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[IEEE 2018 9th Advanced Satellite Multimedia Systems Conference and the 15th Signal Processing for Space Communications Workshop (ASMS/SPSC) - Berlin (2018.9.10-2018.9.12)] 2018 9th Advanced Satellite Multimedia Systems Conference and the 15th Signal Processing for Space Communications Workshop (ASMS/SPSC) - Sparsity-Aided Low-Implementation cost based On-Board beamforming Design for High Throughput Satellite Systems
摘要： Soaring demand for high data rate services entails high throughput satellite (HTS) systems with multi-beam architecture, and full frequency and time resources reuse. However, interference among simultaneously served users is the fundamental factor that is needed to be addressed before enacting HTS system with this architecture. Beamforming has been proposed as a potential technique to mitigate the interference in the literature. Different types of beamforming techniques proposed including beamforming at payload (on-board), beamforming at a gateway and hybrid beamforming. On-board beamforming prevails over other techniques due to its advantages—channel information at payload is more recent than gateway and sharing overhead of channel and symbols across multiple gateways is reduced in a multi-gateway architecture to name a few. Despite these advantages, beamforming at the gateway is usually preferred due to the heavy processing cost incurred in beamforming. Beamforming processing cost can be split into two factors: design cost and implementation cost. While design cost accounts for the cost involved in the design of beamformer, implementation cost accounts for multiplications and additions involved in applying calculated beamformer coefficients to data symbols. Through our study, we noticed that the major contributing factor to processing cost is the implementation cost which accumulates for every data symbol rather than design cost which is incurred only once per channel coherence time which usually relatively longer than many data symbols. Furthermore, the implementation cost is dominated by the multiplications involved. Hence, in this work, we address the issue of implementation cost from the perspective of on-board multiplications. We formulate the problem of minimizing on-board implementation cost (multiplications) of a beamformer as a second-order cone programming problem with the help of (cid:96)1 norm constraint on the beamforming matrix subjected to a minimum signal-to-interference-noise ratio of simultaneously served users and classical total power constraint. We show the efficacy of our algorithm over the traditional power minimization method through Monte-Carlo simulations.
关键词： second-order cone programming,High throughout satellite systems,beamforming,interference
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Portland, OR, USA (2018.9.23-2018.9.27)] 2018 IEEE Energy Conversion Congress and Exposition (ECCE) - Universal Control Strategy using Operating Point Projection Technique for Solar Array Hardware Emulation
摘要： Solar array simulator (SAS) is a special DC power supply that regulates the output voltage or current to emulate characteristics of photovoltaic (PV) panels. Especially, the control of SAS is a challenging task due to the nonlinearity in the output curve, which is dependent on irradiance as well as temperature and is determined by panel materials. Conventionally, both current-mode control and voltage-mode control should be alternated by partitioning the operating curve into multiple sections, which is not only for the measurement noise problem with the feedback sensing but also for the control stability issue near the maximum power point. However, the occurrence of transition among different controllers may deteriorate the overall performance. To eliminate the mode transitions, a novel single controller scheme has been introduced in this paper, where the operating point projection technique enables simple, smooth and numerically stable control. Theoretical consideration on the loop stability issue is discussed and the performance is verified experimentally for the emulation of a PV panel data in view of stability and response speed.
关键词： Photovoltaic systems,Solar array simulator,Feedback control,Solar power
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Electronics, Control, Optimization and Computer Science (ICECOCS) - Kenitra, Morocco (2018.12.5-2018.12.6)] 2018 International Conference on Electronics, Control, Optimization and Computer Science (ICECOCS) - Backstepping Control for Three Phase Single Stage Grid Connected PV System with Improved Power Quality
摘要： The development of PV-systems has increased due to the high demand for clean energy. Used worldwide in the distributed power generation markets, the photovoltaic energy must not only be maximized, but also adapted to the global standards on harmonic emissions towards the power utility. Hence, the tracking of the maximum power point and the harmonic filtering becomes necessary. A three-phase single stage grid-connected Photovoltaic system consisting of a photovoltaic array and a three-phase PWM inverter coupled through the LCL-filter to the electrical grid is studied in this paper. A new control design is developed to maximize power in the side of PV panels and to ensure a unit power factor at the grid side. Grid synchronization is provided by a three-phase PLL (Phase-Locked Loop) and the closed-loop stability is demonstrated using Lyapunov analysis. Simulation results clearly illustrate that the proposed controller has achieved all of its objectives. In order to demonstrate the performance of the LCL-filter in minimizing the harmonics produced by the photovoltaic inverter, the frequency response of the injected currents was compared to that obtained using a simple L-filter.
关键词： backstepping controller,PV systems,maximum power point tracking,three-phase inverter,LCL-filter,unity power factor,grid connection
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe) - Sarajevo, Bosnia and Herzegovina (2018.10.21-2018.10.25)] 2018 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe) - Automated Quantification of PV Hosting Capacity In Distribution Networks Under User-Defined Control and Optimisation Procedures
摘要： With the rising popularity of photovoltaic (PV) power, utility companies are experiencing a growing number of interconnection requests on their networks. Combined with power quality issues, the distribution system operator (DSO) must go through strenuous impact studies before proceeding to the installation of PV systems. To address this issue, this work proposes a tool to rapidly and accurately compute the total PV hosting capacity (PVHC) of their network. Moreover, the proposed tool allows the implementation of user-defined control strategies in order to assess their beneficial effects with respect to the PVHC. In this prospect, we investigated the impact of smart PV inverters. We implemented this tool as a plugin for PowerFactory and tested it on the CIGRE benchmark distribution grid. First, we determined the PVHC with inverters injecting at unity power factor, then we estimated the gains brought by smart inverter control (SIC). The latter increased the hosting capacity by up to 19.7 %.
关键词： smart grids,optimal control,inverters,photovoltaic systems,power quality
更新于2025-09-23 15:22:29
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Cascaded H-Bridge MLI and Three-Phase Cascaded VSI Topologies for Grid-Connected PV Systems with Distributed MPPT
摘要： Cascaded multilevel inverter topologies have received a great deal of attention for grid-connected PV systems. In this paper, three-cascaded multilevel inverter configurations are proposed for grid-connected PV applications. These are the three-phase cascaded H-bridge multilevel inverter topology, three-phase cascaded voltage-source inverter topology using inductors, and three-phase cascaded voltage-source inverter topology using coupled transformers. Distributed maximum power point tracking (MPPT) of PV modules using perturbation and observation algorithm is used for all presented topologies. In all presented configurations, each PV module is connected to one DC-DC isolated ?uk converter for best MPPT achievement. Simulation is achieved by using the SIMULINK environment. The simulation results show that the three proposed topologies function well in improving the grid’s power quality. The grid currents are kept in phase with the grid voltage to ensure unity power factor, and the THD of the grid currents are within the acceptable range. The proposed topologies are experimentally implemented in the lab, and the switching pulses are generated with the help of the MicroLabBox data acquisition system. Comparing the three topologies according to the number of switches, voltage, and current stresses on switches and THD of the generated voltages and grid currents and according to the efficiency has been achieved in this paper, both experimentally and by simulation. The simulation and experimental results and comparisons are presented to verify the proposed topologies’ effectiveness and reliability.
关键词： voltage-source inverter,power quality,distributed MPPT,cascaded multilevel inverter,grid-connected PV systems,H-bridge
更新于2025-09-23 15:22:29
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A Novel Transmitting Module Self-Monitoring Protection System Based On MEMS Sensors and Actuators
摘要： Design, fabrication, and measurements of a novel transmitting module self-monitoring protection system are presented in this letter. Such a system is based on micro-electromechanical systems (MEMS) sensors and actuators for monitoring and protecting the microwave amplifier circuit. The transmitting module self-monitoring protection system consists of the RF MEMS switches, the directional coupler, and the MEMS power sensors. When the microwave amplifier circuit is at an abnormal state ("open," "short," or "overload"), the transmitting module self-monitoring protection system can isolate the microwave amplifier circuit out of order and reconfigure the transmitting module into impedance matching within 36 ms. When the microwave amplifier circuit is at the overload state, the error between the set switching power and the actual switching power is less than 9%. The measured results agree well with the theory.
关键词： Microelectromechanical systems (MEMS) power sensor,microwave amplifier circuit,RF MEMS switch,self-monitoring protection
更新于2025-09-23 15:22:29
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A Dual-Discrete Model Predictive Control-based MPPT for PV systems
摘要： This paper presents a method that overcomes the problem of the confusion during fast irradiance change in the classical MPPTs as well as in model predictive control (MPC)-based MPPTs available in the literature. The previously introduced MPC-based MPPTs take into account the model of the converter only, which make them prone to the drift during fast environmental conditions. Therefore, the model of the PV array is also considered in the proposed algorithm, which allows it to be prompt during rapid environmental condition changes. It takes into account multiple previous samples of power, and based on that is able to take the correct tracking decision when the predicted and measured power differ (in case of drift issue). After the tracking decision is taken, it will be sent to a second part of the algorithm as a reference. The second part is used for following the reference provided by the first part, where the pulses are sent directly to the converter, without a modulator or a linear controller. The proposed technique is validated experimentally by using a buck converter, fed by a PV simulator. The tracking efficiency is evaluated according to EN50530 standard in static and dynamic conditions. The experimental results show that the proposed MPC-MPPT is a quick and accurate tracker under very fast changing irradiance, while maintaining high tracking efficiency even under very low irradiance.
关键词： Buck converter,dc-dc power conversion,Photovoltaic systems,Double cost function,Maximum power point tracking,Drift,EN50530 standard,MPC
更新于2025-09-23 15:22:29
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Spontaneous Charge Generation in Flowing Albumin Solutions at 35 °C and 38 °C
摘要： The time dependence of a charge accumulation in a 10?15 M albumin solution, flowing through a measuring cell of an analytical flow system injector, had a nonlinear character under certain conditions, within a human physiological temperature range. Sharp charge increases depended on albumin concentration. This effect must be taken into consideration when generating models that describe electrokinetic phenomena in flowing protein solutions and when developing analytical flow systems for the registration of biomolecules in low concentration ranges.
关键词： flowing protein solution,charge accumulation,analytical flow-through systems,physiological temperature,serum albumin
更新于2025-09-23 15:22:29
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Economic Analysis for Residential Solar PV Systems Based on Different Demand Charge Tariffs
摘要： It is well known that the use of photovoltaic (PV) systems helps to preserve the environment, produce lower levels of greenhouse gases (GHGs), and reduce global warming, however, whether it is economically profitable for customers or not is highly debatable. This paper aims to address this issue. To be comprehensive, three different types of buildings are considered as case studies. Then, these three buildings are modeled in EnergyPlus to determine the rate of energy consumption. Afterward, comparisons of various solar system sizes based on economic parameters such as the internal rate of return, the net present value, payback period and profitability indexing for various-sized PV systems are carried out. The results show that by the demand charge tariffs, using PV systems has no economic justification. It has been shown that even with neglecting further costs of the PV system like maintenance, by demand charge tariffs, it is not economically beneficial for customers to use the PV systems. Profitability index of all three buildings with various PV power systems is between 0.2 to 0.8, which are by no means is desirable. Moreover, it was found that bigger solar systems are less cost-effective in the presence of demand charges.
关键词： photovoltaic (PV) systems,economic analysis,energy in buildings,EnergyPlus
更新于2025-09-23 15:22:29
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Evaluation of Ground Surface Models Derived from Unmanned Aerial Systems with Digital Aerial Photogrammetry in a Disturbed Conifer Forest
摘要： Detailed vertical forest structure information can be remotely sensed by combining technologies of unmanned aerial systems (UAS) and digital aerial photogrammetry (DAP). A key limitation in the application of DAP methods, however, is the inability to produce accurate digital elevation models (DEM) in areas of dense vegetation. This study investigates the terrain modeling potential of UAS-DAP methods within a temperate conifer forest in British Columbia, Canada. UAS-acquired images were photogrammetrically processed to produce high-resolution DAP point clouds. To evaluate the terrain modeling ability of DAP, first, a sensitivity analysis was conducted to estimate optimal parameters of three ground-point classification algorithms designed for airborne laser scanning (ALS). Algorithms tested include progressive triangulated irregular network (TIN) densification (PTD), hierarchical robust interpolation (HRI) and simple progressive morphological filtering (SMRF). Points were classified as ground from the ALS and served as ground-truth data to which UAS-DAP derived DEMs were compared. The proportion of area with root mean square error (RMSE) <1.5 m were 56.5%, 51.6% and 52.3% for the PTD, HRI and SMRF methods respectively. To assess the influence of terrain slope and canopy cover, error values of DAP-DEMs produced using optimal parameters were compared to stratified classes of canopy cover and slope generated from ALS point clouds. Results indicate that canopy cover was approximately three times more influential on RMSE than terrain slope.
关键词： Structure from Motion (SfM),point cloud classification,unmanned aerial systems (UAS),digital elevation model (DEM)
更新于2025-09-23 15:22:29