bluuebunny/crossref_metadata_2025_split huggingface dataset:
A dynamic functional model of diode bridge rectifier for unbalanced input voltage conditions
Authors: Deriszadeh Adel , Karabasoglu Orkun , Ćalasan Martin P. , Mehdipour Farnaz 
Published: January 2021

AbstractDiode bridge rectifiers are employed in many industrial applications wherein, under practical operating conditions, input voltages can be occasionally or inherently unbalanced. Using the switching function method, this paper proposes a new accurate functional model of the diode bridge rectifier capable of dealing with unbalanced input voltage conditions. To take all degrees of unbalanced conditions into account, this paper introduces uneven commutation intervals phenomenon between diodes occurring under unbalanced voltage conditions and proposes dynamically updating switching functions.
Grid input current feedback active damping control method for IPMSM drives with small DC‐link capacitor
Authors: Yin Quan , Li Haichun , Luo Hui , Wang Qingyi , Miao Jigui , Hou Yanting 
Published: January 2021

AbstractWith large input line inductance and low dc‐link capacitance, the small dc‐link drive system shows an instability problem, which is mainly caused by LC resonance between the line side inductor and the dc‐link film capacitor. This paper proposes a grid current feedback active damping control method to improve system stability and suppress the LC resonance. The feedback variables are analyzed, and the detected grid current is selected. Thus, the damping current is consistent with the LC resonance components in grid current, which benefits the drive system power factor and grid current quality. Furthermore, the grid current feedback control loop has been established, and the feedback gain is designed based on system parameters that can be adjusted to fit different systems. The stability margin and robustness of the drive system to the changes in line inductance and dc‐link capacitance are improved. Compared with the conventional voltage‐based damping method, the power factor is increased to 0.984 and the grid current harmonics are reduced to satisfy the requirements of EN61000‐3‐2. The effectiveness of the proposed active damping method is verified by the experimental results.
Single‐phase AC‐AC Z‐source converter based on asymmetrical gamma structure with continuous input current and safe commutation strategy
Authors: Mousavi Seyyed Mohammad Javad , Babaei Ebrahim , Alizadeh Darioush , Komurcugil Hasan 
Published: January 2021

AbstractThis paper examines a new topology of the AC‐AC Z‐source converter based on asymmetric Gama structure is proposed. The proposed converter has all the common features such as common ground between input and output, realizing the continuous input current and the ability of boost in‐phase and buck out of‐phase. In order to generate a high voltage gain in the proposed converter, a coupled inductor with Gama structure is used. In this structure, as the turn ratio approaches to one, it gives a higher voltage gain. In order to damping the voltage and current overshoots on the proposed converter switches, a safe commutation strategy is used. Due to the specific topology of the proposed converter, the output filter has been eliminated, so the size and cost of the proposed converter are reduced. Circuit analysis and performance principles are presented in detail and a laboratory prototype implemented to confirm the practicality of the proposed converter.
High‐frequency pulse width modulation noise reduction for permanent magnet synchronous motors using hybrid asymmetrical regular sampled modified space‐vector pulse width modulation
Authors: Zhang Wentao , Xu Yongxiang , Yu Guodong , Zou Jibin 
Published: January 2021

AbstractThis paper proposes a strategy called hybrid asymmetrical regular sampled modified space‐vector pulse width modulation technique in two‐level voltage source inverters. Based on the existing modified space‐vector pulse width modulation, the presented strategy further changes the phase voltage waveform and carrier period, therefore not only eliminating the pulse width modulation noise nearby odd‐order carrier frequency but also reducing the noise around even‐order carrier frequency. Moreover, the frequency band is not elevated due to the periodical varying switching frequency. Under the condition of achieving similar high‐frequency harmonic performance, the proposed strategy will save at least 25% switching loss compared with conventional space‐vector pulse width modulation. Moreover, the dynamic performance of the drive system using the hybrid asymmetrical regular sampled modified space‐vector pulse width modulation can also be improved by asymmetrical regular sample. Implementation process has been introduced and the noise elimination principle has been analysed by mathematical demonstration. Finally, the effectiveness of the proposed strategy has been confirmed by simulation and detailed experimental results.
Open‐switch fault diagnosis in three‐level rectifiers based on selective calculation method for instant voltage deviation
Authors: Chen Mingyun , He Yigang , Sui Chunsong 
Published: January 2021

AbstractThis paper presents an open‐switch fault detection, and identification method for a neutral‐point clamped rectifier system. A new calculation method for phase‐to‐phase pole voltage deviations is proposed for reducing calculation errors. In this way, the more accurate diagnosis can be achieved. Both single‐switch faults, and multiple‐switch faults can be identified effectively by using fewer diagnostic variables, which makes the diagnostic method simpler, and more reliable. And all the variables can be simply calculated by signals which are available to the control system of the rectifier, avoiding the use of additional hardware. Moreover, different voltage thresholds are designed for different faulty feature sections to further reduce the diagnostic time. Additionally, a diagnostic result checking method is proposed to avoid the misdiagnosis when considering the effect of outer‐switch faults. Finally, experiments are carried out, and the results show the robustness, and effectiveness of the proposed method.
Optimal energy management for PV‐integrated residential systems including energy storage system
Authors: Varzaneh S. Ghafouri , Raziabadi A. , Hosseinzadeh Mohammad , Sanjari Mohammad J. 
Published: January 2021

AbstractEconomic profit is the main incentive for PV‐integrated residential prosumers, so energy management algorithms play a key role in these systems. The main priority of conventional rule‐based energy management systems (REMS) is to supply the demand. As a result, the total amount of energy sold to the distribution network, and consequently the user profit in such systems, is not considerable. This study proposes a smart energy management system (SEMS) for optimal energy management in a grid‐connected residential photovoltaic (PV) system, including battery as an energy storage unit. The proposed method, which is simulated by MATLAB, using real values for load and PV characteristics, will result in achieving an economic plan for battery operation based on a discretised state of charge of the battery. Experimental tests, carried out to verify the simulation results, demonstrate a noticeable increase in the prosumer benefits as well as the load profile correction compared to the classic energy management algorithms.
A new impedance measurement method and its application to stability analysis of the inverter‐grid system
Authors: Liu Junliang , Du Xiong , Shi Ying , Tai Heng‐Ming 
Published: January 2021

AbstractGrid‐connected inverter have been extensively used in the renewable energy grid‐connect systems, such as solar and wind. Interaction between the grid and the inverter may generate harmonic resonances that lead to reduced power quality and even instability. To analyse the stability of the inverter‐grid system using impedance‐based stability criterion, inverter impedance has to be known. Impedance measurement in the dq‐domain requires the precise synchronous phase angle to obtain accurate measurement. For impedance measurement in the stationary frame, inaccuracy usually results from not considering the effects of grid impedance and the frequency coupling. A new impedance measurement method in the stationary frame is proposed to obtain accurate measurement. The proposed method takes into account the grid impedance and its interaction with the inverter. Thus, it overcomes the limitations of current impedance measurement methods. More important, the proposed method enables accurate stability analysis results, whereas current methods may fail. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed measurement method.
Blackstart from HVDC‐connected offshore wind: Hard versus soft energization
Authors: Jain Anubhav , Saborío‐Romano Oscar , Sakamuri Jayachandra N. , Cutululis Nicolaos A. 
Published: January 2021

AbstractIn recent years, renewable energy sources have been integrated on a large scale in power systems all around the world to address the environmental sustainability concerns. With conventional thermal generators being phased out, large offshore wind power plants present a viable alternative to provide blackstart services for power system restoration. By means of simulations, grid‐forming wind turbines are shown to successfully energize the offshore transformer and the high‐voltage direct current (HVDC) export link in a controlled manner, to ultimately supply onshore block load. Two methods for energizing the offshore network have been compared: the prevalent hard‐switching approach and the more complex soft‐start method. Additionally, control has been implemented to mitigate the significant transients in the export link associated with pre‐charging of the onshore converter. It is shown that soft‐start can provide faster energization with smaller transients compared to hard‐switching. Moreover, the sensitivity analyses performed in this study illustrate the impact of pre‐insertion resistor and voltage ramp‐up rates on transients during hard‐switching and soft‐start, respectively. The results presented also show that grid‐forming wind power plants can deal with controlled pre‐charging of the onshore converter from its DC terminals that is essential for the safe energization and operation of the export link.
Impact analysis of time‐varying voltage‐dependent load models on hybrid DG planning in a radial distribution system using analytical approach
Authors: M.L. Merlin Sajini , S. Suja , S. Merlin Gilbert Raj 
Published: January 2021

AbstractThis paper investigates the impact of time‐varying voltage‐dependent load models on hybrid distributed generation planning studies. Firstly, a multi‐objective index is constructed with indices namely real and reactive power loss index, voltage deviation index, and mega‐volt‐ampere capacity index with an objective of reduction of real and reactive power loss, voltage profile improvement, and decreased line loading. The multi‐objective index derived is minimised to locate the distributed generation. Secondly, the analytical expression is obtained to size the distributed generation units with the time‐varying voltage‐dependent load models and probabilistic nature of solar and wind generation. Finally, the impact of load models with the generation effects is separately analysed for PV/wind (hybrid) distributed generation planning. The proposed perspective was validated on the IEEE 33‐bus, IEEE 69‐bus radial distribution network, and a real 16‐bus distribution substation for its effectiveness because the distributed generators are placed in the distribution side of an electrical network. The outcomes reveal that the distributed generation allocation for time‐varying voltage‐dependent load model and probabilistic nature of solar and wind has significant impacts on the distribution system by reducing real and reactive power loss, improving voltage deviation and reduced mega‐volt‐ampere intake.
Effects of motor–generator pair system on improving inertial response and primary frequency regulation capability of renewable energy
Authors: Gu Yujun , Huang Yongzhang , Li Chenyang , Guan Fei , Fu Wenqi , Zhan Yang , Zhao Haisen 
Published: January 2021

AbstractThe increasing penetration of renewable energy leads to the decrease of inertia and damping for replacing conventional power plants. The motor–generator pair (MGP) is proposed to improve inertial response and frequency regulation capability for the renewable energy. First, the mathematical model of the MGP and the control method of DC‐link voltage are given. Then, the inertial characteristics of the MGP are analysed, and a mass block is designed by analysing the key factor affecting the moment of inertia. The transient processes in two machines are discussed by comparing the variations of the voltage and current vectors. It turns out that the electromagnetic–mechanical coupling is the key to realise the primary frequency regulation without frequency acquisition. The photovoltaic (PV) is chosen to illustrate the mechanism of achieving a better primary frequency response with DC‐link voltage control methods based on the de‐loading and additional frequency deviation strategies. A grid‐scale simulation model is built to verify the effectiveness of the proposed scheme. Furthermore, six groups of experiments are designed and performed on an experimental bench. The simulation and experimental results demonstrate that the inertial response and primary frequency response of PV can be improved effectively by adopting MGP for grid connection.
Contingency‐constrained operation optimization of microgrid with wind and solar generations: A decision‐driven stochastic adaptive‐robust approach
Authors: Ebrahimi Mohammad Reza , Amjady Nima 
Published: January 2021

AbstractThis paper presents a decision‐driven stochastic adaptive‐robust microgrid operation optimization model considering the uncertainties of wind and solar generations, electricity price, and demand as well as the availability uncertainties of microgrid's components. Unlike previous works, this paper utilizes stochastic adaptive‐robust optimization approach to model both continuous and binary uncertainties simultaneously. To do so, adaptive‐robust optimization is used to model the continuous uncertainties, while the binary uncertainties are modelled by means of stochastic programming. An operating dispatchable unit usually exhibits a higher forced outage rate than a de‐committed one. Hence, due to the effect of the optimization decisions on the availability uncertainties, this research work proposes an intrinsic scenario production technique to model these binary uncertainties. In addition, a tri‐level decomposition method is introduced to solve the proposed microgrid operation optimization problem. In this decomposition method, the worst‐case realization of continuous uncertain parameters and unit commitment decisions are determined at each iteration considering the produced scenarios in the previous iteration. Case studies on the IEEE 69‐bus test system exhibit the effectiveness of the proposed decision‐driven stochastic adaptive‐robust model and the proposed solution method.
A state of charge‐based linearised frequency–voltage droop for interlinking converters in an isolated hybrid microgrid
Authors: Malik Sarmad Majeed , Sun Yingyun 
Published: January 2021

AbstractA battery‐dominated hybrid microgrid architecture where various battery modules are linked to the ac bus via converters is presented. A novel frequency–voltage droop scheme is proposed for the interlinking converter connecting the dc and ac grids. The ac grid frequency and dc grid voltage are linked together in outer controller loop through two factors, the ratio of which defines the frequency–voltage droop. This enables autonomous bidirectional power flow and regulation where each grid is supporting the other grid through its surplus power. A state of charge (SOC)‐based control scheme is also proposed for the battery units linked to ac bus which ensures power sharing based on the SOC of individual storage units. The system small‐signal model is developed and a stable range of operation is defined. The impact of number of battery units and SOC of an individual battery on the system performance is also analysed. In addition, the proposed strategy is compared with normalised SOC‐based control to evaluate its feasibility. Simulations in PSCAD/EMTDC show that the proposed SOC‐based scheme helps maintain charge balance while regulating the voltage and frequency and ensuring power flow among battery units and grids.
A full sequence impedance modelling and stability analysis of the virtual synchronous generator with inner loops
Authors: Peng Yang , Wang Yue , Liu Yonghui , Yu Peng , Shu Sirui , Lei Wanjun 
Published: January 2021

AbstractVirtual synchronous generator (VSG) has been widely studied owing to its inertia support to the grid. However, the stability of VSG is not analysed accurately for actual applications in previous studies that overlook voltage and current inner loops of VSG. Since inner loops are essential to control output voltage and current accurately in practical engineering, this study focuses on stability analysis of the interconnection system of VSG and the grid by sequence impedance modelling of VSG with inner loops. The complete sequence impedance model for VSG with inner loops is built and compared with that of the VSG‐ignoring inner loops, and then the stability is analysed based on that. It shows that inner loops bring the risk of instability and oscillation for VSG, which was not predicted in previous studies. Then, the influence of each parameter of inner loops on the impedance and oscillation is analysed, showing that the oscillation can hardly be eliminated by tuning the parameters of inner loops. Therefore, corresponding virtual resistor with proper value is studied and adopted in VSG with inner loops to avoid oscillation. Finally, the correctness of theoretical analysis and the effectiveness of the adopted virtual resistance are verified by the hardware‐in‐the‐loop experiments.
Islanding detection in distributed energy resources based on gradient boosting algorithm
Authors: Azizi Resul , Noroozian Reza 
Published: January 2021

AbstractThis paper proposes a novel passive‐based intelligent method for anti‐islanding. Passive methods generally suffer from the improper tuning of threshold values for measured variables and false detection when the active or reactive power mismatch is small. Conversely, intelligence‐based methods highly depend on the choice of an appropriate model, the universality of data and selected features. In addition, the risk of overfitting and underfitting for a single model due to an improper selected feature or insufficient data is always possible. This condition makes a single classification model unreliable for practical purposes. The method used in this work is a sequential ensemble of intelligence‐based models called gradient boosting. The sequential form of an ensemble is substantially designed to solve the underfitting problem. In addition, by selecting the best combination of features and ensembles, algorithm overfitting can be prevented and the attribute data space can be constructed with maximum discrimination. Furthermore, this condition yields a model with a zero non‐detection zone. As a result, a multi‐objective optimisation method called the non‐dominated sorting genetic algorithm‐III is used to tune the model. The reliability and economy of this method for distribution networks with various types of inverter‐based and synchronous distributed energy resources are demonstrated.
Reference voltage vector based model predictive control for semicontrolled open‐winding flux‐switching permanent magnet generator system with a novel zero‐sequence current suppression strategy
Authors: Zhao Shuangshuang , Yu Feng , Liu Xing , Hua Wei 
Published: January 2021

AbstractThis paper studies a reference voltage vector (RVV) based model predictive control (MPC) for semicontrolled open‐winding flux‐switching permanent magnet generator (SOW‐FSPMG). Common dc bus is adopted in this configuration, thereby leading to zero‐sequence current (ZSC). The first concern of this work is put into proposing a novel ZSC suppression strategy, which is on the basis of the redundant vector pre‐selection. Secondly, a deadbeat flux control (DBFC) is adopted to calculate the RVV. Then, only 4, 3 or 2 vectors adjacent to the RVV are of interest during each sampling period, thereby decreasing the computation burden; meanwhile, a simplified cost function that evaluates the error between the RVV and the prediction voltage vectors is defined. Thirdly, the side effect of dead‐time inherent to voltage source converter (VSC) on the system's steady‐state performance is analysed and discussed. In order to properly leverage the dead‐time, a solution to regulate duty‐cycles of the dead‐time voltage vector and the selected one is studied, by which means, steady‐state performance of the system can be highly improved. Finally, experimental results are presented to verify the correctness and effectiveness of the proposed method.
Feasibility study of a renewable system (PV/HKT/GB) for hybrid tramway based on fuel cell and super capacitor
Authors: Arévalo Paul , Cano Antonio , Benavides Javier , Jurado Francisco 
Published: January 2021

AbstractThe configuration, modelling and control of several possible hybrid systems for the propulsion of the existing tramway in Cuenca‐Ecuador are analysed. The system consists of novel renewable sources: Photovoltaic energy, hydrokinetic turbines and a biomass gasifier, which increases the reliability of the system and reduces CO2 emissions. In addition, a proton exchange fuel cell and a super capacitor thatsupply the necessary power for the tramway, as well as, a hydrogen tank that stores the excess energy. Energy management is done through renewable sources that recharge the super capacitor and the fuel cell at the charging stations along the tramway route. Different renewable hybrid systems have been analysed, which indicates that the most favourable case from a technical, environmental and economic point of view using data analysis and machine learning techniques is S4. Sensitivity analyses allow the study of variables such as CO2, net present cost and COE for different demand variations, as well as, for the minimum state of charge in the super capacitor. The results indicate the optimal net present cost is M$ 1.46 and 0.12 $ kWh−1 in cost of energy, validity of the proposed system in the round trip of the tramway.
Artificial ecosystem‐based optimiser to electrically characterise PV generating systems under various operating conditions reinforced by experimental validations
Authors: Elkholy Mahmoud M. , El‐Hameed Mohamed A. , El‐Fergany Attia A. 
Published: January 2021

AbstractEfficient modelling of photovoltaic (PV) generating units' characteristics to investigate their steady‐state and dynamic impacts on the performances of power systems and electric drives is essential. The current work aims at developing an effective tool based on artificial ecosystem optimiser (AEO) to define (optimally) the uncertain parameters of PV generating units. The root mean squared deviations (RMSDs) along with the predefined inequality constraints formulate the optimization problem to be solved by the AEO. Initially, two test cases with different PV technologies are demonstrated complete with their relevant discussions and necessary validations. At a later stage, real measurements (followed the procedures of IEC 60904) of a commercial PV module namely Ultra 85‐P of Shell PowerMax are made for further experimental validations of the AEO results. Various operating temperatures and sun irradiance levels are investigated among the simulated scenarios. The statistical validations along with predefined indices plus comparisons to other competing methods appraise the results obtained by the AEO. It can be confirmed that the AEO is able to produce best values of unidentified parameters of the PV units with different solar technologies under study with lesser values of RMSDs among other optimisers.