Showing papers on "Inductor published in 1983"

A new zero-ripple switching DC-to-DC converter and integrated magnetics

Abstract: A new switching dc-to-dc converter is synthesized which consist of the least number of storage elements (inductive and capacitive) and switches, and yet truly emulates the ideally desired dc-to-dc transformer having both input and output currents as pure dc quantities with no ripple. This result was facilitated by implementation of a new concept termed integrated magnetics, which leads in some special switching structures to the integration of otherwise independent and separate magnetic components (inductors and transformers) into a single magnetic circuit.

30-MJ superconducting magnetic energy storage system for electric utility transmission stabilization

Abstract: A superconducting magnetic energy storage (SMES) system has been built to damp power oscillations on the Western U.S. Power System, particularly on the Pacific AC Intertie that is used to transmit power from the Northwest to southern California. The 30-MJ superconducting inductor that stores energy for this purpose is contained in a nonconducting dewar and is supported by a helium refrigerator and a gas-handling system mounted on trailers. Energy flows in and out of the inductor at frequencies from 0.1 to 1.0 Hz with power amplitudes up to 11 MW. The principal oscillation to be damped has a characteristic frequency of 0.35 Hz. The superconducting coil maximum current is 5 kA with terminal voltages up to 2.2 kV. The coil interfaces with the Bonneville Power Administration 13.8-kV bus at the Tacoma Substation through a converter and transformers. The system can be operated with the converter either in parallel-bridge mode or for constant VAR control with the bridges in buck-boost mode. The program for the design, fabrication, installation, and the preliminary experimental operation of the system is reviewed.

Induction heating gun

Abstract: This device for inductively heating and fusing thermoplastics includes an alternating current passing through a tank circuit, the inductor member of the tank circuit being wrapped around a curved pole piece of a ferromagnetic material. The magnetic flux arising within the inductor coil member flows to the ends of the pole piece and into a screen placed between the materials to be joined. The flux induces a current in the screen, and heat is generated to melt the thermoplastics together. Because only 30-150 watts of power are passed through the tank circuit, a wire which will remain cool under operational wattage may be selected, making air or fluid cooling unnecessary.

RF electromagnetic field generation apparatus for regionally-focused hyperthermia

Abstract: A hyperthermia treatment device comprises paired multiple feed inductor rings positioned between two capacitor plates, for producing a tuned radiofrequency electromagnetic field. The spatial orientation of the elements and/or the phase of the current flowing through them is variable. Change in the spatial orientation and phase of the inductor rings produce asymmetric magnetic field patterns resulting in the development of asymmetric eddy current patterns orthogonal to the magnetic lines of force. The eddy current patterns are further focused by spatial orientation and phase adjustment of the capacitor plates. A movable grounding point is utilized to further focus induced eddy currents. The device is capable of producing focal hyperthermia at depth to heat specific volumes.

Transition to chaos in a simple nonlinear circuit driven by a sinusoidal voltage source

Abstract: A circuit composed of a sinusoidal voltage source, a linear resistor, a linear inductor, and a diode in series is investigated. Subharmonic solutions of various orders have been found by computer simulations and there is evidence for the presence of chaotic solutions. The diode model used involves a nonlinear capacitor. The transition to chaos follows the same pattern as for iterated maps on an interval.

High frequency ballast circuit

Abstract: A high frequency ballast circuit powered by a dc input voltage source for starting and operating a gas discharge lamp load, comprising: a means for providing drive signals, each the drive signal having a first and second state, a series switch having a conduction channel having a first and second terminal, the series switch having a control terminal responsive to the drive signals, the conduction channel is on (conductive) in responsive to the interval characterized by the first state of the drive signal and off (non-conductive) in response to a drive signal having a second state, and an inductor. A clamp diode is included. The inductor is coupled to the clamp diode cathode and to the series switch. A ballast reactance is included with a a power oscillator circuit, the power oscillator circuit has a transformer having, a primary winding having a first, a second and a center-tap terminal, a drive winding having a first and a second and a center-tap terminal, and an output winding. A reactance tunning means coupled between the transformer primary winding first and second terminal, a first and second drive switch, the primary winding first terminal is coupled to the first drive switch, the primary winding second terminal is coupled to the second drive switch, and the primary winding center-tap is coupled to the inductor; the drive winding first and second terminal are respectively coupled to the first and second a switch control terminals. A boost circuit means, and a timer circuit operating from the boost circuit means power, and means for adjusting the duty cycle ratio of the timer circuit.

Reduction of harmonics in gas discharge lamp ballasts

Abstract: A gas discharge lamp ballast circuit operates at high frequency and is fed from a mains supply through a rectifier having a smoothing capacitor. The invention provides for the load to include an inductor and to return to the rectifier supply at a position isolated from the smoothing capacitor by one or more diodes, and for there to be a discharge path from the smoothing capacitor through the load to charge a control capacitor, and lower the load voltage to allow a rectifier current flow to the load. The smoothing capacitor is charged by current flowing from the inductor during a relaxation phase, to a voltage higher than the peaks of the rectifier. The smoothing capacitor voltage is maintained by proportioning the control capacitor size to cause rectifier current, and not smoothing capacitor discharge, to supply circuit and load losses.

A CMOS magnetic field sensor

Abstract: The authors present a novel, fully integrated magnetic field sensor made in the standard, polysilicon-gate CMOS technology. The circuit shows a sensitivity of 1.2 V/T with 10 V supply voltage and 100 /spl mu/A current consumption. The circuit consists of a pair of split-drain MOS transistors in a CMOS-differential amplifier-like configuration.

Resonant type constant voltage supply apparatus

Abstract: A resonant type constant voltage supply apparatus has a LC series resonance circuit. Energy stored in both a resonance capacitor and a resonance inductor is directly transferred to the output or input terminal of the apparatus. A control transformer is provided in parallel with the resonance capacitor for deriving the energy stored in the resonance capacitor. The amount of the energy stored in the resonance capacitor can be controlled by changing the switching frequency of the apparatus or the inductance of the control transformer, so as to thereby control the amount of energy transferred to the output or input terminal of the apparatus and thereby stabilize the output voltage of the apparatus.

Parallel Operation Techniques of GTO Inverter Sets for Large AC Motor Drives

Abstract: Techniques are presented for using a high-power GTO in a PWM inverter and operating inverter sets in parallel to increase the inverter equipment capacity. The high-power GTO has both a very large turn-off gate current and turn-on gate current for overdrive. It is best to employ an isolation pulse transformer for current amplification as the gate circuit. Also, the high-power GTO, which has a relatively small nonrepetitive controllable current compared with that of a medium- or low-power GTO, in principle can be protected effectively against short circuit faults using fuses. In parallel set operation, the inverter equipment has four typical behavior patterns which arise from differences in GTO switching characteristics. Of these, the behavior pattern in which the current balance is optimized is explained. In addition, the method for designing an interphase reactor as a current balancer and the combination region of GTO characteristics have been given. By means of a parallel set operation test, it has been confirmed that a current unbalance can be suppressed to below ten percent of the peak load current.

The Interaction of Vaccum Arcs with Magnetic Fields and Applications

Abstract: Vacuum arc/magnetic field interactions are reviewed and extended. An axial magnetic field (parallel to current flow) produces a stable and diffuse vacuum arc. These properties have been used to build a reliable dc switch for the Tokamak Fusion Test Reactor at Princeton. The switching duty for this Ohmic Heating Interrupter involves repetitive interruption of 24kA dc against a 27kV recovery voltage. A transverse magnetic field (perpendicular to current flow) produces an unstable arc with an ensuing high arc voltage. This property has been used to complete a metallic return transfer breaker for the Pacific HVDC Intertie, here the switching duty involves interruption of currents up to 2200A dc against an 80kV recovery voltage.

New magnetic structures for switching converters

Abstract: In the past the majority of power processing applications have been centered around a very few standard switching converter topologies. Recently, a number of new converter topologies have been proposed in order to find the best possible electrical inter connection of power processing elements: switches, storage components, and transformers, that would yield the highest efficiency and best performance. However the equally important and complementary problem of their best magnetic interconnection has been completely overlooked. In some new converter structures, the nature of the switching process and existing waveforms allows integration of previously separate inductors and transformers into a single magnetic structure. Several such magnetic core structures are proposed and analyzed, which lead to further converter simplifications and performance improvements.

A New Transmission Line Approach for Designing Spiral Microstrip Inductors for Microwave Integrated Circuits

Abstract: Spiral microstrip inductors with up to two full turns have been modeled by using parallel coupled and single transmission lines. With this method, the electrical characteristics of these inductors, which may be fabricated as elements of MIC and MMIC circuits, can be designed for reactance up to 200 ohms with a maximum error of 15 percent for frequencies up to the K/sub u/ band.

Converter with lossless snubbing components

Abstract: The inverter includes a DC to AC converter circuit including a plurality of transistors which are switched on and off to convert a DC signal into an AC signal. The converter circuit also includes diodes which are alternately forward and reverse biased during the operation of the converter circuit, the diode having a reverse recovery period whenever the diode is switched from a forward to a reverse biased condition during which the reverse resistance of the diode is substantially zero. An inductor is connected to the diode for limiting the current through the diode during the reverse recovery period such that shoot through currents which pass through both the diode and the inductor are limited to desired levels.

Coupled Inductor and Integrated Magnetics Techniques in Power Electronics

Abstract: Energy storage and power processing with magnetic devices is more efficient if the separate inductors and transformers are integrated into a single magnetic structure. The origins and main results of the coupled-inductor and integrated magnetics concepts are reviewed.

Radio frequency induction heating device

Abstract: A radio frequency induction heater for locally heating a metallic work piece. The induction heater comprises an elongated conductor surrounded by a core of magnetic material having a narrow slot formed therein serving as the inductor core air gap. The conductor is connected across a source of radio frequency current. The induction heater is located adjacent the metallic work piece with the inductor core air gap very near (and preferably in contact with) that portion of the metallic work piece to be heated. When the radio frequency current is caused to pass through the conductor, the gap concentrates the flux entering the work piece, inducing voltages in the work piece resulting in eddy currents which flow in the work piece along and parallel to the gap. This, in turn, results in the rapid local heating of a narrow band of the work piece.

Inverter with charging regulator having a variable keying ratio

Abstract: An inverter with a dc-source has a charging condenser connected through a charging diode and a charging inductor to the dc-supply. A charging switch is periodically closed by a control component with a variable keying ratio to connect the charging inductor to the dc-supply. The inverter includes an AC voltage converter with two alternatingly controlled switches supplied with power by the charging condenser, hereinbelow identified as the primary switch and the secondary switch, which are in a series circuit in parallel with the charging condenser. In this arrangement, the control component for the charging switch of the charging regulator is synchronized with a square wave voltage at one of the switches of the alternating voltage converter. The charging switch operates at the same switching frequency as the alternating voltage converter. When the square-wave voltage at a switch of the alternating voltage converter terminates during a non-oscillating condition of the alternating voltage converter, then the charging switch of the charging regulator also remains open. At a disruption, there need, accordingly, only be deactivated the inverter.

Current Fed and Voltage Fed Switching DC/DC Converters - Steady State and Dynamic Models their Applications in Space Technology

Abstract: This paper is a contribution in the developments. of the steady state equations and dynamic representation of current fed switching structures (buck, boost) in continuous mode. The basic principle for the mathematical modelling is the first order expansion of the transition matrices. A comparison with classical voltage fed power cells shows an higher degree in the system transmittances as the consequence of the introduction of a new system variable the input capacitance voltage. Validations are realised on a breadboard PWM shunt regulator.

AC Power line transient suppressing circuit

Abstract: An AC power line transient suppression circuit comprises a bi-directional series breakdown element in combination with a series inductor and a shunt capacitor.

Magnetic reproducing system

Abstract: A magnetic material (1b-2) whose high frequency characteristics vary in response to a signal field recorded on a magnetic recording medium (1) is provided as a magnetic layer in a high frequency coupling circuit including the magnetic recording medium (1) and a reproduction head (5). The coupling degree of the high frequency coupling circuit noticeably varies with the change of the high frequency characteristics of the magnetic material (1b-2), thereby enabling the reproduction of the recorded signal by utilizing the change of the high frequency characteristics.

Ground voltage suppression

Abstract: In a power supply system having a grounded neutral and supplying service equipment through a distribution transformer, a ground voltage suppression device comprises a saturating inductor or like non-linear impedance device connected between the secondary neutral conductor and a normal ground conductor so as to define therewith a neutral-to-ground current path which presents a high impedance to current flow for applied voltages up to a predetermined level.

Power supply device

Abstract: PURPOSE:To protect an auxiliary power supply circuit from a surge voltage, by providing an inductor in series to an auxiliary power supply which supplies a current with no intervention of a phase controller when this controller provided between an AC power supply and a load is nonconductive. CONSTITUTION:A phase controller 1 is provided between an AC power supply 2 and loads 3 and 3. The voltage signal between both terminals of the controller 1 is detected 6, and a switch 5 is closed in a nonconductive period of the controller 1. Thus the power is supplied to the load 3 from an auxiliary power supply 4 via an inductor 7. As a result, the load 3 has no pause period of feed. This, for example, can prevent the flickering of a discharging lamp and deepen the dimming degree. The surge due to thunders arising while the controller 1 is conductive does not affect an auxiliary power supply circuit. However, the surge affect the auxiliry power supply circuit when the controller 1 is not conductive. As a result, the inductor 7 prevents the breakdown of an auxiliary circuit which is due to a sudden rise of the thunders, etc.

Modelling of nonlinear inductor exhibiting hysteresis loops and its application to the single phase parallel inverters

Abstract: A modelling of magnetodynamic fields taking into account dynamic hysteresis loops was previously proposed for predicting three-dimensional magnetodynamic fields in electromagnetic devices [1]. This method is now applied to construct the lumped circuit model for nonlinear inductor exhibiting dynamic hysteresis loops. The lumped circuit model of nonlinear inductor is introduced into the simulation model of single phase paralell inverter, whose various characteristics are calculated and compared with experimental measurements. Good agreement is obtained.

Digital implementation of toner concentration sensing apparatus

Abstract: A toner concentration sensor senses the concentration of toner in the toner system of an electro-photographic printer or copier. A novel circuit improves the toner concentration sensor. The novel circuit is composed of a resonant circuit, a frequency source, and a logic circuit. The resonant circuit is tuned to a selected frequency and has an inductor which creates a field into which the toner system is introduced. A frequency source excites the resonant circuit. A logic circuit receives a signal from the frequency source and an output from the resonant circuit. The logic circuit output is a signal representative of the phase shift between the signal from the frequency source and the output of the resonant circuit. The phase shift is representative of the inductance of the inductor in the presence of said toner system. The measurement of the inductance is representative of the concentration of toner in said toner system.

Experimental and theoretical investigation of the inductance associated with a microstrip antenna feed

Abstract: It has been demonstrated that a microstrip antenna excited in a non-degenerate resonant mode has a driving point impedance which can be modeled as a resonant parallel R-L-C circuit in series with the an inductor. The latter is an inductance which can be associated with the feeding probe or microstrip line feed of the antenna. This paper investigates the variation with feed location of this inductive component both experimentally and by a full modal expansion of the field using the “cavity model”. The results demonstrate that the simple, feed position-independent formula for this inductive component is inadequate for certain applications involving loaded microstrip elements. The results also show that the cavity model can predict the variation of feed inductance with feed location reasonably well except near the edge of the patch. The physical mechanism for the variation of this inductive component as well as the physical reason why the cavity model overestimates this parameter with feeds near the...

Integrable tunable sinusoid oscillator using DVCCS

Abstract: A novel RC-sinewave oscillator configuration using the differential voltage controlled current source (DVCCS) active element is proposed. It has only two resistors and two grounded capacitors. The oscillation frequency can be tuned independently by one resistor at low sensitivities. The circuit has an additional capability of realising active lossless grounded inductors at appropriate ports if any of the capacitors is open-circuited.

Method of operating a gas-discharge lamp

Abstract: In a method of operating a gas-discharge lamp, particularly a fluorescent lamp, a radio-frequency a.c. voltage is generated from a d.c. voltage (UE) with the aid of a semiconductor chopper formed from transistors (4, 8), which a.c. voltage is fed into a series resonance circuit. The series resonance circuit consists of a capacitor (13) and an inductor (12) connected in parallel with the discharge path of the lamp (16). The frequency of the a.c. voltage is selected such that before the ignition of the lamp (16) it is higher, and after the ignition of the lamp (16), in normal operation, it is lower, than the resonance frequency of the undamped series resonance circuit consisting of the inductor (12), and the capacitor (13), the frequency separation being selected to be so great that the oscillator current during the ignition phase is at most three times as great as the normal operation current.

Digitally controlled power supply

Abstract: A high power factor AC to DC power supply having a high frequency pulse producing circuit comprising an inductor supplied with rectified raw AC power through a semiconductor switch which provides dynamic power factor correction by maintaining the width of the on-times of the switch substantially constant throughout each cycle of the input AC power. The peak energy stored in the inductor during the on-times are a function of the amplitude of the instantaneous voltage of said rectified AC power, so that each time the switch is turned off, the output pulse of current supplied to the load by the inductor has a time duration which is a direct function of the instantaneous voltage value of the rectified AC power. The output load has a filter whose time constant is greater than a cycle of said rectified AC power, and the average on-time of said switch is varied over a number of cycles of said AC power to regulate the output voltage of said supply.

Static VAR generator having reduced harmonics

Abstract: There is provided a static VAR generator employing a bank of series-connected inductors, each inductor being supplied by different secondary taps of a step-down transformer. The voltage rating of each inductor is appropriately decreased so as to make their sum correspond to the supply voltage. All but one of the inductors are controlled by thyristors in an on-off fashion to supply reactive power to the network in incremental steps. One of the thyristors is continuously phase-angle fired in combination with the incremental insertion of the other inductors to vary the VAR output over the full range, but generating harmonics that are proportional only to the continuously controlled inductor.

Power-processing unit

Abstract: Power-processing unit uses AC buses (30, 32) to supply all current dependent needs such as connections (54, 56) to an ion thruster through an inductor (88) and the primary of a transformer (90), to assure limited currents to such loads. Where temperature control is also required, such as to the main discharge vaporizer heater connection (36, 38), switches (100, 102) are serially connected with inductor (96) and the primary of transformer (98). Temperature sensor (104) controls the switches (100, 102) for temperature regulation.