A Novel Approach to Accurately Determine the tq Parameter of Thyristors

International audienceThe continued use of high-voltage thyristor devices in industry and their increased use in high-voltage dc transmission systems call for more attention to the properties of these devices. One of the important thyristor parameters is their turn-off time tq, which can be a limiting factor when applying thyristors at elevated switching frequencies. Hence, the accurate measurement of tq and its variation versus the operating conditions remains a crucial task for thyristor converters operating at elevated switching frequencies. In this paper, a proper test circuit for measuring this parameter with a high level of accuracy has been designed and built. Owing to the test circuit specificity, the variation effects of several electrical and physical constraints, such as the forward current IF , the reverse applied voltage VR, the operating temperature To, and the ramp rate of the forward reapplied voltage dVD/dt, on the tq parameter of thyristors are also studied and analyzed based on the physics of semiconductor devices and associated simulations

Coexistence of Bipolar and Unipolar Memristor Switching Behavior

The memristor has been theoretically investigated as one of the fundamental electrical elements by Pr. Leon Chua in 1971. Meanwhile, its electrical characteristics are not yet fully understood. The nonlinear characteristics and the ability to examine large-scale amounts of storing data of this device reveal an interesting development in emerging electronic systems. Research on memristor modeling based on SPICE tools has grown rapidly. This leads us to study the behavior of such devices. Our aim is to simulate different types of memristor behavior. The adjustment of the model is based on the implementation of several parameters, which enables the switching of this device. In this chapter, we prove the flexibility and the correlation of memristor model with different memristive characterization data, by applying different voltage bias, sinusoidal and with a repetitive sweeping. Moreover, we demonstrate the memristor behavior as four types of switching. This includes bipolar switching, unipolar switching, bipolar switching with forgetting effect, and a reversible process between bipolar and unipolar switching. In order to validate this study, we compare our simulation results with experimental data and we prove a good agreement. The SPICE model used in our simulations shows a special advantage for its flexibility and simplicity

Experimental Setup for Underwater Artifact Identification and Signal Analysis using Wavelets

The identification of seabed archaeological objects has become of great importance in the last decades. However, often times identifying and retrieving archeological artifacts is an expensive venture. There is a need to develop economical equipment and efficient signal processing techniques to identify and retrieve underwater artifacts. Current signal processing techniques are quite complex. The purpose of this paper is to first propose a test bed for conducting underwater experiments that can be used in a number of applications such as object identification. The experimental setup uses ultrasound waves. Wavelets are used to de-noise and analyze the ultrasound signals reflected from seabed objects. Results show that the test bed can be easily used to simulate various seabed environments. Experimental results show that Wavelets are an effective tool for signal de-noising and identification purposes

Performance Evaluation of Microfluidically Tunable Microwave Filters

This paper presents a contribution to evaluating the performances of tunable devices devoted to RF applications. It is based on reconfiguration by fluids of a capacitor/inductor associated in a monolithic substrate. Indeed, the association of two microfluidic passive devices on the same wafer allows us to increase the total frequency response of microwaves structures. The study evokes the presence and displacement of different conductive and dielectric liquids in the structure microchannels. The theoretical analysis concerns the association of microfluidic devices, a capacitor and inductor, in parallel topology. The obtained results show a good agreement between electrical parameters and the microwave response. Furthermore, a significant frequency variation from 370 MHz to 1720 MHz is achieved, with a tuning range that reaches 364.8%. The experimental part exhibits the fabrication and characterization of two structures in order to evaluate the response of microfluidic actuation for two architectures: a pass-band filter (presented in prior work) and a stop-band filter. The obtained results are in good agreement with the modeled behavior and demonstrate a large tuning range for the stop-band filter

MODELLING AN INSULATED GATE BIPOLAR

Modelling semiconductor devices using bond graph technique

Performance Evaluation of Microfluidically Tunable Microwave Filters

This paper presents a contribution to evaluating the performances of tunable devices devoted to RF applications. It is based on reconfiguration by fluids of a capacitor/inductor associated in a monolithic substrate. Indeed, the association of two microfluidic passive devices on the same wafer allows us to increase the total frequency response of microwaves structures. The study evokes the presence and displacement of different conductive and dielectric liquids in the structure microchannels. The theoretical analysis concerns the association of microfluidic devices, a capacitor and inductor, in parallel topology. The obtained results show a good agreement between electrical parameters and the microwave response. Furthermore, a significant frequency variation from 370 MHz to 1720 MHz is achieved, with a tuning range that reaches 364.8%. The experimental part exhibits the fabrication and characterization of two structures in order to evaluate the response of microfluidic actuation for two architectures: a pass-band filter (presented in prior work) and a stop-band filter. The obtained results are in good agreement with the modeled behavior and demonstrate a large tuning range for the stop-band filter

A Bond Graph Approach for the Modeling and Simulation of a Buck Converter

This paper deals with the modeling of bond graph buck converter systems. The bond graph formalism, which represents a heterogeneous formalism for physical modeling, is used to design a sub-model of a power MOSFET and PiN diode switchers. These bond graph models are based on the device’s electrical elements. The application of these models to a bond graph buck converter permit us to obtain an invariant causal structure when the switch devices change state. This paper shows the usefulness of the bond graph device’s modeling to simulate an implicit bond graph buck converter

Temperature Dependent Analytical Model for the Threshold Voltage of the SiC VJFET with a Lateral Asymmetric Channel

The wide-bandgap (WBG) semiconductor devices for modern power electronics require intensive efforts for the analysis of the critical aspects of their operation. In recent years, silicon carbide (SiC) based field effect transistor have been extensively investigated. Motivated by the significant employment of the SiC Vertical Junction Field Effect transistors with lateral channel (LC-VJFET) in the development of high-voltage and high temperature applications, the properties of the LC-VJFET device are investigated in this work. The most important normally-ON LC-VJFET parameter is their threshold voltage (VTh), which is defined as the gate-to-source voltage necessary to block the device. The higher complexity of the blocking operation of the normally-ON device makes the accurate knowledge of the VTh as a fundamental issue. In this paper, a temperature dependent analytical model for the threshold voltage of the normally-ON LC-VJFET is developed. This analytical model is derived based on a numerical analysis of the electrical potential distribution along the asymmetrical lateral channel in the blocking operation. To validate our model, the analytical results are compared to 2D numerical simulations and experimental results for a wide temperature range