Phase Balance Research Articles

Modelling of the Anisothermal Phase Transformation of Austenite by Electromagnetic Sensor

The characterization of steel microstructures is an important tool for metallurgists as mechanical properties are controlled by microstructural parameters such as grain size, phase balance and precipitates. This paper describes a model of the phase transformation of tool steel CSN 41 9436. Each of the experimental data was observed by electromagnetic sensor. The mathematic model was developed for an optimizing of tool steel heat treatment. The model was developed from one experiment and next experiments were for an evaluation of the model. A model can be satisfactory used for graphical form of the austenite phase transformation.

Closed-Form Design of Gysel Power Divider With Only One Isolation Resistor

An innovative design of low profile in-phase Gysel power divider (PD) by introducing efficient modifications is presented. The conventional Gysel uses a half-wave line and two isolation resistors as a Π network. The proposed modification converts it to a T network with only one isolation resistor and two quarter-wave lines that can reduce the design complexity, occupied area and fabrication cost. To obtain the accurate values of the line impedance and isolation resistance, closed-form equations based on a new viewpoint are derived. Two prototypes with narrow and broadband characteristics are realized at 3 GHz. The PDs have good magnitude and phase balances and better harmonic performance, compared to the conventional one.

Voltage and frequency controllers for standalone wind energy conversion systems

This study presents the design, development and comprehensive analysis of voltage and frequency controllers (VFCs) for standalone wind energy conversion systems (SWECSs). An isolated asynchronous generator, a synchronous generator (SG) and a permanent magnet SG are used with these SWECSs. These VFCs are developed with three-phase generators driven through a wind turbine to feed three-phase and single-phase loads. A battery energy storage system is used invariably with each system configuration to facilitate load leveling under change in wind speeds and consumer loads. The performance of VFCs are demonstrated to validate its operation as a load leveler, load balancer, phase balancer, neutral current compensator and an active filter along with a VFC.

A Hybrid SIW and GCPW Guided-Wave Structure Coupler

Since substrate integrated waveguide (SIW) is not directly compatible with active circuits, additional transitions to planar transmission lines are indispensable. In this letter, a novel hybrid SIW-CPW structure coupler applying an antenna feeding network is presented. SIW is used as the radiating portion while coplanar waveguide (CPW) is the input matching portion that is connected directly to the active circuits. Without any transition structure, the whole system can be more compact. In addition, this hybrid coupler has a relative bandwidth of over 30% with the broadband amplitude and phase balance characteristic of CPW.

Using Phase Swapping to Solve Load Phase Balancing by ADSCHNN in LV Distribution Network

There are a large amount of advantages to make efficient load phase balancing, such as loss minimization, energy restoration, security, reliability and voltage balance. Optimal load phase balance is obtained by solving the load re-distribution problem as a combinatorial optimization problem. This enables the best switching option that gives a balanced load arrangement among the phases and minimizes power loss to be arrived at. In this paper, adding decaying self-feedback continuous neural network (ADSCHNN) is applied to realize phase swapping for load re-arrangement in the low voltage circuit of the distribution network. The network energy function of the ADSCHNN is constructed for objective function that defines the load phase balancing problem. The ADSCHNN is applied to solve the problem when load is represented in terms of current flow at the connection points, and when load is defined in terms of the real power. The results obtained using ADSCHNN are compared with those from a heuristic algorithm, and from fuzzy logic expert system. Simulations results on real practical data show that the ADSCHNN is very effective and outperforms other known algorithms in terms of the maximum difference of the phase currents or powers.

Phasor-based assessment for harmonic sources in distribution networks

Phasor-based interdependencies of multiple harmonic sources, especially Distributed Energy Resources, on distribution networks are analyzed in this paper. A new index, Phasor Harmonic Index (IPH), is proposed by the authors. IPH considers both harmonic source magnitude and phase angle for different harmonic orders. Other commonly used harmonic indices are based solely on magnitude of waveforms. A very detailed model of a distribution network is used in the harmonic assessment. With the help of the detailed distribution network model, the phase couplings and the phase balancing impacts on harmonic propagation between three phases are investigated. Moreover, effects of harmonic source phase angle deviations are analyzed at both the customer side and the substation side. This paper investigates the importance of phase angles in harmonic assessment and how distribution network characteristics can be analyzed appropriately with phasor-based harmonic studies. In addition to device level harmonics, system level harmonic propagation need to be considered.

A mesh-independent finite element formulation for modeling crack growth in saturated porous media based on an enriched-FEM technique

In this paper, the crack growth simulation is presented in saturated porous media using the extended finite element method. The mass balance equation of fluid phase and the momentum balance of bulk and fluid phases are employed to obtain the fully coupled set of equations in the framework of $$u{-}p$$ formulation. The fluid flow within the fracture is modeled using the Darcy law, in which the fracture permeability is assumed according to the well-known cubic law. The spatial discritization is performed using the extended finite element method, the time domain discritization is performed based on the generalized Newmark scheme, and the non-linear system of equations is solved using the Newton–Raphson iterative procedure. In the context of the X-FEM, the discontinuity in the displacement field is modeled by enhancing the standard piecewise polynomial basis with the Heaviside and crack-tip asymptotic functions, and the discontinuity in the fluid flow normal to the fracture is modeled by enhancing the pressure approximation field with the modified level-set function, which is commonly used for weak discontinuities. Two alternative computational algorithms are employed to compute the interfacial forces due to fluid pressure exerted on the fracture faces based on a ‘partitioned solution algorithm’ and a ‘time-dependent constant pressure algorithm’ that are mostly applicable to impermeable media, and the results are compared with the coupling X-FEM model. Finally, several benchmark problems are solved numerically to illustrate the performance of the X-FEM method for hydraulic fracture propagation in saturated porous media.

Energy Balance in Al-Co Open-Celled Foam of Transpiration Cooling

Numerical model of one-dimensional steady-state on Alumina-Cordierite (Al-Co) open-celled foam using in transpiration cooling system have been conducted to investigate the local energy balance (LEB) of gas and solid phase within porous plate. Physical properties, i.e., porosity (f), pores per inch (PPI) and thickness (x), of Al-Co open-cellular porous material were 0.87, 13 and 0.103 m, respectively. Two equations of the conservative energy consisting of the gas and solid phase were analyzed. From study, it was found that heat convection (HVF) balanced with heat transfer between two phases/ energy of interaction (INT) for the gas phase case. In the solid phase, heat transfer between two phases (INT) tended to offset heat radiation (HRS). Remarkably, heat conduction of both phases (HDF and HDS) was not effected to the present cooling system. Thus, characteristic of fluid flow effecting by HVF and heat transfer governed from HRS was strongly efficient to transpiration cooling system.

A numerical contact algorithm in saturated porous media with the extended finite element method

In this paper, a coupled hydro-mechanical formulation is developed for deformable porous media subjected to crack interfaces in the framework of extended finite element method. Governing equations of the porous medium consist of the momentum balance of the bulk together with the momentum balance and continuity equations of the fluid phase, known as [InlineEquation not available: see fulltext.] formulation. The discontinuity in fractured porous medium is modeled for both opening and closing modes that results in the fluid flow within the fracture, and/or contact behavior at the crack edges. The fluid flow through the fracture is assumed to be viscous and is modeled by employing the Darcy law in which the permeability of fracture is obtained using the cubic law. The contact condition in fractured porous medium is handled by taking the advantage from two different algorithms of LATIN method and penalty algorithm. The effect of contact on fluid phase is employed by considering no leak-off from/into the porous medium. The nonlinearity of coupled equations produced due to opening and closing modes is carried out using an iterative algorithm in the Newton---Raphson procedure. Finally, several numerical examples are solved to illustrate the performance of proposed X-FEM method for hydro-mechanical behavior of fractured porous media with opening and closing modes.

Synchronization in complex networks of phase oscillators: A survey

The emergence of synchronization in a network of coupled oscillators is a fascinating subject of multidisciplinary research. This survey reviews the vast literature on the theory and the applications of complex oscillator networks. We focus on phase oscillator models that are widespread in real-world synchronization phenomena, that generalize the celebrated Kuramoto model, and that feature a rich phenomenology. We review the history and the countless applications of this model throughout science and engineering. We justify the importance of the widespread coupled oscillator model as a locally canonical model and describe some selected applications relevant to control scientists, including vehicle coordination, electric power networks, and clock synchronization. We introduce the reader to several synchronization notions and performance estimates. We propose analysis approaches to phase and frequency synchronization, phase balancing, pattern formation, and partial synchronization. We present the sharpest known results about synchronization in networks of homogeneous and heterogeneous oscillators, with complete or sparse interconnection topologies, and in finite-dimensional and infinite-dimensional settings. We conclude by summarizing the limitations of existing analysis methods and by highlighting some directions for future research.

Low voltage distribution system planning using diversified demand curves

In this work, the problem of low voltage distribution system planning is solved using diversified peak demand to estimate nodal power injection from the number of users and the diversity curves in demand. The problem is formulated as a model of mixed integer nonlinear programming. To solve the problem, a tabu search algorithm is used. It considers location and design of new and existing elements, phase balance, and system losses. Additionally, it takes into account the relocation of distribution transformers considering existing, new, and in store ones, installation of new primary network to feed distribution transformers, and removing existing elements. The methodology is applied in a Colombian distribution system using three demand scenarios: average demand curves, cumulative maximum demand, and diversity in demand. The results support the validity of the methodology proposed in this article.

Miniaturized 180<formula formulatype="inline"><tex Notation="TeX">$^{\circ}$</tex></formula> Hybrid Coupler in LTCC for L-Band Applications

In this letter, the lumped element technique is used to design a 180 ° hybrid coupler or balun for applications at L1 band. The material system employed is low temperature co-fired ceramic (LTCC), which allows for three-dimensional passive integration. The proposed balun uses a modified equivalent circuit that permits the simultaneous optimization of amplitude and phase balances. A process for the quick tuning of the balun design parameters is also presented. Measurements at 1.575 GHz indicate insertion losses below 0.67 dB, an amplitude imbalance of 0.14 dB, and a phase difference of 179.1 °. To the author's best knowledge, this is the smallest and best performing lumped element balun for applications at L1 band.

질소 보호 가스 첨가가 하이퍼 듀플렉스 스테인리스 밀봉용접재의 마모부식 저항성에 미치는 영향

Duplex stainless steels with nearly equal fraction of the ferrite(<TEX>${\alpha}$</TEX>) phase and austenite(<TEX>${\gamma}$</TEX>) phase have been increasingly used for various applications such as power plants, desalination facilities due to their high resistance to corrosion, good weldability, and excellent mechanical properties. Hyper duplex stainless steel (HDSS) is defined as the future duplex stainless steel with a pitting resistance equivalent (PRE=wt.%Cr+3.3(wt.%Mo+0.5wt.%W)+30wt.%N) of above 50. However, when HDSS is welded with gas tungsten arc (GTA), incorporation of nitrogen in the Ar shielding gas are very important because the volume fraction of <TEX>${\alpha}$</TEX>-phase and <TEX>${\gamma}$</TEX>-phase is changed and harmful secondary phases can be formed in the welded zone. In other words, the balance of corrosion resistance between two phases and reduction of <TEX>$Cr_2N$</TEX> are the key points of this study. The primary results of this study are as follows. The addition of <TEX>$N_2$</TEX> to the Ar shielding gas provides phase balance under weld-cooling conditions and increases the transformation temperature of the <TEX>${\alpha}$</TEX>-phase to <TEX>${\gamma}$</TEX>-phase, increasing the fraction of <TEX>${\gamma}$</TEX>-phase as well as decreasing the precipitation of <TEX>$Cr_2N$</TEX>. In the anodic polarization test, the addition of nitrogen gas in the Ar shielding gas improved values of the electrochemical parameters, compared to the Pure Ar. Also, in the erosion-corrosion test, the HDSS welded with shielding gas containing <TEX>$N_2$</TEX> decreased the weight loss, compared to HDSS welded with the Ar pure gas. This result showed the resistance of erosion-corrosion was increased due to increasing the fraction of <TEX>${\gamma}$</TEX>-phase and the stability of passive film according to the addition <TEX>$N_2$</TEX> gas to the Ar shielding gas. As a result, the addition of nitrogen gas to the shielding gas improved the resistance of erosion-corrosion.

Six‐port QPSK demodulator for optimal K‐band multiport amplifier calibration

A wideband six-port-based demodulator is proposed and applied as a quadrature phase shift keying (QPSK) demodulator for optimal K-band multiport amplifier (MPA) calibration circuitry. The proposed six-port demodulator adopts wideband ring hybrids for optimal 180° phase balance in local oscillator signal paths. In addition, a voltage-controlled reflection-type phase shifter and an attenuator are integrated into the six-port structure to ensure accurate magnitude and phase balance over broadband operation, resulting in optimal phase and amplitude error detection for the MPA system. To verify the proposed structure, RF demodulation of the K-band QPSK modulated signal was demonstrated for purpose of MPA calibration.

Back EMF Analysis of a Novel Linear Flux Switching Motor With Segmented Secondary

A novel linear flux switching motor (LFSM) with simple passive segmented secondary (SSLFSM) is presented in this paper. In this motor, the armature and field winding concentrated coils are wound around mover (primary) teeth alternatively. The structure of this linear motor is different from other types of LFSMs presented in previous research. All LFSMs are suffering from unbalanced back electromotive force (EMF) waveform. The same problem appears in SSLFSM. In this paper, the influence of secondary segments number on back EMF waveform of designed SSLFSM is derived analytically. It is found that the secondary segment numbers have a strong effect on generated back EMF waveform harmonic contents and phase balances. These effects are evaluated by finite-element analysis for different configurations of SSLFSM as well. With analytical and numerical evaluations, a suitable number of secondary segments for minimum harmonic contents and phase unbalances is obtained.

Design of power divider with bandpass response and notched band

A novel multilayer in-phase slotline power divider with bandpass response and one tunable notched band is proposed. The presented power divider employs the structure of microstrip-to-slotline transition to split the input signals over the frequency range 3.5-10 GHz. A wide upper stopband is obtained by using an interdigital configuration and introducing a defected ground structure. A quarter-wavelength short-circuited stub is utilised to obtain the tunable notched band in the passband. The experimental results indicate that the proposed power divider has good phase balance, high isolation between output ports, good return losses at all ports and flat group delay over a wide frequency range.

Numerical simulation on the cracking and failure law of compacted clay lining in landfill closure cover system

SUMMARYAccording to the mass conservation equation of solid phase, water transport, air migration and enthalpy balance equations in a deformable and unsaturated porous medium, and the mechanics model, a thermal‐hydro‐mechanical (THM) coupling mathematical model is developed in order to accurately predict the crack propagation of the compacted clay lining (CCL) in a landfill closure cover system. Numerical simulation analysis of the cracking and failure of the CCL in a landfill closure cover system under complex conditions (landfill gas pressure, variation of soil surface temperature, moisture loss of coverage soil, and uneven settlement of landfilled MSW (municipal solid waste)) is performed. The results show that the cracks are discovered firstly on the soil surface and then extend to the deeper cover system and became bigger. The cracks had broken through the closure cover system at 30 days. Over the depth range of 0.06 m, the change rate of settlement is found to be the highest because of the strong influence of temperature. The rise of temperature around the cracks is fast when the CCL is broken through by the cracks. There is a hollow area near the cracks over the depth range from 0.15 to 0.7 m, and the temperature stabilize at around 11°C without any obvious reduction. Under the condition of evaporation, the main crack in the CCL is similar to a pumping well, which causes more rapid moisture content reduction around the cracks. Vertical deformation increases linearly with depth in the process of deformation and cracking of CCL induced by uneven settlement of landfilled MSW. Copyright © 2014 John Wiley &amp; Sons, Ltd.

POWER DIVIDER BASED ON STEPPED-IMPEDANCE SLOTLINE

A novel 180 - out-of-phase power divider based on stepped-impedance slotline is presented in this article. This power divider employs one T-junction formed by microstrip line and slotline to obtain two out-of-phase dividing signals. Stepped-impedance slotline and lumped resistor are introduced to improve the isolation between output ports. The experimental data show that the proposed power divider has good performance on insertion loss, return losses, isolation, phase balance, as well as group delay over the wide band 5GHz{10GHz.

BANDPASS-RESPONSE POWER DIVIDER WITH HIGH ISOLATION

A novel wideband multilayer power divider with high isolation and bandpass response is presented in this article. This presented power divider employs microstrip-slotline coupling structure to realize the basic function of dividing input power. One lumped isolation resistor is introduced to improve the isolation between output ports. In order to solder the chip resistor between output branches, bending microstrip structure is utilized. For the sake of rejecting the unwanted signals locating in adjacent channels, interdigital structure and defected ground structure are designed to obtain a bandpass response and a wide upper stopband. The experimental results have indicated that the proposed wideband power divider has good performance on return losses, isolation, amplitude and phase balances, as well as group delay over the band 4.5GHz{10GHz.

UWB MULTILAYER POWER DIVIDER WITH HIGH ISOLATION

A novel compact slotline power divider is proposed in this article. This presented power divider employs a novel conflguration with one lumped resistor, which makes it surpass most antecedent UWB power dividers based on microstrip-to-slotline transitions in aspect of isolation between output ports and return losses at output ports. The simulated and measured results illustrate the good performances of the novel power divider on return losses at all ports, isolation, amplitude and phase balances between output ports, as well as group delay over the wide frequency band from 3.8GHz to 10.4GHz.