Variable Induction Research Articles

Inductive sensing of air bubbles in intravenous fluids: A novel approach for patient safety

In this study, a magnetic sensing approach is proposed for detecting air bubbles in intravenous fluids (IVs). To the author's knowledge, this is the first paper to apply magnetic sensing technology for the detection of air bubbles in an IV fluid. The approach is based on a compact, portable, and cost-effective sensor prototype that utilizes an LC resonator and a microcontroller. To validate the detecting system, an IV fluid containing air bubbles is passed through a medical tube, and the tube is passed over a planar coil. The magnetic interaction during the flow of the IV fluid with air bubbles is monitored and logging in real time. Air bubbles of 38, 44, 63 and 75 mm3 in IV fluid were successfully detected by the proposed sensing approach. Besides, the detection system is able to determine the flow direction, which is not encountered in alternatives such as capacitive sensing. The measurements from the established test setup, an average air bubble of 28 mm3 causes an inductance variation of approximately 2.8 nH.

Innovative Test Bench for RF and High-Voltage Component Characterization for MRI Applications: A Comprehensive Review

This scientific paper presents a detailed exploration of the electrical characterization of commercially available trimmers, conducted in collaboration with Siemens Medical. The study encompasses the establishment of a specialized measurement bench for impulse mode electrical tests, involving the adaptation of the signal generator with an adjustable supercapacitor and variable inductance. For precise measurements, a carefully designed filtering system prevents voltage overshoots. Given the critical sensitivity of voltage and frequency measurements for passive components in RF and high-voltage applications, the methodology is further refined to achieve optimal compromises across various parameters. The primary objective remains the determination of the voltage across the evaluated capacitor using the proportionality coefficient 𝛼, essential for accurate trimmer characterizations. In this paper, useful insights are provided into the electrical characterization of trimmers, as well as a refined methodology designed for RF and high-voltage applications. The findings presented herein enhance our understanding of trimmer behavior, offering potential implications for improved component selection and performance in a range of electrical systems.

Parameter Identification for Maximum Torque per Ampere Control of Permanent Magnet Synchronous Machines under Magnetic Saturation

This paper applies the identified parameters of permanent magnet synchronous machines (PMSMs) for the maximum torque per ampere control (MTPA) under magnetic saturation. The variation in magnet flux with current is determined using a position offset approach while the variation in q-axis inductance with the current is estimated from the d-axis voltage equation afterward. In addition, the d-axis inductance is estimated at standstill by the injection of a small amplitude of high frequency d-axis current. The curve-fitted results of estimated parameters under different saturation conditions are then employed to aid the derivation of MTPA control law. The proposed method is experimentally verified on two prototype PMSMs. Experimental results show that compared with conventional MTPA schemes using fixed values of magnetic parameters, the proposed method can increase maximum output torque by 2.1% and 3.2% on two prototype PMSMs, respectively.

A Variable Speed Induction Motor Drive With 24-Stepped Voltage Waveform Throughout Modulation Range

Multi-level inverters produce low order harmonics in over-modulation region, which can be eliminated by generating polygonal space vector structure. A variable speed induction motor drive to generate 24-stepped voltage waveform throughout modulation range is proposed in this article. An open-end winding configuration induction motor (OEIM) is fed with primary and secondary inverter from both the ends of OEIM and generates a 24-stepped phase voltage. The proposed scheme also produces 96-stepped phase voltage waveform at extreme modulation index with highly suppressed higher order harmonics and excellent quality phase voltage. The motor terminal sees a 24-stepped waveform at all speeds, devoid of low order harmonics up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$19^{th}$</tex-math></inline-formula> order. The scheme does not require vector timing calculation due to availability of highly dense 24-sided polygonal structure. Primary and secondary inverters are derived by cascading flying capacitor and CHB cells. Experimental verifications are performed on in-house developed laboratory prototype. Motor phase voltage and phase current waveforms during steady state and transient conditions justifies performance of the proposed scheme. Dynamic performance and floating capacitors voltage balancing method are verified by experimental results.

Realization of a Three-Switch Leg/Phase Inverter for Nine-Phase Variable Pole– Phase Induction Machine With Phase Grouping Concepts

In this paper, a 3-switch leg/phase inverter topology is realized for 9-phase variable pole-phase induction motor (9Ph-VPIM) drives. The 3-switch legs (3SL) in the proposed inverter are controlled with two non-intersecting phase shifted references to achieve a 3-level voltage excitation for each phase winding. These two non-intersecting references per leg limit the possible modulation index (MI) and may require a higher DC link voltage. The split winding concept and the phase grouping solutions are used to enhance the MI. In the split winding concept, phase winding of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2n</i> pole machine is divided into <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> number of distinct windings and excited with the same voltage for attaining a uniform air gap flux. These coils are called cognate voltage coils (CVC). With these CVCs, different possible groupings are proposed to enhance the MI of a proposed 3SL/phase inverter. The symmetrical and efficient phase grouping solutions are analyzed and tested with an improved modulation index. Moreover, the proposed 9Ph-VPIM drive is controlled with carrier-based 3-φ SVPWM to further enhance the DC link voltage utilization. The proposed inverter will feed the effective phase by a 3-level voltage with suppressed harmonics resulting in a superior torque ripple. The proposed 3SL/phase inverter fed 5-hp 9Ph-VPIM drive is validated with the experimental prototype.

A novel methodology for transformer winding defects diagnosis based on its measured frequency response signal impedance morphology interpretation

This article proposes the characteristics study of the key parameters of power transformer winding (viz. the equivalent capacitance and the equivalent inductance) extracted from the frequency response analysis (FRA) of the winding. However, the FRA curve of the winding can be divided into three frequency ranges (low, medium, and high), where; the low and the high frequency response (LFR and HFR) ranges represent the inductive and capacitive effects of the winding respectively, which can establish best analysing and interpreting tool of the winding response behaviour to diagnose their failures. Furthermore, real axial deformations were carried out on a winding constructed for this study. In addition, the variation of the equivalent inductance and capacitance obtained from the impedance curve in the LFR and HFR ranges were analysed to locate and evaluate the faulty states with the reference state of the winding. Consequently, the proposed method provides a tool for locating and assessing the internal faults severity in power transformer windings.

Voltage and Current Control Strategy for Grid Connected WECS Employing Two and Three Level Voltage Source Converters

This paper presents voltage and current control strategy for grid connected variable speed wind turbine induction generator employing two and three level voltage source inverters. Induction generators are widely used because of its low cost, robust construction and capability of feeding active power to load without getting reactive power from separate source. The mechanical energy required to drive the generator is obtained from a variable speed wind turbine. Three phase induction machine is excited from a three phase voltage source converter. The DC voltage of the capacitor is inverted and fed to the three phase grid using a current controlled voltage source inverter. Control strategy has been developed for maintaining the DC link voltage constant and also to feed the power at unity power factor to the grid, even though there is variation in wind speed. It is also shown that the harmonics are considerably reduced when a two level inverter is replaced by a three level inverter. The simulation study has been carried out using MATLAB/Simulink. Simulation results indicate the feasibility of control strategy.

Diagnosis of Static Eccentricity in 400 kW Induction Machine Based on the Analysis of Stator Currents

Current spectrums of a four pole-pair, 400 kW induction machine were calculated for the cases of full symmetry and static eccentricity. The calculations involve integration of 93 electrical plus four mechanical ordinary differential equations. Electrical equations account for variable inductances affected by slotting and eccentricities. The calculations were followed by Fourier analysis of the stator currents in steady state operation. Zooms of the current spectrums, around the 50 Hz fundamental harmonic as well as of the main slot harmonic zone, were included. The spectrums included in this paper are referred to both calculated and measured currents.

Spectrum of Induction Machine Stator Currents, Affected By Clutch Wobbling and Mixed Eccentricity

Current spectrum of a four pole-pairs, 550 kW, induction machine were calculated for the cases of full symmetry, clutch wobbling, static and mixed (static + dynamic) eccentricity. The calculations involve integration of 93 electrical plus four mechanical ordinary differential equations. Electrical equations account for variable inductances affected by slotting and eccentricities. The calculations were followed by Fourier analysis of the stator currents in steady state operation. Zooms of the current spectrums, around the 50 Hz fundamental harmonic as well as of the main slot harmonic zone, of both calculated and measured currents are included.

Finite element analysis of cross fluid model over a vertical disk suspended to a tetra hybrid nanoparticles mixture

Nanoparticles have numerous applications and are used frequently in different cooling, heating, treatment of cancer cells and manufacturing processes. The current investigation covers the utilization of tetra hybrid nanofluid (aluminum oxide, iron dioxide, titanium dioxide and copper) for Crossflow model over a vertical disk by considering the shape effects (bricks, cylindrical and platelet) of nanoparticles, electro-magneto-hydrodynamic effect and quadratic thermal radiation. In the current inspection model is first derived given PD-equations and then altered into a system of OD-equations by including similarity variables. The converted ordinary differential equations are solved by using the finite element procedure and the impact of the solution against numerous involved parameters is displayed through tables and graphs. It is observed that tetra-hybrid nanoparticles are recommended better in industrial applications where the highest production of thermal energy. Moreover, an enhancement of thermal production can be achieved utilizing different values of the magnetic parameter, time relaxation number, variable thermal radiation number and magnetic induction number but the opposite trend has been noticed with the effects of radiation number.

Emergent magneto-inductance effect in permalloy thin films on flexible polycarbonate substrates at room temperature

Emergent inductance has attracted significant interest for its relevance in both interesting fundamental physics and practical applications in magnetic devices that demand miniaturization without compromising inductance. In this Letter, we report the discovery of a stepwise magnetic field-induced emergent magneto-inductance (EML) effect in Permalloy (Py) thin films deposited on polycarbonate (PC) substrates. Remarkably, Py/PC devices exhibit an exceptionally large inductance variation exceeding 1 μH at room temperature, and intriguingly, a sign reversal of inductance occurs around the zero magnetic field. The dependencies of the EML effect on frequency, step magnetic field changes, and film width can be explained from the theory based on the spin motive force driven by transient domain wall motion. This study opens up exciting avenues for advancing our understanding of emergent inductance in fundamental physics and paves the way for practical applications in flexible magnetic devices.

Theoretical analysis of AC current supply of doubly salient permanent magnet machine with quasi sinusoidal back-EMF and inductance variations

Theoretical analysis of AC current supply of doubly salient permanent magnet machine with quasi sinusoidal back-EMF and inductance variations

Analysis of variable inductor employing vegetable-based transformer oil with magnetic nanoparticles

Variable inductors using magnetorheological fluids have recently been successfully applied to power-conversion devices; however, the thermal properties of Vegetable oil-based Magnetic Nanofluids (VMNFs) have not been investigated. In this study, the temperature characteristics of a variable inductor embedded with a VMNF were analyzed by developing a multiphysics analysis method and verified experimentally. To analyze the temperature distribution efficiently, a coupled analysis of the Magnetoquasistatic (MQS) field and steady-state heat transfer field based on the finite-element method was performed. The B-H curves of the VMNF and ferrite core were obtained via magnetic property measurement experiments, and the input waveforms were measured from the current and high-frequency pulse voltages applied to the variable inductor of the DC–DC converter. To predict the temperature rise of the VMNF-gap variable inductor, the power dissipation was determined using the Steinmetz experimental equation modified by the Bertotti model in the electronic system solver and input as a heat source in the steady-state heat-transfer analysis. The temperature increase predicted by the multiphysics analysis method agreed well with the experimental data, and an increasing the concentration of magnetic nanoparticles had a cooling effect. The developed MQS–thermal field coupled analytical method and the cooling properties of VMNFs can be applied to the design of power-conversion devices operating with high-frequency power sources.

A D-Band Differential Phase Shifter Based on a Transmission Delay Line With Variable Inductors and Capacitors

A D-Band Differential Phase Shifter Based on a Transmission Delay Line With Variable Inductors and Capacitors

Callusogenesis and Organogenesis of Thymus Cultivars In Vitro

The article is devoted to the in vitro cultivation of three Russian cultivars of two Thymus species (Th. vulgaris and Th. serpyllum) in order to study the possibility of induction of callusogenesis and organogenesis. The developed technology opens up prospects for the induction of somaclonal variability, obtaining the source material for breeding, as well as regeneration of thyme plants after genetic transformation. For the study, we used nutrient media based on the mineral composition of the Murashige and Skoog medium with the addition of auxin (indole-3-butyric acid, indole-3-acetic acid) and cytokinin (6-benzyladenine, kinetin) substances. For the induction of callusogenesis, the use of stem explants on nutrient media supplemented with 2,4-dichlorphenoxyacetic acid (1 or 2 mg/L) can be recommended. The efficiency of shoot organogenesis also depends on the type of explant, and its rather low values in most experimental variants are apparently due to the accumulation of endogenous auxins and phenolic compounds. Thus, a cultivar-specific morphogenetic response to the use of various phytohormones and growth regulators was established, as well as the influence of the explant type on the efficiency of morphogenic processes.

Analysis and Validation of a Novel Symmetrical Structure for Toroidal Variable Power Inductors in Energy Storage Systems

Analysis and Validation of a Novel Symmetrical Structure for Toroidal Variable Power Inductors in Energy Storage Systems

A Wireless Power Transfer System With High Misalignment Tolerance Based on Dual Side Variable Inductor Control

A Wireless Power Transfer System With High Misalignment Tolerance Based on Dual Side Variable Inductor Control

Dual Position Offset Injection based Multi-Parameter Decoupled Estimation of PMSM Considering Signal Injection Induced Inductance Variation

Dual Position Offset Injection based Multi-Parameter Decoupled Estimation of PMSM Considering Signal Injection Induced Inductance Variation

Modeling and Control of WPT Systems in the Presence of Load and Mutual Inductance Variations

Modeling and Control of WPT Systems in the Presence of Load and Mutual Inductance Variations

Role of Lipopolysaccharides in the Inflammation and Pyroptosis of Alveolar Epithelial Cells in Acute Lung Injury and Acute Respiratory Distress Syndrome.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) represent a spectrum of common critical respiratory conditions characterized by damage and death of alveolar epithelial cells (AECs). Pyroptosis is a form of programmed cell death with inflammatory characteristics, and activation of pyroptosis markers has been observed in AECs of patients with ALI/ARDS. Lipopolysaccharides (LPS) possess strong pro-inflammatory effects and are a crucial pathological factor leading to ALI in patients and animals. In LPS-induced ALI models, AECs undergo pyroptosis. However, physiologically and pathologically relevant concentrations of LPS lead to minor effects on AEC cell viability and minimal induction of cytokine release in vitro and do not induce classical pyroptosis. Nevertheless, LPS can enter the cytoplasm directly and induce non-classical pyroptosis in AECs when assisted by extracellular vesicles from bacteria, HMGB1, and pathogens. In this review, we have explored the effects of LPS on AECs concerning inflammation, cell viability, and pyroptosis, analyzing key factors that influence LPS actions. Notably, we highlight the intricate response of AECs to LPS within the framework of ALI and ARDS, emphasizing the variable induction of pyroptosis. Despite the minimal effects of LPS on AEC viability and cytokine release in vitro, LPS can induce non-classical pyroptosis under specific conditions, presenting potential pathways for therapeutic intervention. Collectively, understanding these mechanisms is crucial for the development of targeted treatments that mitigate the inflammatory responses in ALI/ARDS, thereby enhancing patient outcomes in these severe respiratory conditions.