Thermal Cycling in Converter IGBT Modules with Different Cooling Systems in Pitch- and Active Stall-Controlled Tidal Turbines

This paper compares active and passive cooling systems in tidal turbine power electronic converters. The comparison is based on the lifetime of the IGBT (insulated gate bipolar transistor) power modules, calculated from the accumulated fatigue due to thermal cycling. The lifetime analysis accounts for the influence of site conditions, namely...

Effect of Element Number Reduction on Inter-User Interference and Chip Temperatures in Passively-Cooled Integrated Antenna Arrays for 5G

The impact of reducing the total number of elements in passively-cooled, chip-integrated and space-tapered 5G base station antenna arrays on inter-beam interferences and chip temperatures is investigated for multi-user spacedivision-multiple-access applications. A convex element position optimization algorithm is used to synthesize the array...

Heat Transfer Enhancement in Passively Cooled 5G Base Station Antennas Using Thick Ground Planes

The thermal and electromagnetic effects of varying the ground plane thickness and aperture size of the 5G integrated base station antennas are investigated. A double-sided PCB structure is designed with antennas and digital beamforming chips on the opposite sides. Fully-passive cooling is achieved by using fanless CPU coolers attached to the...

Multiple Beam Synthesis of Passively Cooled 5G Planar Arrays Using Convex Optimization

An extended-feature, system-driven convex algorithm for the synthesis of uniform-amplitude, irregular planar phased arrays with simultaneous multi-beam optimization for mm-wave 5G base station applications in multi-user scenarios is presented. The inter-user interferences are suppressed by minimizing the maximum sidelobe level (SLL) for a...

Thermal-Aware Synthesis of 5G Base Station Antenna Arrays: An Overview and a Sparsity-Based Approach

Heat removal capabilities and radiation performances of several sparse antenna array topologies are studied for cooling enhancement in 5G millimeter-wave base station antennas. Both electromagnetic and thermal aspects are jointly considered for the first time in array layout optimization and a novel connection between layout sparsity and thermal...

Simulating natural ventilation in large sports buildings: Prediction of temperature and airflow patterns in the early design stages

In large sport’s buildings, a big part of energy can be saved by providing natural instead of mechanical ventilation. However, additional challenges arise while controlling airflow and temperatures in different zones. These measures<br/>highly depend on the shape, construction and ventilation openings, which are mostly decided in the early...