Voltage Transfer Function Research Articles

Voltage Distortion Approach for Output Filter Design for Off-Grid and Grid-Connected PWM Inverters

This paper proposes a novel voltage distortion approach for output filter design based on the voltage transfer function for both off-grid and grid-connected Pulse Width Modulation (PWM) Inverters. The method explained in detail is compared to conventional methods. A comparative analysis is performed on an example of L and LCL-filter design. Simulation and experimental results for the off-grid and the grid-connected single phase inverter prove our theoretical predictions. It was found that conventional methods define redundant values of the output filter elements. Assumptions and limitations of the proposed approach are also discussed.

Small-Signal Analysis of a Differential Two-Stage Folded-Cascode CMOS Op Amp

Using a simplified high-frequency smallsignal equivalent circuit model for BSIM3 MOSFET, the fully differential two-stage folded-cascode CMOS operational amplifier is analyzed to obtain its smallsignal voltage transfer function. As a result, the expressions for dc gain, five zero frequencies, five pole frequencies, unity-gain frequency, and phase margin are derived for op amp design using design equations. Then the analysis result is verified through the comparison with Spice simulations of both a high speed op amp and a low power op amp designed for the 0.13 ㎛ CMOS process.

Analysis and Design of a Wireless Power Transfer System With an Intermediate Coil for High Efficiency

This paper presents a theoretical analysis, an optimal design method, and experimental results for a wireless power transfer (WPT) system with an intermediate coil. The analytical expression of the dc voltage transfer function is presented and discussed. In a two-coil WPT system, which has low coupling coefficient, the intermediate coil boosts the apparent self-inductance and magnetizing inductance of the primary side at around the resonance frequency of the intermediate coil, so that the apparent coupling coefficient is compensated. The coupling coefficient makes the system efficiency increase and induces bifurcation phenomenon. From the analysis, this paper proposes an optimal design method using the second resonance frequency operation with the bifurcation phenomenon and presents design procedure for high efficiency. A prototype of the WPT system with the intermediate coil is implemented and experimented to verify the validity of the analysis and the proposed design method. The prototype operates at 100 kHz switching frequency and has an air gap between primary and secondary side of 200 mm. An overall system efficiency of 95.57% has been achieved at 6.6 kW of output power.

Research on input‐voltage feedforward control for high‐order converter topologies

The input-voltage feedforward control for the high-order converter is researched in this study. Input-voltage feedforward control can significantly reduce the audio susceptibility, that is, the input voltage to output voltage transfer function of DC–DC converter. The unified feedforward controller forms in different control modes have been derived. If the converter's model is a high-order model, its desired feedforward controller to eliminate audio susceptibility is complex. In this study, a decomposition block diagram for high-order controller is given so the complex controller can be realised by the composition of simple controllers. When the desired controller is impossible for realisation, its proportional form can be applied to the converter to decrease the audio susceptibility in the low-frequency range. The effective frequency range is related to the main circuit parameters of the converter. The conclusions have been verified by simulation and experiment results.

Unified Synthesis of Tapped-Inductor DC-to-DC Converters

Tapped-inductor variations of single-switch, single-diode, dc-to-dc converters are categorized based on a new unified sequential circuit topology and mathematical transformation approach, all seeded from a basic buck–boost converter and its transfer function. Classification focuses on identifying two different ac circuit coupled inductor arrangements of the basic buck–boost dc-to-dc converter. Subsequent dc circuit sequential manipulation yields all 11 known, documented, in theory, in simulation and practically, tapped-inductor dc-to-dc converter topologies. The procedure not only generates sequences of topologies, but also generates the voltage transfer functions without recourse to analysis of the circuit internal operating mechanisms. Consequently, two converter classes group the 11 known tapped-inductor topologies, which is at least one fewer topology classes than universally accepted. The methodology yields two new classes of three and ten coupled inductor converter topologies, all with new transfer functions. The new analysis approach is adaptable to the analysis of all single-switch, single-diode, (noncoupled inductor), dc-to-dc converters (single and two inductor topologies), formulated from the basic buck–boost converter.

Voltage transfer function as an optical method to characterize electrical properties of liquid crystal devices.

The voltage transfer function is a rapid and visually effective method to determine the electrical response of liquid crystal (LC) systems using optical measurements. This method relies on crosspolarized intensity measurements as a function of the frequency and amplitude of the voltage applied to the device. Coupled with a mathematical model of the device it can be used to determine the device time constants and electrical properties. We validate the method using photorefractive LC cells and determine the main time constants and the voltage dropped across the layers using a simple nonlinear filter model.

A Two-Mode Control Scheme With Input Voltage Feed-Forward for the Two-Switch Buck-Boost DC–DC Converter

The two-switch buck-boost (TSBB) converter is suitable for wide input voltage applications. In order to achieve high efficiency over the entire input voltage range, the TSBB converter is operated in buck mode at high input voltage and boost mode at low input voltage. Such operation is called the two-mode control scheme. The objective of this paper is to propose an input voltage feed-forward (IVFF) method to reduce the influence of the input voltage disturbance on the output voltage. The small-signal models of the TSBB converter are built, and based on which, the IVFF functions under different operating modes of the TSBB converter are derived. The IVFF function in boost mode is simplified for easy implementation. The two-mode control scheme with IVFF compensation is then proposed for the TSBB converter, which realizes automatic selections of operating modes and the corresponding IVFF functions. Besides, nearly smooth switching between buck and boost modes is also guaranteed. For exhibiting the advantages of the proposed control scheme clearly, comparisons between the two-mode control with and without IVFF compensation have been presented in this paper, including the output signal of the voltage regulator and input-to-output voltage transfer function. Finally, a 250−500-V input, 360-V output, and 6-kW-rated power prototype is fabricated to validate the effectiveness of the proposed control scheme in the laboratory, and the experimental results show that the TSBB converter has an improved input transient response and high efficiency over the entire input voltage range with this proposed control scheme.

Interfacing renewable energy sources for maximum power transfer—Part I: Statics

Abstract The manuscript reveals combined source-converter-load dynamics of interfacing renewable energy generators by means of terminal voltage control, aimed to track a Maximum Power Line. Control-to-input voltage transfer functions are calculated for three basic DC–DC converters based power electronic interfaces operating in both current and voltage control modes; respective stability assessment is performed as well for each arrangement. In order to generalize the derived dynamics, it is shown that photovoltaic and wind generators may be represented by similar electrical equivalent circuits, possessing comparable small-signal dynamics. It is exposed that dynamic impedance of renewable energy generators is both operating point and environmental conditions dependent and hence plays a crucial role in the combined source-converter-load dynamics from affecting system damping to causing open-loop instability in particular arrangements. Consequently, special care must be taken when designing power electronic interface intended to operate as a renewable energy generator power processor while at the same time the controller must be robust enough to ensure system stability for all expected environmental conditions. In addition, in case fixed closed-loop behavior is required through the whole operating range of the system, some kind of adaptive mechanism is required to estimate the dynamic impedance online. Several particular case examples of the proposed method presented in the literature are reviewed.

Highly accurate spectral retardance characterization of a liquid crystal retarder including Fabry-Perot interference effects

Multiple-beam Fabry-Perot (FP) interferences occur in liquid crystal retarders (LCR) devoid of an antireflective coating. In this work, a highly accurate method to obtain the spectral retardance of such devices is presented. On the basis of a simple model of the LCR that includes FP effects and by using a voltage transfer function, we show how the FP features in the transmission spectrum can be used to accurately retrieve the ordinary and extraordinary spectral phase delays, and the voltage dependence of the latter. As a consequence, the modulation characteristics of the device are fully determined with high accuracy by means of a few off-state physical parameters which are wavelength-dependent, and a single voltage transfer function that is valid within the spectral range of characterization.

Analysis of Half-Wave Class DE Low $dv\!/\!dt$ Rectifier at Any Duty Ratio

Class DE low dv/dt rectifiers realize high-frequency high-efficiency rectification and low-diode voltage stress which is no more than the output voltage. Half-wave Class DE low dv/dt rectifier, which is one of the Class DE rectifiers, realizes the common ground between the input port and the output port. In this paper, the half-wave Class DE low dv/dt rectifier is analyzed for any diode-ON-duty ratio. The equations of the waveforms, the input and output powers, the current and voltage transfer functions, the current and voltage stresses, the power-output capability, and the power conversion efficiencies are obtained. Moreover, the characteristics of the normalized output power, the normalized input resistance and capacitance, the current and voltage transfer functions, and the power-output capability are clarified as functions of the diode-ON-duty ratio. The performance has been confirmed with the circuit experiment and the simulation in steady state. In the experiment and the simulation, the characteristics of the output voltage and the power conversion efficiency against the amplitude of the input current, the operating frequency and the load resistance have been obtained. The experimental results well agreed with the simulation results.

Design for Efficiency Optimization and Voltage Controllability of Series–Series Compensated Inductive Power Transfer Systems

Inductive power transfer (IPT) is an emerging technology that may create new possibilities for wireless power charging and transfer applications. However, the rather complex control method and low efficiency remain the key obstructing factors for general deployment. In a regularly compensated IPT circuit, high efficiency and controllability of the voltage transfer function are always conflicting requirements under varying load conditions. In this paper, the relationships among compensation parameters, circuit efficiency, voltage transfer function, and conduction angle of the input current relative to the input voltage are studied. A design and optimization method is proposed to achieve a better overall efficiency as well as good output voltage controllability. An IPT system design procedure is illustrated with design curves to achieve a desirable voltage transfer ratio, optimizing between efficiency enhancement and current rating of the switches. The analysis is supported with experimental results.

Novel Reciprocal Self-Sensing Techniques for Tapping-Mode Atomic Force Microscopy

We evaluate two novel reciprocal self-sensing methods for tapping-mode atomic force microscopy (TM-AFM) utilizing charge measurement and charge actuation, respectively. A microcantilever, which can be batch fabricated through a standard microelectromechanical system (MEMS) process, is coated with a single piezoelectric layer and simultaneously used for actuation and deflection sensing. The setup enables the elimination of the optical beam deflection technique which is commonly used to measure the cantilever oscillation amplitude. The voltage to charge and charge to voltage transfer functions reveal a high amount of capacitive feedthrough which degrades the dynamic range of the sensors significantly. A feedforward control technique is employed to cancel the feedthrough and increase the dynamic range from less than 1 dB to approximately 30 dB. Experiments show that the conditioned self-sensing schemes achieve an excellent signal-to-noise ratio and can therefore be used to provide the feedback signal for TM-AFM imaging.

State Variable Model for Considering the Parasitic Inductor Resistance on the Open Loop Performance of DC to DC Converters

This paper shows DC and small-signal circuit models for the PWM DC to DC buck, boost and back/ boost converters with the equivalent series resistance of the inductor. The DC voltage transfer function and the efficiency of the converter are derived from the DC model. Small-signal open-loop characteristics are derived from the small-signal model based on a state variable model. A design example proves the performance of the circuit and verification of the model.

Techniques of Power Phase-Noise Optimization of 2.4 / 4.8 GHz CMOS VCO with Switched Capacitor Array Using Bondwire Inductor

This paper presents theoretical analysis of the maximum operating frequency of proposed Source Degeneration (SD) and Conventional CML D-Latch are estimated. The approach is based on the voltage transfer function, which is derived from small signal model of the circuit. Design approach with pre and post layout simulation results have been presented in detail and compared the performance in terms of power consumption, self oscillation frequency, sensitivity and supply voltage. With example shows the, all pMOS Voltage Controlled Oscilaator (VCO) with MOS capacitor switched capacitor array (SCA) generates the high frequency sinewave reference signals fed in to both divider for to get quadrature (Q) sinewave signals. Off Chip Bondwire inductor is used instead of on chip spiral inductor in all-pMOS VCO as it have high quality factor. Also, it will neglect the variations of carrier frequency and it gives additional performance like phase noise, power consumption, area than using spiral inductor. Even if use spiral inductor in all-pMOS VCO, Bondwire inductor also presents due to low impedance path between drain and ground terminal. Various optimization techniques are implemented while designing a QVCO, which facilitates is used to achieve a low power low phase noise performance. Compared to other types of QVCO, the conventional QVCO shows good phase noise performance than normally achieved 6 dB phase noise improvement with carrier frequency. The simulated results shows about 5 dB, 4 dB, 4 dB and 4 dB of phase noise improvement at 10 kHz, 100 kHz, 1 MHz and 3 MHz offset frequency from the 2.4 GHz carrier frequency. This combinational topology doesn't consume additional power and area than others and shows with improved phase noise performance. The pre and post layout simulation results are compared of both proposed (SD) and conventional QVCO, which is designed in 180 nm CMOS technology as 1V.

Liquid crystal retarder spectral retardance characterization based on a Cauchy dispersion relation and a voltage transfer function

We present a methodology for the spectral characterization of the optical modulation properties of a liquid crystal retarder (LCR). The method includes its complete description with a single Cauchy dispersion relation and a single voltage transfer function. As a result, an accurate description of the LCR retardance is achieved, both versus applied voltage and versus wavelength, with very few parameters. Finally, an imaging polarimetric system has also been developed to characterize the spatial variations in the device.

Analysis and Implementation of a Half Bridge Class-DE Rectifier for Front-End ZVS Push-Pull Resonant Converters

An analysis of the junction capacitance in resonant rectifiers which has a significant impact on the operating point of resonance circuits is studied in this paper, where the junction capacitance of the rectifier diode is to decrease the resonant current and output voltage in the circuit when compared with that in an ideal rectifier diode. This can be represented by a simplified series resonant equivalent circuit and a voltage transfer function versus the normalized operating frequency at varied values of the resonant capacitor. A low voltage to high voltage push-pull DC/DC resonant converter was used as a design example. The design procedure is based on the principle of the half bridge class-DE resonant rectifier, which ensures more accurate results. The proposed scheme provides a more systematic and feasible solution than the conventional resonant push-pull DC/DC converter analysis methodology. To increase circuit efficiency, the main switches and the rectifier diodes can be operated under the zero-voltage and zero-current switching conditions, respectively. In order to achieve this objective, the parameters of the DC/DC converter need to be designed properly. The details of the analysis and design of this DC/DC converter’s components are described. A prototype was constructed with a 62–88 kHz variable switching frequency, a 12 VDC input voltage, a 380 VDC output voltage, and a rated output power of 150 W. The validity of this approach was confirmed by simulation and experimental results.

DC-to-DC Converters With Continuous Input and Output Power

This paper presents three topological classes of dc-to-dc converters, totaling nine converters (each class with three buck, boost, and buck-boost voltage transfer function topologies), which offer continuous input and output energy flow, applicable and mandatory for renewable energy source, maximum power point tracking and maximum source energy extraction. A current sourcing output caters for converter module output parallel connection. The first class of three topologies employs both series input and output inductance, while anomalously the other two classes of six related topologies employ only either series input (three topologies) or series output (three topologies) inductance. All nine converter topologies employ the same elements, while additional load shunting capacitance creates a voltage sourcing output. Converter time-domain simulations and experimental results for the converters support and extol the concepts and analysis presented.

Impact of Skin Effect, Resistive and Dielectric Losses on Current Estimation and Reliability of ULSI Interconnects

In this study, a series connection system of interconnects and gates is studied. In the system, we focus on skin effect, resistive and dielectric losses in previous level interconnects and the impact of their variations on the fast current estimation and the lifetime calculation of the post level interconnects. The changes in cross-section dimensions of interconnects are used to represent their differences in resistances, dielectric losses and skin effect in actual circuits or to represent the process of Electro Migration (EM). Through the analysis of the voltage transfer function of interconnects, the different roles of skin effect, resistive and dielectric losses in signal attenuation for interconnects of various cross-sections are pointed out. The study shows that the input voltage waveforms of the post level interconnects will change if the cross-section sizes of the previous level interconnects vary. By means of showing the changing tendencies of current and lifetime estimation results affected by the cross-section dimensions of the previous interconnects, we indicate that the fast current and reliability estimation results will not be accurate enough if these effects are not included.

Active Electrically Small Antenna Based on Superconducting Quantum Array

We introduce Superconductive Quantum Arrays (SQAs) and propose to use these structures as active Electrically Small Antennas (ESA). Several prototypes of the active ESA were fabricated using Nb process with critical current density 4.5 kA/cm2 and experimentally evaluated. The magnetic field to voltage transfer function linearity up to 70 dB was measured, and transfer factor dV/dB up to 6.5 mV/{\mu}T was observed for the ESA prototype containing 560 cells.

Energy-aware analysis of electrically long high speed I/O links

This paper presents a novel approach for an energy-aware analysis of electrically long high speed I/O links. ABCD-parameters are used to analyze the passive link model, which takes into account termination impedances at transmitter and receiver as well as the network parameters of the interconnect. Voltage transfer function and input impedance of the link model are used to carry out a combined evaluation of frequency dependent signal transmission and power consumption of the link. The combined analysis allows to carry out an optimization of the energy efficiency under the given constraints. It is applied to a realistic high speed backplane link, which is modeled using measured interconnect network parameters. Simulated interconnect network parameters are used to study the impact of link improvements on signal transmission and power consumption.