THERMAL AND ELECTRO-THERMAL MODELING OF COMPONENTS AND SYSTEMS: A REVIEW OF THE RESEARCH AT THE UNIVERSITY OF PARMA

This paper reviews the activity carried out at the Department of Information Engineering of the University of Parma, Italy, in the field of thermal and electro-thermal modeling of devices, device and package assemblies, circuits, and systems encompassing active boards and heat-sinking elements. This activity includes: (i) Finite-Element 3D simulation for the thermal analysis of a hierarchy of structures ranging from bare device dies to complex systems including active and passive devices, boards, metallizations, and air- and water-cooled heat-sinks, and (ii) Lumped-Element thermal or electro-thermal models of bare and packaged devices, ranging from purely empirical to strictly physics- and geometry-based

THERMAL AND ELECTRO-THERMAL MODELING OF COMPONENTS AND SYSTEMS: A REVIEW OF THE RESEARCH AT THE UNIVERSITY OF PARMA

This paper reviews the activity carried out at the Department of Information Engineering of the University of Parma, Italy, in the field of thermal and electro-thermal modeling of devices, device and package assemblies, circuits, and systems encompassing active boards and heat-sinking elements. This activity includes: (i) Finite-Element 3D simulation for the thermal analysis of a hierarchy of structures ranging from bare device dies to complex systems including active and passive devices, boards, metallizations, and air- and water-cooled heat-sinks, and (ii) Lumped-Element thermal or electro-thermal models of bare and packaged devices, ranging from purely empirical to strictly physics- and geometry-based

A physical large-signal model for GaN HEMTs including self-heating and trap-related dispersion

We show results of a self-consistent large-signal electro-thermal GaN HEMT model that includes trap related and self-heating dispersion effects. Both self-heating and trap dynamics are treated with a strictly physical approach that makes it easier to link the model parameter with the physical HEMT structure and material characteristics. The model, implemented in ADS, is applied to measured DC data taken at ambient temperatures between 200 K and 400 K, with excellent results. Several examples are given of dynamic HEMT simulation, showing the co-existence and the interaction of temperature- and trap related dispersive effects

Thermal and electro-thermal modeling of electronic devices and systems for high-power and high-frequency applications

Questo lavoro è incentrato sulla modellazione termica ed elettro-termica di dispositivi elettronici per applicazioni ad alta potenza ed alta frequenza. Quattro argomenti principali vengono affrontati: 1) il metodo agli Elementi Finiti (FEM) viene impiegato per studiare gli aspetti termici e fluido-termo-dinamici in alimentatori di potenza progettati per funzionare, con vincoli termici stringenti, in esperimenti di Fisica delle Alte Energie. 2) Un’ampia analisi è stata effettuata riguardo alla modellazione auto-consistente, elettro-termica a grande segnale di dispositivi elettronici, con la creazione di modelli termici dinamici, non-lineari, a parametri concentrati (costruiti con resistenze e capacità termiche), che si possono utilizzare con simulatori circuitali in maniera tale da poter essere accoppiati in modo auto-consistente con modelli (tipo SPICE) elettro-termici, a grande segnale dei dispositivi elettronici (HEMTs, MOSFETs). Questi modelli termici a parametri concentrati sono costruiti basandosi sulla struttura fisica del dispositivo, senza parametri di fitting, e sono stati confrontati con modelli FEM equivalenti (che invece non possono essere usati in simulatori circuitali assieme a modelli elettrotermici dei componenti), con eccellente accordo tra i due modelli. Quando l’approccio fisico non si può utilizzare, un metodo empirico per ricavare una rete dinamica compatta tipo Foster viene illustrato. 3) Il progetto di un banco di misura della temperatura su componenti integrati mediante tecnica di termo-riflettanza (ad alta risoluzione spaziale) viene illustrato. 4) Il progetto di un banco elettronico per la generazione di impulsi ad alta tensione (kV), con durata dell’ordine dei nanosecondi, da utilizzarsi in applicazioni biomedicali, assieme alla costruzione ed al collaudo di alcune sue parti, vengono illustrati.This work is focused on the thermal and electro-thermal modeling of electronic devices for high-power and high-frequency applications. This work covers four main topics: 1) the Finite Element Method (FEM) is used to study thermal and fluid-thermal aspects in power supplies, designed to meet stringent thermal constraints, to be used in High-Energy Physics Experiments. 2) An extensive analysis has been carried out about the self-consistent, electro-thermal large-signal modeling of electron devices, with the creation of non-linear, dynamic lumped-element (LE) thermal models (made of thermal resistances and thermal capacitances) suitable to insertion into circuit CAD tools, to be self-consistently coupled with large-signal, electro-thermal SPICE-like models of electron devices (HEMTs, MOSFETs). These LE thermal models are built in a physics-based way, and they were found to be in excellent agreement with Finite Element models (which, conversely, do not lend themselves to insertion into circuit-CAD tools), without using fitting parameters. When the physics-based approach is not suitable, an empirical approach to the creation of compact Foster dynamic LE models is shown. 3) The design of a bench for carrying out high-spatial resolution temperature measurements (on integrated components), using the thermo-reflectance technique, is illustrated. 4) The design of an electronic bench capable of generating high-voltage (kV), nano-second time duration pulses for biomedical applications is described, as well as the manufacturing and the assembly of some parts

Characterizing and Modeling Transient Behavior in Power Electronic Circuits with Wide Bandgap Semiconductors and in Maximum Power Point Tracking for Photovoltaic Systems

This dissertation examines the transient characteristics in next generation power electronic circuits at both the device-level and the systems-level. At the device-level, the effect of the parasitic capacitances on the switching performance of emerging wide bandgap semiconductors (WBG) is evaluated. Equivalent device models based on gallium nitride (GaN) and silicon carbide (SiC) are implemented in SaberRD and MATLAB, and transient switching characteristics are analyzed in great detail. The effects of the parasitic capacitances on detrimental circuit behavior such as “overshoot,” “ringing,” and “false turn-on” are investigated. The modeled results are supplemented and validated with experimental characterization of the devices in various power conversion circuits. The models can be used to aid in the design of next generation WBG devices so that the undesirable transient effects displayed by contemporary versions of these devices can be mitigated. At the systems-level, the transient overshoot demonstrated by conventional maximum power point tracking algorithms for photovoltaic power conversion systems is investigated. An adaptive controller is implemented so that the operating point can converge to the optimal power point rapidly with minimal overshoot. This new controller overcomes the parasitic components inherent to the power converter which limit its ability to deliver maximum power rapidly. It will be shown that with the new controller, the maximum power point is attainable in 4 milliseconds. The work accomplished in this dissertation lays a foundation for power electronic engineers to integrate semiconductor device theory with control theory to optimize the performance of next generation power conversion systems