Multiport Structures Research Articles

Evaluation of cavitation phenomena in three-way globe valve through computational analysis and visualization test

A three-way valve has a multi-port structure with three openings, which allows control of the fluid direction. However, owing to the complicated trim shape of the internal flow, an irregular fluid flow occurs, which hinders precise fluid flow control. In severe cases, cavitation induces mechanical damage owing to abrupt changes in the fluid direction. In this study conducted a computational fluid dynamics (CFD) analysis was performed to estimate the localized cavitation around the bottom plug of the three-way valve. To quantify localized cavitation, the percentage of cavitation (POC) was derived using the vapor volume fraction (VVF). The POC, defined by the cavitation occurrence zone with VVF > 0.5 divided by the volume of the cavitation danger zone, was 34.90%. Cavitation at this POC level could cause mechanical damage; therefore, a size optimization was performed. The lengths of the optimized waist and tail regions of the bottom plug were obtained wherein the POC level decreased by 19.06%. In addition, experiments were conducted using a flow visualization test setup. The experimental results were quantified into the POC employing the image gradients method, and the results were in good agreement with the CFD analysis.

An MTPZC for the Integration of RESs using Analysis, Modeling, Control, and Implementation

This article presents a novel approach to enhance the efficiency, control, and power management capabilities of traditional Zeta Converters in renewable energy applications. The proposed particle swarm optimization (PSO)-modified three-port zeta converter (MTPZC) features a multiport structure with dedicated input ports for photovoltaic (PV) and battery sources, along with an output port. The integration of PSO optimization aims to optimize maximum power point tracking to enhance energy extraction. Extensive simulations and experimental validations showcase the MTPZC's superior performance in power extraction from both PV and Battery sources. This innovative design positions the converter as a promising solution for multiport energy conversion systems in renewable energy applications. The article contributes to the advancement of power electronics by offering improved reliability and efficiency. Simulation results, validated in MATLAB and compared with existing methods, demonstrate an impressive efficiency of 97.8%. The MTPZC outperforms existing approaches, indicating lower converter losses and highlighting its potential for practical implementation in diverse renewable energy systems.

High-Gain Multiport DC-DC Converter Topologies for Renewable Energy Applications: A Comprehensive Review

Renewable energy sources have emerged as favorable alternatives for meeting ever-increasing global energy demand. To harness the maximum efficiency from renewable sources, dc-dc converters play a crucial role. While the design of dc-dc converters varies depending on specific application, certain features such as multiport capability and high gain are generally desirable. Multiport structures offer advantages such as compactness and cost reduction, allowing for the efficient integration of various energy sources, storage units, and loads. On the other hand, high gain characteristics enable the step-up of output voltages from renewable energy sources to usable levels. In recent years, numerous converter topologies proposed to address these requirements and enhance overall system performance. This study aims to assist and provide guidance to researchers in the field by reviewing and comparing the most recent advancements in the design and implementation of multiport high-gain dc-dc converters for renewable energy applications. Through a comprehensive analysis of the existing literature, the primary objective of this study is to facilitate knowledge transfer, identify research gaps, and inspire future research endeavors in this domain. By synthesizing the knowledge gained from these studies, researchers can contribute to ongoing advancement of multiport converter technology in the context of renewable energy applications.

Firing Process Modeling of a Soft Recoil Gun Based on Interval Uncertainty Parameter Identification

PurposeThe soft recoil firing technology is an important way to reduce the recoil force of a gun. To further improve the effect of the recoil mechanism and provide a test prediction method for soft recoil firing, a new multi-port structure of the recoil mechanism with a central port and variable depth wall grooves is proposed to research the working characteristics of a soft recoil gun. MethodsTo describe the firing law of a soft recoil gun, this paper establishes its differential equations of firing motion, constructs the analytical model of each subsystem in the system, and acquires a relatively comprehensive way to describe the firing motion process for this soft recoil system. The flow distribution Bernoulli equation is established with CFD fluid simulation to improve the model accuracy. On this basis, the interval uncertainty theory and genetic algorithm are applied to establish the parameter identification model of the firing process. The typical parameters of the soft recoil gun are identified and obtained with the test data of the first round. ResultsThe similarity rate between the simulation and test data can reach up to 92.78%. Moreover, the corresponding simulation results match the test data under the second and third rounds. It is proved that the correct modeling and effective identification results provide theoretical guidance for the design of a soft recoil gun.

Low-Overhead RF Impedance Measurement Using Periodic Structures

Due to the need for higher reliability and performance from RF circuits, multi-port reflectometers are increasingly used as low-overhead impedance monitors. In this work, using periodic structures as multi-ports is proposed. Periodic structures impose a new constraint on the multi-port theory and simplify it significantly. This simplification leads to closed form solution for calibration and measurement procedures. The closed-form solution also shows that any arbitrary periodic structure will always have a unique solution for both procedures. Therefore, the proposed technique does not rely on frequency-dependent behavior of devices, such as directivity and phase shift to measure impedance. This fact leads to increased bandwidth and simplified design procedure. In addition, proposed multi-port structures can be calibrated by using fewer known loads than existing multi-port techniques. This fact, coupled with the closed-form solution, reduces computation overhead and test time. The theory and its robustness against non-idealities, such as part-to-part variation, are verified with Monte-Carlo simulations. A practical embodiment of the technique is demonstrated with EM simulations and hardware experiments. In this embodiment, the multi-port structure is embedded into an LC matching network. Hardware experiments show that the embedded multi-port structure can measure test loads with high accuracy from 1.5 GHz to 3.5 GHz, without degrading matching network performance.

Ultra-Wideband Six-Port Network Miniaturization—Matching

AbstractIn this paper, a new design approach for the six-port (SP) junction is introduced. The proposed design includes a generalized broadband matching and smooth miniaturization scheme and is extendable for any passive multiport structure. A multilayer technology and a microstrip to slot coupling operation are employed for the designed SP, which comprises power divider and three hybrid couplers. The conducted measurements of the constructed SP junctions validates the design approach. Optimal performance of the SP network in terms of miniaturization, bandwidth, and response accuracy were obtained for the 5G low band.

Theoretical Study and Systematic Design of Multiport Wire Antenna

This work presents a systematic study of multi-port wire antennas (MPWA) as a step toward reconfigurable radiation apertures, an essential component in modern wireless systems. We predict the surface current distribution (SCD) of the multi-port structure and derive a closed-form relation for the radiation pattern of the aperture as a function of its input port excitations. Based on this, we present a design procedure for optimal selection of port locations and their respective input excitations with a desired radiation pattern in mind. Finally, we develop a computationally efficient method to derive the impedance matrix of the multi-port aperture all without the need for full-wave simulation. As an example, we use this method to design a 15-port mm-wave antenna. We demonstrate that for a selected aperture size and port locations and only by adjusting the phases and amplitudes of excitation, we can reconfigure the MPWA to synthesize a desired beam at any frequency within the 20-40GHz range. There is good agreement between results predicted by this method compared to those from EM-based simulations, enabling an efficient and scalable approach for designing multi-port radiators.

A Novel Surrogate-Based Approach to Yield Estimation and Optimization of Microwave Structures Using Combined Quadratic Mappings and Matrix Transfer Functions

Yield estimation and yield-driven design optimization play important roles in microwave design. Existing surrogate-based yield estimation/optimization methods need to develop separate surrogate models or a large surrogate model with high complexity to deal with multiport problems, which is computationally inefficient. This article proposes a novel surrogate-based method to expedite yield estimation/optimization of multiport microwave structures using combined quadratic mappings and matrix-valued transfer functions. For multiport structures, the responses of different transfer functions corresponding to different pairs of input–output ports are computed with separate residues, while the responses of transfer functions for all pairs of input–output ports are computed with a common set of poles. Taking advantage of this, we propose to formulate a set of quadratic functions to map the relationship between the separate residues and statistical/geometrical parameters while employing merely one quadratic function to map the relationship between the common poles and statistical/geometrical parameters. The resultant mappings together with the matrix-format transfer function form an efficient surrogate to expedite the yield estimation and optimization processes for microwave structures. Compared with existing surrogate-based methods, the proposed method can achieve similar yield estimation accuracy in a shorter time due to fewer electromagnetic (EM) simulations. Three microwave structures are used to demonstrate the advantages of the proposed method. Based on accurate yield estimations, we further perform yield-driven design optimization incorporating the proposed surrogate for all the three examples.

The Pumping Performance of a Multiport Hybrid Molecular Pump and Its Effect on the Inspection Performance of a Helium Mass Spectrometer Leak Detector

The multiport hybrid molecular pump is a new type of molecular pump that was specifically designed for use in helium mass spectrometer leak detectors. This pump enables the instrument to detect both downstream and counter-current leaks. Access to different extraction ports can fulfill various leak detection requirements, which broadens the application range of these detectors and improves their detection efficiency. This paper establishes a model for the calculation of the parameters of a helium mass spectrometer leak detector under fine inspection conditions, studies the influence of different turbine blade parameters and fine inspection port positions on pumping performance and leak detection, discusses a method to determine turbine blade parameters and fine inspection port positions under fine inspection conditions, and provides a theoretical basis for the development of helium mass spectrometer leak detection technology and the optimization of multiport hybrid molecular pump structures. The results show that reducing the blade inclination and increasing the number and height of blades can improve the detection sensitivity. Provided that the hybrid molecular pump has good pumping capacity, the helium mass spectrometer leak detector can obtain high detection sensitivity when the single blade inclination angle is 25°, the number of turbine blades is 25 to 30, the blade height is 3 mm, and the blade thickness is 0.6 mm to 0.8 mm. To determine the position of the inspection port, it is necessary to consider the actual requirements of the leak detector, such as the working pressure of the inspected parts, the leakage rate and the minimum detectable leakage rate. When the inspection port is between the 7th- and 8th-stage blade rows, optimum working pressure of the mass spectrometer chamber for better leak detection performance and large pressure detection range are guaranteed.

Grid-Forming Operation of Energy-Router Based on Model Predictive Control with Improved Dynamic Performance

The focus of this study is on the grid-forming operation of the Energy Router (ER) based on Model Predictive Control (MPC). ER is regarded as a key component of microgrids. It is a converter that interfaces the microgrid (s) with the utility grid. The ER has a multiport structure and bidirectional energy flow control. The ER concept can be implemented in Nearly Zero-Energy Buildings (NZEB) to provide flexible energy control. A concept is proposed where the ER works as a single grid-forming converter. The challenge is to keep the predefined reference voltage and frequency inside the NZEB in all possible modes, including the idle operation mode, current sources, and nonlinear load control. To gain stability and output voltage quality, the MPC is proposed. The design of the modified MPC algorithm with improved dynamics performance is explained. PLECS software is utilized to verify the proposed algorithm. The results demonstrate the suitable performance of the proposed control method in terms of total harmonic distortion of the output voltage. The influence of weighting coefficiencies is evaluated, showing the higher impact of the capacitor filter voltage on lowering the total harmonics distortion of the output voltage. Finally, the capability of the control system toward step change in the reference value is evaluated.

A Convolution Neural Network Implemented by Three 3 × 3 Photonic Integrated Reconfigurable Linear Processors

The convolution neural network (CNN) is a classical neural network with advantages in image processing. The use of multiport optical interferometric linear structures in neural networks has recently attracted a great deal of attention. Here, we use three 3 × 3 reconfigurable optical processors, based on Mach-Zehnder interferometers (MZIs), to implement a two-layer CNN. To circumvent the random phase errors originating from the fabrication process, MZIs are calibrated before the classification experiment. The MNIST datasets and Fashion-MNIST datasets are used to verify the classification accuracy. The optical processor achieves 86.9% accuracy on the MNIST datasets and 79.3% accuracy on the Fashion-MNIST datasets. Experiments show that we can improve the classification accuracy by reducing phase errors of MZIs and photodetector (PD) noises. In the future, our work provides a way to embed the optical processor in CNN to compute matrix multiplication.

A Modified Phase Shift Control of the Dual Active Bridge-Based Modular Power Electronic Transformer to Minimize the LVdc Side Voltage Ripples Under Unbalanced Load Conditions

Power Electronic Transformers (PETs) are considered as an emerging solution for power conversion due to their benefits over the low frequency power transformers (LFPTs) such as lower size, multi-port structure and different control functionalities. However, unbalanced load conditions may limit the reduction of size due to using bulky capacitors to absorb the resulting 2^nd harmonic voltage oscillations. This paper aims to provide a solution to this problem in the Dual Active Bridge (DAB)-based Modular Multilevel Converter Power Electronic Transformers (MMC-PET). In this study, a modified phase shift control strategy for the DAB isolation stage is presented. In this strategy, the duty cycle is allowed to change sinusoidally around the operating point. This consequently transfers the power oscillations to the HV side where their effect is less significant. The system is simulated using Matlab-Simulink under different unbalanced load conditions. Besides, the theoretical analysis and the simulation results are experimentally validated using a laboratory prototype. According to the obtained results, the proposed controller succeeded to reduce the voltage ripples from 7.5% to 0.2% and this helps in replacing large Aluminum electrolytic capacitors with low size film capacitors and consequently reducing the system overall size and volume which is a great benefit.

Effect of probing signal on the output signals spectrum of nonlinear spin waves in a cross based on waveguides of iron-yttrium garnet film

Subject. A change in the spectrum of spin waves (SW) in a magnetic cross is investigated when two signals pass through it: a pump signal and a probe signal. Objective. Detection of specific features in formation of the spectra of the output signals of SW in the multiport structure based on a yttrium iron garnet (YIG) film in the case of excitation of two magnetostatic surface waves (MSSW) simultaneously by the input antenna, where the first, with power higher than the first-order parametric instability threshold is the pump, and the second one is a probe. Methods. The experiments were performed for a cross structure from YIG film in the form of two orthogonal waveguides with the SW wire antennas placed at the ends of the waveguides, where one of the antennas on the transversely magnetized waveguide was considered as the input. Result. It was found that by choosing the probing signal frequency, one can significantly (by 10 dB) change the relative signal levels for the satellite waves at the output antennas, which are secondary MSSWs with some new frequencies and appear in the output signals spectrum as a result of the thresholdless processes of merging of parametric spin waves generated by MSSW pumping. In this case the secondary MSSWs frequencies can differ at the output antennas located on orthogonal waveguides. Discussion. The discovered effect is associated with the nonreciprocal nature of propagation of both the pumping wave and the waves generated at parametric instability condition in the structure.

A Single-Stage Multi-Port Buck-Boost Inverter

This article presents a novel inverter topology with a multi-port structure, which aims to connect two independent dc sources to a three-phase load by using single-stage power conversion. The proposed inverter has been developed to be used in hybrid renewable energy applications such as photovoltaic (PV), fuel cell (FC), and battery energy storage systems. Compared to the conventional hybrid dual-source inverters that use a multi-input dc-dc converter to provide a dc-link voltage at the input of the inverter stage, the proposed dual-source inverter uses an integrated dc-ac power conversion stage. The conventional topologies use bulky electrolytic capacitors at the input of the inverter stage, which leads to lower voltage gain and reliability due to high parasitic ESR/ESL and short lifetime of these capacitors. Moreover, compared to existing multi-port voltage source inverters, the proposed topology uses lower semiconductors, cost, and weight and has higher voltage gain. Besides, the proposed topology draws continuous current from both input ports and there is magnetic isolation between the input sources, which makes it suitable for hybrid PV and FC systems. In the proposed topology, two interlocked impedance networks are used, which are connected by coupled inductors, diodes, and capacitors. The proposed topology uses a simple switching method that is implemented with low-cost microcontrollers. The analysis and performance of the proposed inverter are verified through both computer simulations and experimental results of a 600 W-50 Hz laboratory prototype using the simple boost-SPWM modulation method.

Comprehensively Efficient Analysis of Nonlinear Wire Scatterers Considering Lossy Ground and Multi-tone Excitations

In this paper based on intelligent water drops algorithm (IWD), comprehensively nonlinear analysis of nonlinearly loaded wire scatterers are carried out. The analyses involve two stages. First, the problem is modeled as a nonlinear multi-port equivalent circuit and it is then reformulated into an optimization problem which is solved by the IWD. The simulation results are compared with harmonic balance (HB), arithmetic operator method (AOM), approximate methods and experiment. Analysis of the problem under strongly nonlinear loads, presence of lossy ground, multi-port structures, and multi-ton excitations are included to cover all the complex aspects. In one hand, the proposed modeling approach is in excellent agreement with other conventional techniques. On the other hand, the run time is considerably reduced.

Voltage Source Operation of the Energy-Router Based on Model Predictive Control

The energy router (ER) is regarded as a key component of microgrids. It is a converter that interfaces the microgrid(s) with the utility grid. The energy router has a multiport structure and bidirectional energy flow control. The energy router concept can be implemented in nearly zero energy buildings (NZEB) to provide flexible energy management. We propose a concept where ER is working as a single grid-forming converter with a predefined voltage reference. The biggest challenge is to maintain regulated voltage and frequency inside the NZEB in the idle operation mode, where traditional regulators, e.g., proportional-resonant (PR), proportional-integral-derivative (PID), will not meet the control design requirements and could have unstable behavior. To gain the stability of the system, we propose model predictive control (MPC). The design of the MPC algorithm is explained. A simulation software for power electronics (PLECS) is used to simulate the proposed algorithm. Finally, the simulation results are verified on an experimental prototype.

Fast S-Parameter TAN Model of n-Port Lumped Structures

This paper deals with the fast S-parameter modeling of multi-port lumped structures. The developed model is based on unfamiliar formalism using the tensorial analysis of networks (TAN). The modeling methodology is described with the general abstract topology and different application cases. The methodology consists, first, in elaborating the equivalent graph topology of the considered problem. Then, it is followed by the TAN mathematical abstraction, including, successively, the branch and mesh space analyses. The problem metric can be written with the tensorial Ohm's law expressed in function of the covariant voltage, contravariant current, and the twice covariant impedance in the mesh spaces. The equivalent Z-matrix of the considered multi-port structure is established from an innovative reduction method of the mesh impedance. The S-parameter model is extracted from the Z-to-S matrix transform. The effectiveness of the established fast S-parameter TAN modeling is validated with three cases of proof of concept constituted by TT-cell, the TTT-cell two-port circuit, and four-port structure inspired from the 3D coaxial shielded cable. As expected, an excellent agreement between the S-parameters calculated from the TAN model and simulated from the commercial tools from DC to some hundred's megahertz is obtained. In the future, the developed model is outstandingly beneficial for fast and accurate applications notably for the conduced shielded cable electromagnetic compatibility analysis.

A ZERO-Power Sensor Using Multi-Port Direct-Conversion Sensing

This paper presents a class of zero-power microwave sensor architecture based on the direct-conversion principle to eliminate data processing at the Internet of Things sensors and provide unpowered nodes. A base station (BS) transmits a single tone signal at the frequency of $f_{0}$ /2 toward the sensing node using an antenna. At the node, an antenna receives the signal, and a passive frequency doubler makes the frequency twice. Then, a multi-port structure directly modulates the sensing data at the frequency of $f_{0}$ and sent back to the BS by an antenna. The multi-port circuit has one input, one output, and some loading ports. In this paper, a six-port modulator and four similar sensitive capacitive resonators are used. A pair of resonators senses the variation of a sample under test (SUT) while the other pair is covered by a reference or known material. At the BS, any quadrature receiver can be used to demodulate sensing data. Here, a similar six-port structure is used to extract data and find the SUT variations. An example one-node system is implemented at $f_{0} = 2.45$ GHz and evaluated by some standard SUTs. To support multiple nodes, a smart directional antenna is necessary at the BS, which also improves the overall efficiency of the system.

A rigorous matrix procedure for calculating the line constants and wave parameters of uniform MTLs using SMT/PMU

Summary Real-time monitoring of the operation state of wide-area transmission line links has become possible with the help of phasor meter units. Synchronized information acquired by phasor meter units needs to be adequately processed to permit the accurate estimation of the line constants of the transmission link. In this paper, a novel general rigorous compact procedure for correctly processing the measured voltage and current phasors of uniform multiconductor transmission line systems is proposed. The procedure based on the ABCD matrix and on modal analysis techniques applies to transposed or untransposed multiconductor transmission lines, with arbitrary geometry, number of conductors, and length. The proposed algorithm, adequate for multiport structures, avoids the approximations usually required by ordinary methods mostly focused on lumped parameters and on 2-port approaches. The proposed matrix procedure is illustrated and validated using simulation results.

Design and construction of multi-port solid state structure for the Rhodotron accelerator

RF generation and method used for coupling power to the acceleration cavity are important issues in the RF accelerators. In this study, a high power vacuum tube was replaced with several medium power solid state amplifiers coupled through a multi-port structure in the Rhodotron-TT200 accelerator. To this end, a multi-port structure was implemented on a small aluminum model cavity for 1 to 9 ports and all main parameters affecting return loss, quality factor, coupling coefficient and RF power were investigated by calculation, simulation and experimental tests. Then, three 20 kW solid state amplifiers were designed and constructed. The outputs of these amplifiers were coupled to the Rhodotron acceleration cavity by three input ports based on the results obtained from the model cavity for generation of 5 MeV electron beam. In this method, several smaller amplifiers were used instead of a single high power amplifier. As such, acceleration cavity plays the role of power combiner in addition to its primary role and there is no need to a high power combiner. The results showed that the number of ports, port positions, angle between ports and phase of input signals, significantly affect the acceleration electrical field in the cavity. Also, experimental tests revealed that three constructed RF power supplies are enough for the generation of 5 MeV electron beam in the Rhodotron accelerator. Considering the advantages of the solid state amplifiers, application of multi-port structure and solid state amplifiers could be expanded in the industrial electron accelerators.