Multi-phase Switching Research Articles

Electrical tuning of phase-change antennas and metasurfaces.

The success of semiconductor electronics is built on the creation of compact, low-power switching elements that offer routing, logic and memory functions. The availability of nanoscale optical switches could have a similarly transformative impact on the development of dynamic and programmable metasurfaces, optical neural networks and quantum information processing. Phase-change materials are uniquely suited to enable their creation as they offer high-speed electrical switching between amorphous and crystalline states with notably different optical properties. Their high refractive index has already been harnessed to fashion them into compact optical antennas. Here, we take the next important step, by showing electrically-switchable phase-change antennas and metasurfaces that offer strong, reversible, non-volatile, multi-phase switching and spectral tuning of light scattering in the visible and near-infrared spectral ranges. Their successful implementation relies on a careful joint thermal and optical optimization of the antenna elements that comprise a silver strip that simultaneously serves as a plasmonic resonator and a miniature heating stage. Our metasurface affords electrical modulation of the reflectance by more than fourfold at 755 nm.

Automatic Current Balance for Multi-Phase Switching Converters with Ripple Control or Soft Switch

This paper proposes a new multi-phase switching converter with atuotomatic current barance technique. It is well-known that the multi-phase switching converter is suitable to handle large output current with small output voltage ripple for the buck converters which use the clock pulse. This paper investigates a multi-phase controlled method for the ripple-controlled converters and the soft switching converters, that use no clock pulse; for this reason, these converters are difficult to realize multi-phase converter configurations. There are some multi-phase hysteretic controlled converters; they utilize a main clock generator or an external sub-clock pulse, which has the master-slave synchronization method. But it is difficult to respond to a frequency change of the master converter. These multi-phase converters have not considered the imbalance among phase currents caused by variations of inductors and semiconductor switches in the power stage. For the commercialized multi-phase Voltage Regulating Modules (VRMs), the inductors and the semiconductor switches are selected to adjust the balance among the phase currents. However, there is no multi-phase soft switching converter.Then we have developed the multi-phase ripple-controlled converter and the multi-phase soft switching converter with the technique of detecting 180-degree from the variable operating frequency of the main converter. Moreover, in these converters, there appears the current imbalance because of the element variations among inductors and capacitors, if some cares are not taken there. Then we have developed the automatic correction for the current imbalance by modifying the width of the Constant On Time (COT) pulse or modifying the slope of the saw-tooth signal.

Essential Features/Issues of a Multi-Phase Switching Synchronous Buck Regulator

Essential Features/Issues of a Multi-Phase Switching Synchronous Buck Regulator

Modularity for Paralleling Different Rated Power Supplies Using Multi-Phase Switching Methods

This paper proposes a modularity for paralleling different rated power supplies without adding a circuit in the feedback loop by using direct and overlapped switching methods. Unlike an isolated output diode, the use of an isolated output switch composed of two Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) can reduce power dissipation. The control module includes switches and a micro-programmed controlled unit that realizes the modularity by using multi-phase switching methods. The proposed module was studied, and experiments of two rated power supplies (60 and 45 W) were conducted to verify the studied results.

Circuit Level Model of Miniature Circuit Breakers

We present a black-box model of miniature circuit breakers having a realistic physical background. In compliance with basic physics, engineering know-how and magneto-hydro-dynamics arc simulations, two sets of differential-algebraic equations are derived to model air plasma chemical dynamics and its interaction with breaker's physical environment (chamber shape, splitter plates, arc traveling). A numerically efficient and accurate electrical model at the breaker terminals is proposed. Its behavior is shown by comparing simulations with short-circuit experiments. Applications are at system level, including simulation of networks with several breakers, such as multiphase switching transients, selectivity, and coordination with fuses, other breakers and surge protection devices.

Inkless Writing and Self-Erasing Security Feature of (Z)-1,2-Diarylacrylonitrile-Based Materials: A Confidential Data Communication

Development of a novel organic luminescent material for inkless writing, and self-erasing application is a remarkable solution to reduce paper waste, recycling cost in the printing industry. These innovative materials also offer to reduce global warming due to the lower consumption of paper made from plants. To this endeavor, herein we report the design, synthesis and simple material fabrication of a donor-acceptor type (Z)-1,2-diarylacrylonitrile (1) compound, which in solid state displayed highly contrast and reversible vapochromism under the visible light as well as UV light. We found a unique multiphase luminescence switching from green (λmax = 535 nm) to yellow (λmax = 566 nm) and to orange-red (λ = 580, 640 nm) in solid state. This multiphase switching is induced through the gradual exclusion of entrapped DMSO molecules from the crystalline rod-like materials. Utilizing this purely organic material, we have demonstrated reversible inkless writing/printing on a cellulose strip by employing photothermal effect of sunlight in which sunlight acts as an "inkless pen". We were able to print complex designs utilizing this technique, which is invisible in ambient light and brighter in UV light. To our delight, the writing is self-erasable on keeping at sunlight for the prolonged period, upon keeping at ambient temperature, or instantly on warming. This remarkably smart function of our material offers cost-effective and environmentally benign technique for security data communication and confidential data printing.

Comparison of Phase-shifters for Multiphase Power Converters

Much interest has been shown in multiphase switching power converters. This is due to their advantages, such as a higher current capability, improved dynamic response, or reduced harmonics, which compensate for their increased component count. As a drawback, multiphase controllers become more complex than their one-phase counterparts. However, digital controllers help to solve the new problems, such as multiple driving signal generation, current sharing among phases, or phase shifting. This work focuses on the generation of multiple driving signals that are interleaved, i.e., phase shifted. Two alternative phase-shifters are proposed and compared. Both have been designed in a hardware description language, suitable for implementation in field programmable gate arrays or application-specific integrated circuits.

Analysis of the effect of periodic fluctuation of switching instants on the transfer characteristics of switched capacitor networks

A complete description of switched capacitor networks which include an arbitrary number of non-uniform input and output phases is presented on the basis of the generalized phase transfer matrix by extending a previously introduced state space approach. the input frequency harmonic (main harmonic) of the periodically time-varying system transfer function is obtained and the effect of periodic fluctuation of the switching instants on the transfer characteristics of the switched capacitor filters is analysed. This procedure also facilitates the evaluation of the effects of non-uniform multiphase switching. Application of the results to a switched capacitor filter shows that the frequency response is very sensitive to the fluctuation of switching instants.

Flux synthesizing linear induction motor with super multiphase switching

AbstractA novel concept of structure and control of linear induction motors (LIMs) called “Flux Synthesizing Linear Induction Motors (FSLIMs),” is proposed where each slot has a conductor carrying an electric current whose amplitude and phase angle are controlled with super multiphase switching devices. It is well known that an LIM has the merits of direct drive and simple structure. However, a conventional LIM has low power factor and energy efficiency. The end effect is one of the significant reasons for the bad characteristics. Strategies against the effect have been limited by conventional three‐phase winding.On the other hand, high‐speed power‐switching devices are available at a reasonable cost. A super multiphase drive enables more freedom for controls with the proposed structure of the FSLIM. Basic characteristics of a tubular test LIM with twelve slots have been measured and calculated to investigate an appropriate flux synthesis. As a result, an appropriate switching scheme which synthesizes sinusoidal distribution of the gap flux density, enables the end‐effects to be suppressed and, consequently, improves the energy efficiency. In addition, basic conditions for the field‐coordinated oriented control of a thrust force are satisfied by keeping the amplitude of the gap flux constant with the flux synthesis.

Flux Synthesizing Linear Induction Motor with Super Multi-Phase Switching.

Authors have proposed a novel concept of structure and control of linear induction motors (LIMs) named “Flux Synthesizing Linear Induction Motors (FSLIMs)”, where each slot has a conductor carrying an electric current whose amplitude and phase angle are controlled with super multi-phase switching devices. It is well-known that a LIM has the merits of direct drive and simple structure. A conventional one has, however, low power factor and energy efficiency; the end-effect is one of the significant reasons for the bad characteristics. Strategies against the effect have been limited by conventional three-phase windings. On the other hand, high-speed power switching devices are available with a reasonable cost. A super multi-phase drive enables more freedom for controls with the proposed structure of the FSLIM. Basic characteristics of a tubular test LIM with twelve slots have been measured and calculated to investigate an appropriate flux synthesis. As results, an appropriate switching scheme, which synthesizes sinusoidal distribution of the gap flux density, enables to suppress the end-effects, and to improve, consequently, the energy efficiency. In addition, basic conditions for the field-coordinateds oriented control of a thrust force are satisfied by keeping the amplitude of a gap flux constant with the flux synthesis.

A Cancellation Method for Simulating Multiphase Switching Operations

This paper presents a generalized mathematical model for simulating multiphase switching operations. The development of this model entails the extension of well-known cancellation techniques in such a manner as to obtain an automatic switching format that is compatible with an existing digital computer transient program. The validity of this model is demonstrated by the comparative results of previously conducted field tests and analog computer studies.