Power Factor Improvement Research Articles

Review on Power Factor Improvement of Vernier Machines

Review on Power Factor Improvement of Vernier Machines

Br doping-induced evolution of the electronic band structure in dimorphic and hexagonal SnSe2 thermoelectric materials.

SnSe2 with its layered structure is a promising thermoelectric material with intrinsically low lattice thermal conductivity. However, its poor electronic transport properties have motivated extensive doping studies. Br doping effectively improves the power factor and converts the dimorphic SnSe2 to a fully hexagonal structure. To understand the mechanisms underlying the power factor improvement of Br-doped SnSe2, the electronic band parameters of Br-doped dimorphic and hexagonal SnSe2 should be evaluated separately. Using the single parabolic band model, we estimate the intrinsic mobility and effective mass of the Br-doped dimorphic and hexagonal SnSe2. While Br doping significantly improves the mobility of dimorphic SnSe2 (with the dominant hexagonal phase), it results in a combination of band convergence and band flattening in fully hexagonal SnSe2. Br-doped dimorphic SnSe2 is predicted to exhibit higher thermoelectric performance (zT ∼0.23 at 300 K) than Br-doped fully hexagonal SnSe2 (zT ∼0.19 at 300 K). Characterisation of the other, currently unidentified, structural phases of dimorphic SnSe2 will enable us to tailor the thermoelectric properties of Br-doped SnSe2.

Design of a power factor repair tool for UKM

The home industry has an important role in improving the community's economy. Energy needs also increase, with this the existing load on the home industry becomes more varied, especially inductive loads that cause a decrease in power factor, this needs to be overcome by improving the power factor by adding a compensator to the network. Because production on a home industry scale is not as continuous in large industries, a power factor improvement tool is needed that works automatically. This study aims to design a power factor improvement tool that works automatically to improve the power factor in the home industry, where the tool works according to network requirements. The Arduino micro controller is used as an automatic controller in the design of this power factor improvement tool, with input using a voltage sensor and a current sensor SCT-013, which is then processed by Arduino to get the power factor value and control the relay to adjust the capacitor requirements to compensate for the inductive load on the network. The results of this study are that the power factor in the household industry can be improved to more than 0.9, the power used in the network is more effective and is absorbed by the load more effectively and the reactive power in the network becomes small or even non- existent.

Improved design and analysis for electromagnetic performance of magnetic geared permanent magnet machine according to winding pattern and segmentation of permanent magnet

This paper presents an analysis of the operating principle of magnetic geared permanent magnet machines (MGPMMs), electromagnetic analysis results according to the winding pattern, and a method for improving power factor and loss characteristics. To improve electromagnetic performance, the air gap magnetic flux density was calculated using the finite element method, and the harmonics of the inner and outer air gap magnetic flux densities was analyzed using the fast Fourier transform (FFT). From the FFT results, harmonic orders that affect electromagnetic performance were presented, and the electromagnetic analysis results were compared to derive correlations with torque ripple and losses. In addition, a design method for improving electromagnetic performance and operating characteristics was proposed by comparing power factors according to winding pattern. In particular, to improve the robust design and efficiency of MGPMM, a method of reducing eddy current loss by segmenting permanent magnets was addressed. The proposed analysis and design method can be widely used in the design and characteristic analysis of MGPMM.

Reduction Method of Carbon Emission in Chemical Plants: Comparison of Middle East, Southeast Asia, and Korea

There are various methods to reduce greenhouse gas emissions in the construction and operational processes of chemical plants; however, the greenhouse gas reduction effects, investment costs, and benefits of their application have not been evaluated. Therefore, this study proposes greenhouse gas reduction measures that can be applied to chemical plant projects, including photovoltaic power generation, power factor improvement, VSD (Variable Speed Drive) motors, LED (Light Emitting Diode) lighting, and minimizing on-site business trips. Subsequently, the potential greenhouse gas reduction, estimated costs, and expected benefits for each measure were calculated by region. Among these measures, power factor improvement demonstrated the highest CO<sub>2</sub> reduction potential, with an estimated investment cost as low as 27 USD/tCO<sub>2</sub>, making it an effective greenhouse gas reduction strategy. Additionally, LED lighting and minimizing on-site business trips, which require little initial investment, should be implemented promptly. The proposed five measures, considering the potential reduction in greenhouse gas emissions, estimated investment costs, and benefits, can be applied to identify ways to significantly reduce greenhouse gas emissions in new chemical plants.

Low lattice thermal conductivity and improved power factor in Ga-substituted CuSbTe2 alloys for mid-temperature thermoelectric application

Low lattice thermal conductivity and improved power factor in Ga-substituted CuSbTe2 alloys for mid-temperature thermoelectric application

High Thermoelectric Performance Related to PVDF Ferroelectric Domains in P-Type Flexible PVDF-Bi0.5Sb1.5Te3 Composite Film.

There is increasing demand to power Internet of Things devices using ambient energy sources. Flexible, low-temperature, organic/inorganic thermoelectric devices are a breakthrough next-generation approach to meet this challenge. However, these systems suffer from poor performance and expensive processing preventing wide application of the technology. In this study, by combining a ferroelectric polymer (Polyvinylidene fluoride (PVDF, β phase)) with p-type Bi0.5Sb1.5Te3 (BST) a thermoelectric composite film with maximum is produced power factor. Energy filter from ferroelectric-thermoelectric junction also leads to high Seebeck voltage ≈242µVK-1. For the first time, compelling evidence is provided that the dipole of a ferroelectric material is helping decouple electron transport related to carrier mobility and the Seebeck coefficient, to provide 5× or more improvement in thermoelectric power factor. The best composition, PVDF/BST film with BST 95wt.% has a power factor of 712µW•m-1K-2. A thermoelectric generator fabricated from a PVDF/BST film demonstrated Pmax T 12.02µW and Pdensity 40.8Wm-2 under 50K temperature difference. This development also provides a new insight into a physical technique, applicable to both flexible and non-flexible thermoelectrics, to obtain comprehensive thermoelectric performance.

Power factor improvement using silicon based switching devices for changing load parameters

Systems power factor provides information on how effectively it uses the electrical power being provided to hold out real work. Losses rise as a results of poor power factor, and therefore the utility is penalized. In general, inductive loads, which are reactive in nature, make up AC loads. As a result, loads require and consume reactive power from the supply source which leads to excessive voltage drop in the line if they draw a lot of lagging current from the source, which could potentially result in the line's voltage collapsing if the drop is too high. When inductors cause a phase difference between voltage and current, the information is sent to the micro-controller, where the program takes control and activates the right number of opto-isolators interfaced to the triac silicon-based semiconductor device at its output to bring shunt capacitors into the load circuit to improve power factor to the desired range Semiconductors such as silicon or germanium are generally used for making triac. The most commonly used is silicon, due to its high abundance and the fact that it can operate at a higher temperature than germanium.

High Performance Thermoelectric Power of Bi0.5Sb1.5Te3 Through Synergistic Cu2GeSe3 and Se Incorporations.

Bi2Te3-based alloys are the benchmark for commercial thermoelectric (TE) materials, the widespread demand for low-grade waste heat recovery and solid-state refrigeration makes it imperative to enhance the figure-of-merits. In this study, high-performance Bi0.5Sb1.5Te3 (BST) is realized by incorporating Cu2GeSe3 and Se. Concretely, the diffusion of Cu and Ge atoms optimizes the hole concentration and raises the density-of-states effective mass (md *), compensating for the loss of "donor-like effect" exacerbated by ball milling. The subsequent Se addition further increases md *, enabling a total 28% improvement of room-temperature power factor (S2σ), reaching 43.6µWcm-1K-2 compared to the matrix. Simultaneously, the lattice thermal conductivity is also significantly suppressed by multiscale scattering sources represented by Cu-rich nanoparticles and dislocation arrays. The synergistic effects yield a peak ZT of 1.41 at 350K and an average ZT of 1.23 (300-500K) in the Bi0.5Sb1.5Te2.94Se0.06 + 0.11 wt.% Cu2GeSe3 sample. More importantly, the integrated 17-pair TE module achieves a conversion efficiency of 6.4%, 80% higher than the commercial one at ΔT=200K. These results validate that the facile composition optimization of the BST/Cu2GeSe3/Se is a promising strategy to improve the application of BST-based TE modules.

Thermoelectric performance of chalcogenide-free CaAl-layered double hydroxide–antimony trioxide nanowire composites with low thermal conductivity

Thermoelectric (TE) materials have attracted considerable interest for their potential and the figure of merit ZT serves as a crucial metric for evaluating TE performance. Chalcogenide materials, such as tellurium (Te) and selenium (Se), have been favored for high-performance TE applications. However, their toxic nature raises concerns, demanding exploration of non-toxic alternatives suitable for human-contacting devices.This study focused on antimony trioxide (Sb2O3) due to its high Seebeck coefficient and explored the potential of layered double hydroxide (LDH) materials as a non-toxic alternative for efficient TE materials. Composites of Sb2O3 nanowires integrated with 2D CaAl-LDH were synthesized to reduce thermal conductivity and improve TE performance. The composites displayed enhanced electrical conductivity, resulting in a significantly improved power factor. The introduction of CaAl-LDH facilitated the charge carrier transport paths, leading to better electrical performance. Furthermore, the composites exhibited reduced thermal conductivity due to phonon scattering at the heterointerfaces between Sb2O3 and CaAl-LDH. As a result, the Sb2O3/CaAl-LDH_70 composite achieved a maximal ZT value of 0.0485 at 473 K, demonstrating promising potential for LDH-based composites as environmentally friendly TE materials. These findings contribute to sustainable energy conversion technologies, ensuring progress towards more efficient and biocompatible TE materials.

A New Hybrid Concentrated-Winding Concept With Improved Power Factor for Permanent Magnet Vernier Machine

This paper investigates a high power-factor permanent magnet vernier machine (PMVM) equipped with low-coupling hybrid concentrated-winding (CW). The proposed hybrid-CW, carrying both star- and delta-winding sets, exhibits a good filtering property to both sub- and super-order harmonics. Through the meticulous design of the short coil pitch, the ratio of inductance to magnet flux linkage is decreased, leading to a great improvement in power factor. The proposed low-coupling winding design contributes to further power factor improvement by reducing the inductance while retaining the magnet flux linkage. It is revealed that the mutual coupling between different coils of single phase and that between different windings of three phases are suppressed significantly in the hybrid-CW, thus leading to high power factor and potentially high fault tolerance. Finite element results show that the proposed hybrid-CW PMVM exhibits a significantly improved power factor up to 0.96 from 0.83 and 0.75, as compared with two counterpart PMVMs with open-slot and split-tooth structures, respectively. Benefiting from the magnetic gearing effect, the proposed PMVM has a promising active torque density of 40 Nm/L. Taking end-winding volume into consideration, the proposed PMVM exhibits an actual torque density of 21.98 Nm/L, which is 22.52% and 52.43% higher than the investigated open-slot and split-tooth counterpart PMVMs. Finally, a prototype is fabricated and tested to validate the high-power-factor and high-torque-density features of the proposed hybrid-CW PMVM.

Power Quality Improvement using Shunt Active Power Filter: An Industrial Zone Case Study

Power quality (PQ) improvement using active power filters (APF) is a topic of growing interest. APFs are effective in reducing harmonic distortion and improving power factor. They can be used in a variety of applications to improve the performance and reliability of electrical equipment. To address concerns with PQ improvement, this study offers an application of shunt APF in an industrial zone smart grid. the non-linear loads and unpredictable harmonics produced by on-grid PV inverters that represent the architecture of an industrial smart grid. Utilizing the MATLAB/SIMULINK software suite, a detailed design of the APF and associated hysteresis current control technique is provided. The findings demonstrate that APF is a useful tool for reducing total harmonic distortion (THD) and has a quick dynamic reaction to control grid voltage and power factor.

Molecular Engineering for Enhanced Thermoelectric Performance of Single-Walled Carbon Nanotubes/π-Conjugated Organic Small Molecule Hybrids.

Hybridizing single-walled carbon nanotubes (SWCNTs) with π-conjugated organic small molecules (π-OSMs) offers a promising approach for producing high-performance thermoelectric (TE) materials through the facile optimization of the molecular geometry and energy levels of π-OSMs. Designing a twisted molecular structure for the π-OSM with the highest occupied molecular orbital energy level comparable to the valence band of SWCNTs enables effective energy filtering between the two materials. The SWCNTs/twisted π-OSM hybrid exhibits a high Seebeck coefficient of 110.4 ± 2.6 µV K-1 , leading to a significantly improved power factor of 2,136 µW m-1 K-2 , which is 2.6 times higher than that of SWCNTs. Moreover, a maximum figure of merit over 0.13 at room temperature is achieved via the efficient TE transport of the SWCNTs/twisted π-OSM hybrid. The study highlights the promising potential of optimizing molecular engineering of π-OSMs for hybridization with SWCNTs to create next-generation, efficient TE materials.

Challenges of ANN in Adapting to Abrupt Parameters Variations for Shunt Active Filter

The purpose of the shunt active power filter (SAPF) goes beyond simply improving power factor; it also aims to mitigate unwanted harmonic currents generated by nonlinear loads. This research introduces a SAPF equipped with an identification and control method utilizing artificial neural networks (ANN). Various techniques are employed for harmonic identification, including traditional p-q theory and the relatively recent approach of artificial neural networks. Achieving satisfactory identification and control characteristics is challenging when dealing with the nonlinearity of the system, particularly in situations involving rapid nonlinear load fluctuations. This study represents a systematic effort to address this challenge by enhancing the SAPF with a method for harmonics identification and DC link voltage control based on ANN. This approach is tested on the SAPF under conditions of fast, nonlinear load variations. The study includes both computer simulations and experimental results, which provide evidence of the viability and effectiveness of the proposed active power filter.

Optimal capacitor planning for power factor improvement using hybrid particle swarm and harmony search optimization

Industrial loads reduce the Power Factor (PF) of supply systems, causing increases in power losses, damaging equipment and higher utility bills. Optimization techniques are used in planning reactive sources to improve PF of power systems. However, conventional techniques suffer difficulties in passing over local optimal, divergence risk, constraints handling or computing higher order derivatives. Herein, the hybridization of Particle Swarm and Harmony Search Algorithm (PS – HSA) is developed for optimal capacitor planning to improve PF, and comparison is made with the Enhanced Particle Swarm Optimization (EPSO) and Improved Adaptive Harmony Search Algorithm (IAHSA). The test systems are the Modified IEEE 6 and 16 buses and nodes respectively. To create semblance of industrial load dominated power systems, the test networks were modified by increasing the reactive load demand at all buses of the IEEE 6 and 16 by 50% and 70% respectively. The capacitor is modelled as static shunt-controlled element deployed to inject reactive power at buses/nodes. Results show that for IEEE 6 buses, PF improved from 0.68 to 0.8983, 0.8986 and 0.8992 with EPSO, IAHSA and hybrid PS – HSA respectively. Similarly, in IEEE 16 nodes, PF improved from 0.76 to 0.9439, 0.943, and 0.944 with EPSO, IAHSA and hybrid PS – HSA respectively. Furthermore, real power losses reduced from 16.94 MW to 14.03 MW in IEEE 6 buses, translating to 17.2% reduction with the hybrid PS - HSA. While in IEEE 16 nodes, reduction is from 0.719 MW to 0.69 MW accounting for 4% reduction, also with the hybrid PS - HSA.

Optimal Battery Energy Storage Control for Multi-Service Provision Using a Semidefinite Programming-Based Battery Model

Battery energy storage systems (BESS) capable of simultaneously providing multiple grid services can assist a distribution grid operator in overcoming various challenges due to the high penetration of distributed solar photovoltaics and accelerated electrification. The seamless provision of multiple services can be ensured with BESS control decisions based on an accurate model reflecting the battery characteristics. Thus, this paper presents a novel Li-ion battery model based on linear matrix inequalities along with a semidefinite programming (SDP)-based model to determine the optimal BESS control decisions for the provision of multiple services in distribution systems. Peak shaving, power factor improvement, and electricity cost savings are considered for the services. Moreover, the mathematical analysis reveals that the original nonconvex problem can be equivalently transformed into the SDP model. The effectiveness of using BESS in the distribution system is verified through simulations using real-world data. Ultimately, a comparative analysis with a conventional linear model demonstrates that the proposed battery model reduces the energy losses in the batteries, in the simulation condition, and help maintain the battery states within normal operating limits.

Power quality improvement in distributed generation system using intelligent control methods

Hybrid <span>electric power generation and its integration with the grid to supply consumer demand is main focus of this paper. The use of nonlinear load and advanced power electronic equipment-based devices at the consumer end introduces power quality issues in the power system network in terms of voltage and current. This paper explains the design of a control algorithm for a unified power quality conditioner used for mitigating both voltage and current-based power quality issues. The dynamic voltage restorer of unified power quality controller (UPQC) is designed with a unit vector control algorithm and the distribution static synchronous compensator (DSTATCOM) is designed with fuzzy logic and adaptive network-based fuzzy inference system based instantaneous reactive power theory control algorithm. The simulation model built using the MATLAB platform includes a three-phase voltage source along with hybrid electric power generation connected to linear and non-linear loads operating under different conditions. The result is analyzed in terms of voltage and current total harmonic distortion compared with IEEE 512 power quality standards and power factor improvement. The paper shows the adaptive neuro-fuzzy inference systems (ANFIS)-based control algorithm gives better results in terms of total harmonic distortion (THD) compared to the fuzzy-based control algorithm. The power factor is improved using ANFIS-based controller proving the efficiency of the controller</span>.

Enhanced Thermoelectric Performance of p-Type Mg3-xZnxSb2/Sb Composites: The Role of ZnSb/Sb Composites.

Mg3Sb2-based Zintl compounds have garnered recent attention as promising materials for thermoelectric applications due to their low thermal conductivity and high zT values as n-type materials. However, the zT values of p-type materials are lower compared to their n-type counterparts. Through a straightforward process involving cold pressing and evacuating-and-encapsulating sintering, we have successfully synthesized a variety of p-type Mg3-xZnxSb2/Sb composites by adding the ZnSb-4%Sb composite into the Mg3Sb2 host material. Structural analyses have provided insights into the role of the ZnSb-4%Sb composite, demonstrating its significance in Zn doping on the Mg sites and Sb acting as an additive in the composite. The introduction of Zn on the Mg tetrahedral sites enhances the concentration of carriers, while the presence of highly conductive Sb grains facilitates the movement of charge carriers between adjacent Mg3-xZnxSb2 grains, thereby promoting mobility. Consequently, the electrical resistivity of the Mg3-xZnxSb2/Sb composites decreases as the Zn content increases. At 710 K, the Mg1.91Zn1.09Sb2/Sb composite exhibits the lowest resistivity, measuring 5.1 mΩ-cm, which is 46 times lower than that of the Mg3Sb2 host. Furthermore, the zT value of the Mg3-xZnxSb2/Sb composites increases with higher Zn content (x), benefiting from a combination of an improved power factor and reduced thermal conductivity. Significantly, our straightforward fabrication process enables us to achieve a maximum zT value of 0.58 at 710 K for the Mg1.91Zn1.09Sb2/Sb composite. This achievement can primarily be attributed to the 8-fold enhancement in power factor compared to the Mg3Sb2 host.

Fractional delay Newton structure for Lagrangian interpolation in PV integrated grid connected system

SummaryThis paper proposes a fractional delay (FD) Newton structure for Lagrangian interpolation in single phase grid integrated photovoltaic (PV) system. The structure has been designed for achieving shunt compensation and as a phase locked loop circuit for synchronization. The designed controller performs multiple tasks of feeding the active power to meet the load demand and simultaneously providing reactive power compensation, power factor improvement, and compensating other power quality voltage and load current harmonics. Further, synchronization poses a severe challenge in integrating the PV power electronic converters to the grid. The FD filter is used to discretize the continuous time signal at any time instant using interpolation algorithm employing the non‐integral value of the sampling rate delays. The FD delay filter is made adaptive and self‐learning by using least mean square algorithm. The designed synchronization technique meets the objective of faithfully tracking the phase of the grid voltage under all grid disturbances such as under voltage, overvoltage, frequency variations, and phase angle disturbances in a precise manner.

Implementation of Power Factor Correction using Asynchronous Boost Converter on Single Phase Full-Bridge Diode

In various industrial applications, the use of a power supply that uses a conventional diode single-phase rectifier topology results in high harmonic values in the electricity distribution system. One of the real impacts of this harmonic value is the heating of the electric power system equipment and power losses. High rms current values due to harmonics often cause problems in protection settings in addition to efficiency problems. The percentage value between the total harmonic component and the fundamental component is called THD (Total Harmonic Distortions). Therefore, in this study an asynchronous dc-dc boost converter is connected to the output side of a single-phase diode rectifier which is capable of improving power factor and low harmonics. So that a THD value of less than 15%, PF (Power Factor) = 0.92-1 and a sinusoidal input current can be obtained. The implementation results show that the PFC (Power Factor Correction) method can work well on single-phase diode rectifiers.