Thermal modeling and characterization for designing reliable power converters for LHC power supplies (original) (raw)

Thermal modeling and characterization of power converters for LHC power supplies

2013

Ab strac t-Power supplies for LHC experiments require DC-DC power converters able to work in very hostile environment. The APOLLO collaboration, funded by the Italian Istituto Nazionale di Fisica Nucleare (INFN), aims to study dedicated topologies and to design, build and test demonstrators, developing the needed technology for the industrialization phase. Besides the presence of radiation and magnetic fields, thermal specifications are particularly stringent in the working environment. In order to have the wanted features in terms of reliability and availability during the experimental activity, these power electronics circuits must be cooled by specifically designed water heat sinks, and an accurate thermal design is mandatory in order to guarantee safe and reliable operation. In this paper thermal characterization is used for tuning a coupled thermo-fluid-dynamic 3D numerical model, for both the water heat sink and the whole system. Based on this model an optimized water heat sink was designed and fabricated. Thermal characterization of the power converter demonstrator in different operating conditions shows good agreement with simulation results.

Thermal optimization of water heat sink for power converters with tight thermal constraints

Microelectronics Reliability, 2013

The aim of this work is to show how it is possible to improve the reliability of a power converter by means of thermal-fluid dynamic numerical analysis. Power electronic converters such as those for High Energy Physics Experiments (HEPEs), must operate in hostile environment with tight thermal constraints and the reliability must be high because of the inaccessibility during the experiments and the high costs of the overall setup. Due to the high power density, the presence of closed environments and the requirement of non-thermal interaction with other subsystems, a liquid cooling system is mandatory. 3D FEM and/or FVM simulations can be used to analyze thermal fluid dynamic behavior of those systems and can be a useful support to design heat sinks optimized for specific applications. We show a comparison of different heat sink solutions to improve the thermal management of a 1.5 kW DC/DC hybrid power module.

Power converters for future LHC experiments

Journal of Instrumentation, 2012

The paper describes power switching converters suitable for possible power supply distribution networks for the upgraded detectors at the High Luminosity LHC collider. The proposed topologies have been selected by considering their tolerance to the highly hostile environment where the converters will operate as well as their limited electromagnetic noise emission. The analysis focuses on the description of the power supplies for noble liquid calorimeters, such as the Atlas LAr calorimeters, though several outcomes of this research can be applied to other detectors of the future LHC experiments. Experimental results carried on demonstrators are provided.

Heat management for power converters in sealed enclosures: A numerical study

Microelectronics Reliability, 2009

This paper compares four assembly solutions for power converters operating in sealed enclosures with tight temperature specifications. The specific application of interest is one of the DC/DC converters of a power supply system to be used in high-energy-physics experiments: the sealed case must not significantly alter the temperature of the surrounding components (detectors and their electronics). The comparison is made using 3D Finite Element thermal modeling. The standard FR4 board solution is shown not to be viable under these tight temperature specs; we therefore explore alternative assemblies for the stack connecting the active devices to the heat-sink.

Thermal Design and Performance of the Electrical Distribution Feed Box of the LHC prototype cell

The Electrical Distribution Feed Box (DFBS) is a 4.5 K saturated liquid helium cryostat constructed for the Large Hadron Collider (LHC) Prototype Cell (String 2). The thermal design of the DFBS is presented, with emphasis on the modelling of the cooling of the current lead chimneys via the helium bath boil-off gas and on the design of the lambda plate. The expected performance is compared to measurements done during the first operation phase of the LHC prototype cell.

Advanced Thermal Simulator Testing: Thermal Analysis and Test Results

AIP Conference Proceedings, 2008

Work at the NASA Marshall Space Flight Center seeks to develop high fidelity, electrically heated thermal simulators that represent fuel elements in a nuclear reactor design to support non-nuclear testing applicable to the development of a space nuclear power or propulsion system. Comparison between the fuel pins and thermal simulators is made at the outer fuel clad surface, which corresponds to the outer sheath surface in the thermal simulator. The thermal simulators that are currently being tested correspond to a SNAP derivative reactor design that could be applied for Lunar surface power. These simulators are designed to meet the geometric and power requirements of a proposed surface power reactor design, accommodate testing of various axial power profiles, and incorporate imbedded instrumentation. This paper reports the results of thermal simulator analysis and testing in a bare element configuration, which does not incorporate active heat removal, and testing in a water-cooled calorimeter designed to mimic the heat removal that would be experienced in a reactor core.

Thermal modeling and design of power converters with tight thermal constraints

Microelectronics Reliability, 2012

The aim of this paper is to show and discuss results of 3D finite-element simulations for thermal management design with tight constraints taking care of reliability aspects of hybrid power converters. A procedure to obtain simplified but accurate device models has been shown together with experimental validation. The simplified models have been used for converter module modeling. The same procedure has been applied to analyze the thermo-fluid dynamic problem of a whole converter comprising of three modules, inner air and enclosure.

Thermal Vacuum Chamber Test of a DC-DC Converter

A voltage multiplier (DC-DC converter) is tested in simulated space environment to establish a benchmark result for further studies. The literature includes a variety of methods to design such systems; however, test results are very rare.