Variable Resistive Load Research Articles

Adaptive Sliding Mode Observer Design for Switching Power Converters

In this paper, a nonlinear adaptive super-twisting(STW) sliding mode observer is proposed for a three-cell converter. The aim is to reduce the number of sensors in such system by estimating all the capacitor voltages only with the measurement of load current. The gains of super-twisting algorithm are allowed to adapt to ensure the establishment of the sliding mode in the presence of uncertainties with unknown bounds. The hybrid behavior of the converter is also taken into account when designing the observer. The recent concept of Z (T N ) – observability is applied to analysis the observability of the switching system in order to obtain the estimation of the voltage across each capacitor. Simulation results show the efficiency and robustness of the proposed observer with respect to load resistance variation.

Transferred Power Control for ICPT Pick-ups Utilizing Dynamically Switched Inductor*

This paper presents a method to maintain the output voltage constant under variable load resistance for ICPT power pick-ups. A phase-controlled variable inductor is dynamically swithched to detune/tune the resosant circuit according to the load resistance of the power pickup. Variations of the open circuit voltage and degraded resonance capacitor caused by high temperature are compensated by controlling the conduction delay angle of the phase-controlled inductor with deliberately designed resonant circuit parameters. The effect of equivalent inductance of the variable inductor on the power flow is analyzed theoretically with fundamental component ac analysis. Simulation results show that with the proposed method, a significant improvement is achieved in regulating transferred power of variable ratings.

RFID Passive Gas Sensor Integrating Carbon Nanotubes

Carbon nanotube (CNT) composites are sensitive to the presence of gases due to their high surface-to-volume ratio and hollow structure that are well suited for gas molecule absorption and storage. Such sensing capability is here integrated with UHF RF identification (RFID) technology to achieve passive and low-cost sensors, remotely readable. CNT film (buckypaper) is used as a localized variable resistive load integrated into a tag antenna, which becomes able to transduce the presence of hazardous gas in the environment, ammonia in this case, into a change of its electromagnetic features. The dynamic range and the hysteresis of the radio sensor are investigated by simulations, equivalent circuits, and articulated experimentations within a true RFID link, providing the proof of concept and some guidelines for tag design.

Design of 1-Kb eFuse OTP Memory IP with Reliability Considered

In this paper, we design a 1-kb OTP (Onetime programmable) memory IP in consideration of BCD process based EM (Electro-migration) and resistance variations of eFuse. We propose a method of precharging BL to VSS before activation of RWL (Read word-line) and an optimized design of read NMOS transistor to reduce read current through a non-programmed cell. Also, we propose a sensing margin test circuit with a variable pull-up load out of consideration for resistance variations of programmed eFuse. Peak current through the nonprogrammed eFuse is reduced from 728 ㎂ to 61 ㎂ when a simulation is done in the read mode. Furthermore, BL (Bit-line) sensing is possible even if sensed resistance of eFuse has fallen by about 9 ㏀ in a wafer read test through a variable pull-up load resistance of BL S/A (Sense amplifier).

A Stand-Alone Induction Generator with Improved Stator Flux Oriented Control

A Stand-Alone Induction Generator with Improved Stator Flux Oriented ControlThis paper presents an improved stator flux oriented (SFO) control system for a stand-alone induction generator. The induction generator supplies a variable resistive dc load. In order to provide an essentially constant terminal voltage, the product of the rotor speed and the stator flux reference should remain constant. However, in this case the control system is not able to function properly at different loads and dc-link voltages. In this paper, we introduce a new algorithm in which this product is constant at certain dc-load and dc-link voltage references. The dependence of the stator flux reference on the dc load and dc voltage reference is mapped using an artificial neural network (ANN). We also present an analysis of the efficiency of the SFO control system, as well as its performance during transients, over a wide range of both dc-link voltage references and loads. The validity of the proposed approach is verified by realistic simulation in a Matlab-Simulink environment.

Controller Design for Small Wind Generator with ADRC

Abstract The small wind generator is generally composed with permanent magnetism synchronic generator (PMSM) and other components, and the small wind generator is mainly employed to the single customer, hence it is important to keep the stability and the max power obtaining. The controller of it is only designed to adjust the generator and the current converter disregarding of the others. The controller for this purpose is presented in the paper and control theory is auto disturbance rejection controller (ARDC) which is a new control theory that doesn’t need the exact object model. The variation of load resistance is observed and estimated by an extended state observer, which is the core of the ADRC. So the nonlinear parts of the wind turbine can be considered as the disturbance which is estimated by an additional state. The Matlab simulink software and labsystem have been carried out and the results confirm that thedesigned controller with ADRC is satisfied.

Application of a Robust Fuzzy Sliding Mode Controller Synthesis on a Buck-Boost DC-DC Converter Power Supply for an Electric Vehicle Propulsion System

The development of electric vehicle power electronics system control, composed of DC-AC inverters and DC-DC converters, attract much research interest in the modern industry. A DC-AC inverter supplies the high-power motor torques of the propulsion system and utility loads of electric vehicles, whereas a DC-DC converter supplies the conventional low-power and low-voltage loads. However, the need for high-power bidirectional DC-DC converters in future electric vehicles has led to the development of many new topologies of DC-DC converters. The nonlinear control of power converters is an active research area in the field of power electronics. This paper focuses on the use of the fuzzy sliding mode strategy as a control strategy for buck-boost DC-DC converter power supplies in electric vehicles. The proposed fuzzy controller specifies changes in control signals based on the surface and knowledge on surface changes to satisfy the sliding mode stability and attraction conditions. The performance of the proposed fuzzy sliding controller is compared to that of the classical sliding mode controller. The satisfactory simulation results show the efficiency of the proposed control law, which reduces the chattering phenomenon. Moreover, the obtained results prove the robustness of the proposed control law against variations in load resistance and input voltage in the studied converter.

Modeling and Design Methodology of High-Efficiency Class-F and Class-${\hbox{F}}^{{\hbox{-}1}}$ Power Amplifiers

In this paper, efficiency-limiting physical constraint effects imposed on the knee voltage, along with a variation of the optimum load resistance, are investigated for highly efficient Class-F and Class- amplifiers. First, for an accurate analysis and comparison, new current waveform models are identified, and a realistic approach incorporated using a nonzero knee voltage and voltage-dependent nonlinear capacitance is employed to derive the voltage waveforms of the amplifiers. An analysis is performed to show the efficiency, output power, power gain, and output power compression points for both modes. Using this knowledge, along with a complete performance comparison, we provide a direction for optimizing the amplifier design. The analytic results are further verified based on the measured results of 3.54-GHz Class-F and Class- amplifiers using a commercial 60-W peak-to-envelope power gallium-nitride device. The experimental results show that Class-F and Class- amplifiers operate at drain efficiencies of 69.9% and 69.4% at saturated output powers of 47.4 and 47.2 dBm, respectively. These remarkably similar performances have excellent agreement with the predicted analysis at our operational frequency.

Characterization of a Common-Source Amplifier Using Ferroelectric Transistors

This paper presents empirical data that was collected through experiments using a FeFET in the established common-source amplifier circuit. The unique behavior of the FeFET lends itself to interesting and useful operation in this widely used common-source amplifier. The paper examines the effect of using a ferroelectric transistor for the amplifier. It also examines the effects of varying load resistance, biasing, and input voltages on the output signal and gives several examples of the output of the amplifier for a given input. The difference between a common-source amplifier using a ferroelectric transistor and that using a MOSFET is addressed.

Dynamic characteristics of organic bulk-heterojunction solar cells

Transient characteristics of organic bulk-heterojunction solar cells have been studied using pulsed laser probing. An analysis of the photoresponse waveforms of a typical solar cell measured by varying load resistance within broad range at different values of the bias voltage provided detailed information on the photocell parameters that characterize electron-transport properties of active layers. It is established that the charge carrier mobility is sufficient to ensure high values of the fill factor (∼0.6) in the obtained photocells. On approaching the no-load voltage, the differential capacitance of the photocell exhibits a sixfold increase as compared to the geometric capacitance. A possible mechanism of recombination losses in the active medium is proposed.

Micro power generation of PMN‐PZT triple morph cantilever for electric harvesting devices

AbstractPiezoelectric cantilever was manufactured using the PMN‐PZT thick film for electric harvesting device. In order to find the better properties, the piezoelectric cantilever was manufactured by two forms (bi‐morph and triple‐morph). The generation characteristics were investigated according to the variations of frequency, load resistance and mass weight. The piezoelectric cantilever output voltage increased according to the increase of load resistance and the output power quality was also investigated by changing the load resistance, mass weight and frequency. The bi‐morph piezoelectric cantilever output power which resulted from the conditions of 33 kΩ, 0.25 g, 197 Hz was 230 μW at 2.75VRMS. And then, Average micro power from triple‐morph piezoelectric cantilever was 432 μW, 6.57 VRMS at 154 Hz. This paper presented the possibility of electric harvesting devices with using PMN‐PZT triple‐morph cantilever for remote control and sensor node. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Chip‐implementation of a self‐tuning nonlinear function control for DC‐DC converters

PurposeThe DC‐DC converters which convert one level of electrical voltage to the desired level are widely used in many electrical peripherals. During the past two decade, many different control laws have been developed. The proportional‐integral (PI) control and sliding‐mode control have been carried out for the DC‐DC converters since they are simple to implement and easy to design. However, its performance using PI control and sliding‐mode control is obviously quite limited. The purpose of this paper is to a self‐tuning nonlinear function control (STNFC) propose for the DC‐DC converters. The adaptation laws of the proposed STNFC system are derived in the sense of Lyapunov function, thus not only the controller parameters can be online tuned itself, but also the system's stability can be guaranteed.Design/methodology/approachIn general, the accurate mathematical models of the DC‐DC converters are difficult to derive. This paper proposes a model‐free STNFC design method. Since the proposed STNFC uses a simple fuzzy system with three fuzzy rules base to implement the control law, the computational loading of the fuzzy inference mechanism is slight. So the proposed STNFC system is suitable for the real‐time practical applications. The controller parameters of the proposed STNFC system can online tune in the Lyapunov sense, thus the stability of closed‐loop system can be guaranteed.FindingsThe proposed STNFC system is applied to a DC‐DC converter based on a field‐programmable gate array chip. The experimental results are provided to demonstrate the proposed STNFC system can cope with the input voltage and load resistance variations to ensure the stability while providing fast transient response.Originality/valueThe proposed STNFC approach is interesting for the design of an intelligent control scheme. The main contributions of this paper are: the successful development of STNFC system without heavy computational loading. The parameter‐learning algorithm is design based on the Lyapunov stability theorem to guarantee the system stability; the successful applications of the STNFC system to control the forward DC‐DC converter. And, the proposed STNFC methodology can be easily extended to other DC‐DC converters.

Micro Power Generation of PMN-PZT Triple Morph Cantilever for Electric Harvesting Devices

Piezoelectric cantilever was manufactured using the PMN-PZT thick film for electric harvesting device. In order to find the better properties, the piezoelectric cantilever was manufactured by two forms (bi-morph and triple-morph). The generation characteristics were investigated according to the variations of frequency, load resistance and mass weight. The piezoelectric cantilever output voltage increased according to the increase of load resistance and the output power quality was also investigated by changing the load resistance, mass weight and frequency. The bi-morph piezoelectric cantilever output power which resulted from the conditions of 33 kΩ, 0.25 g, 197 Hz was 230 μW at 2.75VRMS. And then, Average micro power from triple-morph piezoelectric cantilever was 432 μW, 6.57 VRMS at 154 Hz. This paper presented the possibility of electric harvesting devices with using PMN-PZT triple-morph cantilever for remote control and sensor node. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

ELECTRICAL PROPERTIES OF PIEZOELECTRIC TRANSFORMER USING PSN-PMN-PZT CERAMICS

ABSTRACT In this study, Pb(Sb1/2Nb1/2)O3-Pb(Mn1/3Nb2/3) O3-Pb(Zr0.49Ti0.51)O3 (abbreviated as PSN-PMN-PZT) composition ceramics was sintered at 1230∼1270°C for developing the composition for piezoelectric transformer. At the ceramic composition sintered at 1250°C, Density, electromechanical coupling factor (kp) and mechanical quality factor (Qm) showed the excellent values of 7.78[g/cm3], 0.59 and 1931, respectively, suitable for piezoelectric transformer application. The single layer Rosen-type piezoelectric transformers were also sintered at the sintering temperature of 1250°C and manufactured with the size of 48 × 10 × 2 mm3, respectively, using the composition ceramics. And then, their electrical properties were investigated according to the variations of frequency and load resistance. At the load resistance of 150 kΩ, the voltage step-up ratio of the transformers showed the maximum values at the vicinity of 68.4KHz. And also, at that load resistance, piezoelectric transformers showed the temperature rises of about 6°C at the output power of 5W. At transformer with high effective electromechanical coupling factor(keff) and high piezoelectric constant(d33), lower temperature increase was relatively appeared. And also, the piezoelectric transformer was reviewed for the voltage down of igniter type energy harvesting piezoelectric device.

Dynamical analysis of a novel zero‐voltage‐switching‐PWM DC‐DC half‐bridge converter

In this work, based on the duty‐cycle‐shifted‐PWM half‐bridge converter, a zero‐voltage‐switching‐PWM (ZVS‐PWM) half‐bridge converter is proposed. Both main switches of the proposed converter achieve zero‐voltage‐switching and the converter uses constant‐frequency operation. The small‐signal mathematical model for the ZVS‐PWM half‐bridge converter is derived. Notably, it is verified that the dynamical behavior of the ZVS‐PWM half‐bridge converter is better than that of the conventional PWM half‐bridge converter from a system point of view. The accuracy of theoretical results is verified by simulation and experimental results. A classical controller is then designed to achieve fast output voltage regulation despite variations in line voltage and load resistance.

Study of Multilevel Programming in Programmable Metallization Cell (PMC) Memory

Programmable metallization cell (PMC) memory, also known as conductive bridging RAM (CBRAM), is a resistive-switching memory based on non-volatile formation and dissolution of a conductive filament (CF) in a solid electrolyte. Although ease of fabrication, promising performance and multilevel (ML) capability make the PMC a possible candidate for post-flash non-volatile memories, further physical understanding is required to better assess its true potential. In this work, we investigate the kinetics involved in the programming operation (i.e., transition from the high resistance to the low resistance state), which occurs by voltage-driven ion migration and electrochemical deposition, and results in CF formation and growth. The main kinetic parameters controlling the programming operation are extracted from our electrical data. Also, CF growth and corresponding resistance decrease is shown to be controllable with reasonable accuracy in pulse mode by employing a variable load resistance which can dynamically control the programming kinetics. A semi-analytical physical model is shown to account for experimental data and allows for the engineering of fast and reliable ML programming in one transistor-one resistor (1T-1R) devices.

Demonstration of a wireless, self-powered, electroacoustic liner system

This paper demonstrates the system operation of a self-powered active liner for the suppression of aircraft engine noise. The fundamental element of the active liner system is an electromechanical Helmholtz resonator (EMHR), which consists of a Helmholtz resonator with one of its rigid walls replaced with a circular piezoceramic composite plate. For this system demonstration, two EMHR elements are used, one for acoustic impedance tuning and one for energy harvesting. The EMHR used for acoustic impedance tuning is shunted with a variable resistive load, while the EMHR used for energy harvesting is shunted to a flyback power converter and storage element. The desired acoustic impedance conditions are determined externally, and wirelessly transmitted to the liner system. The power for the receiver and the impedance tuning circuitry in the liner are supplied by the harvested energy. Tuning of the active liner is demonstrated at three different sound pressure levels (148, 151, and 153 dB) in order to show the robustness of the energy harvesting and storage system. An acoustic tuning range of approximately 200 Hz is demonstrated for each of the three available power levels.

Self-regulating fuzzy control for forward DC–DC converters using an 8-bit microcontroller

A self-regulating fuzzy control (SRFC) design method is proposed; this control system uses a gradient rule modification method to regulate the fuzzy rules. Moreover, to reduce the number of fuzzy rules and to strengthen the robustness of SRFC, a self-regulating fuzzy sliding-mode control (SRFSMC) design method is also developed. Both the SRFC and SRFSMC systems contain two sets of fuzzy inference logic, one being the control regulator and the other the rule modifier. The proposed SRFC and SRFSMC systems can automatically regulate the fuzzy rules to achieve satisfactory performance and make the computation easy and, hence, they are suitable for real-time control. Finally, the proposed SRFC and SRFSMC systems are applied to control a forward DC-DC converter to illustrate their effectiveness. A microcontroller-based experimental system is implemented. Experimental results show that the proposed SRFC and SRFSMC systems are robust with regard to different input voltages and load resistance variations for the forward DC-DC converter.

Characteristics analysis of a high speed permanent magnet synchronous generator using the transfer relations theorem and equivalent circuit method

This paper presents analytical methods to predict the magnetic field distribution, electrical parameters, and output characteristics of a high speed synchronous generator equipped with surface-mounted permanent magnet. In order to analyze the magnetic field distribution and to estimate the electrical parameters, electromagnetic transfer relation (TR) theorem is employed. Moreover, output characteristics for variable resistive load and the operating speed are also obtained by solving the permanent magnet machine’s equivalent circuit equation. The analytical results are validated extensively by nonlinear finite element analysis and experimental results.

人工心臓用経皮伝送システムにおける電力伝送範囲拡大に関する検討

Transcutaneous Energy Transmission System (TETS) has an advantage to send power inside the body without penetrating to the skin by a wire. It does not only prevent the patients from infection-associated syndromes but also it aims at improvement of their's Quality Of Life (QOL). However, TETS is weak a magnetic coupling, and becomes a problem of the coil heating from the power loss. Moreover, TETS has a difficulty that it has to operate under an unstable coupling factor and varying load resistance. In this paper, we examined the method of obtaining a stable output voltage for TETS system according to kinds of the artificial heart.