Showing papers on "RLC circuit published in 2009"

High Step-Up Active-Clamp Converter With Input-Current Doubler and Output-Voltage Doubler for Fuel Cell Power Systems

Abstract: A high-efficiency high step-up DC-DC converter is proposed for fuel cell power systems. The proposed system consists of an input-current doubler, an output-voltage doubler, and an active-clamp circuit. The input-current doubler and the output-voltage doubler provide a much higher voltage conversion ratio without using a high turns ratio in the transformer and increase the overall efficiency. A series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the rectifying diodes. The active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. The operation principle of the converter is analyzed and verified. A 1 kW prototype is implemented to show the performance of the proposed converter. The prototype achieved a European efficiency of 96% at an input voltage of 30 V.

Power supply system

Abstract: PROBLEM TO BE SOLVED: To suppress variation in inductance of a feeder line for supplying power in non-contact manner. SOLUTION: A resonant capacitor 111 is connected to a feeder line 110, constituting a resonance circuit together with the feeder line 110. A feeder line pseudo unit 120 is connected in parallel to the feeder line 110. A power source 300 outputs an AC current of specified frequency to the feeder line 110 by an inverter circuit. The switching frequency of the power source 300 is so adjusted as to agree with the resonance frequency of a circuit consisting of the feeder line pseudo unit 120 and resonant capacitor 111 as well as the feeder line 110. An inductive reactance component ln occurs at the feeder line 110 when a mobile body receives power supply from the feeder line 110, however, since a reactor Lp and resistor Rp are connected in parallel to the ln, the effect of ln is suppressed. COPYRIGHT: (C)2009,JPO&INPIT

Wireless power transmission device

Abstract: In one embodiment, a power reception device includes a load circuit, to which a first signal having a first power value is supplied from a first resonance circuit connected to a power reception coil, and a first transceiver which transmits the first power value to a power transmission device. The power transmission device includes a second resonance circuit including a plurality of inductors and capacitors to which a second signal having a second power value is input, a power transmission coil connected to the second resonance circuit, a second transceiver which receives the first power value from the first transceiver, and a first control circuit which calculates power transmission efficiency using the first power value and the second power value and adjusts at least one of inductance values of the inductors and/or at least one of capacitance values of the capacitors based on the power transmission efficiency.

Dynamic antenna tuning circuit for a radio frequency identification reader

Abstract: A resonant antenna circuit for a radio frequency identification (RFID) reader generates an electrical signal for activating a passive identification tag. The identification tag in turn generates a coded electrical signal that is detected by the reader. The electrical characteristics of the resonant circuit are actively and dynamically altered so that the antenna performs more optimally during the transmit and receive intervals.

Resonant Contactless Energy Transfer With Improved Efficiency

Abstract: This paper describes the theoretical and experimental results achieved in optimizing the application of the series loaded series resonant converter for contactless energy transfer. The main goal of this work is to define the power stage operation mode that guarantees the highest possible efficiency. The results suggest a method to select the physical parameters (operation frequency, characteristic impedance, transformer ratio, etc.) to achieve that efficiency improvement. The research clarifies also the effects of the physical separation between both halves of the ferromagnetic core on the characteristics of the transformer. It is shown that for practical values of the separation distance, the leakage inductance, being part of the resonant inductor, remains almost unchanged. Nevertheless, the current distribution between the primary and the secondary windings changes significantly due to the large variation of the magnetizing inductance. An approximation in the circuit analysis permits to obtain more rapidly the changing values of the converter parameters. The analysis results in a set of equations which solutions are presented graphically. The graphics show a shift of the best efficiency operation zone, compared to the converter with an ideally coupled transformer. Experimental results are presented confirming that expected tendency.

Wireless power supply system, wireless power transmitting device, and wireless power receiving device

Abstract: A wireless power supply system includes: a wireless power transmitting device configured to include a variable resonant circuit having a variable-controllable resonant frequency characteristic, and to transmit electric power wirelessly via the variable resonant circuit; a power transmission control unit configured to variably control the resonant frequency characteristic of the variable resonant circuit; and a plurality of wireless power receiving devices configured to include respective unique resonant circuits having respective unique resonant frequency characteristics which are different to each other, and to wirelessly receive power from the wireless power transmitting device by a magnetic field resonance mode arising as a result of the unique resonant circuit tuning to a resonant frequency of the variable resonant circuit

Zero-current-switching multilevel modular switched-capacitor dc-dc converter

Abstract: This paper presents a quasi-resonant technique for multilevel modular switched-capacitor circuit (MMSCC) to achieve zero-current-switching (ZCS) without increasing cost and sacrificing reliability. This zero-current-switching multilevel modular switched-capacitor circuit (ZCS-MMSCC) employs the stray inductance existing in the circuit as the resonant inductor to resonate with the capacitor and provide low dv/dt and low switching loss for the device. The ZCS-MMSCC does not utilize any additional components to achieve ZCS and solves the current and voltage spike problem during the switching transition, thus leading to reliable and high efficiency advantages over traditional MMSCC. Furthermore, the ZCS-MMSCC reduces the capacitance needed the circuit; in this case, the bulky capacitors present in traditional MMSCC to attain high efficiency is not necessary any more. A 150 W four-level ZCS-MMSCC prototype has been built. Simulation and experimental results are given to demonstrate the validity and features of the soft switching switched-capacitor circuit.

Programmable radio frequency waveform generator for a synchrocyclotron

Abstract: A synchrocyclotron comprises a resonant circuit that includes electrodes having a gap therebetween across the magnetic field. An oscillating voltage input, having a variable amplitude and frequency determined by a programmable digital waveform generator generates an oscillating electric field across the gap. The synchrocyclotron can include a variable capacitor in circuit with the electrodes to vary the resonant frequency. The synchrocyclotron can further include an injection electrode and an extraction electrode having voltages controlled by the programmable digital waveform generator. The synchrocyclotron can further include a beam monitor. The synchrocyclotron can detect resonant conditions in the resonant circuit by measuring the voltage and or current in the resonant circuit, driven by the input voltage, and adjust the capacitance of the variable capacitor or the frequency of the input voltage to maintain the resonant conditions. The programmable waveform generator can adjust at least one of the oscillating voltage input, the voltage on the injection electrode and the voltage on the extraction electrode according to beam intensity and in response to changes in resonant conditions.

Selectable resonant frequency transcutaneous energy transfer system

Abstract: An inductive power transfer system includes a number of controllable reactive components ( 3, 6, 12, 13, 16 ) that allow the resonant frequency of a primary and/or secondary resonant circuit to be controllably varied to thereby control power available to a load ( 10 ).

Results of Investigation of Multicell Converters With Balancing Circuit—Part II

Abstract: This paper presents the results of an investigation of the multilevel multicell converters with a passive RLC balancing circuit applied for the maintenance of the voltage sharing on the capacitive sources of the converters. The topologies of DC/DC, AC/AC, DC/AC, and AC/DC multicell converters were analyzed. For the purpose of multilevel modulation, a multicell converter employs several capacitors that are connected to every cell-the flying capacitors, charged to a given level of voltage. An inadequate relation between the voltages across the flying capacitors (the unbalance state) results in the increase of the voltages above their rated values across the switches. An RLC series circuit (a balancing circuit) with the properly selected resonance frequency is connected in parallel to the load in order to eliminate the unbalance. The balancing process with the use of passive RLC depends on the configuration and parameters of the balancing circuit, the parameters of the converter, as well as on the operating conditions. This paper presents the mathematical description of both the converter and the balancing process, the balancing circuit approach in the different topologies of the multicell converters, a selection of the balancing circuit parameters, and the analysis of the improper control conditions.

Antenna and radio IC device

Abstract: An antenna includes a feeder terminal and a resonance circuit. The resonance circuit is defined by a capacitance element and an inductance element and includes first and second radiation plates. The capacitance element is electromagnetically coupled to the first radiation plate, and the inductance element is electromagnetically coupled to the second radiation plate. A radio IC device includes an electromagnetic coupling module including a feeder circuit substrate on which a radio IC chip is mounted, and radiation plates. The feeder circuit substrate includes an inductance element and a capacitance element. One of the radiation plates faces and is magnetically coupled to the inductance element. The other radiation plate faces and is electrically coupled to the capacitance element. The radio IC chip is operated by signals received by the radiation plates, and a response signal from the radio IC chip is radiated from the radiation plates.

An unequal dual-frequency wilkinson power divider with optional isolation structure

Abstract: In this paper, we propose a generalized Wilkinson power divider operating at two arbitrary frequencies with unequal power dividing ratio. To achieve unequal power division and perfect matching at dual-frequency, a novel structure consisted of four dual-frequency transformers in two sections is proposed. For the compact power divider, the parallel and series RLC structures can be chosen to obtain effective isolation between the two outports according to different frequency ratios. Furthermore, the closed-form design equations of the unequal dual-frequency power divider are derived based on circuit theory and transmission line theory. Finally, simulation and experiment results of two examples including parallel and series RLC structures indicate that all the theoretical features of these unequal power dividers can be fulfilled at dual-frequency simultaneously.

A Novel Three-Phase Hybrid Active Power Filter With a Series Resonance Circuit Tuned at the Fundamental Frequency

Abstract: In this paper, a novel three-phase hybrid active power filter (HAPF) with a series resonance circuit tuned at the fundamental frequency is proposed for simultaneously suppressing harmonic currents and compensating high-capacity reactive power in high- or medium-voltage power systems. To reduce its rated capacity, the active power filter is shunted to the series resonance circuit by a matching transformer and, thus, greatly reduces its current requirements as well as voltage ratings of semiconductor switching devices. The passive power filters are used to compensate the reactive power with a constant capacity. The validity and effectiveness of this novel HAPF system have been verified by simulation and industrial application results.

Predictive Stator Current Control for Medium Voltage Drives With LC Filters

Abstract: The switching frequency of power semiconductor devices in high-power medium voltage drives is limited due to high switching losses. These drives often comprise an LC output filter. The filter introduces a resonant circuit that may be excited, for instance, by fast control transients. One option to avoid such oscillations is to apply damping control methods, which on the other hand usually require switching frequencies well above the filter resonance. This paper presents a predictive stator current controller that avoids the excitation of the filter resonance, realizes active damping and enables fast current control while maintaining low switching frequency. Feasibility and good dynamic performance of the proposed control method is demonstrated by simulation results of a 2.4 kV induction motor drive and by experimental results obtained from a 55 kW prototype ac drive.

Design of AC resonant inductors using area product method

Abstract: There are no well-established criteria for selecting the core for the design of resonant inductors. This paper presents new expressions of the area product for resonant inductors. By using proposed expressions, the area-product value can be calculated from loaded-quality factor of a resonant circuit, output power, and operating frequency assuming the window utilization factor and the maximum flax density. The area-product value expressed in terms of the loaded-quality factor is a good criterion for selecting the core. The design examples are given for single-wire winding and multiple-strand winding with a gapped core taking into account skin, proximity, and fringing effects.

An Efficient High-Frequency Drive Circuit for GaN Power HFETs

Abstract: The requirements for driving gallium nitride (GaN) heterostructure field-effect transistors (HFETs) and the design of a resonant drive circuit for GaN power HFET switches are discussed in this paper. The use of wideband III-nitride (such as GaN) devices today is limited to telecom and low-power applications. The current lack of high-frequency high-power drivers prevents their application in power converters. The proposed circuit is based upon resonant switching transition techniques, by means of an LC tag, to recover part of the power back into the voltage source in order to reduce the power loss. This circuit also uses level shifters to generate the zero and negative gate-source voltages required to turn the GaN HFET on and off, and it is highly tolerant to input-signal timing variances. The circuit reduces the overall power consumed in the driver and thus reduces the power loss. This is particularly important for high-frequency driver operation to take full advantage, in terms of efficiency, of the superior switching speed of GaN devices. In this paper, the topology of the low-power-loss high-speed drive circuit is introduced. Some simulation results and preliminary experimental measurements are discussed.

A Dual-Band CMOS Voltage-Controlled Oscillator Implemented With Dual-Resonance LC Tank

Abstract: A new fully integrated, dual-band CMOS voltage controlled oscillator (VCO) is presented. The VCO is composed of n-core cross-coupled Colpitts VCOs and was implemented in 0.18 mum CMOS technology with 0.8 V supply voltage. The circuit allows the VCO to operate at two resonant frequencies with a common LC tank. The VCO has two control inputs, one for continuous control of the output frequency and one for band switching. This VCO is configured with 5 GHz and 12 GHz frequency bands with differential outputs. The dual-band VCO operates in 4.78-5.19 GHz and 12.19-12.61 GHz. The phase noises of the VCO operating at 5.11 and 12.2 GHz are -117.16 dBc/Hz and -112.15 dBc/Hz at 1 MHz offset, respectively, while the VCO draws 3.2/2.72 mA and 2.56/2.18 mW consumption at low/high frequency band from a 0.8 V supply.

Automatic tuning for wireless power transfer

Abstract: In one embodiment, a wireless power transfer system has a wireless power transmitter and receiver. The transmitter has a transmitting resonant circuit that resonates at a first frequency and a signal generator that generates a signal at a second frequency. The transmitter also has a power detector that measures reflected power at the transmitting resonant circuit, and an auto-tuner that generates transmitter tuning parameters for adjusting the first and second frequencies to reduce reflected power. The receiver has a receiving resonant circuit that resonates at a third frequency based on a receiver tuning parameter. The receiver tuning parameter is generated by a power detector that measures power generated at the receiving resonant circuit, and an auto-tuner that generates the receiver tuning parameter to increase the load power.

A Family of Single-Stage Resonant AC/DC Converters With PFC

Abstract: A family of novel, single-stage, isolated, resonant-based AC/DC power supply circuits with inherently high power factor is presented in this paper. The three topologies in the family are transformer isolated; they contain a bulk energy storage capacitor to enable output voltage holdup, and they also contain a resonant circuit in which a resonant capacitor is connected directly across the mains input rectifier. The presence of this resonant circuit results in AC line current being drawn over much of the line cycle, as well as in soft switching of the power devices. The rectifier-compensated fundamental-mode approximation (RCFMA) method is used to provide an accurate yet simple analysis of the circuit. Experimental results for closed-loop operation of two of the topologies are also presented. This family of single-stage, high-power-factor converters provides for simple control and high-frequency operation, due to the resonant configuration of the power circuit, without the excessive conduction loss of fully resonant techniques.

Methods and apparatus for a dimmable ballast for use with led based light sources

Abstract: Methods and apparatus for powering a dimmable ballast operating with LED light source(s) are provided. In one embodiment, the ballast circuit includes sections comprising: power input, full wave bridge rectifier, voltage regulator, integrated circuit driver, switching transistors, bypass capacitor, resonant circuit, rectifier diodes, and an LED light source. The resonant circuit receives energy from the voltage source and the bypass capacitor every switching cycle, and provides current to the rectifier diodes and one or more LEDs for generating light. Further, because the current flowing into the resonant circuit is substantially sinusoidal and in line with the input voltage, the circuit exhibits a desirable power factor. The ballast circuit can also effectively dimmed over a wide range using a phase angle dimmer, allowing further energy savings.

Article having electromagnetic coupling module attached thereto

Abstract: An article having an electromagnetic coupling module attached thereto includes an electromagnetic coupling module and a PET bottle having the electromagnetic coupling module bonded thereto. The electromagnetic coupling module includes a wireless IC chip arranged to process transmission and reception signals and the feed circuit board having the wireless IC chip mounted thereon. The feed circuit board includes a feed circuit including a resonant circuit having a predetermined resonant frequency. The feed circuit performs characteristic impedance matching between the PET bottle and the wireless IC chip. The PET bottle functions as a radiator arranged to radiate a transmission signal supplied from the feed circuit using electromagnetic field coupling and to supply a received reception signal to the feed circuit using electromagnetic field coupling.

Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling

Abstract: An electrosurgical generator is disclosed. The electrosurgical generator includes a power supply for generating a DC voltage. The electrosurgical generator also includes a first parallel inductor-capacitor circuit being driven by a first signal at a first predetermined frequency and a second parallel inductor-capacitor circuit driven by a second signal at the first predetermined frequency phase shifted 180 degrees. The electrosurgical generator further includes a series inductor-capacitor resonant circuit operably connected in series with a primary winding of a transformer. The first and second parallel inductor-capacitor circuits are operably connected to the transformer, such that the first inductor-capacitor circuit generates a positive half sine wave and the second inductor-capacitor circuit generates a 180 degrees phase-shifted positive half sine wave to generate a full sine wave in a secondary winding of the transformer.

Comparison of active and passive damping methods for application in high power active power filter with LCL-filter

Abstract: LCL-type filter possessing sufficient attenuation ratio for switching ripple with small LC parameters is appropriate to be used as output filter to get high slew rate of compensation current. However, LCL-filter, as a three order resonant circuit itself, is difficult to be stable. This paper compares active and passive methods for LCL filter resonance damping; assesses their suitability for the high power active power filter application and presents their benefits and drawbacks. The results presented show that both methods compensate harmonics effectively and attenuate switching ripple sufficiently. However, there are still some differences both in the filtering performance and the power losses in the high power application. The active methods require more sensors and increase algorithm complexity, while additional damping resistors are needed in the passive methods and result in large losses. Simulation validates the feasibility of the method proposed by this paper.

Characteristics and Design of an Asymmetrical Duty-Cycle-Controlled LCL-T Resonant Converter

Abstract: The characteristics of an asymmetrical duty cycle (ADC) controlled LCL-T resonant converter operating at the resonant frequency are studied by solving the state-space model of the converter. Four operating modes are identified having different circuit waveforms representing different device conduction sequences, thereby creating different conditions during the device switching. The mode boundaries are obtained and plotted on the D-Q plane. A region on the D-Q plane is identified for the converter design, where the switches operate under zero-voltage-switching condition. A prototype 500 W, 100 kHz converter is designed and built to experimentally demonstrate the operating modes, control characteristics, and performance of ADC-controlled LCL-T resonant converter.

A Single-Stage High-Power-Factor Electronic Ballast With ZVS Buck–Boost Conversion

Abstract: This paper proposes a novel single-stage high-power-factor electronic ballast via the integration of a derivative buck-boost converter and a half-bridge resonant inverter. The derivative buck-boost converter employs two coupled inductors with an appropriate turn ratio to conduct the current from the input line source into the designated power switches. With the tactful topology and delicately designed circuit parameters, both the active power switches of the resonant inverter can retain the zero voltage switching, resulting in a high circuit efficiency. A prototype circuit designed for a T8-36W rapid-start fluorescent lamp was built and tested to verify the analytical predictions, and satisfactory results were obtained experimentally.

Analysis and design of wideband passive UHF RFID tags using a circuit model

Abstract: The great majority of commercial UHF RFID tags are based on dipole antennas using a modification of a T-match as a matching circuit. The literature contains examples of wideband matching, but provides little insight as to how wideband behavior is achieved. Here, we present a simple circuit-based theory to describe the antenna, matching circuit, and IC behavior; we present an approach for developing an impeding matching strategy to maximize bandwidth; and we present a concrete example and analysis using a method of moments (MoM) numerical solver. The results show very good agreement with theory.

Study on a Novel Hybrid Active Power Filter Applied to a High-Voltage Grid

Abstract: A novel hybrid active power filter (HAPF) applied to a high-voltage grid is proposed. The passive filter of this topology can be used for reactive power compensation as well as for harmonic mitigation caused by the nonlinear load. The active power filter, which is shunted to a fundamental resonance circuit, is connected in series with a matching transformer, thus forming the injection-type hybrid active power filter. Because of this advantage, it is effective to be used in the high-voltage distribution grid. The basic principle of this topology is introduced particularly. Then, the steady compensation characteristic and the resonance-damping characteristic of this system are analyzed in detail. The principle about the designing method of HAPF is proposed. A HAPF prototype with the proposed designing method was built, and installed in a copper plan in Southern China. Experimental and application results prove that the proposed HAPF is good in harmonics elimination, reactive power compensation, and reliability.

Analysis and design of a current-fed zero-voltage-switching and zero-current-switching CL-resonant push-pull dc-dc converter

Abstract: A current-fed zero-voltage-switching (ZVS) and zero-current-switching (ZCS) CL-resonant push-pull DC-DC converter is presented in this paper. The proposed push-pull converter topology is suitable for unregulated low-voltage to high-voltage power conversion with low ripple input current. The resonant frequency of both capacitor and inductor is operated at approximately twice the main switching frequency. In this topology, the main switch is operated under ZVS because of the commutation of the transformer magnetising current and the parasitic drain-source capacitance. Because of the leakage inductance of the transformer and the resonant capacitance from the resonant circuit, both the main switch and output rectifier are operated by implementing ZCS. The operation and performance of the proposed converter has been verified on a 400-W prototype.

High efficiency contactless energy transfer system with power electronic resonant converter

Abstract: A novel Inductive Contactless Energy Transfer (ICET) system is presented in this paper. The energy is transferred using a rotatable air gap transformer and a power electronic converter. To minimize total losses of the system a series resonant circuit is applied, assuring zero current switching condition for IGBT power transistors. The analytical expression of the transfer dc voltage gain is given and discussed. The developed ICET system is characterized by high efficiency and fast FPGA based controller and protection system. The resonant frequency is adjusted by extreme regulator which follows instantaneous value of primary peak current. Simulated and experimental results which verify and illustrate operation of developed 3 kW laboratory model are presented.

Unequal dual-frequency Wilkinson power divider including series resistor-inductor-capacitor isolation structure

Abstract: A novel Wilkinson power divider operating at arbitrary dual-frequency (namely dual band) with unequal power dividing ratio is proposed here. The asymmetric structure that consists of seven sections transmission lines with different characteristics impedances is given to satisfy the unequal and matching characteristic. To obtain the ideal isolation, a series resistor-inductor-capacitor (RLC) structure is applied. Furthermore, the closed-form design equations of the proposed dual-frequency power divider are derived based on circuit theory and ideal transmission line theory. Finally, calculation, simulation and measurement results of an example indicate that all the theoretical features of the unequal power divider can be fulfilled at the desired dual-frequency simultaneously.