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PhD Scholars (1)

A. S. Kartheek Bandi, "Unenclosed Noninvasive Current Measurement Techniques using Magnetic Sensors", Thesis, Jan 2019 - till date

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A Noninvasive Current Measurement Technique Using Magnetic Sensors for Concealed ConductorsIn this article, we present an innovative noninvasive current measurement technique utilizing magnetic sensors (MSs). Our proposed technique, comprising a current probe and an interface circuit, ensures precise MS orientation and positioning during current measurements on conductors. The current probe houses five MSs strategically positioned for minimal conductor access, while the interface circuit processes sensor output to optimize probe alignment. These distinctive features enable accurate current measurements even on concealed or inaccessible conductors, such as those positioned behind walls. To validate the efficacy of our approach, we designed and constructed a portable handheld current probe along with the interface circuit and conducted comprehensive laboratory testing. Comparative analysis with a standard current measurement system demonstrated our system’s accuracy. Across a current range of 0–15 A, we achieved an observed accuracy within ±0.84% with a resolution of approximately 0.04 A. Notably, within the 5–10-A range, the system exhibited enhanced accuracy of ±0.56%. Moreover, the proposed design’s versatility allows for seamless adaptation to various current ranges, enabled by the selection of MSs with specific sensitivities.

A Simplified Tilt-Resilient Probe Design for Noninvasive Current Measurement Using Magnetic SensorsThis article presents a new simplified design of a noninvasive current probe that accurately measures current flowing through a conductor using magnetic sensors. The innovative design incorporates four magnetic sensors on the base of a 3-D printed current probe. A suitable interface circuit processes the output of the magnetic sensors of the probe to accurately determine the unknown current. The probe head is suitably designed to have a pointed axis of axial length <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R$</tex> to accurately place the magnetic sensors at a calibrated distance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R$</tex> from the center of the conductor. Experimental validation was conducted on a prototype of the proposed current probe and the effect of the tilt of the probe in three-dimensional space was studied. The prototype of the current probe was designed for a range of (0–50) A. The accuracy of the designed current probe is observed to be 1.83 % when measuring a current range of (0–15) A and 0.93 % for a current range of (16–50) A. The proposed design ensures accurate positioning and orientation of the current probe for current measurement with fewer positional adjustments required to compensate for the effect of tilt compared to previous topology.

MS Scholars (2)

Vineeta Gupta, "Analog Interface Circuits for Structural Damage Detection via Electro-Mechanical Impedance Methodology", Thesis Submitted on July 2024.

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Simplified Phase-sensitive Rectifier-based Resistance Measurement Circuit for Cost-effective Structural Damage Detection using Electro-Mechanical Impedance MethodThis paper presents a novel approach for damage detection in structures, using the resistance of a piezoelectric transducer measured by the Electro-Mechanical Impedance (EMI) method. We simplify the measurement of the resistance of the transducer with an approximate equation, thus reducing computational complexity. The conventional approach to measuring resistance involves the measurement of excitation and response parameters of a sensor using voltage and phase measurement units. In this work, we designed an interface circuit, employing a phase-sensitive rectifier to transform the phase component of the transducer impedance into a straightforward DC value, eliminating the need for a separate phase measurement unit. Remarkably, the system operates autonomously and does not require high sampling rate analog-to-digital converters and external computer processing, which are common in other topologies. The efficiency of the proposed system is validated through a cost-effective prototype implemented with a microcontroller and comparing its performance with a standard LCR meter. The approximated equation introduces a worst case of ± 2 % error in the computation of resistance when compared to the resistance measured using conventional approaches. The system's efficacy is further demonstrated through induced damage on a thin aluminum sheet using a steel nut positioned at various distances from the transducer.

Makireddy Poojitha "A Novel Capacitive Sensor-Based Measurement System to Determine the Direction of Motion of Humans", Thesis, July 2023.

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A Comparison-Based Interface Circuit for Detection of Motion Direction of Humans Using Capacitive SensorThis article presents a novel, noncontact capacitive principle-based measurement system to detect the proximity and motion direction of humans while disregarding other objects. The proposed system uses a three-electrode coplanar capacitive sensor architecture that can be easily mounted on the side jamb of the door. A novel comparison-based interface circuit is incorporated into the system, which creates a distinct pattern for different directions of human motion. The working principle of the sensing system is based on the shielding effect, where the sensor capacitances decrease when humans pass through the doorway. The interface circuit is designed to accommodate both symmetrical and asymmetrical capacitive sensor configurations. The overall power consumption of the experimental prototype developed is approximately 27 mW and costs around U.S. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\$}$ </tex-math></inline-formula> 15. The designed interface circuit has the ability to tolerate a sensor leakage resistance as low as 0.2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> with an error of 0.262% and offers a power line interference (PLI) attenuation of −90.42 dB. The system’s versatility and potential are demonstrated through extensive testing, and the results are presented. Furthermore, a negative capacitance shunt-based feedback scheme in the interface circuit is proposed, which not only enhances the detection range to 70 cm but also alleviates the performance requirements of integrated circuits (ICs) used in the prototype. Consequently, the system’s overall cost is reduced to U.S. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\$}$ </tex-math></inline-formula> 11. In addition, the power dissipation can be further minimized by employing compact, low-power-consuming ICs.

MTech Scholars (5)

Gayatri B, "A New Impedance to Digital Converter for Grounded Sensors", Ongoing.
Mani Shankara nasar Reddy, "A Dual Slope To Digital Converter For Direction Detection Of Humans Using Capacitive Sensors", Ongoing.
Kunchakara Shashank,"Non-Invasive Power Measurement Technique of Live Wire Using a Combined Magnetic Capacitive Sensor", 2024.
R K Sri Hari, "Development of Ultra-Low Power Ultrasound System with 128 Channels Transmitter, 64 Channels Receiver using Delay And Sum Based Digital Beamformer", 2024.
Yadla Srinivasarao, "Interface circuit for proximity detection using differential capacitive sensor", 2024.

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