according to the Modelica.Media specification, one model for R134a and one model for humid air. Both models were used for complex air conditioning system simulation e.g. of aircraft.
Technische Universität Dresden, where the Modelica.Magnetic.FluxTubes library was originally developed, extended this library with hysteresis models. Simulation of static (ferromagnetic) and dynamic (eddy current) hysteresis allows for estimation of iron losses in transformers and electrical machines and hence, e.g., for subsequent simulation of heating.
In addition, Modelica models of one- and three-phase transformers were developed. Compared to the simple transformer models already included in the Modelica Standard library, the models developed include a transformer’s magnetic subsystem and hence consider saturation and core losses. The developed hysteresis and transformer models were validated with in-house measurements.
Furthermore, the Modelica.Magnetic library was extended by electrical machine models based on look-up tables. These models allow for dynamic simulation of machines with saturation and non-linear torque-current-angle characteristics.
Technische Universität München developed a Modelica Wavelet library for capture, identification and analysis of processes. This library allowed new signal processing methods for analysis, reconstruction and modelling of signals. That improved the power quality assessment in physical systems, e.g. in electrical systems of aircraft.
Work performed and achieved results:
Technische Universität Dresden, where the Modelica.Magnetic.¬FluxTubes library was originally developed, has extended this library with magnetic hysteresis models. Computation of static (ferromagnetic) and dynamic (eddy current) hysteresis now allows for accurate estimation of iron losses and hence, e.g., for subsequent simulation of heating. This becomes increasingly important with the growing requirements regarding energy efficiency and mass power densities during the design process of electromagnetic components and systems. In addition, models for one- and three phase transformers have been developed. Compared to simple transformer models already included in the Modelica Standard Library, the developed models include the transformer’s magnetic subsystem and hence consider saturation, remanence and core losses. A material library allows for simple adaption of the hysteresis elements to a specific material characteristic. That material library is mainly based on in-house measurements, contains hysteresis characteristics of different steel sheet qualities and cobalt-iron alloys, and is included in the Modelica.Magnetic.-FluxTubes library extension. The hysteresis elements and transformer models developed within MoMoLib have been successfully validated with in-house measurements.
XRG Simulation GmbH implemented two fluid property models, one for R134a and one for humid air, into a new Modelica library called MoMoLib. The models make use of interfaces provided by the Modelica.Media package (part of the Modelica Standard Library issued by the Modelica Association). Thus, the fluid property models can be used by any thermo-hydraulic Modelica model which refers to this interface specification.
The R134a model refers to Tillner-Roth’s fundamental equation of state and further models for dynamic viscosity, thermal conductivity and surface tension. The humid air is modeled as an ideal mixture of real gases including liquid water, steam and ice formation and dissociation. As a byproduct a separate model for air as a real gas has been implemented which can be used independently. All models were validated comparatively with software implementations of the corresponding references (RefProp and LibHuAir). Deviations were in general smaller or much smaller than 1%. The models have been integrated into Modelica Standard Library 3.2.1 and will be further exploited by XRG in the commercial XRG Media library.
Technische Universität München has developed a comprehensive Modelica Wavelet library for capture, identification and analysis of processes. This library provides new signal processing methods for analysis, reconstruction and modelling of signals, which will improve the power quality assessment in physical systems, e.g. in electrical systems of aircraft. The Modelica Wavelet library includes fifteen commonly used wavelet families. It provides functions for continuous wavelet transform, forward and inverse discrete transforms, and multi-level decomposition and reconstruction in one-dimensional space. In addition, special application tools for multi-resolution analysis and wavelet denoising are provided. Moreover, example models have been implemented to provide the users a quick start point to build up their own algorithms.