Prediction of system-level emissions performance via equipment shelf primary power bus frequency response characteristics
This paper reports an interesting extension of the frequency response testing technique to characterize real-world EMC conditions as encountered in the Product Realization cycle. It is demonstrated that the behavior of the Primary Power Bus of a system Equipment Shelf is a reliable predictor of the system’s EMC performance. In particular, the Conducted and Radiated Emissions characteristics of the system are anticipated before the system is fully assembled, and long before System-Level formal compliance testing is done. The frequency pass-bands and resonances of the Primary Power Bus are identified and these outcomes are closely correlated with independently obtained Conducted and Radiated Emissions spectra for the populated system Equipment Shelf.
An empirical model for simulating the system-level radiated emissions behavior of interconnected units and modules
The paper presents an empirical model for simulating the radiated emissions behavior of a system by incorporating several types of topological information and laboratory data gathered from independent tests. Using 3D EM field simulation software, the model can anticipate the behavior of different system configurations using the same units and modules. This model can also help reduce the number of required system-level tests when appraising the impact of minor hardware changes on the radiated emissions behavior of the system.
The microscale obstacle-resolving meteorological model MITRAS v2.0: model theory
Abstract. This paper describes the developing theory and underlying
processes of the microscale obstacle-resolving model MITRAS version 2. MITRAS
calculates wind, temperature, humidity, and precipitation fields, as well as
transport within the obstacle layer using Reynolds averaging. It explicitly
resolves obstacles, including buildings and overhanging obstacles, to
consider their aerodynamic and thermodynamic effects. Buildings are
represented by impermeable grid cells at the building positions so that the
wind speed vanishes in these grid cells. Wall functions are used to calculate
appropriate turbulent fluxes. Most exchange processes at the obstacle
surfaces are considered in MITRAS, including turbulent and radiative
processes, in order to obtain an accurate surface temperature. MITRAS is also
able to simulate the effect of wind turbines. They are parameterized using
the actuator-disk concept to account for the reduction in wind speed. The
turbulence generation in the wake of a wind turbine is parameterized by
adding an additional part to the turbulence mechanical production term in the
turbulent kinetic energy equation. Effects of trees are considered
explicitly, including the wind speed reduction, turbulence production, and
dissipation due to drag forces from plant foliage elements, as well as the
radiation absorption and shading. The paper provides not only
documentation of the model dynamics and numerical framework but also a solid
foundation for future microscale model extensions.
