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1
Kumar, Geddam Kiran, and Devaraj Elangovan. "Review on fault‐diagnosis and fault‐tolerance for DC–DC converters." IET Power Electronics 13, no. 1 (2020): 1–13. http://dx.doi.org/10.1049/iet-pel.2019.0672.
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Caseiro, Luís, and André Mendes. "Fault Analysis and Non-Redundant Fault Tolerance in 3-Level Double Conversion UPS Systems Using Finite-Control-Set Model Predictive Control." Energies 14, no. 8 (2021): 2210. http://dx.doi.org/10.3390/en14082210.
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Fault-tolerance is critical in power electronics, especially in Uninterruptible Power Supplies, given their role in protecting critical loads. Hence, it is crucial to develop fault-tolerant techniques to improve the resilience of these systems. This paper proposes a non-redundant fault-tolerant double conversion uninterruptible power supply based on 3-level converters. The proposed solution can correct open-circuit faults in all semiconductors (IGBTs and diodes) of all converters of the system (including the DC-DC converter), ensuring full-rated post-fault operation. This technique leverages the versatility of Finite-Control-Set Model Predictive Control to implement highly specific fault correction. This type of control enables a conditional exclusion of the switching states affected by each fault, allowing the converter to avoid these states when the fault compromises their output but still use them in all other conditions. Three main types of corrective actions are used: predictive controller adaptations, hardware reconfiguration, and DC bus voltage adjustment. However, highly differentiated corrective actions are taken depending on the fault type and location, maximizing post-fault performance in each case. Faults can be corrected simultaneously in all converters, as well as some combinations of multiple faults in the same converter. Experimental results are presented demonstrating the performance of the proposed solution.
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Ravyts, Simon, Mauricio Dalla Vecchia, Giel Van den Broeck, and Johan Driesen. "Review on Building-Integrated Photovoltaics Electrical System Requirements and Module-Integrated Converter Recommendations." Energies 12, no. 8 (2019): 1532. http://dx.doi.org/10.3390/en12081532.
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Since building-integrated photovoltaic (BIPV) modules are typically installed during, not after, the construction phase, BIPVs have a profound impact compared to conventional building-applied photovoltaics on the electrical installation and construction planning of a building. As the cost of BIPV modules decreases over time, the impact of electrical system architecture and converters will become more prevalent in the overall cost of the system. This manuscript provides an overview of potential BIPV electrical architectures. System-level criteria for BIPV installations are established, thus providing a reference framework to compare electrical architectures. To achieve modularity and to minimize engineering costs, module-level DC/DC converters preinstalled in the BIPV module turned out to be the best solution. The second part of this paper establishes converter-level requirements, derived and related to the BIPV system. These include measures to increase the converter fault tolerance for extended availability and to ensure essential safety features.
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Aguayo-Alquicira, Jesus, Iván Vásquez-Libreros, Susana Estefany De Léon-Aldaco, et al. "Reconfiguration Strategy for Fault Tolerance in a Cascaded Multilevel Inverter Using a Z-Source Converter." Electronics 10, no. 5 (2021): 574. http://dx.doi.org/10.3390/electronics10050574.
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The cascade multilevel inverters are widely used in industrial manufacturing processes for DC-AC conversion. Therefore, the reliability and efficiency improvement, optimized control, and fault-tolerant strategies are areas of interest for researchers. The fault tolerance strategies applied to cascade multilevel inverters are classified as material redundancy and analytical redundancy. This paper presents the use of the Z-source converter as a fault reconfiguration method applied to a cascade multilevel inverter. On the one hand, the proposed approach has the characteristic of combining the use of material redundancy (modifying the output voltage by changing the Z-source operation), and on the other hand, it has the use of analytical redundancy (modifying the switching sequence of the multilevel inverter, changing from symmetrical to asymmetrical operation mode). This approach has been validated by experimental results of the system under fault-free conditions and employing the Z-source converter as the main fault reconfiguration element. The proposed fault reconfiguration strategy allows the cascaded multilevel inverter to continue to operate even in the presence of a fault by having continuous operation.
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Benali, Abdelkrim, Mounir Khiat, and Mouloud Denai. "Voltage profile and power quality improvement in photovoltaic farms integrated medium voltage grid using dynamic voltage restorer." International Journal of Power Electronics and Drive Systems (IJPEDS) 11, no. 3 (2020): 1481. http://dx.doi.org/10.11591/ijpeds.v11.i3.pp1481-1490.
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<p class="Abstract">In this paper, we have presented a simulation study to analyze the power quality of three phases medium voltage grid connected with distribution generation (DG) such as photovoltaic (PV) farms and its control schemes. The system uses two-stage energy conversion topology composed of a DC to DC boost converter for the extraction of maximum power available from the solar PV system based on incremental inductance technique and a three-level voltage source inverter (VSI) to connect PV farm to the power grid. To maintain the grid voltage and frequency within tolerance following disturbances such as voltage swells and sags, a fuzzy logic-based Dynamic Voltage Restorer is proposed. The role of the DVR is to protect critical loads from disturbances coming from the network. Different fault conditions scenarios are tested and the results such as voltage stability, real and reactive powers, current and power factor at the point of common coupling (PCC) are compared with and without the DVR system.</p>
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Gruson, François, Amine Tlemcani, Yafang Li, Philippe Delarue, Philippe Le Moigne, and Xavier Guillaud. "Model and control of the DC–DC modular multilevel converter with DC fault tolerance." EPE Journal 30, no. 4 (2020): 153–64. http://dx.doi.org/10.1080/09398368.2020.1750847.
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Luna, Benjamin Vidales, José Luis Monroy-Morales, Manuel Madrigal Martínez, Domingo Torres-Lucio, Serge Weber, and Patrick Schweitzer. "Analysis of Internal Signal Perturbations in DC/DC and DC/AC Converters under Arc Fault." Energies 14, no. 11 (2021): 3005. http://dx.doi.org/10.3390/en14113005.
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The constant increase in electrical energy consumption has led to a growth of photovoltaic installations (PV) along with the corresponding power converters for proper operation. Power electronics converters represent a challenge to maintain the system’s performance and safety; one such problem is series DC Arc Fault (AF). DC AFs lead to fire risk, damaging the main bus and the loads when not detected and interrupted in time. Therefore, research about DC AFs in power electronics converters must be carried out to predict the behavior and help avoid damage to the system. In this work, an innovative hybrid multilevel inverter for PV applications is used to explore the effect of series DC AFs in the converters’ internal signals, with the aims of setting the bases for the development of a detection system for power electronics. Both stages of conversion (DC/DC and DC/AC) are presented. In addition, the placement of the MPPT converter was considered for the tests. The AF experimental tests were performed with a generator based on the UL1699B specifications. The measurements of signals were performed in strategic points of the DC side, and changes and how to exploit them are discussed. This study contributes to a better understanding of the DC AF phenomenon and provides new insights for the development of new PV system protections.
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Zhou, Shijia, Fei Rong, Zhangtao Yin, Shoudao Huang, and Yuebin Zhou. "HVDC Transmission Technology of Wind Power System with Multi-Phase PMSG." Energies 11, no. 12 (2018): 3294. http://dx.doi.org/10.3390/en11123294.
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The high voltage DC (HVDC) transmission technology of wind power system, with multi-phase permanent magnetic synchronous generator (PMSG) is proposed in this paper. Each set of three-phase winding of the multi-phase PMSG was connected to a diode rectifier. The output of the diode rectifier was connected by several parallel isolated DC–DC converters. Each DC–DC converter was connected to a sub-module (SM). All SMs and two inductors were connected in a series. The proposed wind power system has several advantages including, transformerless operation, low cost, low voltage stress, and high fault tolerance. The maximum power point tracking (MPPT) and energy balance of the DC–DC converters were achieved by controlling the duty cycles of the DC–DC converters. The HVDC transmission was achieved by the nearest level control (NLC) with voltage sorting. The simulation model with 18-phase PMSG was established. Experimental results were also studied based on RT-Lab.
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Lee, Chun-Kwon, Gyu-Sub Lee, and Seung-Jin Chang. "Solution to Fault of Multi-Terminal DC Transmission Systems Based on High Temperature Superconducting DC Cables." Energies 14, no. 5 (2021): 1292. http://dx.doi.org/10.3390/en14051292.
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In this paper, we developed the small-signal state-space (SS) model of hybrid multi-terminal high-voltage direct-current (HVDC) systems and fault localization method in a failure situation. The multi-terminal HVDC (MTDC) system is composed of two wind farm side voltage-source converters (VSCs) and two grid side line-commutated converters (LCCs). To utilize relative advantages of the conventional line-commutated converter (LCC) and the voltage source converter (VSC) technologies, hybrid multi-terminal high-voltage direct-current (MTDC) technologies have been highlighted in recent years. For the models, grid side LCCs adopt distinct two control methods: master–slave control mode and voltage droop control mode. By utilizing root-locus analysis of the SS models for the hybrid MTDC system, we compare stability and responses of the target system according to control method. Furthermore, the proposed SS models are utilized in time-domain simulation to illustrate difference between master–slave control method and voltage droop control method. However, basic modeling method for hybrid MTDC system considering superconducting DC cables has not been proposed. In addition, when a failure occurs in MTDC system, conventional fault localization method cannot detect the fault location because the MTDC system is a complex form including a branch point. For coping with a failure situation, we propose a fault localization method for MTDC system including branch points. We model the MTDC system based on the actual experimental results and simulate a variety of failure scenarios. We propose the fault localization topology on a branch cable system using reflectometry method. Through the simulation results, we verify the performance of fault localization. In conclusion, guidelines to select control method in implementing hybrid MTDC systems for integrating offshore wind farms and to cope with failure method are provided in this paper.
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M., Venkateswaran, Govindaraju C., and Santhosh T.K. "Integrated predictive control and fault diagnosis algorithm for single inductor-based DC-DC converters for photovoltaic systems." Circuit World 47, no. 1 (2020): 105–16. http://dx.doi.org/10.1108/cw-11-2019-0166.
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Purpose Power converters are an integral part of the energy conversion process in solar photovoltaic (PV) systems which is used to match the solar PV generation with the load requirements. The increased penetration of renewable invokes intermittency in the generated power affecting the reliability and continuous energy supply of such converters. DC-DC converters deployed in solar PV systems impose stringent restrictions on supplied power, continuous operation and fault prediction scenarios by continuously observing state variables to ensure continuous operation of the converter. Design/methodology/approach A converter deployed for a mission-critical application has to ensure continuous regulated output for which the converter has to ensure fault-free operation. The fault diagnostic algorithm relies on the measurement of a state variable to assess the type of fault. In the same line, a predictive controller depends on the measurement of a state variable to predict the control variable of a converter system to regulate the converter output around a fixed or a variable reference. Consequently, both the fault diagnosis and the predictive control algorithms depend on the measurement of a state variable. Once measured, the available data can be used for both algorithms interchangeably. Findings The objective of this work is to integrate the fault diagnostic and the predictive control algorithms while sharing the measurement requirements of both these control algorithms. The integrated algorithms thus proposed could be applied to any converter with a single inductor in its energy buffer stage. Originality/value laboratory prototype is created to verify the feasibility of the integrated predictive control and fault diagnosis algorithm. As the proposed method combine the fault detection algorithm along with predictive control, a load step variation and manual fault creation methods are used to verify the feasibility of the converter as with the simulation analysis. The value for the capacitors and inductors were chosen based on the charge-second and volt-second balance equations obtained from the steady-state analysis of boost converter.
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Banteywalu, Solomon Mamo, Getachew Bekele, Baseem Khan, Valentijn De Smedt, and Paul Leroux. "A High-Reliability Redundancy Scheme for Design of Radiation-Tolerant Half-Duty Limited DC-DC Converters." Electronics 10, no. 10 (2021): 1146. http://dx.doi.org/10.3390/electronics10101146.
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Redundancy techniques are commonly used to design radiation- and fault-tolerant circuits for space applications, to ensure high reliability. However, higher reliability often comes at a cost of increased usage of hardware resources. Triple Modular Redundancy (TMR) ensures full single fault masking, with a >200% power and area overhead cost. TMR/Simplex ensures full single fault masking with a slightly more complicated circuitry, inefficient use of resource and a >200% power and area overhead cost, but with higher reliability than that of TMR. In this work, a high-reliability Spatial and Time Redundancy (TR) hybrid technique, which does not abandon a working module and is applicable for radiation hardening of half-duty limited DC-DC converters, is proposed and applied to the design of a radiation-tolerant digital controller for a Dual-Switch Forward Converter. The technique has the potential of double fault masking with a <2% increase in resource overhead cost compared to TMR. Moreover, for a Simplex module failure rate, λ, of 5%, the Reliability Improvement Factor (RIF) over the Simplex system is 20.8 and 500 for the proposed technique’s two- and three-module implementations, respectively, compared to a RIF over the Simplex system of only 7.25 for TMR and 14.3 for the regular TMR/Simplex scheme.
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Li, Po, Xiang Li, and Tao Zeng. "A Fast and Simple Fault Diagnosis Method for Interleaved DC-DC Converters Based on Output Voltage Analysis." Electronics 10, no. 12 (2021): 1451. http://dx.doi.org/10.3390/electronics10121451.
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Interleaved DC-DC converters have been widely used in power conversion due to their high efficiency and reliability. In the application of new energy, this plays an increasingly important role in the grid-connected power generation of wind, solar, and tidal energy. Therefore, it is crucial to ensure the reliability and proper operation of interleaved DC-DC converters. We studied an open circuit fault (OCF) diagnosis method for a three-phase interleaved buck converter. We propose a non-invasive diagnosis method based on the output voltage using the harmonic amplitude and phase at the switching frequency as the diagnostic criteria. Evaluation was carried out on a hardware-in-the-loop (HIL) test platform to prove the validity of the proposed method. The results show that the presented method had high accuracy and robustness against OCFs, which could otherwise damage the system.
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Wang, Zhuodi, Kejun Li, Jun Liang, Kaiqi Sun, Jinyu Wang, and Zhijie Liu. "Coordinated Control Strategy of CU-MTDC under Abnormal Conditions Considering Power Supply Security." Applied Sciences 11, no. 4 (2021): 1539. http://dx.doi.org/10.3390/app11041539.
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The coastal urban multi-terminal DC (CU-MTDC) is a prospective solution for enhancing the power supply security of the coastal urban power (CUP) grid and integrating the large-scale offshore wind farm. However, the large DC disturbances may significantly impact the CUP power supply security. The existing DC unbalanced power distribution methods are difficult to be applied in the CU-MTDC because of the complicated optimization process and the expansion of the influence range of a DC fault. To solve the above problems, this paper proposes a coordinated control strategy of CU-MTDC under abnormal conditions. First, calculation principles for the active power reference of center coastal urban power (CCUP) grid converters are proposed. Second, a DC unbalanced power coordinated distribution strategy under abnormal conditions is used based on the dynamic priority control to ensure power supply security of the critical AC lines. Third, the controller parameters of CCUP grid converters are calculated. Through a simple control process, the number of the regulation converters is dynamically scheduled according to the DC unbalanced power. The DC fault influence range on the urban power grid can be limited in a sufficiently small area. Simulation verified the effectiveness of the proposed control strategy.
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Zhu, Qinyue, Wei Dai, Lei Guan, Xitang Tan, Zhaoyang Li, and Dabo Xie. "A Fault-Tolerant Control Strategy of Modular Multilevel Converter with Sub-Module Faults Based on Neutral Point Compound Shift." Energies 12, no. 5 (2019): 876. http://dx.doi.org/10.3390/en12050876.
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In view of the complex calculation and limited fault tolerance capability of existing neutral point shift control algorithms, this paper studies the fault-tolerant control method for sub-module faults in modular multilevel converters on the basis of neutral point compound shift control strategy. In order to reduce the calculation complexity of shift parameters in the traditional strategy and simplify its implementation, an improved AC side phase voltage vector reconstruction method is proposed, achieving online real-time calculation of the modulation wave adjustment parameters of each phase required for fault-tolerant control. Based on this, a neutral point DC side shift control method is proposed to further improve the fault tolerance capability of the modular multilevel converter (MMC) system by compensating the fault phase voltage with non-fault phase voltage. By means of the compound shift control strategy of the DC side and AC side of the neutral point, an optimal neutral point position is selected to ensure that the MMC system output line voltage is symmetrical and the amplitude is as large as possible after fault-tolerant control. Finally, the effectiveness and feasibility of the proposed control strategy are verified by simulation and low-power MMC experimental system testing.
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Kim, Ui-Jin, and Seok-Gyu Oh. "New Sub-Module with Reverse Blocking IGBT for DC Fault Ride-Through in MMC-HVDC System." Energies 14, no. 6 (2021): 1551. http://dx.doi.org/10.3390/en14061551.
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When integrating multi-grid renewable energy systems, modular multi-level converters (MMCs) are promising for high-voltage DC (HVDC) transmission. Because of the characteristics of the system, however, it is more difficult to prevent a fault at the DC terminal than at the AC terminal of the MMC. Accordingly, a fault ride-through (FRT) strategy for the operation of the MMC in the DC terminal is required for stable system operation. In this paper, a solution for closed-circuit overcurrent caused by a permanent line-to-line DC fault is proposed. This method is able to reduce the fault current through the adjustment of the slope of the total voltage in the system by operating a sub-module having lower switching losses and fewer passive devices compared with existing topologies. Additionally, through the equivalent circuit of the proposed scheme in a sub-module in case of a fault, the FRT mechanism for the fault current is explained. The feasibility of this proposed technique was verified through time-domain simulations implemented by Powersim, Inc.
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Renaudineau, Hugues, Pol Paradell-Solà, Lluís Trilla, Alber Filba-Martinez, David Cardoner, and José Luis Domínguez-García. "Reliability Assessment of a Fault-Tolerant PV Multistring Inverter." Energies 13, no. 24 (2020): 6525. http://dx.doi.org/10.3390/en13246525.
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In photovoltaic (PV) systems, the reliability of the system components, especially the power converters, is a major concern in obtaining cost effective solutions. In order to guarantee service continuity in the case of failure of elements of the PV converter, in particular, semiconductor switching devices, a solution is to design power converter with fault-tolerance capability. This can be realized by aggregating hardware redundancy on an existing converter, providing the possibility of replacement of faulty elements. This paper evaluates the reliability of a fault-tolerant power electronics converter for PV multistring application. The considered fault-tolerant design includes a single redundant switching leg, which is used in order to reconfigure the structure in case of a switch failure either on DC-AC or DC-DC stages. This paper details the reliability estimation of the considered PV multistring fault-tolerant converter. Furthermore, a comparison with a conventional structure without fault-tolerant capability is provided. The results show that the introduction of a single redundant leg allows for improving the converter mean time to failure by a factor of almost two and it reduces, by half, the power loss due to system-failure shutdowns in PV applications, while only increasing the converter cost by 2–3%.
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YAQOBI, Mohammad Aman, Hidehito Matayoshi, Natarajan Prabaharan, Hiroshi Takahashi, Ashraf M. Hemeida, and Senjyu Tomonobu. "Interconnected standalone DC microgrid fault protection based on Self-Adaptive DC fault current limiter with hybrid solid state circuit breaker." AIMS Energy 9, no. 5 (2021): 991–1008. http://dx.doi.org/10.3934/energy.2021045.
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<abstract><p>DC system has the potential of vast and rapid fault current generation due to multiple (line and converters) discharge capacitors and small impedance of DC lines. DC fault current spreads through the system exponentially compared to AC. Such an unexpected huge current causes a voltage drop, impacts the normal operation of system components and exposes the system to a great challenge for fault detection and interruption. For prevention of system destruction during the fault, multiple approaches such as application of Mechanical Circuit Breakers (MCBs), fuses, Solid State Circuit Breaker (SSCB), and Hybrid Solid-State Circuit Breaker (HSSCB) have been proposed and applied. In DC fault applications, fast fault detection and interruption without any interference to the other components are quite important. Therefore, semiconductor breakers have been implemented to meet the DC fault protection requirements with a high-speed operation where traditional MBs have failed. Due to the high conduction loss and low efficiency of semiconductor switches, for fast and efficient DC fault interruption, different Fault Current Limiter (FCL) types are suggested. Although a high impedance FCL can prevent the voltage fluctuations due to the current decline, it can cause operation speed issues, coordination troubles, overheat, and malfunction of protective components in a fault situation.</p> <p>This paper focused on a combination of two-way HSSCB with a self-adapt DC short current limiter, ultra-fast switch, and power electronic switch to overcome the above challenges. It can efficiently and fast fault current limiting response with low conducting loss and appropriate cooperation among protective components in a low voltage DC system. The MATLAB/Simulink is used to analyze the effectiveness and consistency of the proposed FCL-HSSCB in 400 <italic>V</italic> interconnected standalone DC microgrids.</p></abstract>
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Keskar, Neeraj A., and Gabriel A. Rincón-Mora. "One Clock-Cycle Response 0.5 m CMOS Dual-Mode DC-DC Bypass Boost Converter Stable over Wide Variations." Advances in Power Electronics 2010 (May 11, 2010): 1–9. http://dx.doi.org/10.1155/2010/253508.
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Power supplies in portable applications must not only conform and adapt to their highly integrated on-chip and in-package environments but also, more intrinsically, respond quickly to fast load dumps to achieve and maintain high accuracy. The frequency-compensation network, however, limits speed and regulation performance because it must cater to all combinations of filter capacitor , inductor L, and 's equivalent series resistance resulting from tolerance and modal design targets. As such, it must compensate the worst-case condition and therefore restrain the performance of all other possible scenarios, even if the likelihood of occurrence of the latter is considerably high and the former substantially low. Sigma-delta () control, which addresses this issue in buck converters by easing its compensation requirements and offering one-cycle transient response, has not been able to simultaneously achieve high bandwidth, high accuracy, and wide compliance in boost converters. This paper presents a dual-mode boost bypass converter, which by using a high-bandwidth bypass path only during transient load-dump events was experimentally 1.41 to 6 times faster than the state of the art in current-mode boost supplies, and this without any compromise in compliance range (0–50 m, 1–30 H, and 1–350 F).
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Ismail, Adla, Lotfi Saidi, and Mounir Sayadi. "Wind turbine power converter fault diagnosis using DC-link voltage time–frequency analysis." Wind Engineering 43, no. 4 (2019): 329–43. http://dx.doi.org/10.1177/0309524x19858252.
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With the developments in power electronic devices, there is increasing use of the insulated gate bipolar transistor devices in power converters. Power converters are more and more gaining attention in the wind energy conversion system. In this article, a grid-connected wind energy conversion system is considered. Wind energy conversion system optimal operation requires a diagnostic method for back-to-back power converter to be addressed in detail in this article. Therefore, an open-circuit switching fault diagnosis method for a back-to-back power converter is developed to improve the system reliability and optimize the produced power and also achieve its real operational cost. In this work, we investigate only the DC-Link voltage signal and we use the time–frequency analysis to achieve the diagnosis purpose. The scheduled diagnosis approach is divided into two tasks: the first one is the fault detection task and the second one is the fault localization task. The main novelty of the proposed diagnosis approach is to localize the appropriate faulty power converter, that is, rotor side power converter or grid side power converter. Also, this approach is able to localize faults when there is a simultaneous fault on both power converters. Simulations are carried out to verify the robustness of the proposed diagnosis approach. The achieved simulation results would help in diagnosing of Back-to-back power converter that would expectedly cancel the traditional diagnosis method.
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Heras-Cervantes, Mario, Adriana del Carmen Téllez-Anguiano, Juan Anzurez-Marín, and Elisa Espinosa-Juárez. "Analysis and Comparison of Fuzzy Models and Observers for DC-DC Converters Applied to a Distillation Column Heating Actuator." Mathematical and Computational Applications 25, no. 3 (2020): 55. http://dx.doi.org/10.3390/mca25030055.
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In this paper, as an introduction, the nonlinear model of a distillation column is presented in order to understand the fundamental paper that the column heating actuator has in the distillation process dynamics as well as in the quality and safety of the process. In order to facilitate the implementation control strategies to maintain the heating power regulated in the distillation process, it is necessary to represent adequately the heating power actuator behavior; therefore, three different models (switching, nonlinear and fuzzy Takagi–Sugeno) of a DC-DC Buck-Boost power converter, selected to regulate the electric power regarding the heating power, are presented and compared. Considering that the online measurements of the two main variables of the converter, the inductor current and the capacitor voltage, are not always available, two different fuzzy observers (with and without sliding modes) are developed to allow monitoring the physical variables in the converter. The observers response is compared to determine which has a better performance. The role of the observer in estimating the state variables with the purpose of using them in the sensors fault diagnosis, using the analytical redundancy concept, likewise, from the estimation of these variables other non-measurable can be determined; for example, the caloric power. The stability analysis and observers gains are obtained by linear matrix inequalities (LMIs). The observers are validated by MATLAB® simulations to verify the observers convergence and analyze their response under system disturbances.
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Rodrigues, Justino, Carlos Moreira, and João Peças Lopes. "Fault-Ride-Through Approach for Grid-Tied Smart Transformers without Local Energy Storage." Energies 14, no. 18 (2021): 5622. http://dx.doi.org/10.3390/en14185622.
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The Smart Transformer (ST) is being envisioned as the possible backbone of future distribution grids given the enhanced controllability it provides. Moreover, the ST offers DC-link connectivity, making it an attractive solution for the deployment of hybrid AC/DC distribution grids which offer important advantages for the deployment of Renewable Energy Sources, Energy Storage Systems (ESSs) and Electric Vehicles. However, compared to traditional low-frequency magnetic transformers, the ST is inherently more vulnerable to fault disturbances which may force the ST to disconnect in order to protect its power electronic converters, posing important challenges to the hybrid AC/DC grid connected to it. This paper proposes a Fault-Ride-Through (FRT) strategy suited for grid-tied ST with no locally available ESS, which exploits a dump-load and the sensitivity of the hybrid AC/DC distribution grid’s power to voltage and frequency to provide enhanced control to the ST in order to handle AC-side voltage sags. The proposed FRT strategy can exploit all the hybrid AC/DC distribution grid (including the MV DC sub-network) and existing controllable DER resources, providing FRT against balanced and unbalanced faults in the upstream AC grid. The proposed strategy is demonstrated in this paper through computational simulation.
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Pang, Yuqi, Gang Ma, Xunyu Liu, Xiaotian Xu, and Xinyuan Zhang. "A New MMC Sub-Module Topology with DC Fault Blocking Capability and Capacitor Voltage Self-Balancing Capability." Energies 14, no. 12 (2021): 3409. http://dx.doi.org/10.3390/en14123409.
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A large number of modular multilevel converters (MMC) are connected to HVDC transmission systems nowadays. This paper aims at the short-circuit fault in the DC line of the HVDC transmission system and the problem of capacitor voltage imbalance in MMC, proposing a new type of MMC sub-module, which has both the DC fault self-clearing ability and the capacitor voltage self-balancing ability. This sub-module combines the topology of half bridge and full bridge. It uses the reverse capacitor voltage to forcibly turn off the conducting diode to block the fault current loop. At the same time, the two capacitances charge and discharge states are consistent by utilizing the operating mode of the sub-module. It is possible to directly achieve a self-balancing capacitor voltage without complex balancing voltage control. The MATLAB/Simulink simulation verifies the effectiveness of the DC fault blocking capability and capacitor voltage balance capability of the proposed sub-module.
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Zhang, Jingru, Baina He, Xingmin He, Yanchen Dong, and Renzhuo Jiang. "Research on fault clearing scheme for half-bridge modular multilevel converters high voltage DC based on overhead transmission lines." International Journal of Emerging Electric Power Systems 22, no. 1 (2020): 61–72. http://dx.doi.org/10.1515/ijeeps-2020-0085.
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Abstract When a short-circuit fault occurs on the transmission lines of high voltage DC transmission system based on modular multilevel converters, the fault cannot be cleared by adjusting the converter control system, which results in longer recovery time. Aiming at the problem above, a fault self-clearing scheme based on the fault clearing module for the half-bridge converter station is proposed. Combined with the actual operating status of the flexible DC transmission project, centralized parameter models are utilized to analyze the fault self-clearing mechanism. Besides, the impact of the discharge branch on the fault clearing effect is studied in depth to provide a design consideration for the fault clearing module and improve the comprehensive benefits of the proposed scheme. PSCAD/EMTDC simulation results show that the introduction of the fault clearing module in the half-bridge converter station can effectively suppress the fault short-circuit current and shorten the fault clearing time. In addition, circuit breakers on both sides of the line do not need to be tripped, providing a reliable guarantee for the subsequent adaptive restart process.
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Ince, Mehmet, Ender Yilmaz, Wei Fu, et al. "Fault-based Built-in Self-test and Evaluation of Phase Locked Loops." ACM Transactions on Design Automation of Electronic Systems 26, no. 3 (2021): 1–18. http://dx.doi.org/10.1145/3427911.
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With the increasing pressure to obtain near-zero defect rates for the automotive industry, there is a need to explore built-in self-test and other non-traditional test techniques for embedded mixed-signal components, such as PLLs, DC-DC converters, and data converters. This article presents a very low-cost built-in self-test technique for PLLs specifically designed for fault detection. The methodology relies on exciting the PLL loop in one location via a pseudo-random signal with noise characteristics and observing the response from another location in the loop via all digital circuitry, thereby inducing low area and performance overhead. The BIST circuit along with a PLL under test is designed in 65 nm technology. Fault simulations performed at the transistor and system-level show that the majority of non-catastrophic faults that result in parametric failures can be detected with the proposed approach.
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Damian, Ioan-Cătălin, Mircea Eremia, and Lucian Toma. "Fault Simulations in a Multiterminal High Voltage DC Network with Modular Multilevel Converters Using Full-Bridge Submodules." Energies 14, no. 6 (2021): 1653. http://dx.doi.org/10.3390/en14061653.
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The concept of high-voltage DC transmission using a multiterminal configuration is presently a central topic of research and investment due to rekindled interest in renewable energy resource integration. Moreover, great attention is given to fault analysis, which leads to the necessity of developing proper tools that enable proficient dynamic simulations. This paper leverages models and control system design techniques and demonstrates their appropriateness for scenarios in which faults are applied. Furthermore, this paper relies on full-bridge submodule topologies in order to underline the increase in resilience that such a configuration brings to the multiterminal DC network, after an unexpected disturbance. Therefore, strong focus is given to fault response, considering that converters use a full-bridge topology and that overhead power lines connect the terminals.
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Boukhris, Youness, Aboubakr El Makrini, Hassan El Moussaoui, and Hassane El Markhi. "Low Voltage Ride-through Capability Enhancement of Doubly Fed Induction Generator Based Wind Turbines under Voltage Dips." International Journal of Power Electronics and Drive Systems (IJPEDS) 6, no. 4 (2015): 808. http://dx.doi.org/10.11591/ijpeds.v6.i4.pp808-818.
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<span lang="EN-US">Based on the advantages of doubly fed induction generator (DFIG)-based wind turbine (WT). This paper proposes a new control strategy to improve the ride-through capability of DFIG-based WTs in the event of a grid fault. The proposed method is performed by using the DFIG converters control and the addition of the damping resistances connected to the DC circuit, to follow the requirements defined by the grid codes. The proposed ride-through solution limits the peak values of the DC link voltage, the rotor inrush current, electromagnetic torque and DFIG transient response at the times of occurrence and clearing the fault. The proposed solution is simulated and compared with the crowbar solution using MATLAB/Simulink environment.</span>
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Zafeiratou, Igyso, Ionela Prodan, and Laurent Lefévre. "A Hierarchical Control Approach for Power Loss Minimization and Optimal Power Flow within a Meshed DC Microgrid." Energies 14, no. 16 (2021): 4846. http://dx.doi.org/10.3390/en14164846.
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This work considers the DC part of a hybrid AC/DC microgrid with a meshed topology. We address cost minimization, battery scheduling and the power loss minimization within the power distribution network through constrained optimization. The novelty comes from applying differential flatness properties to the microgrid components and formulating the cost and constraints in terms of the associated B-splines parametrization of the flat outputs (the voltages and currents of the system). This allows us to obtain optimal power profiles to minimize the power dissipation and the cost of the electricity purchase from the external grid. These profiles are tracked by a model predictive controller at the higher level, while at a a lower level a controller deals with the operation of the switches within the DC/DC converters. Extensive simulations under nominal and fault-affected scenarios using realistic data validate the proposed approach.
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Babaei, Ebrahim, Mohammad Shadnam Zarbil, and Elias Shokati Asl. "A Developed Structure for DC–DC Quasi-Z-Source Converter with High Voltage Gain and High Reliability." Journal of Circuits, Systems and Computers 28, no. 01 (2018): 1950012. http://dx.doi.org/10.1142/s0218126619500129.
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In this paper, a developed structure for DC–DC quasi-Z-source (QZS) converters is proposed. First, the proposed two-stage structure is presented and analyzed. Then, the proposed structure is extended to [Formula: see text] stages and its relations are calculated. Compared with other conventional structures, the proposed structure has higher voltage gain and higher reliability. The proposed topology is suitable for high power applications. To have the correct performance of conventional QZS converter, all impedance network elements must be intact. In the case of small failure in one of the elements, the operation of the whole system is disrupted. The proposed structure has high reliability because when one stage fails, the fault management system separates that stage from the other stages and the remaining stages continue to transmit power. In this paper, in addition to analyzing the operation of the proposed converter in different operating modes, calculations of voltage gain, voltage stresses across capacitors and reliability analysis are also presented. Reliability is calculated according to well-known Markov model. Moreover, a comprehensive comparison in terms of voltage gain and reliability is made between the proposed converter and the other conventional structures. Also, the rating values of inductors and capacitors are designed. Finally, experimental and simulation results are presented by using power system computer-aided design (PSCAD) software to verify the theories.
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Moosavi, Saeid, Hesam Akbari, and Saeed Valipour. "An Open-Circuit Fault Detection Method with Wavelet Transform In IGBT-Based DC/AC Inverter Used in Electric Vehicles." International Journal of Power Electronics and Drive Systems (IJPEDS) 9, no. 3 (2018): 1240. http://dx.doi.org/10.11591/ijpeds.v9.i3.pp1240-1250.
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<span>Today power electronics play an important role in the electric industry. Power electronic converters are an inseparable component in power systems. One of these converters is DC/AC inverter that is widely used in power systems, industrial applications, electric motor drive and electric vehicles. Due to the tense situation with the complexity that exists in these applications, inverters are exposed to failure. The fault occurring in inverter can cause disturbance and damaging harmonics, cut some industrial processes to in the power system or in the case of electric vehicles, causing irreparable damage. For this reason, detecting faults in the inverter is very important. In this paper, open circuit fault of IGBT in an electric vehicle has been examined. We use three-phase current and wavelet transform to identify the state of the system and we can extract current waveform characteristics. We use neural network algorithm for fault detection and classification. An electric vehicle in 5 different speeds and 5 different torque and a total of 220 failure modes have been studied and tested. The results show the method has been succeeded to detection all forms of defined faults</span>
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Tadeusiewicz, Michał, and Stanisław Hałgas. "Multiple Soft Fault Diagnosis of Nonlinear DC Circuits Considering Component Tolerances." Metrology and Measurement Systems 18, no. 3 (2011): 349–60. http://dx.doi.org/10.2478/v10178-011-0002-1.
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Multiple Soft Fault Diagnosis of Nonlinear DC Circuits Considering Component TolerancesThis paper is devoted to multiple soft fault diagnosis of analog nonlinear circuits. A two-stage algorithm is offered enabling us to locate the faulty circuit components and evaluate their values, considering the component tolerances. At first a preliminary diagnostic procedure is performed, under the assumption that the non-faulty components have nominal values, leading to approximate and tentative results. Then, they are corrected, taking into account the fact that the non-faulty components can assume arbitrary values within their tolerance ranges. This stage of the algorithm is carried out using the linear programming method. As a result some ranges are obtained including possible values of the faulty components. The proposed approach is illustrated with two numerical examples.
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de Souza, Victor Ramon França Bezerra, Luciano Sales Barros, and Flavio Bezerra Costa. "Modular Multilevel Converter for Low-Voltage Ride-Through Support in AC Networks." Energies 14, no. 17 (2021): 5314. http://dx.doi.org/10.3390/en14175314.
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New grid-connected systems have imposed additional requirements regarding reliability, power quality, high levels of power processing capacity, and fault support, where power converters have a crucial role in fulfilling these requirements. Overcoming one of these challenges, this paper proposes a new alternative application to improve the low-voltage ride-through (LVRT) support based on the arm impedance employment of the modular multilevel converter (MMC) by attenuating the fault impacts, avoiding overcurrents and overvoltages. This proposal does not require additional hardware or control loops for LVRT support, only using PI controllers. This paper evaluates symmetrical and asymmetrical grid fault impacts on the converter DC side of four converter topologies: two-level voltage source converter topology (2L-VSC), neutral point clamped (NPC), MMC, and 2L-VSC equipped with a DC-chopper, employing the same control structure for the four topologies, highlighting that the MMC contributed better to LVRT improvement under severe grid conditions.
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Song, Sen, Wei Li, Kai Ni, Hui Xu, Yihua Hu, and Jikai Si. "Modular Multi-Port Ultra-High Power Level Power Converter Integrated with Energy Storage for High Voltage Direct Current (HVDC) Transmission." Energies 11, no. 10 (2018): 2711. http://dx.doi.org/10.3390/en11102711.
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To connect renewable energy sources (RESs) with a unity-grid, energy storage (ES) systems are essential to eliminate the weather fluctuation effect, and high voltage direct current (HVDC) transmission is preferred for large-scale RESs power plants due to the merits of low cost and high efficiency. This paper proposes a multi-port bidirectional DC/DC converter consisting of multiple modules that can integrate ES system and HVDC transmission. Thanks to the adoption of three-port converters as submodules (SMs), ES devices, for example, batteries, can be decentralized into SMs and controlled directly by the SMs. Additionally, SMs are connected in a scalable matrix topology, presenting the advantages of flexible power flows, high voltage step-up ratios and low voltage/current ratings of components to satisfy the requirements of HVDC transmission. Furthermore, the control flexibility and fault tolerance capability are increased due to the matrix topology. In this paper, the analysis of the novel modular multi-port converter is introduced, and its functions are verified by the simulation results in PSIM.
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Akhmatov, Vladislav. "Variable-Speed Wind Turbines with Doubly-Fed Induction Generators Part III: Model with the Back-to-back Converters." Wind Engineering 27, no. 2 (2003): 79–91. http://dx.doi.org/10.1260/03095240360698537.
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A model of the back-to-back converter is set up and implemented in the simulation tool PSS/E as a user-developed model. This model is applied with that of the doubly-fed induction generator (DFIG), described in previous parts of this work [parts II and I]. The latter models variable-speed wind turbines in power stability investigations. Subjected to a short circuit fault, there will be a risk of converter blocking, followed by tripping of the wind turbine [1, 3]. The main reasons of blocking are over-current in the rotor converter and over-voltage in the dc-link. The DFIG model, with representation of the back-to-back converter, results in (a) more accurate replication of the current in the rotor converter and (b) improved computation of the dc-link voltage. These improvements are compared with the model with representation of the rotor converter only. Hence, the DFIG model with representation of the back-to-back converters might be preferred, in practical investigations of power system stability, to models with representation of the rotor converter only.
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Khatir, Mohamed, Sid-Ahmed Zidi, Samir Hadjeri, and Mohammed-Karim Fellah. "Dynamic Performance of a Back-to-Back HVDC Station Based on Voltage Source Converters." Journal of Electrical Engineering 61, no. 1 (2010): 29–36. http://dx.doi.org/10.2478/v10187-010-0004-9.
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Dynamic Performance of a Back-to-Back HVDC Station Based on Voltage Source Converters The recent developments in semiconductors and control equipment have made the voltage source converter based high voltage direct current (VSC-HVDC) feasible. This new DC transmission is known as "HVDC Light or "HVDC Plus by leading vendors. Due to the use of VSC technology and pulse width modulation (PWM) the VSC-HVDC has a number of potential advantages as compared with classic HVDC. In this paper, the scenario of back-to-back VSC-HVDC link connecting two adjacent asynchronous AC networks is studied. Control strategy is implemented and its dynamic performances during disturbances are investigated in MATLAB/Simulink program. The simulation results have shown good performance of the proposed system under balanced and unbalanced fault conditions.
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Oto, Yoshiaki, Toshihiko Noguchi, and Melinda Badriatul Fauziah. "Experimental Verification of Fault Tolerant Operation Focusing on DC-Bus Battery Failure in Dual Inverter Motor Drive." World Electric Vehicle Journal 10, no. 4 (2019): 65. http://dx.doi.org/10.3390/wevj10040065.
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Recently, a dual inverter motor drive feeding an open-end winding permanent magnet (PM) motor has been studied, aiming for the improvement of total efficiency and a fault tolerant function of hybrid and electric vehicles. The authors have studied the fault tolerant operation of the DC-bus battery, where the failed inverter is operated only with a capacitor across the DC-bus and a space vector modulation (SVM) is employed to regulate the capacitor voltage. In our previous research, the SVM techniques for the fault tolerant operation in a low-modulation-index have been proposed. However, it was difficult to have fault tolerance in a high-modulation-index case. The voltage margin in the fault situation is limited because the failed inverter is operated with the capacitor. In this paper, the SVM technique to achieve the fault tolerant operation in the high-modulation-index state is investigated. The novel point of this paper is that the proposed technique introduces a field-weakening control in order to reduce the command voltage vector within the controllable voltage region. The proposed technique was verified through experimental tests and its operational characteristics were compared with the normal operation, from the viewpoints of the total harmonic distortion (THD) and the efficiencies of the inverters and the motor.
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Oni, Oluwafemi Emmanuel, Kamati I. Mbangula, and Innocent E. Davidson. "A Review of LCC-HVDC and VSC-HVDC Technologies and Applications." Transactions on Environment and Electrical Engineering 1, no. 3 (2016): 68. http://dx.doi.org/10.22149/teee.v1i3.29.
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High Voltage Direct Current (HVDC) systems has been an alternative method of transmitting electric power from one location to another with some inherent advantages over AC transmission systems. The efficiency and rated power carrying capacity of direct current transmission lines highly depends on the converter used in transforming the current from one form to another (AC to DC and vice versa). A well configured converter reduces harmonics, increases power transfer capabilities, and reliability in that it offers high tolerance to fault along the line. Different HVDC converter topologies have been proposed, built and utilised all over the world. The two dominant types are the line commutated converter LCC and the voltage source converter VSC. This review paper evaluates these two types of converters, their operational characteristics, power rating capability, control capability and losses. The balance of the paper addresses their applications, advantages, limitations and latest developments with these technologies.
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Lamo, Paula, Angel de Castro, Alberto Sanchez, Gustavo A. Ruiz, Francisco J. Azcondo, and Alberto Pigazo. "Hardware-in-the-Loop and Digital Control Techniques Applied to Single-Phase PFC Converters." Electronics 10, no. 13 (2021): 1563. http://dx.doi.org/10.3390/electronics10131563.
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Power electronic converters for power factor correction (PFC) play a key role in single-phase electrical power systems, ensuring that the line current waveform complies with the applicable standards and grid codes while regulating the DC voltage. Its verification implies significant complexity and cost, since it requires long simulations to verify its behavior, for around hundreds of milliseconds. The development and test of the controller include nominal, abnormal and fault conditions in which the equipment could be damaged. Hardware-in-the-loop (HIL) is a cost-effective technique that allows the power converter to be replaced by a real-time simulation model, avoiding building prototypes in the early stages for the development and validation of the controller. However, the performance-vs-cost trade-off associated with HIL techniques depends on the mathematical models used for replicating the power converter, the load and the electrical grid, as well as the hardware platform chosen to build it, e.g., microprocessor or FPGA, and the required number of channels and I/O types to test the system. This work reviews state-of-the-art HIL techniques and digital control techniques for single-phase PFC converters.
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Mohan, M., and K. Panduranga Vittal. "Design and Transient Studies on Multi-Terminal VSC-HVDC Systems Interconnecting Offshore Wind Farms." ECTI Transactions on Electrical Engineering, Electronics, and Communications 17, no. 2 (2019): 181–92. http://dx.doi.org/10.37936/ecti-eec.2019172.215486.
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In recent years, offshore wind energy has increased significantly. The continuous increase in the offshore wind power generation level brings the requirement of the offshore wind farms (OWFs) integration with an AC grid. The multi-terminal (MT) voltage source converters (VSC)-based high voltage direct current (HVDC) transmission system is an emerging technology and also the best option to interconnect the large-scale OWFs to the AC grid. This paper presents the design, modeling, and control of MT VSC-HVDC transmission system linked offshore wind farms. Different cases of MT VSC-HVDC transmission systems are developed, and its simulation studies are carried out using PSCAD/EMTDC. The test results show the transient performance of the MT VSC-HVDC transmission systems under various AC and DC fault conditions. The studies also include the influence of wind variabilities as in the form of gust and ramp pattern during steady state and fault conditions.
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Ge, Yuxue, Bifeng Song, Yang Pei, Yves Mollet, and Johan Gyselinck. "A fuzzy logic based method for fault tolerant hierarchical load management of more electric aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 10 (2018): 3846–56. http://dx.doi.org/10.1177/0954410018807598.
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With the increasing number of electrical loads, load management of the more electric aircraft becomes crucial for reliability and efficiency. One of the major challenge is to develop an optimal and reliable adaptive power control. This paper presents a three-level load management method with dedicated time steps for fault tolerance and increasing calculation efficiency. Both the operative mode and the health level of the loads are taken into account in the control using fuzzy logic. The electrical system of a V-tail more electric aircraft that consists of a generator, an auxiliary power unit, and several AC/DC buses and loads is examined by the proposed method in normal and faulty cases. Compared with some conventional methods, the proposed load management method has the advantage of efficiently shedding loads according to the power imbalance and the fault situation.
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Gencer, Altan. "Analysis and Control of Low-Voltage Ride-Through Capability Improvement for PMSG Based on an NPC Converter Using an Interval Type-2 Fuzzy Logic System." Elektronika ir Elektrotechnika 25, no. 3 (2019): 63–70. http://dx.doi.org/10.5755/j01.eie.25.3.23678.
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Wind farms must be linked to the grid during the voltage sag. Therefore, the improvement of low-voltage ride-through (LVRT) capability of wind turbine (WT) is a vitally issue. Protection system based on an interval type-2 fuzzy logic system (IT-2 FLC) is presented to improvement of LVRT capability of permanent magnet synchronous generator (PMSG) based on WT during the voltage dip. The presented control system prevents the power converters from the damaging effects of over-voltage during LVRT time. In addition to, the proposed protection system based on IT-2 FLC provides constant DC link voltage, reduces the amplitude of stator fault voltages, and enhances all response of PMSG. The proposed method is applied wind turbine using a 1.5MVA PMSG during different voltage sag types in the MATLAB/Simulation. The effectiveness of presented technique is verified by simulation results.
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Wang, Qinghua, Yuexiao Yu, Hosameldin O. A. Ahmed, Mohamed Darwish, and Asoke K. Nandi. "Open-Circuit Fault Detection and Classification of Modular Multilevel Converters in High Voltage Direct Current Systems (MMC-HVDC) with Long Short-Term Memory (LSTM) Method." Sensors 21, no. 12 (2021): 4159. http://dx.doi.org/10.3390/s21124159.
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Fault detection and classification are two of the challenging tasks in Modular Multilevel Converters in High Voltage Direct Current (MMC-HVDC) systems. To directly classify the raw sensor data without certain feature extraction and classifier design, a long short-term memory (LSTM) neural network is proposed and used for seven states of the MMC-HVDC transmission power system simulated by Power Systems Computer Aided Design/Electromagnetic Transients including DC (PSCAD/EMTDC). It is observed that the LSTM method can detect faults with 100% accuracy and classify different faults as well as provide promising fault classification performance. Compared with a bidirectional LSTM (BiLSTM), the LSTM can get similar classification accuracy, requiring less training time and testing time. Compared with Convolutional Neural Networks (CNN) and AutoEncoder-based deep neural networks (AE-based DNN), the LSTM method can get better classification accuracy around the middle of the testing data proportion, but it needs more training time.
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Wang, Qinghua, Yuexiao Yu, Hosameldin O. A. Ahmed, Mohamed Darwish, and Asoke K. Nandi. "Fault Detection and Classification in MMC-HVDC Systems Using Learning Methods." Sensors 20, no. 16 (2020): 4438. http://dx.doi.org/10.3390/s20164438.
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In this paper, we explore learning methods to improve the performance of the open-circuit fault diagnosis of modular multilevel converters (MMCs). Two deep learning methods, namely, convolutional neural networks (CNN) and auto encoder based deep neural networks (AE-based DNN), as well as stand-alone SoftMax classifier are explored for the detection and classification of faults of MMC-based high voltage direct current converter (MMC-HVDC). Only AC-side three-phase current and the upper and lower bridges’ currents of the MMCs are used directly in our proposed approaches without any explicit feature extraction or feature subset selection. The two-terminal MMC-HVDC system is implemented in Power Systems Computer-Aided Design/Electromagnetic Transients including DC (PSCAD/EMTDC) to verify and compare our methods. The simulation results indicate CNN, AE-based DNN, and SoftMax classifier can detect and classify faults with high detection accuracy and classification accuracy. Compared with CNN and AE-based DNN, the SoftMax classifier performed better in detection and classification accuracy as well as testing speed. The detection accuracy of AE-based DNN is a little better than CNN, while CNN needs less training time than the AE-based DNN and SoftMax classifier.
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Huang, Chen, Lidan Zhou, Zujia Cao, and Gang Yao. "Fault-Tolerant Control Strategy with Asymmetric Phase Currents for Single to Four-Phase Open-Circuit Faults of Six-Phase PMSM." Energies 14, no. 11 (2021): 3163. http://dx.doi.org/10.3390/en14113163.
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Multi-phase motors and generators are regarded with great fault tolerance capability, especially on open-circuit faults. Various mathematics analytical methods are applied for their fault control. In this paper, a fault-tolerant control strategy with asymmetric phase current for the open-circuit faults with arbitrary phases in the six-phase PMSM (six-phase permanent magnetic synchronous motor, 6P-PMSM) system, is proposed for better electrical and dynamical performance of the machine. An innovative mathematical model for PMSM under one to four-phase-open circuit faults are established considering the asymmetry of the machine. Combining with time-varying relations in machines’ working conditions, targeted decoupling transformation matrixes of every kind of open-circuit faults are settled by voltage equations under different faults. Modified control strategy with a connection between the neutral point and the inverter’s DC side is presented, which aims at increasing the system redundancy and reducing the amplitude of phase currents. Besides, improved control loops with two layers are put forward as well, with which the PMSM system acquires fewer harmonics in phase current and smoother electromagnetic torque. Simulation and experimental results of open-circuit faults are provided for verification of the theoretical analysis.
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Ren, Wen, and Sencai Lai. "Embedded Electronic Jacquard Guide Bar: A New Approach to Warp Knitting Using the Machine Jacquard Control System." Fibres and Textiles in Eastern Europe 26, no. 6(132) (2018): 95–101. http://dx.doi.org/10.5604/01.3001.0012.5172.
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A fluorine-containing acrylate copolymer emulsion was prepared in this study, which was The jacquard control system is one of the crucial parts of a warp knitting machine. In this paper, we present a new jacquard control scheme called the embedded electronic jacquard guide bar (EEJGB). In this scheme, the Micro-Controller Unit (MCU), jacquard driver circuit, DC powers, and communication interfaces are integrated to achieve a simple structure, high reliability as well as ease of installation and maintenance. Specifically an innovative communication strategy with the advantages of fault tolerance and automatic addressing based on the Modbus serial bus is formulated. This paper describes the design of the hardware structure, communication methods of EEJGB, and printed circuit board (PCB), provided to demonstrate the feasibility of the method proposed.
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R., Uthra, and Suchitra D. "Fault Ride Through in Grid Integrated Hybrid System Using FACTS Device and Electric Vehicle Charging Station." Energies 14, no. 13 (2021): 3828. http://dx.doi.org/10.3390/en14133828.
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Adopting eco-friendly solutions is the need of the hour in order to downscale carbon emissions and the fast depletion of fossil fuels. Hybrid energy systems provide one such optimistic sustainable solution for power generation in a grid integrated system as well as for stand-alone applications. With grid integrated systems, there are many grid codes to be maintained such as voltage stability, frequency deviation and Fault Ride Through Capability (FRT). In a hybrid system, the propensity of the PV/Wind system to remain connected at the moment of short electric fault is identified as FRT. This paper elucidates the voltage compensation using an Electric Vehicle (EV) charging station or a Flexible AC Transmission System (FACTS) device depending on the intensity of fault that occurs at the Point of Common Coupling (PCC) in grid integrated hybrid systems. When a fault occurs at the PCC, depending on the intensity of the voltage sag either the EV charging station or a FACTS device, namely a Dynamic Voltage Restore (DVR), provides the voltage compensation. The voltage obtained from an EV charging station or DVR is conditioned using power converters and fed to the PCC to even out the discrepancy in the voltage that is effected due to the fault. Even though charges electric vehicles continuously, the EV charging station gives priority to supply voltage for compensation whenever a fault occurs at the grid. If the intensity of voltage sag due to fault is between 0.9 to 0.51 p.u, the EV charging station provides voltage compensation, and for voltage sag between 0.5 to 0.2 p.u, DVR takes over to provide voltage compensation for the continuous sustainability of the grid. The proposed system makes use of an existing source such as an EV charging station as a supplementary device to provide compensation, and also has a backup supplementary device DVR in case of any non-availability of the EV charging station. Thus, the voltage compensation in turn facilitates the parameters such as DC link voltage and the grid voltage to stay within the pertinent limits in the event of a fault at the grid. The system was simulated using MATLAB Simulink and the results were verified.
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Li, Jian, Kunpeng Pan, and Qingyu Su. "Sensor fault isolation for DC-DC converters via switched affine systems." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, July 20, 2020, 095965182093969. http://dx.doi.org/10.1177/0959651820939694.
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The main purpose of this article is to study the sensor fault isolation for DC-DC converters, taking the single-ended primary industry converter as an example. To achieve the purpose of the research, we model the DC-DC converters as switched affine systems and design a bank of sliding mode observers for each corresponding sensor fault. By comparing the threshold with the residual estimation function produced by each sliding model observers, we can diagnose which sensor faults are occurring. Finally, three sensor faults are given as simulation examples to verify the feasibility of the proposed scheme.
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Muniappan, Mohan. "A comprehensive review of DC fault protection methods in HVDC transmission systems." Protection and Control of Modern Power Systems 6, no. 1 (2021). http://dx.doi.org/10.1186/s41601-020-00173-9.
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AbstractHigh voltage direct current (HVDC) transmission is an economical option for transmitting a large amount of power over long distances. Initially, HVDC was developed using thyristor-based current source converters (CSC). With the development of semiconductor devices, a voltage source converter (VSC)-based HVDC system was introduced, and has been widely applied to integrate large-scale renewables and network interconnection. However, the VSC-based HVDC system is vulnerable to DC faults and its protection becomes ever more important with the fast growth in number of installations. In this paper, detailed characteristics of DC faults in the VSC-HVDC system are presented. The DC fault current has a large peak and steady values within a few milliseconds and thus high-speed fault detection and isolation methods are required in an HVDC grid. Therefore, development of the protection scheme for a multi-terminal VSC-based HVDC system is challenging. Various methods have been developed and this paper presents a comprehensive review of the different techniques for DC fault detection, location and isolation in both CSC and VSC-based HVDC transmission systems in two-terminal and multi-terminal network configurations.
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Pang, Yuqi, Gang Ma, Xiaotian Xu, Xunyu Liu, and Xinyuan Zhang. "RNN-based Fault Detection Method for MMC Photovoltaic Grid-connected System." Recent Advances in Electrical & Electronic Engineering (Formerly Recent Patents on Electrical & Electronic Engineering) 14 (September 17, 2021). http://dx.doi.org/10.2174/2352096514666210917150429.
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Background: Fast and reliable fault detection methods are the main technical challenges faced by photovoltaic grid-connected systems through modular multilevel converters (MMC) during the development. Objective: Existing fault detection methods have many problems, such as the inability of non-linear elements to form accurate analytical expressions, the difficulty of setting protection thresholds and the long detection time. Method: Aiming at the problems above, this paper proposes a rapid fault detection method for photovoltaic grid-connected systems based on Recurrent Neural Network (RNN). Results: The phase-to-mode transformation is used to extract the fault feature quantity to get the RNN input data. The hidden layer unit of the RNN is trained through a large amount of simulation data, and the opening instruction is given to the DC circuit breaker. Conclusion: The simulation verification results show that the proposed fault detection method has the advantage of faster detection speed without difficulties in setting and complicated calculation.
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Okedu, Kenneth E., and Hind F. A. Barghash. "Investigating Variable Speed Wind Turbine Transient Performance Considering Different Inverter Schemes and SDBR." Frontiers in Energy Research 8 (January 19, 2021). http://dx.doi.org/10.3389/fenrg.2020.604338.
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In wind energy applications, voltage source converters are employed to achieve energy conservation. Recently, multilevel converters have been showing promising advantages compared to the traditional 2-level converter scheme, due to the fact that they can overcome certain limitations during transient conditions. This paper investigates the transient performance of variable DFIG-based speed wind turbines taking into account different scheme configurations of the power converter system. The schemes investigated are a 2-level six step IGBT inverter, a parallel interleaved 2-level six step IGBT inverter, and a 3-level IGBT inverter. All schemes were compared during severe three-phase to ground fault at the terminal of the DFIG wind turbine using the conventional Phase Lock Loop (PLL) and a DC-chopper protection. A coordinated approach of improving the performance of all the converter schemes with series dynamic braking resistor (SDBR) was analyzed. Investigation of the best location for the SDBR in the DFIG architecture considering the best switching signal was also carried out. Furthermore, a new control strategy of PLL for the DFIG system was proposed in conjunction with the SDBR scheme for the converter systems. Simulations were carried out in Power System Computer Aided Design and Electromagnetic Transient Including DC (PSCAD/EMTDC). The results show that the proposed PLL and SDBR hybrid scheme in the various inverter topologies considered in the study can enhance the performance of the wind generator variables during severe three-phase to ground fault. This is because the proposed hybrid scheme could help to boost the capability of the current and recovery of the wind generator after post-fault scenarios. Also, the voltage source converter leg switched output voltage would be enhanced to maximum change in common mode voltage by the inverter schemes’ modulation of the space vector using the proposed strategy.
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Metwally Mahmoud, Mohamed, Hossam S. Salama, Mohamed M. Aly, and Abdel-Moamen M. Abdel-Rahim. "Design and implementation of FLC system for fault ride-through capability enhancement in PMSG-wind systems." Wind Engineering, December 23, 2020, 0309524X2098177. http://dx.doi.org/10.1177/0309524x20981773.
Full textAbstract:
Fault ride-through (FRT) capability enhancement for the growth of renewable energy generators has become a crucial issue for their incorporation into the electricity grid to provide secure, reliable, and efficient electricity. This paper presents a new FRT capability scheme for a permanent magnet synchronous generator (PMSG)-based wind energy generation system using a hybrid solution. The hybrid solution is a combination of a braking chopper (BC) and a fuzzy logic controller (FLC). All proportional-integral (PI) controllers which control the generator and grid side converters are replaced with FLC. Moreover, a BC system is connected to the dc link to improve the dynamic response of the PMSG during fault conditions. The PMSG was evaluated on a three-phase fault that occurs on an electrical network in three scenarios. In the first two scenarios, a BC is used with a PI controller and FLC respectively. While the third scenario uses only FLC without a BC. The obtained results showed that the suggested solution can not only enhance the FRT capability of the PMSG but also can diminish the occurrence of hardware systems and reduce their impact on the PMSG system. The simulation tests are performed using MATLAB/SIMULINK software.