Inductor

About: Inductor is a research topic. Over the lifetime, 52565 publications have been published within this topic receiving 484068 citations. The topic is also known as: passive two terminal.

Model of laminated iron-core inductors for high frequencies

Abstract: We propose a model with frequency-dependent lumped parameters to represent the behavior of laminated iron-core inductors that are used in switching converters, i.e., for excitation frequencies above several kilohertz. The model applies to laminated iron cores with air gaps. We show that the core parameters can be calculated by using the same analytical expressions as those valid for gapless cores if a properly defined equivalent magnetic permeability is introduced instead of the iron sheet permeability. We compare the inductor model parameters calculated as functions of frequency with those obtained by measurements for two test inductors. The behavior of the inductors showed that the effects due to the eddy currents in the laminated iron core and the turn-to-turn and turn-to-core stray capacitances become significant in different frequency ranges.

A single-inductor 0.35µm CMOS energy-investing piezoelectric harvester

Abstract: Because miniaturized systems store little energy, their lifespans are often short. Fortunately, vibrations are consistent and abundant in many applications, so ambient kinetic energy can be a viable source. Vibrations induce the charges in piezoelectric transducers to build electrostatic forces that damp vibrations and convert kinetic energy into the electrical domain. The shunting switches and switched-inductor circuit of bridge rectifiers in [1-2] increase this output energy by extending the damping (i.e., harvesting) duration within a vibration cycle. Because the output voltages of bridge rectifiers clamp and limit the electrical damping forces built, switched-inductor converters in [3-4], whose damping voltages can exceed their rectified outputs, draw more power from vibrations. Still, electrical-mechanical coupling factors in tiny transducers are low, so electrical damping forces (i.e., voltages) remain weak. Investing energy into the transducer can increase this force, but unlike in [5-6], which demand multiple inductors and high-voltage sources, the system presented here invests energy with only one inductor at low voltages.

Toroidal choke inductor for wireless communication and control

Abstract: An induction choke in a petroleum well where a voltage potential is developed across the choke to power and communicate with devices and sensors in the well. Preferably, the induction choke is a ferromagnetic material and acts as an impedance to a time-varying current, e.g. AC. The petroleum well includes a cased wellbore having a tubing string positioned within and longitudinally extending within the casing. A controllable gas lift valve, sensor, or other device is coupled to the tubing. The valve sensor, or other device is powered and controlled from the surface. Communication signals and power are sent from the surface using the tubing, casing, or liner as the conductor with a casing or earth ground. For example, AC current is directed down a casing or tubing or a lateral where the current encounters a choke. The voltage potential developed across the choke is used to power electronic devices and sensors near the choke. Such induction chokes may be used in many other applications having an elongated conductor such as a pipe, where it is desirable to power or communicate with a valve, sensor, or other device without providing a dedicated power or communications cable.

Self-sustained oscillating resonant converters operating above the resonant frequency

Abstract: This paper presents a new control technique for resonant converters. Unlike conventional variable frequency control which externally imposes the switching frequency, the proposed scheme is based on controlling the displacement angle between one of the resonant circuit variables, typically the current through the resonant inductor, and the voltage at the output of the inverter. As a result, zero-voltage switching (ZVS) can be ensured over a wide operating range. The proposed control technique cam be applied for series, parallel, and series-parallel resonant converters. As an example, the static characteristics and dynamic model of a series-parallel resonant converter with the proposed controller are derived and the system behaviour is investigated in detail. Experimental results are given to demonstrate the operation of resonant converters with the proposed controller and to validate the analysis.

Ballasts for operating light emitting diodes in AC circuits

Abstract: Several types of ballast circuits for operating one or many LEDs in AC circuits finding particular use in aircraft lighting panels are disclosed. The first type is a linear transfer function ballast using inductors to limit diode current, and capacitors to ensure unity input power factors. The second type is a non-linear transfer function ballast using inductors to limit current, capacitors to ensure unity input power factor, and diodes shunted across one or many series connected inductors to steepen the transfer function. The aim of steepening the transfer function is to imitate the voltage—brightness characteristic of incandescent bulbs, thereby providing a direct replacement aerospace lighting solution compatible with existing AC light dimmers. It is also possible to configure the ballasts of the present invention to function with a DC input voltage.