Showing papers on "RLC circuit published in 1986"

Zero-voltage switching quasi-resonant converters

Abstract: A quasi-resonant converter is disclosed as comprising a power source, a load and a resonant switch circuit for periodically connecting the power source to the load The resonant switch circuit includes a switch for connecting the power source to the load and for disconnecting the power source from the load, and a resonant circuit comprised of a resonant capacitor and a resonant inductor The switch is operated at a switching frequency in excess of 1 MHz and in the order of 10 to 20 MHz or greater The resonant circuit is connected to the switch to impose thereon a voltage waveform as developed across the resonant capacitor The resonant capacitor and the resonant inductor have respective impedances selected to shape the voltage waveform such that a zero-voltage condition is imposed upon the switch when it is disposed to its on state, whereby the parasitic capacitive losses associated with the switch are eliminated

Zero-current switching quasi-resonant converters operating in a full-wave mode

Abstract: A family of quasi-resonant converters for providing regulated power is disclosed as comprising a voltage source, a load and a resonant switch circuit, for periodically connecting the voltage source to the load. The resonant switch circuit includes a switch, and a resonant circuit comprised of a resonant capacitor and a resonant inductor. The switch is actuated to its first state to permit a current flow in a first direction from the voltage source to the load and to block a current flow in a second, opposite direction, and deactuated to a second state to permit a current flow in the second direction from the load to the voltage source and to block the current flow in the first direction, whereby the quasi-resonant converter is operative in a full-wave mode. More specifically, the switch in its first state couples the resonant capacitor and the resonant inductor together to form a resonant switch circuit. The impedances of the resonant capacitor and the resonant inductor are selected to establish a resonating current waveform on the resonant inductor to apply zero-current conditions to the switch at turn on and turn off.

Resonant converters with secondary-side resonance

Abstract: A family of quasi-resonant converters is disclosed as comprising a voltage source, a transformer having primary and secondary windings, and a switch for periodically coupling the voltage source to the primary winding, whereby a charging current appears on the secondary winding. The transformer exhibits a characteristic leakage inductance. A capacitor exhibiting a characteristic capacitance is coupled to the secondary winding to form a resonant circuit including the leakage inductance and the capacitor. The secondary winding is coupled to apply the charging current to the capacitor. A rectifying circuit couples the capacitor to a load, whereby the voltage stored in the capacitor is delivered to the load. The capacitor is directly connected to the secondary winding and to the rectifying circuit to permit positive and negative going voltages to be stored therein, whereby magnetic flux within the core of the transformer is dissipated and the transformer magnetically reset.

Static power conversion and apparatus having essentially zero switching losses

Abstract: A high efficiency power converter is achieved utilizing a resonant DC link between a DC source, such as a converter rectifying power from an AC power system, to a variable frequency voltage source inverter. A resonant circuit composed of an inductor and capacitor is connected to the DC power supply and to a DC bus supplying the inverter and is caused to oscillate stably at a high frequency to provide a uni-directional voltage across the DC bus which reaches zero volts during each cycle of oscillation of the resonant circuit. The switching devices of the inverter are controlled to switch on and off only at times when the DC bus voltage is zero, thereby eliminating switching losses in the inverter. The resonant circuit can be caused to oscillate utilizing pairs of switching devices in the inverter or a separate switching device across the capacitor, which again are caused to switch on and off only at times of zero voltage on the DC bus. For AC to AC conversion, enabling bi-directional power flow, the switching devices of the power source which converts AC power to DC power may have switching devices which are also switched only at the times of zero voltage so that switching losses in these devices is also minimized.

Method and apparatus for coupling transceiver to power line carrier system

Abstract: A method and apparatus for efficiently coupling a transceiver to an AC power line transmission system. The preferred embodiment of the coupling system comprises a line coupling network and first and second filter ports. The first filter port is connected to a resonant circuit having bandpass filtering characteristics adapted to the specific needs of the transmitter portion of the transceiver. The second filter port is isolated from the low impedance of the AC power line and is connected to a high quality factor filter having bandpass filtering characteristics adapted to the specific needs of the receiver portion of the transceiver.

Resonant inverter with improved control

Abstract: A resonant inverter is operated in a manner to provide a substantially constant output voltage to a load. The inverter is controlled using either a frequency control mode or a phase shift control mode. In the frequency control mode, a constant output voltage is maintained through frequency variation of the rectangular wave signal applied to the resonant circuit of the inverter. In the phase shift control mode, constant output voltage is maintained by phase shifting one component signal of the rectangular wave signal relative to another component signal thereof while maintaining constant the frequency of both component signals. Mode switching occurs automatically at the extremities of the operating frequency range of controllable switch means in the resonant inverter.

Capacitance-type material level indicator

Abstract: A system for indicating the level of material in a vessel as a function of material capacitance comprising a resonant circuit including a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An rf oscillator has outputs coupled to the resonant circuit and to a phase detector for detecting variations in phase angle as a function of probe capacitance. Level detection circuitry is responsive to an output of the phase detector and to a reference signal indicative of a predetermined level of material for indicating material level as a function of a difference between capacitance at the probe and the reference signal. An automatic calibration circuit adjusts the resonance characteristics of the parallel resonant circuit. A remote module provides facility for initiating a system-test and a system-calibrate operation, either individually or sequentially.

Series resonant converter

Abstract: A series resonant converter is disclosed, in which a series resonant circuit consisting of a resonant capacitor and a resonant inductor is connected in series with AC input terminals of a rectifier. Positive current and negative current are alternately caused to flow from a power supply through the series combination of the series resonant circuit and rectifier through on-off control of a plurality of switch elements, thereby obtaining a DC voltage from the rectifier. A parallel resonant circuit is provided in series with the series resonant circuit. The resonant frequency of the parallel resonant circuit is lower than the resonant frequency of the series resonant circuit and higher than the audible frequency range.

Control of a series resonant converter

Abstract: A series resonant converter is interposed between an unregulated voltage source and an output circuit. The converter employs a pair of power switches each, when on, completing a series resonant circuit from the source to a resonant tank circuit including the primary winding of a transformer coupled to the output circuit. The power switches are alternately turned on and off so that sinusoidal current pulses alternately flow in opposite directions in the primary winding at a frequency dependent on input and output conditions. The current flowing in the resonant circuit is monitored and the power switches are additionally controlled to prevent turn on of one switch and turn off of the other when current is still flowing in the resonant circuit.

Secondary-side resonance for high-frequency power conversion

Abstract: A systematic approach is proposed that enables the use of the leakage inductance of the power transformer and a secondaryside capacitor to form a resonant tank for very high frequency power conversion. Several new quasi-resonant converter topologies based on this technique are derived.

Impedance matched, high-power, rf antenna for ion cyclotron resonance heating of a plasma

Abstract: A resonant double loop radio frequency (rf) antenna for radiating high-power rf energy into a magnetically confined plasma. An inductive element in the form of a large current strap, forming the radiating element, is connected between two variable capacitors to form a resonant circuit. A real input impedance results from tapping into the resonant circuit along the inductive element, generally near the midpoint thereof. The impedance can be matched to the source impedance by adjusting the separate capacitors for a given tap arrangement or by keeping the two capacitances fixed and adjustng the tap position. This results in a substantial reduction in the voltage and current in the transmission system to the antenna compared to unmatched antennas. Because the complete circuit loop consisting of the two capacitors and the inductive element is resonant, current flows in the same direction along the entire length of the radiating element and is approximately equal in each branch of the circuit. Unidirectional current flow permits excitation of low order poloidal modes which penetrate more deeply into the plasma.

DC-to-AC Series-Resonant Converter System with High Internal Frequency Generating Synthesized Waveforms for Multikilowatt Power Levels

Abstract: A new method of power pulse modulation with internal frequencies of tens of kHz and suited for multikilowatt power levels is applied to a series-resonant converter system for generating synthesized unipolar and bipolar waveforms. The high pulse frequency allows the principle of modulation and demodulation to be applied for fast system response and output waveforms with low distortion and prevents excessive stresses on components. Natural current commutation of the thyristors is obtained by the use of a series-resonant circuit for power transfer and control. Test results of a 4-kW thyristor converter system generating sinusoidal and nonsinusoidal waveforms independently of the load characteristics demonstrate the significant aspects for this class of power conversion. The material presented indicates the capability of the system to avoid excessive component stresses as well as the possibilities for fast-acting four-quadrant dc-to-dc, single-phase or polyphase dc-to-ac and ac-to-ac converter systems.

Inductive magnetic field generator

Abstract: An article surveillance system includes a power line activated inductive magnetic field generator having an on duty cycle portion considerably less than 50%. A transformerless AC power line to DC converter and switching circuitry are connected to a series resonant circuit including a coil for deriving the AC inductive magnetic field. During on duty cycle portions, the switches are activated and connected to the series resonant circuit and the power supply to cause resonant current to flow in the series circuit at an activation frequency for the switches, causing the coil to generate the magnetic field at the activation frequency.

A Synthesis Method for One-Port and Multi-Port Equivalent Networks for Analysis of Power System Transients

Abstract: Equivalent networks can be used in power system simulation to reduce simulation equipment or computer time and memory space. In this paper, an iterative method is developed for synthesizing one-port equivalent networks by the removal of poles corresponding to resonances of the driving-point impedance or admittance function. This results in networks formed by the series or parallel connection of modular RLC circuits. The RLC values are calculated using a parameter-optimization technique. Multi-port equivalent networks are first configured as ? or T forme composed of one-port network branches and the latters are then synthesized by the proposed method for one-port equivalent networks.

Buck-boost parallel resonant converter with inductive energy recovery circuit

Abstract: A DC-AC converter circuit for a power supply contains a parallel resonant circuit topology. Accordingly, stray capacitance associated with the converter forms a part of the resonant circuit and assists in setting the resonant frequency thereof. The energy in the stray capacitance which is normally lost is recovered by the resonant circuitry. A coupled inductor is connected in series with a primary winding of an output transformer of the converter. The coupled inductor includes a resonating inductor winding and an energy recovery winding which are tightly wound out of phase with one another. Energy from the resonant inductor winding is coupled to the recovery winding when the switching elements of the converter are switched on and off. Therefore, energy otherwise dissipated in switching operation is conserved by being returned to its source. Further, the switching elements of the converter are connected in series through diodes to the return line. Consequently the converter is capable of operating either in a buck or boost mode and to switch from one mode of operation to the other.

Experimental study of the frequency limits of a resonant tunneling oscillator

Abstract: An equivalent circuit obtained from microwave impedance and power data is proposed for a resonant tunneling diode. The four‐element circuit consists of a series R and C in parallel with a nonlinear negative differential conductance −G, the combination in turn in series with a resistor r. The resistive cut‐off frequency predicted by this model depends on both the RC and RG products. Detection at THz frequencies is also explained by the model.

Resonant inverter having improved control at enablement

Abstract: Improved control of a resonant inverter upon enablement from a disabled state is achieved by restricting, to a frequency remote from resonance, the rectangular wave signal applied to the resonant circuit immediately subsequent to enablement, and by controllably sweeping the rectangular wave signal frequency toward resonance until a desired output voltage or current is reached. Closed loop variation of the rectangular wave signal frequency applied to the resonant circuit is employed to maintain a constant output voltage or current once the desired value is reached.

Portable, batteryless, frequency divider consisting of inductor and diode.

Abstract: A batteryless, portable, frequency divider, consisting of a single resonant circuit consisting of an inductor (L1) and a diode (D1). The resonant circuit detects electromagnetic radiation at a first predetermined frequency and responds to said detection by transmitting electromagnetic radiation at a second frequency that is one-half of the first frequency. The circuit is resonant at the second frequency when the voltage across the diode is zero. The frequency divider is utilized in a presence detection system that uses a tag containing the frequency divider. The system transmits electromagnetic radiation at the first frequency into a surveillance zone, and detects the second frequency to detect the presence of the tag in the surveillance zone.

Analysis of the static and dynamic characteristics of push-pull parallel resonant converters

Abstract: The basic circuit of a push-pull parallel resonant converter with an input inductor is analyzed for the continuous conduction mode and the discontinuous conduction mode concerning the output-inductor current. It is found that the output voltage of this resonant converter is controlled by varying the switching frequency in the discontinuous conduction mode, while another power controller is required in the continuous conduction mode. The static and dynamic characteristics are examined analytically and experimenta1ly.

Series resonant converter with parallel resonant circuit

Abstract: A parallel resonant circuit for use in a series resonant converter. The parallel resonant circuit is located between the clamp diodes and the dominant series resonant capacitors of the converter. The parallel resonant circuit has a predetermined resonant frequency which is set to be above the telephone voice band. The circuit limits the operating frequency of the converter for light loads to be no lower than the parallel resonant frequency.

Device for the generation of ozone and a process for its operation

Abstract: A device and process for the generation of ozone using an ozone generator having two electrodes connected across the secondary winding of a high voltage transformer, the primary winding of which is connected to a converter which supplies thereto a square wave current of variable amplitude and variable frequency. A compensation coil is connected across either the primary winding or the secondary winding of the transformer. The ozone generator includes a solid dielectric and a gas path between its two electrodes. The inductance of the compensating choke and the operating frequency of the converter are selected such that the resonance frequency of the resonant circuit formed by the ozone generator and the compensation choke lies below the operating frequency of the converter current supply in any operating condition. In this way the degree of utilization of medium voltage converters of converter-fed ozone generators is significantly increased by connecting a compensation choke (6) in parallel to the ozone generator (5) and by dimensioning it suitably.

Microwave Resonator Circuit Model from Measured Data Fitting

Abstract: An iterative procedure is developed for least squares estimation, from measured impedance data, of the parameters specifying a lumped-element resonant circuit equivalent to a dielectric resonator single resonance. The procedure is applicable to large sets of measured data obtained by an automatic network analyzer.

High-frequency narrow-band active filters

Abstract: Switched-capacitor F/V and V/F converters have been presented. Because they consist of common parts, they can be realized in the IC form compatible with each other. ,The accurate conversion over the wide dynamic range is possible with the integrated converters because their operation is insensitive to the offset voltages of op-amps and parasitic capacitances. Therefore, as versatile analog building blocks, these converters will find wide application. Specifically, the signal processing of a capacitive transducer and an analog divider are new and promising application made possible with the V/F converter presented herein. IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS, VOL. CAS-33, NO. 8, AUGUST 1986

Torque measurement transducer

Abstract: The invention relates to a transducer for measuring the torque transmitted through a shaft 20 which comprises a passive resonant circuit 10, 12 including an inductor 12 and a capacitor 10 mounted on the shaft 20 and having a resonance frequency which varies as a function of the transmitted torque, and a circuit 16, 18 inductively coupled to the resonant circuit and sensitive to variations in the resonance frequency. In a preferred embodiment, the capacitor has plates (10a, Fig. 3) movable relative to one another and connected for rotation with different, longitudinally spaced, respective parts of the shaft so that the capacitance of the capacitor varies as a function of the transmitted torque, and the inductor is wound about an axis parallel to that of the shaft.

Broadbanded microstrip antenna having series-broadbanding capacitance integral with feedline connection

Abstract: The feedline connection to a microstrip antenna patch is designed to integrally include a predetermined capacitance for broadbanded operation. RLC parameters of a parallel circuit model for a specific radiator for a given feedpoint location are measured or otherwise determined. A series LC feed network is then employed and predetermined series LC parameters are chosen so as to optimize the desired bandwidth for the resulting two-stage band pass filter network. The resulting broadbanded microstrip antenna system, network may provide an operating bandwidth on the order of 30% (with less than 2:1 VSWR).

Low phase noise two port voltage controlled oscillator

Abstract: A low noise two port voltage controlled oscillator having a coarse tuning circuit serially connected to an inductor to form a resonant circuit. A fine tuning circuit is serially connected between the resonant circuit and the input to the amplifier. A large capacitance series silicon varactor minimizes noise at the frequency of operation while optimizing the coarse tuning range.

Ring type resonator

Abstract: PURPOSE: To block a harmonic frequency of a resonance frequency or an optional frequency by providing a 2nd transmission line coupled in a way of distribution with a part of a 1st transmission line of ring form and providing a capacitor between the 1st transmission line and ground. CONSTITUTION: A tuning capacitor 7 and a resonance transmission line 8 form the titled ring type resonator having a mode close to the TEM mode. The resonance frequency depends on the tuning capacitor capacitance and the length of the resonance transmission line. A coupling capacitor 6 exists as the input/ output terminal of the resonance circuit. One capacitor 6 is provided in general as the input/output terminal of the resonance circuit and further, the resonance transmission line 8 and a coupling transmission line 9 are coupled in a distribution way to form another input/output terminal thereby isolating the input and output. Moreover, a frequency block capacitor 11 is provided between the line 8 and ground in the vicinity of the distributed coupling, and the harmonic frequency of the resonance frequency or an optional frequency is blocked by adjusting the capacitance and said distributed coupling condition. COPYRIGHT: (C)1987,JPO&Japio

Inductive proximity switch having switched capacitor for controlling hysteresis

Abstract: An inductive proximity switch which consists of an oscillator with an externally controllable resonant circuit as well as of a switching amplifier controllable by the oscillator. It further has a feed or biasing circuit for the oscillator and the switching amplifier. Connected in parallel with the capacitor of the resonant circuit is a capacitor with an electronic switch, the electronic switch being responsive to the output of the switching amplifier. Thereby a simple switching hysteresis is obtained.

Raster correction circuit

Abstract: In a deflection apparatus which corrects for inside pincushion distortion, a deflection winding and a retrace capacitance form a retrace resonance circuit during a retrace interval. A trace capacitance forms a trace resonant circuit with the deflection winding during the trace interval. A circuit branch, that includes a second capacitance and an inductance, is coupled to the trace capacitance during the trace interval to form a second resonant circuit with the trace capacitance having a resonance frequency that is substantially higher during the trace interval than that of the trace resonant circuit. A current in the circuit branch, that is modulated in accordance with the modulated voltage, modulates the trace parabolic voltage across the trace capacitance in a manner to reduce inside pincushion distortion. The trace capacitance acts as a bypass capacitor around the inductance during retrace to prevent the inductance from affecting the retrace voltage.