Santanu Sharma

Electronic differential for electric vehicle with single wheel reference

This paper presents technique of implementing an electronic differential system (ED) for a rear wheel driven electric vehicle (EV) using DC motors. The system uses one of the front wheel speed and angle as reference for calculation of the velocity of the other wheels. The system consists of a shaft encoder that has been used to measure the angular speed of the wheel motors. A microcontroller based control approach is implemented to provide the rotational speeds of both wheel motors according to different vehicle speeds and steering angles. The effectiveness of the control method is validated using experimental data. The preliminary result shows that the proposed system can effectively work at different turning angles during cornering.

Characterisation of a Schottky ISFET as Hg-MOSFET and as cytochrome P450-ENFET

ABSTRACT A cost-effective and simple method is proposed wherein a Schottky ion sensitive field effect transistor (Schottky ISFET)-based sensor is characterised as metal oxide semiconductor and enzyme field effect transistor (ENFET). This technique involves deposition of mercury (Hg) as gate material over the sensing layer mitigating the complexity of fabrication process, thereby eliminating the need of refabricating an identical device. A Schottky-based ISFET simplifies the fabrication process as the requisite for doping of source and drain regions becomes redundant. Steps involved in lithography process for fabricating metal oxide semiconductor field effect transistor (MOSFET) are reduced with the use of liquid metal Hg as gate over layer. Such a device can be transformed back to an ISFET without any additional etching process. Furthermore, the same ISFET device can be utilised as an ENFET when the former is used in conjunction with a biological element. In this work, a Schottky-based ISFET has been characterised as Hg-MOSFET and as cytochrome P450-ENFET. Multiple tests on the device exhibit that the same ISFET sensor can be used both as a MOSFET and an ENFET with good repeatability and versatility without losing its sensitivity.

Modelling of reference electrode for a SÌ3N4 gate pH ISFET

Ion sensitive field effect transistor (ISFET), which is a modification of metal oxide semiconductor field effect transistor, is a successor of the glass pH electrode. Since its inception over the four decades and beyond, it has witnessed a growing demand in various fields such as medical, food safety, military, waste water management etc. Proper positioning of the reference electrode in an ISFET device is very essential for the pH measurement process. In this work, a model for proper positioning of reference electrode with respect to the SÌ3N4 sensing surface of an ion sensitive field effect transistor has been developed. The model has been simulated in MATLAB simulation environment. The simulation results show that obtaining unambiguous reading is possible only when the reference electrode is placed more than the three times of the debye length of the electrolyte solution. This also gives an idea about the overall size of the measurement system.

A method for determination of depletion width of single and double gate junction less transistor

This paper presents a method for determining the depletion width of single and double gate Junction Less transistor. By solving 1D Poissons equation the depletion width expression is obtained. The variation of depletion width for both n-channel and p-channel device with doping concentration, gate voltage, drain to source voltage and dielectric constant of gate dielectric are shown.

Scale length determination of Gate all around (Octagonal cross section) Junctionless Transistor

A method for scale length determination of Gate all around (Octagonal cross section) Junctionless Transistor is reported in this paper. The scale length expression is obtained by solving the 3D Poissons equation. Variation of scale length with gate oxide thickness, side length of octagon and dielectric constant is shown. The Transverse and central electrostatic potential profile is also shown for different values of gate oxide thickness, side length of octagon, Channel length and Drain voltage and Gate Voltage are shown. Longitudinal electric field profile for different value of drain voltage is also shown. The scale length value decreases linearly with decreasing gate oxide thickness and side length of octagon and decreases nonlinearly with increasing dielectric constant.

Modeling a Nano Cylindrical MOSFET Considering Parabolic Potential Well Approximation

In this paper an analytical surface potential-based model considering the quantum mechanical effect at the semiconductor-oxide interface of a nanoscale cylindrical MOSFET is developed. The model considers the decoupling of the Poisson’s and Schrodinger’s equations via parabolic potential well approximation instead of fully self-consistent approach. Using the developed model, the effect of variation on surface potential, threshold voltage, drain current, with the extension into the saturation regime alongwith the variation of substrate doping, silicon pillar diameter, drain to source voltage, and gate to source voltage are observed. While obtaining the results, a large discrepancy in the device characteristics from the classical analysis is seen and this proves the need for quantum analysis to be done for highly doped substrates.

Estimation of coulombic efficiency of lead acid battery for range determination of electric vehicle

The coulomb counting method gives vital information for determination of state-of-charge (SOC) of battery, which in turn is a useful method for range determination of an electric vehicle. By investigating the charging and discharging characteristics for a number of cycles of operation, coulombic efficiency of the battery is determined. The variation observed in coulombic efficiency with respect to the number of cycle was empirically modeled with the help of polynomial as well as exponential curve fitting method in Matlab. Models thus developed was again validated for the later cycles of operation. The empirical model derived with the polynomial curve fitting was found to be the best suited for the requirement of the range detection system of an electric vehicle. A hardware related to this work is also developed.

Scale length determination of Gate all around (regular pentagonal cross section) fully depleted junction less transistor

This paper presents a method for scale length determination of a Gate all around (regular pentagonal cross section) fully depleted Junctionless transistor (JLT). The scale length expression is obtained by solving the 3D Poissons equation. Variation of scale length with gate oxide thickness, side length of pentagon and dielectric constant is shown. The Transverse electrostatic potential profile is also shown for different values of gate voltage, gate oxide thickness, side length of pentagon, channel length and drain voltage. The Central electrostatic potential profile is also shown for different values of gate oxide thickness, side length of pentagon, gate voltage and drain voltage.