Showing papers on "LC circuit published in 2009"

Model Predictive Control of an Inverter With Output $LC$ Filter for UPS Applications

Abstract: The use of an inverter with an output LC filter allows for generation of output sinusoidal voltages with low harmonic distortion, suitable for uninterruptible power supply systems. However, the controller design becomes more difficult. This paper presents a new and simple control scheme using predictive control for a two-level converter. The controller uses the model of the system to predict, on each sampling interval, the behavior of the output voltage for each possible switching state. Then, a cost function is used as a criterion for selecting the switching state that will be applied during the next sampling interval. In addition, an observer is used for load-current estimation, enhancing the behavior of the proposed controller without increasing the number of current sensors. Experimental results under linear and nonlinear load conditions, with a 5.5-kW prototype, are presented, verifying the feasibility and good performance of the proposed control scheme.

Control and Resonance Damping of Voltage-Source and Current-Source Converters With $LC$ Filters

Abstract: In this paper, the closed-loop control of both voltage-source converter (VSC) and current-source converter (CSC) systems with LC filters is investigated, with a focus being put on the damping of LC resonance. First, both single-loop and multiloop control schemes for a voltage-source inverter (VSI) with output LC filter are analyzed, where the design and tuning procedure can also be applied to a current-source inverter (CSI) with output CL filter. It is shown that both VSI and CSI systems are subject to LC resonance, even with multiloop control, while the CSI system is also subject to LC resonant frequency variations. On the other hand, the LC resonant frequencies in both current-source rectifier (CSR) and voltage-source rectifier (VSR) systems with input LC filter circuits are relatively fixed due to the small variation range of source impedance. To further dampen the LC resonance in these converter systems, active damping techniques such as virtual harmonic damper and control-signal-shaping methods are investigated, and their implementation into the converter systems is discussed in detail. Experimental results from both a VSC system and a CSC system are obtained.

Inductive power supply with duty cycle control

Abstract: An inductive power supply that maintains resonance and adjusts duty cycle based on feedback from a secondary circuit. A controller, driver circuit and switching circuit cooperate to generate an AC signal at a selected operating frequency and duty cycle. The AC signal is applied to the tank circuit to create an inductive field for powering the secondary. The secondary communicates feedback about the received power back to the primary controller. The power transfer efficiency may be optimized by maintaining the operating frequency substantially at resonance, and the amount of power transferred may be controlled by adjusting the duty cycle.

Wireless energy repeater

Abstract: Embodiments of the invention are disclosed for generating a first alternating current in a resonant receiving coil at a resonant frequency in a self-resonant circuit tuned to resonate at substantially the same resonant frequency as a resonant transmitting coil in a self-resonant circuit of a wireless charger, the resonant receiving coil operating as a magnetically coupled resonator with the resonant transmitting coil. The separation distance between the two coils may be several times larger than geometric sizes of the coils. The embodiments convert the first alternating current in a power control circuit to a second alternating current at a different frequency than the resonant frequency. The embodiments drive a the power transmitting coil using the second alternating current to inductively couple with a proximately located power receiving coil in a user's device, to provide power to the power receiving coil in the user's device by contact-less electromagnetic induction.

Design and Analysis of a 90 nm mm-Wave Oscillator Using Inductive-Division LC Tank

Abstract: A 60 GHz voltage-controlled oscillator with an inductive division LC tank has been designed in 90 nm CMOS. The analysis of the oscillator shows that the presence of higher harmonics, the capacitance nonlinearity and the very high K VCO are critical for the phase noise performance of oscillators. Therefore, a pseudo-differential amplifier is employed in this design because of its high linearity. Furthermore, the proposed inductive division reduces the phase noise by increasing the signal amplitude across the varactor, without affecting the operation mode of the cross-coupled pair transistors. It also helps to increase the tuning range by isolating the varactor from the parasitic capacitances of the transistors and interconnects. The mm-wave oscillator is fabricated in a 90 nm CMOS technology. Under 0.7 V supply, the oscillator achieves a tuning range from 53.2 GHz to 58.4 GHz, consuming 8.1 mW. At 58.4 GHz, the phase noise is -91 dBc/Hz at 1 MHz offset. Under 0.43 V supply, the oscillator achieves a tuning range from 58.8 to 61.7 GHz. At 61.7 GHz, the phase noise is -90 dBc/Hz @1& MHz offset with a power consumption of only 1.2 mW.

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.

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.

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.

Method and apparatus for wireless transmission and reception of electric power

Abstract: An electric transmission system utilizes charge displacement for the wireless delivery of electric power. A transmitter for radiating a charge displacement current at a frequency of approximately 2 to 7 kHz to a receiver located remote from the transmitter. The receiver receives the charge displacement current and converts the current into a form of electric power usable by an electrical device coupled to the receiver. The transmitter may use a step up transformer with an input approximating a series of step function pulses at the intended transmission frequency to produce the required high voltage for transmission. The primary winding of the transformer is part of a tuned circuit having a resonant frequency higher than the frequency of the charge displacement current radiated.

Damped input filter design of matrix converter

Abstract: This paper deals with the input filter design of matrix converter Regard the matrix converter as a buck type PWM rectifier in the input side, the transfer function of input current using LC input filter is deduced The parameter selection approach for the capacitor and inductor is presented It has been verified that when LC circuit is adopted in the input filter, the input current will oscillate near the LC resonant frequency in both steady state and start-up process for the very low damping factor, and then the input current waveforms will be distorted An improved input filter topology to increase the damping factor is then presented, and the damping resistance parameter selection method of the input filter is presented based on frequency response approach To avoid the current spike at the start-up process, a start-up circuit is then proposed The improved input filter has been tested on a 55kW matrix converter prototype and good performances are achieved

Power supply unit, hard disk drive and method of switching the power supply unit

Abstract: Zero volt switching during a light load is performed in such a manner that through an ON/OFF control of switches provided for a full bridge circuit and the synchronous rectifier switches in a rectifier and smoothing circuit, a resonant peak voltage necessary for the zero voltage switching determined by the output current flowing to output terminals, a resonant inductor and a resonant capacitor capacitance is ensured so that an energy accumulated in the rectifier and smoothing circuit is returned to the full bridge circuit so as to act as equivalent as when the output current is increased and to increase the current flowing through the full bridge circuit.

Crystal oscillator for surface mounting

Abstract: A crystal oscillator includes an oscillator circuit, a main body, a first switching circuit, a second switching circuit, and a voltage detecting circuit. The oscillator circuit includes an IC chip including an output circuit and a function circuit. The crystal element includes a first excitation electrode and a second excitation electrode. The main body houses the oscillator circuit and the crystal element and includes a power supply terminal, a ground terminal, an output terminal, and a function terminal. The output terminal is electrically connected to the output circuit and the first excitation electrode via the first switching circuit. The function terminal is electrically connected to the function circuit and the second excitation electrode via the second switching circuit. The first switching circuit and the second switching circuit are operated on the basis of a switching signal from the voltage detecting circuit connected to the power supply terminal.

Analysis on output LC filters for PWM inverters

Abstract: The cutoff frequency of output LC filters of PWM inverters limits the control bandwidth of the converter system while it attenuates voltage ripples caused from the inverter switching. For a selected cutoff frequency of an output LC filter, infinite number of L-C combinations is possible. This paper analyses the characteristics of output LC filters for PWM inverters in the view of L-C combinations. Practical circuit conditions such as no-loads, full resistive-loads, and inductive-loads are considered in the analysis. This paper proposes a design criterion and a design example for the L-C filter combination considering both the control performance and the size of PWM inverters. An experimental PWM inverter system based on the proposed output LC filter design guideline is built and tested.

Active stabilization of a poorly damped input filter supplying a constant power load

Abstract: The presence of an LC input filter in an electrical system often results in degradation of dynamic performance and instability of the system. This paper addresses the global stability study of an electrical system comprised of a DC power supply, an LC Filter and an actuator (inverter - Permanent Magnet Synchronous Motor or induction motor). Circle Criterion is used to study the global stability of the system. In the proposed approach the control structure of the electrical system is slightly modified to implement a nonlinear stabilization structure for improving large signal stability of the system and thus allows reducing the DC link capacitance value. An electrical system consisted of an LC input filter connected to an inverter-PMSM designed for aircraft application is treated as an illustrative example.

High Efficiency Soft-Switching Boost Converter Using a Single Switch

Abstract: This paper presents a new soft-switching boost converter based on the LC resonance and passive clamping technique without additional active switches. The circuit achieves high efficiency and low voltage stress by adopting a soft switching method using LC resonance. This paper gives a mathematical analysis of each mode and a detailed design procedure of the proposed boost converter. First of all, the operational principles are verified through simulation results. Then, according to the design procedure, we designed and built a 1.5[kW] prototype soft switching boost converter. Through the experimental results, we demonstrated the validity and usefulness of the proposed boost converter.

MEMS-Based Tunable LC Bandstop Filter With an Ultra-Wide Continuous Tuning Range

Abstract: This letter presents a new microelectromechanical system-based tunable LC filter that utilizes a tunable capacitor and a tunable inductor in a single device. An electrically floating metal plate is located between the tunable capacitor and the tunable inductor. As the floating metal plate is thermally moved and used commonly for both the capacitor and inductor, the device provides an ultra-wide continuous frequency tuning range by a simultaneous increase or decrease of the capacitance and inductance. The fabricated tunable LC filter showed a continuous frequency tuning ratio in excess of 127% in a range of 8.8 GHz to more than 20 GHz.

Resonant converter equipped with a phase shifting output circuit

Abstract: A resonant converter equipped with a phase shifting output circuit includes a resonant circuit to receive input power and regulate to become at least one resonant power, a switch unit to switch an ON period for the input power to pass through the resonant circuit and a power transformation circuit to regulate the resonant power and output a transformed power. The resonant converter further has a primary output circuit and at least one secondary output circuit. The primary output circuit regulates the transformed power to become a primary output power. A resonant control unit captures a feedback signal from the primary output circuit and generates a resonant control signal. A phase shifting control unit receives the resonant control signal and regulate to become a phase shifting driving signal. The secondary output circuit is controlled by the phase shifting driving signal and provides a secondary output power.

Accessing nanomechanical resonators via a fast microwave circuit

Abstract: We demonstrate how to fully electrically detect the vibrations of conductive nanomechanical resonators up to the microwave regime. We use the electrically actuated vibrations to modulate an LC tank circuit, which blocks the stray capacitance and detect the created sideband voltage by a microwave analyzer. We prove the technique up to mechanical frequencies of 200 MHz. Finally, we estimate how one could approach the quantum limit of mechanical systems.

A 56GHz LC-tank VCO with 17% tuning range in 65nm bulk CMOS for wireless HDMI applications

Abstract: A voltage controlled oscillator (VCO) with 56GHz central frequency and 17% tuning range is presented. The oscillation frequency is tuned both by an analog input and a three-bit digital control bus using the same type of differential varactors. It achieves a record FOM T (considering tuning range) of 186.8 dBc/Hz and it is able to address the full wireless HDMI band. The VCO is implemented in a 65nm bulk CMOS process and dissipates 15 mW from a 1.2 V supply.

Non-contact power transmission apparatus and design method

Abstract: A non-contact power transmission apparatus is disclosed. The non-contact power transmission apparatus includes an alternating-current power source and a resonant system. The resonant system includes a primary coil connected to the alternating-current power source, a primary-side resonance coil, a secondary-side resonance coil, and a secondary coil is connected to a load. The apparatus also has a first capacitor and a second capacitor. A first resonant frequency, which is a resonant frequency of the primary-side resonance coil and the first capacitor, and a second resonant frequency, which is a resonant frequency of the secondary-side resonance coil and the second capacitor, are set to be equal to each other. The frequency of an alternating voltage of the alternating-current power source is set to match with the first resonant frequency and the second resonant frequency.

Scaling $LC$ Oscillators in Nanometer CMOS Technologies to a Smaller Area But With Constant Performance

Abstract: We present an oscillator design method that reduces the area of LC oscillators in extremely scaled CMOS technologies by taking advantage of the high fT of the transistors. The oscillator is scaled to operate at a higher frequency and is followed by a fixed-ratio divider. It maintains the same power consumption and performance for a given wanted output frequency while occupying a much smaller area. In principle, by scaling up the oscillation frequency N times, a factor of 1/N 2 can be obtained in inductor area reduction. Simulated results show that with uniformly scaled inductors, the figure of merit (FoM) of the scaled oscillators at 1, 2, 4, and 8 GHz can be within a 1-dB difference, whereas the figure of merit normalized for area (FoMA) improves with the oscillation frequency.

LC -Tank Colpitts Injection-Locked Frequency Divider With Even and Odd Modulo

Abstract: A new injection-locked frequency divider (ILFD) using a standard 0.18 mum CMOS process is presented. The ILFD is based on a differential Colpitts voltage controlled oscillator (VCO) with a direct injection MOSFET for coupling an external signal to the resonators. The VCO is composed of two single-ended VCOs coupled with two transformers. Measurement results show that at the supply voltage of 1.4 V the divider's free-running frequency is tunable from 4.77 to 5.08 GHz, and the proposed circuit can function as a first harmonic injection-locked oscillator, divide-by-2, -3, and -4 frequency divider. At the incident power of 0 dBm the divide-by-2 operation range is from the incident frequency 7.7 to 11.5 GHz and the divide-by-4 operation range is from the incident frequency 18.9 to 20.2 GHz.

Non-contact electric power transmission circuit

Abstract: A non-contact electric power transmission circuit according to an embodiment of the invention includes an electric power transmission circuit and an electric power receiving circuit. The electric power transmission circuit includes a full bridge circuit and a resonant type full bridge circuit. A direct-current power supply is used as an input of the full bridge circuit, the full bridge circuit includes two sets of switching elements, two switching elements being connected in series in each set of the switching elements, a drive circuit alternately feeds a pulse signal to gates of the switching elements to perform switching of the direct-current input in the full bridge circuit, and a serial resonant circuit of a resonant capacitor and an electric power transmission coil is connected to an output of the full bridge circuit in the resonant type full bridge circuit. The electric power receiving circuit includes an electric power receiving coil and a rectifying and smoothing circuit. The electric power receiving coil is electromagnetically coupled to the electric power transmission coil, and the rectifying and smoothing circuit rectifies an output of the electric power receiving coil. In the non-contact electric power transmission circuit, a push-pull output PWM control circuit is provided in the drive circuit that controls the full bridge circuit, and only one of the switching elements in each set of switching elements performs a regenerative operation. Therefore, a non-contact electric power transmission circuit in which the resonant type full bridge circuit can be controlled by PWM control at a level similar to that of a phase shift operation can be provided.

A New Microwave Bandstop Filter Using Defected Microstrip Structure (DMS)

Abstract: This paper presents a new bandstop fllter by creation of some slots on the strip. These slots perform a serious LC resonance property in certain frequency and suppress the spurious signals. In the high frequencies applications, the board area is seriously limited, so using this fllter; the circuit area is minimized. The proposed fllter is very suitable for high density MMIC circuits.

Vacuum-Gap Capacitors for Low-Loss Superconducting Resonant Circuits

Abstract: Low-loss microwave components are used in many superconducting resonant circuits from multiplexed readouts of low-temperature detector arrays to quantum bits. Two-level system defects in amorphous dielectric materials cause excess energy loss. In an effort to improve capacitor components, we have used optical lithography and micromachining techniques to develop superconducting parallel-plate capacitors in which lossy dielectrics are replaced by vacuum gaps. Resonance measurements at 50 mK on lumped LC circuits that incorporate these vacuum-gap capacitors (VGCs) reveal loss tangents at low powers as low as 4 times 10-5, significantly lower than with capacitors using amorphous dielectrics. VGCs are structurally robust, small, and easily scaled to capacitance values above 100 pF.

Single-isolation pressure increase and reduction type multi-input direct current converter

Abstract: The invention relates to a single-isolation combination pressure increase and reduction type multi-input direct current converter, wherein the circuit structure is formed by connecting one multi-input single-output high-frequency inverter circuit, a plurality of common-ground input LC filters and one common output high-frequency isolation transformation energy-storage commutation filter circuit, wherein each input end of the multi-input single-output high-frequency inverter circuit is correspondingly connected with the output end of each input LC filter and the output end of the multi-input single-output high-frequency inverter circuit is connected with the input end of the high-frequency transformer. The converter has features of input direct current power supply common-ground, no insulation between the high-frequency inverter circuits, insulation between output and input, strong voltage match capability, time-sharing power supply of multi-input power supply, simple circuit topology, common use of output high-frequency transformer and energy-storage commutation filter circuit, high power density, high conversion efficiency, small output voltage ripple, low cost and wide application foreground, as the key technique for a distribution type power supply system of various renewable energy resources.

A gate-modulated CMOS LC quadrature VCO

Abstract: A quadrature voltage-controlled oscillator (QVCO) based on the time-varying gate-modulated coupling of two LC tank VCOs is introduced. Using a standard 0.18μm CMOS process, the new topology is compared to the conventional series QVCO in terms of start-up loop gain, quadrature phase accuracy, phase noise, tuning range, and voltage headroom characteristics. In addition to comparable phase noise performance, the gate-modulated QVCO (GM-QVCO) also exhibits superior quadrature phase accuracy, and suitability for low power supply voltage designs that use cascode current sources and active loads. It draws 2.4 mA from a 1.8 V power supply, displays a phase noise of −122 dBc/Hz @ 1MHz offset, and has a quadrature phase error of 0.4°.

Driving a mass spectrometer ion trap or mass filter

Abstract: A radio frequency (RF) drive system and method for driving the ion trap or mass filter of a mass spectrometer has a programmable RF frequency source coupled to a RF gain stage. The RF gain stage is transformer coupled to a tank circuit formed with the ion trap or mass filter. The power of the RF gain stage driving the ion trap or mass filter is measured using a sensing circuit and a power circuit. A feedback value is generated by the power circuit that is used to adjust the RF frequency source. The frequency of the RF frequency source is adjusted until the power of the RF gain stage is at a minimum level.