Viorel-Georgel Dumitru

SOI sensing technologies for harsh environment

This paper reviews and addresses certain aspects of Silicon-On-Insulator (SOI) technologies for a harsh environment. The paper first describes the need for specialized sensors in applications such as (i) domestic and other small-scale boilers, (ii) CO2 Capture and Sequestration, (iii) oil & gas storage and transportation, and (iv) automotive. We describe in brief the advantages and special features of SOI technology for sensing applications requiring temperatures in excess of the typical bulk silicon junction temperatures of 150oC. Finally we present the concepts, structures and prototypes of simple and smart micro-hotplate and Infra Red (IR) based emitters for NDIR (Non Dispersive IR) gas sensors in harsh environments.

SOI membrane-based pressure sensor in stress sensitive differential amplifier configuration

This paper introduces a pressure sensing structure configured as a stress sensitive differential amplifier (SSDA), built on a Silicon-on-Insulator (SOI) membrane. Theoretical calculation show the significant increase in sensitivity which is expected from the pressure sensors in SSDA configuration compared to the traditional Wheatstone bridge circuit. Preliminary experimental measurements, performed on individual transistors placed on the membrane, exhibit state-the-art sensitivity values (1.45mV/mbar).

Studies for an optimal balancing system for Li ion batteries based on state of health assessment

Li-ion batteries are the most popular energy storage choice for a wide range of applications, especially electric and hybrid electric vehicles, because of their superior characteristics in comparison to the other energy storage technologies. It has been observed that there are significant differences regarding parameters within the same batch of batteries manufactured and that mainly due to technological barriers which cannot be over passed without expensive efforts. To avoid additional stress and battery premature destruction it is necessary to develop a new approach for balancing between cells during electrical or hybrid-electrical vehicles driving cycles. This paper presents a thorough behavioral study of Li-ion cells during the ageing phenomenon, as well as the possibility of employing electrochemical impedance spectroscopy for assessing the batteries state-of-health. The latter can be used to further develop a coherent algorithm to be employed in a smart adaptive balancing system.