8,439 research outputs found

    Passivity-based Rieman Liouville fractional order sliding mode control of three phase inverter in a grid-connected photovoltaic system

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    Photovoltaic (PV) system parameters are always non-linear due to variable environmental conditions. The Maximum power point tracking (MPPT) is difficult under multiple uncertainties, disruptions and the occurrence of time-varying stochastic conditions. Therefore, Passivity based Fractional order Sliding-Mode controller (PBSMC) is proposed to examine and develop a storage function in error tracking for PV power and direct voltage in this research work. A unique sliding surface for Fractional Order Sliding Mode Control (FOSMC) framework is proposed and its stability and finite time convergence is proved by implementing Lyapunov stability method. An additional input of sliding mode control (SMC) is also added to a passive system to boost the controller performance by removing the rapid uncertainties and disturbances. Therefore, PBSMC, along with globally consistent control efficiency under varying operating conditions is implemented with enhanced system damping and substantial robustness. The novelty of the proposed technique lies in a unique sliding surface for FOSMC framework based on Riemann Liouville (R-L) fractional calculus. Results have shown that the proposed control technique reduces the tracking error in PV output power, under variable irradiance conditions, by 81%, compared to fractional order proportional integral derivative (FOPID) controller. It is reduced by 39%, when compared to passivity based control (PBC) and 28%, when compared to passivity based FOPID (EPBFOPID). The proposed technique led to the least total harmonic distortion in the grid side voltage and current. The tracking time of PV output power is 0.025 seconds in PBSMC under varying solar irradiance, however FOPID, PBC, EPBFOPID, have failed to converge fully. Similarly the dc link voltage has tracked the reference voltage in 0.05 seconds however the rest of the methods either could not converge, or converged after significant amount of time. During solar irradiance and temperature change, the photovoltaic output power has converged in 0.018 seconds using PBSMC, however remaining methods failed to converge or track fully and the dc link voltage has minimum tracking error due to PBSMC as compared to the other methods. Furthermore, the photovoltaic output power converges to the reference power in 0.1 seconds in power grid voltage drop, whereas other methods failed to converge fully. In addition power is also injected from the PV inverter into the grid at unity power factor

    Modelling, control design, and analysis of the inner control's loops intended for single‐phase voltage‐controlled inverter‐based microgrid

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    In voltage-controlled voltage source inverters (VSIs)-based microgrids (MGs), the inner control is of prime interest task for guaranteeing safe and stable operation. In this paper, an in-depth investigation of the modelling, control design, and analysis of the voltage and current inner control loops intended for single-phase voltage-controlled VSIs is established. The main objective of this work is to provide a comprehensive study of the mathematical modelling, control design, and performance evaluation of the inner control's loops considering different proportional-integral (PI) controller types with and without compensation, and to determine the optimal scheme that can offer better performance in terms of implementation simplicity, robustness, and transient and steady-state responses. Thus, the mathematical closed-loop models of designed outer voltage and inner current control schemes based on PI, P, and feedforward controllers with and without compensation are, first, derived. Following this, a systematic and effective control design for tuning the different PI controllers’ parameters is proposed. Furthermore, an analysis revealing the performance of the designed voltage and current control schemes is provided. This analysis enables us to choose a P controller and PI feedforward controller for the current control loop and the voltage control loop, respectively. The chosen P and PI controllers should be simple; meanwhile, they should offer a wide bandwidth. A simulation study is carried out in MATLAB/Simulink software to assess the performance of the adopted inner control scheme for both linear and non-linear loads. In addition, an experimental setup, based on a TMS320F2837xD ÎŒC, of a single-phase VSI supplying linear and non-linear loads is built to verify the effectiveness and the robustness of the adopted inner controller. The results demonstrated: (1) the necessity of introducing the compensation term, which is responsible for offering control improvement against voltage perturbation, (2) the high tracking performance of the chosen controller in terms of dynamic and steady-state responses as well as its simplicity of implementation

    Data quality processing for photovoltaic system measurements

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    The operation and maintenance activities in photovoltaic systems use meteorological and electrical measurements that must be reliable to check system performance. The International Electrotechnical Commission (IEC) standards have established general criteria to filter erroneous information; however, there is no standardized process for the evaluation of measurements. In the present work we developed 3 procedures to detect and correct measurements of a photovoltaic system based on the single diode model. The performance evaluation of each criterion was tested with 6 groups of experimental measurements from a 3 kWp installation. Based on the error of the 3 procedures performed, the most unfavorable case has been prioritized. Then, the reduction of errors between the estimated and measured value has been achieved, reducing the number of measurements to be corrected. For the clear sky categories, the coefficient of determination is 0.9975 and 0.9961 for the high irradiance profile. Although an increase of 2.5% for coefficient of determination has been achieved, the overcast sky categories should be analyzed in more detail. Finally, the different causes of measurement error should be analyzed, associated with calibration errors and sensor quality

    Low‐computation‐burden model predictive current control for the grid‐tied quasi‐Z‐source inverter

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    Abstract The appealing design known as the quasi‐Z‐source inverter (qZSI) can function in both buck and boost modes. In the meantime, model predictive control (MPC) for power transformers has attracted a lot of interest. In order to improve performance and solve the shortcomings of the current MPC, this paper suggests a low‐computation‐burden model predictive current control (LCB‐MPCC) for the grid‐tied qZSI. Two active vectors, one zero vector, and one shoot‐through (ST) vector are used in the production of the output voltage. To get around the weighting factor, a modified sliding‐mode control technique is suggested for instantly controlling the inductor current and capacitor voltage to their regulating spots. The duty cycle of the ST vector is acquired by the dead‐beat control to restrict the inductor current and significantly reduce the inductor current ripple. Additionally, an effective and quick optimal sector selection strategy is provided that uses a look‐up table to pick the optimal sector rather than a number of intricate calculations. Therefore, the proposed LCB‐MPCC greatly reduces the computational burden. To demonstrate the efficacy and benefits of the suggested technique, simulation and experimental results are presented

    An efficient unused integrated circuits detection algorithm for parallel scan architecture

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    In recent days, many integrated circuits (ICs) are operated parallelly to increase switching operations in on-chip static random access memory (SRAM) array, due to more complex tasks and parallel operations being executed in many digital systems. Hence, it is important to efficiently identify the long-duration unused ICs in the on-chip SRAM memory array layout and to effectively distribute the task to unused ICs in SRAM memory array. In the present globalization, semiconductor supply chain detection of unused SRAM in large memory arrays is a very difficult task. This also results in reduced lifetime and more power dissipation. To overcome the above-mentioned drawbacks, an efficient unused integrated circuits detection algorithm (ICDA) for parallel scan architecture is proposed to differentiate the ‘0’ and ‘1’ in a larger SRAM memory array. The proposed architecture avoids the unbalancing of ‘0’ and ‘1’ concentrations in the on-chip SRAM memory array and also optimizes the area required for the memory array. As per simulation results, the proposed method is more efficient in terms of reliability, the detection rate in both used and unused ICs and reduction of power dissipation in comparison to conventional methods such as backscattering side-channel analysis (BSCA) and network attached storage (NAS) algorithm

    1. Helgoland Power and Energy Conference - 24. Dresdener Kreis 2023

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    Der Sammelband "1. Helgoland Power and Energy Conference" beinhaltet neben einem kurzen Bericht zum 24. Treffen des Dresdener Kreises 2023 wissenschaftliche BeitrĂ€ge von Doktoranden der beteiligten Hochschulinstitute zum Thema Elektroenergieversorgung. Der Dresdener Kreis setzt sich aus der Professur fĂŒr Elektroenergieversorgung der Technischen UniversitĂ€t Dresden, dem Fachgebiet Elektrische Anlagen und Netze der UniversitĂ€t Duisburg-Essen, dem Fachgebiet Elektrische Energieversorgung der Leibniz UniversitĂ€t Hannover und dem Lehrstuhl Elektrische Netze und Erneuerbare Energie der Otto-von-Guericke UniversitĂ€t Magdeburg zusammen und trifft sich einmal im Jahr zum fachlichen Austausch an einer der beteiligten UniversitĂ€ten

    Optimal battery thermal management for electric vehicles with battery degradation minimization

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    The control of a battery thermal management system (BTMS) is essential for the thermal safety, energy efficiency, and durability of electric vehicles (EVs) in hot weather. To address the battery cooling optimization problem, this paper utilizes dynamic programming (DP) to develop an online rule-based control strategy. Firstly, an electrical–thermal-aging model of the LiFePO4 battery pack is established. A control-oriented onboard BTMS model is proposed and verified under different speed profiles and temperatures. Then in the DP framework, a cost function consisting of battery aging cost and cooling-induced electricity cost is minimized to obtain the optimal compressor power. By exacting three rules ”fast cooling, slow cooling, and temperature-maintaining” from the DP result, a near-optimal rule-based cooling strategy, which uses as much regenerative energy as possible to cool the battery pack, is proposed for online execution. Simulation results show that the proposed online strategy can dramatically improve the driving economy and reduce battery degradation under diverse operation conditions, achieving less than a 2.18% difference in battery loss compared to the offline DP. Recommendations regarding battery cooling under different real-world cases are finally provided

    Performance evaluation and control of an MMC active rectifier with half-bridge and full-bridge submodules for HVDC applications

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    Dissertation (MEng (Electrical Engineering))--University of Pretoria, 2021.The modular multilevel active rectifier was designed and evaluated, whereby the half bridge and the full bridge DC-DC converters as its submodules for the high voltage direct current transmission were compared. It was found that, by taking advantage of the unipolar modulation scheme in the full bridge converter, the switching losses in the two converters are equal when they are both operated in the linear modulation region. Furthermore, operating the full bridge converter in the overmodulation region does not give it a pronounced advantage over the half bridge converter. The conduction losses in the full bridge converter are two times higher than those in the half bridge converter, due to double the number of semiconductor devices. However, using the half bridge converter in the high voltage direct current modular multilevel converter requires an expensive DC-side breaker, while use of the full bridge converter eliminates the need for such a breaker due to the intrinsic DC-side fault current blocking capability. The clear choice between the two requires industry cost data. A design methodology for the submodule capacitor average voltage loop controllers for phase-shifted carrier modulated modular multilevel converters was carried out from first principles. The methodology enables design of such controllers to be carried out in a step by step and straightforward manner without resorting to simulation or guesswork. A simple but effective submodule capacitor sizing method was proposed. The resulting submodule capacitor size was shown to be smaller than those resulting from other sizing methods proposed in the literature while achieving the submodule capacitor voltage ripple specifications. A robust DC bus voltage controller design for modular multilevel rectifiers was presented, whereby a design method for multilevel voltage source converters with DC link capacitors was adopted for modular multilevel rectifiers. Since the modular multilevel converters for HVDC application are designed without the DC-link capacitor to mitigate the effects of a possible DC-side fault current, the submodule capacitors in the modular multilevel converter acted as an equivalent DC link capacitor to accomplish the design.Electrical, Electronic and Computer EngineeringMEng (Electrical Engineering)Unrestricte

    Grand Design and Economic Analysis of Solar-Wind Hybrid Renewable Energy Systems in MSTP Jepara

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    Marine Science Techno Park (MSTP) Jepara is a center of technology implementation aimed to encourage community economy development in the maritime sector. At present, Marine Science Techno Park (MSTP) Jepara’s electrical energy source is supplied by Perusahaan Listrik Negara (PLN), with coal-powered steam turbine generators as the main source of electrical energy generation. Therefore, a cleaner and more sustainable means of electrical energy generation is needed to fulfill the high energy demand. With this in mind, Universitas Diponegoro, as the proposer, in collaboration with MSTP Jepara, as the recipient, proposes the initiation of Hybrid Renewable Energy Systems (HRES) Power Plant construction as a way of obtaining an environmentally friendly and sustainable source of energy in this research as well as addressing the issues in the previous HRES simulations and implementations. This article will discuss various scenarios, their feasibility for implementation, and the economic returns gained from HRES installation on-site
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