Hasil untuk "Applications of electric power"

D. Molzahn, Florian Dörfler, H. Sandberg et al.

Siqi Li, C. Mi

D. Larbalestier, A. Gurevich, D. Matthew Feldmann et al.

Line A. Roald, David Pozo, A. Papavasiliou et al.

Electric power systems and the companies and customers that interact with them are experiencing increasing levels of uncertainty due to factors such as renewable energy generation, market liberalization, and climate change. This raises the important question of how to make optimal decisions under uncertainty. This paper aims to provide an overview of existing methods for modeling and optimization of problems affected by uncertainty, targeted at researchers with a familiarity with power systems and optimization. We also review some important applications of optimization under uncertainty in power systems and provide an outlook to future directions of research.

Van-Binh Vu, Duc-Hung Tran, Woojin Choi

When compared to plugged-in chargers, inductive power transfer (IPT) methods for electric vehicle (EV) battery chargers have several benefits, such as greater convenience and higher safety. In an EV, the battery is an indispensable component, and lithium-ion batteries are identified as the most competitive candidate to be used in EVs due to their high power density, long cycle life, and better safety. In order to charge lithium-ion batteries, constant current/constant voltage (CC/CV) is often adopted for high-efficiency charging and sufficient protection. However, it is not easy to design an IPT battery charger that can charge the batteries with a CC/CV charge due to the wide range of load variations, because it requires a wide range of variation in its operating frequency, duty, or phase-shift. Furthermore, zero phase angle (ZPA) condition for the primary inverter cannot be achieved over the entire charge process without the help of additional switches and related driver circuits to transform the topology. This paper proposes a design method that makes it possible to implement the CC/CV mode charge with minimum frequency variation during the entire charge process by using the load-independent characteristics of an IPT system under the ZPA condition without any additional switches. A theoretical analysis is presented to provide the appropriate procedure to design the double-sided LCC compensation tank which can achieve both CC and CV mode charge under ZPA condition at two different resonant frequencies. As a consequence, the proposed method is advantageous in that the efficiency of compensation tank is very high due to achieving the perfect resonant operation during the entire charge process. A 6.6-kW prototype charger has been implemented to demonstrate the feasibility and validity of the proposed method. A maximum efficiency of 96.1% has been achieved with a 200-mm airgap at 6.6 kW during the CC mode charge.

Di Wang, Sam Hemming, Yuhang Yang et al.

Aviation electrification has been in the spotlight over the last decade, expected to lead to a more sustainable future. As the power demand and the voltage level of onboard electric power systems dramatically increase, multilevel inverters (MLIs) have attracted the attention of the aviation industry for their superior performance. This article reviews MLIs for electric aircraft applications. The functions of MLIs in different subsystems of electric aircraft are summarized. The advantages of MLIs compared with their two-level counterparts in electric aircraft, in terms of efficiency, power density, reliability, costs, and power quality, are evaluated through a literature review and case studies. Technical innovations with respect to the design, control, modulation, and prototyping of MLIs for aviation applications are also introduced. Finally, future trends of MLIs for electric aircraft applications are discussed.

Qiang HUANG, Kuan LI, Rongqi FAN et al.

Renewable energy connected modular multilevel converter high-voltage direct-current (MMC-HVDC) system should have the capability of fault ride-through when the AC grid fails. However, it is difficult to quickly and reliably achieve fault ride-through via cooperative control if there is no high-speed communication between renewable energy and MMC-HVDC converters. Additionally, the droop coefficient in traditional voltage drop control is set to a linear constant, which makes it difficult to fast match under different fault conditions and results in a longer step delay, leading to high voltage operation of the DC system during the fault. Aiming at the existing problems mentioned above, the dynamic characteristics of the DC system and the principles of traditional voltage drop control are analyzed, which provides a basis for fast power matching on both sides of the DC system. Then, a fault ride-through control based on fast matching power for renewable energy connected MMC-HVDC is proposed. Finally, simulations based on PSCAD/EMTDC show that fault ride-through capability is reliable by using the proposed control method. Compared with traditional voltage drop control, the proposed control method significantly reduces the step delay, limits the rise of DC voltage and achieves fast and reliable fault ride-through.

Mohamed Rayane LAKEHAL, Amine MEZENNER, Naouel ARAB et al.

The estimation of plant disease intensity is essential for various purposes, including monitoring epidemics, understanding yield loss, and evaluating treatment effects. Despite the availability of sensor technology to measure disease severity using the visible spectrum or other spectral range imaging, deep learning has emerged as a recent and advanced technique for image processing and data analysis. To enhance the severity estimation in diseased leaves, a CNN ensemble is proposed by fusing deep features extracted from outputs of fully connected layers of various CNN models. A SVM (Support Vector Machine) is utilized to achieve the classification stage. Experiments are carried out on wheat leaf images infected by the Yellow rust disease. Experiments conducted using three CNN models that are VGG16, MobileNetV2 and a customized CNN reveal that the CNN ensemble outperforms individual models.

А.H. Tkachuk, A.A. Humeniuk, O.O. Dobrzhansky et al.

The article examines modern approaches to improving the energy efficiency of electric drives in the context of implementing the concept of smart energy networks (Smart Grid). Particular attention is given to the integration of electric drives as active participants in the energy balance, capable not only of consuming energy but also of adaptively regulating their operating modes in accordance with network parameters, load conditions, and the state of renewable energy sources. The study emphasizes the feasibility of using intelligent control systems that ensure high-quality regulation and reduced energy consumption under dynamically changing external conditions. Methods of energy consumption optimization based on adaptive control of variable-frequency drives are analyzed. The principles of using load forecasting algorithms are considered, enabling the formation of optimal operating profiles in advance and preventing peak overloads in the grid. The potential of regenerative operating modes, which allow excess energy during braking or speed reduction to be returned to the grid or local storage systems, is highlighted. This approach improves the overall efficiency of electric drive systems and reduces power losses. The results of simulation modeling performed in MATLAB/Simulink, using adaptive regulators and load models, confirm the effectiveness of the proposed strategies. It has been established that the application of intelligent control algorithms reduces the electricity consumption of electric drives compared to traditional control methods, increases the power factor, and decreases harmonic distortion levels in the grid by 25–30 %. Additionally, it is demonstrated that the use of adaptive regulators ensures system stability even under varying motor parameters and external disturbances. The practical implementation of such solutions is feasible in a wide range of applications: industrial production lines, electric transport systems, and integrated energy complexes with renewable sources. This opens new prospects for the development of energy-efficient Smart Grid systems with a high level of flexibility, reliability, and self-recovery capability after disturbances. The proposed approaches contribute to shaping a new paradigm of electric drives focused on minimizing energy losses and enhancing the overall efficiency of modern power systems.

Zhi-Bing Li, Wei-Jiang Chen, Hao Wang et al.

To address the mitigation of excessive short-circuit currents in power grids and the arcing-resistant technology for large oil-filled equipment, this paper proposes a 550 kV fast SF6 circuit breaker solution, the equipment development and engineering implementation were systematically executed to validate the technology. A new electromagnetic repulsion trip device is used to replace the traditional electromagnet, achieving rapid conversion of the control valve oil circuit and reducing the mechanism activation time from the conventional <inline-formula> <tex-math notation="LaTeX">$10\sim 14$ </tex-math></inline-formula> ms to within 4 ms; by enhancing the operating power of the hydraulic disc spring mechanism, the output force is increased, and the buffer design is optimized, reducing the opening time from <inline-formula> <tex-math notation="LaTeX">$19\sim 25$ </tex-math></inline-formula> ms to within 8 ms; the design of SF6 arc-extinguishing chamber is improved and optimized from the aspects of contact gap, arc-blowing pressure, and electric field distribution, reducing the short arcing time from <inline-formula> <tex-math notation="LaTeX">$12\sim 14$ </tex-math></inline-formula> ms to within 8 ms. The successful development of the 550 kV fast SF6 circuit breaker achieves a breaking current of 63 kA, a breaking time of no more than 25 ms (approximately half that of conventional circuit breakers). The developed fast circuit breaker has been successfully applied in the Shunjiang sub-station 500kV short-circuit current flexible suppression demonstration project, and further enhances reliability with pilot applications for arcing-resistant of converter transformers at the Dongping and Bangguo converter stations of the Jinshang-Hubei and Longdong-Shandong &#x00B1;800 kV ultra-high voltage direct current transmission projects, respectively, with good application prospects.

P. B. Bobba, Lakshmi Sri Harshitha Yerraguntla, Sathvika Pisini et al.

In recent years solid-state batteries, have emerged leading research focus, due to their distinct advantages over conventional batteries. Solid-state batteries, having solid electrolytes, offer higher energy and power density, enhanced safety features and longer lifespan. This makes them ideal in fulfilling demand for energy storage in electric vehicle, and smart grid applications. This study aims to evaluate various types of solid-state batteries, analysing their properties, advantages, and disadvantages, assessing their viability in EV applications. The objective is to identify and recommend the most effective solid-state battery that aligns with the specific demands and operational conditions of electric vehicles and conduct a comprehensive analysis of anode and cathode elements of one of the solid-state batteries in their fresh and damaged state using scanning electron microscopy (SEM).

Guvanthi Abeysinghe Mudiyanselage, Niloufar Keshmiri, A. Emadi

Resonant converters are attractive for DC-DC converter applications of electric vehicles (EVs) due to their wide range of soft switching and less output filter requirements compared to dual active bridge (DAB) converters. However, the design and control implementation of resonant converters is comparatively challenging due to the nonlinearities introduced with the resonant tank. LLC and CLLC resonant converters are popular among the resonant converter topologies, while new topologies are being derived based on the basic resonant converter topologies. This paper conducts a review on the basic resonant converter topologies, modes of operation of the resonant converter, modeling and control techniques, and special design considerations for resonant converter design. Existing topologies and control techniques of resonant converters enabling the derivation of new converter topologies and control methodologies, are investigated.

S. Usha, P. Geetha, A. Geetha et al.

In recent scenarios, induction motors are used in many different fields due to their small size, advanced technology, and capacity to handle large amounts of power. One of the annoying downsides of conventional AC traction drive systems is the engine's speed and the uncertainty of the ripple content. The goal of the proposed work is to use various control techniques to analyze and enhance the performance of two five-phase induction motors that are supplied in parallel via an inverter. The control techniques are scalar control, six-step voltage type source inverter (VSI), space vector modulation (SVM) based VSI inverter, field-oriented control, model reference adaptive system-based field-oriented control (FOC), direct torque control (DTC), direct torque control -SVM, model reference adaptive system based direct torque control-SVM for traction application. The modified space vector modulation-based induction motor (IM) sensorless drive is realized together with a comparison of several control strategies. It makes use of direct torque control approaches with a model reference adaptive system (MRAS). An IM is designed, and performances are analyzed in high-speed and low-speed regions. Two bogies sets were considered in the closed-loop scheme, tested under parameter variations and in low-speed areas. The simulation result examined the most significant control methods for an IM fed by an inverter for electric traction applications. The performance of the torque in terms of reduced torque ripple in the IM drive is analyzed. The proposed direct torque control technique will reduce torque harmonic ripple by 100 % under the steady-state condition. Under a change in a parameter, the torque harmonic ripple is decreased by 99 %. For the IM drive, the hardware implementation of the advanced control approaches is examined.

Marie Peyrard, Gilles Jacquemod, Nicolas Froidevaux

Power integrity is a critical aspect of microcontroller (MCU) system design. The present tendency of increasing current density and operating frequency, along with decreasing operating voltage, significantly diminishes voltage margins. Given the cost efficiency required for MCU systems, this context places important constraints on the design of the power distribution network (PDN), which directly impacts power supply noise. Therefore, characterizing the PDN is necessary. This paper introduces a cost-effective measurement and modeling method to estimate the die-package resonance frequency of the PDN, a major threat to power integrity. The method, applied to two 32-bit MCUs from STMicroelectronics with varying PDN configurations, enables the identification of the die-package resonance frequency. The results lead to the refinement of the die capacitance model for both cases, with a maximum relative error of less than 7%. The final objective is to implement the measurement system in the die in order to adjust the PDN if necessary.

F. Lu, Hua Zhang, C. Mi

Ali Ghaffarpour, Matin Vatani, Mohammad Amin Jalali Kondelaji et al.

Abstract Here, the authors propose two new Permanent Magnet (PM) embedded linear switched reluctance motors; one is a modular linear hybrid reluctance motor (MLHRM), and the other one is a segmental linear hybrid reluctance motor (SLHRM). Both structures employ PMs between the side teeth of the modules/segments. The main contribution of the PMs is to increase the air‐gap flux density, which results in an enhanced thrust, and decrease the magnetic saturation in iron parts. The magnetic equivalent circuit model is used to demonstrate the positive effect of inserting PMs in the MLHRM and SLHRM compared to their PMless counterparts. The optimal pole number and design procedure are illustrated. The simulation results are obtained in terms of static thrust, flux linkage, flux density distributions, and steady‐state current and thrust. The results show that the proposed MLHRM and SLHRM offer a higher thrust and lower current compared to their PMless form. Also, the PMs decrease the root mean square (RMS) current under the steady‐state performance of the motors, in which a higher thrust is produced with a lower RMS current. Finally, the MLHRM and SLHRM are fabricated and the test results are obtained and compared with the simulations, which illustrate a satisfactory agreement.

H. Chiang

Muhammad A. Butt, Nikolay L. Kazanskiy, Svetlana N. Khonina

A Bragg grating (BG) is a one-dimensional optical device that may reflect a specific wavelength of light while transmitting all others. It is created by the periodic fluctuation of the refractive index in the waveguide (WG). The reflectivity of a BG is specified by the index modulation profile. A Bragg grating is a flexible optical filter that has found broad use in several scientific and industrial domains due to its straightforward construction and distinctive filtering capacity. WG BGs are also widely utilized in sensing applications due to their easy integration and high sensitivity. Sensors that utilize optical signals for sensing have several benefits over conventional sensors that use electric signals to achieve detection, including being lighter, having a strong ability to resist electromagnetic interference, consuming less power, operating over a wider frequency range, performing consistently, operating at a high speed, and experiencing less loss and crosstalk. WG BGs are simple to include in chips and are compatible with complementary metal-oxide-semiconductor (CMOS) manufacturing processes. In this review, WG BG structures based on three major optical platforms including semiconductors, polymers, and plasmonics are discussed for filtering and sensing applications. Based on the desired application and available fabrication facilities, the optical platform is selected, which mainly regulates the device performance and footprint.

Zeyu Liu, Yan Hu, Bingyi Zhang et al.

Abstract This article presents a novel asymmetric spoke‐type rotor structure. It is used to reduce rotor magnetic flux leakage, torque ripple and no‐load back‐EMF distortion rate while increasing the motor output torque. The traditional method of optimizing torque pulsation is the inverse cosine function, which gives a sinusoidal distribution of the air‐gap magnetic field under no‐load conditions of the motor. The fundamental wave magnetic field of the air‐gap synthetic magnetic field under the load is offset from the no‐load air‐gap magnetic field. This paper presents the design theory and method of the new type of the asymmetric rotor. Asymmetric spatial harmonics are introduced to the rotor so that the motor has a sinusoidal distribution of the rated load air‐gap field under MTPA control. In order to verify the superiority of the new rotor, the performance of four different spoke‐type rotor structure motors under the same pole‐slot combination was compared. Finally, an experimental prototype is built to verify the theoretical reliability against the design of this paper.

TAN Fenglei, XU Gang, LI Yifeng et al.

As the transformer top oil temperature is affected by many factors such as weather conditions and tidal current loads,it is difficult to improve the forecasting accuracy. To solve this problem,a method of transformer top oil temperature forecasting based on similar day and similar hour is proposed,which is to further select the similar hour corresponding to each hour of the day to be forecast within the similar days,and then use the similar hour to forecast transformer top oil temperature. Firstly,K-means clustering based on meteorological factors and the principle of'near big,far small' are used to select similar days from the historical samples. On the basis of the definition and description of similar hour,the calculation steps of the oil temperature forecasting method are given by using back propagation (BP) neural network and linear weighted method,which is applied to top oil temperature forecasting of a ultra-high voltage main transformer in Jiangsu. Finally,the results show that the proposed method has high accuracy on forecasting top transformer oil temperature,which verifies its feasibility and validity.