Supply Control Research Articles

On outdoor testing procedures of large samples of PV modules

AbstractSTC power control of PV module supply requires testing large samples of modules with low uncertainty. This paper analyses the feasibility of outdoor measurements with the modules kept at their operating positions. The classical procedure of recording I‐V curves and translating them to STC in accordance with IEC‐60891:2021 using the cell temperature directly observed at a few points of the rear of the module entails expanded uncertainties larger than 3% (k = 2), which is too much for this procedure being accepted in quality controls with contractual consequences. A convenient procedure for overcoming this barrier consists in comparing the I‐V curves of a tested and a reference module of the same type, both working under the same operating conditions. The latter is mostly secured if they are in adjacent positions. However, when the procedure is applied to large samples of PV modules kept in their operating positions, the distance between both modules can reach tens of meters and significant inter‐module temperature differences can arise. A method for counterbalancing these differences consists of correcting the measured power values by considering the temperature difference observed at the back‐sheet centres of the tested and the reference modules. That also provides clues to estimating the uncertainty of the results. This procedure has been applied in seven testing campaigns, carried out at commercial PV plants. Dedicated instrumentation, based on two radio linked I‐V tracers, allowing the simultaneous measurement of the I‐V curves and of the temperature at the centres of the reference and the tested modules, has been developed for that. The resulting uncertainties are similar to those corresponding to high‐quality solar simulators and low enough for dealing, in practice, with strict quality control requirements.

Impact of Automation on Enhancing Energy Quality in Grid-Connected Photovoltaic Systems

Rapid growth in the integration of new consumers into the electricity sector, particularly in the industrial sector, has necessitated better control of the electricity supply and of the users’ op-erating conditions to guarantee an adequate quality of service as well as the unregulated dis-turbances that have been generated in the electrical network that can cause significant failures, breakdowns and interruptions, causing considerable expenses and economic losses. This research examines the characteristics of electrical variations in equipment within a company in the industrial sector, analyzes the impact generated within the electrical system according to the need for operation in manufacturing systems, and proposes a new solution through automation of the regulation elements to maintain an optimal system quality and prevent damage and equipment failures while offering a cost-effective model. The proposed solution is evaluated through a reliable simulation in ETAP (Energy Systems Modeling, Analysis and Optimization) software, which emulates the interaction of control elements and simulates the design of electric flow equipment operation. The results demonstrate an improvement in system performance in the presence of disturbances when two automation schemes are applied as well as the exclusive operation of the capacitor bank, which improves the total system current fluctuations and improves the power factor from 85.83% to 93.42%. Such a scheme also improves the waveform in the main power system; another improvement result is when simultaneously operating the voltage and current filter together with the PV system, further improving the current fluctuations, improving the power factor from 85.83% to 94.81%, achieving better stability and improving the quality of the waveform in the main power grid.

Optimized Water Supply in a Solar Evaporator for Simultaneous Freshwater Production and Salt Recycle.

Solar desalination has shown great potential in alleviating global water scarcity. However, the trade-off between energy efficiency and salt rejection remains a challenge, restricting its practical applications. In this study, we report a three-dimensional nitrocellulose membrane-based evaporator featuring a high evaporation rate (1.5 kg m-2 h-1) and efficient salt precipitation at the edges. Additionally, the salt is isolated from the photothermal area of the evaporator and falls automatically with a salt recovery rate of 97 g m-2 h-1 in brine with 10 wt % salt content. The distinctive performance is attributed to the precise water supply control, which was adjusted by changing the resistance force and driven force in the evaporator. With a high evaporation rate, stable performance, and specific salt recovery ability, this solar evaporation structure holds great potential in water desalination and resource recovery.

Applying blockchain to quality food products: a marketing perspective

PurposeThe purpose of this paper is to enrich the knowledge about blockchain (BC) technology implementation in the agri-food industry by providing an interpretive framework of the key marketing opportunities and challenges, related to the adoption of BC for Geographical Indication (GI) products.Design/methodology/approachThe study adopts an explorative qualitative research design through the cognitive mapping technique applied to the cognition of different market players involved in agri-food BC projects: farmers, distributors, companies and consultancies.FindingsThis study presents a comprehensive examination of the marketing impacts of BC across various marketing objectives, including product enhancement, brand positioning, consumer relationships, market access and supply chain relationships. It highlights the capability of BC to facilitate data-enabled ecosystems within the agri-food sector, involving supply chain actors and control agencies. Additionally, the study sheds light on the challenges (technological, collaborative, political, financial and organizational) associated with the implementation of BC in the marketing of agri-food products.Research limitations/implicationsThis work provides a comprehensive examination of the relevance of BC in the marketing activities of firms, particularly in the context of quality food products. It highlights the main areas of impact and effects and emphasizes the complexity of the phenomenon, which extends beyond its technical issues. Furthermore, it offers a systematic exploration of the challenges associated with the adoption of BC in marketing activities, thus contributing to a broader understanding of the implications of BC adoption in companies' marketing strategies.Practical implicationsThe practical implications for this work addresses both GI companies and policy makers. Implications for companies relate to the market benefits associated with the implementation of BC, which allow further strengthening of market positioning, relationships of trust within the supply chain and integration between physical and digital market channels. The study also systematizes the challenges underlying the implementation of BC projects. The implications for policy makers regard the role they have to play in BC projects at regulatory, financial and policy levels.Originality/valueStudies focusing on BC applications in marketing are still limited and characterized by a very narrow perspective (especially in the food industry). This study contributes to the conceptual design of the marketing applications of BC in the agri-food sector. The value of the study also lies in having framed the marketing impacts of BC in a holistic perspective, along with the technological and non-technological challenges that are related to the integration of BC in marketing strategy and operations.

Microbial estimation using real-time monitoring of vegetable wash water quality parameters

The real-time effectiveness of washing fresh-cut produce is hard to evaluate because it is impossible to rapidly measure the bacteria levels in the produce and wash water during a continuous washing step. This study aimed to investigate the correlation between microbial levels (total aerobic bacteria [TAB] and coliforms) and water quality parameters (turbidity, color, salinity, and temperature) during the processing of salted Chinese cabbages. Results showed that wash water and cabbage samples were contaminated with TAB and coliforms but not Escherichia coli. Turbidity, as a measure of the wash water quality, had a wide measurement range (0.48–43.48 NTU). There was a very high positive correlation between the TAB levels in all four washing tanks and turbidity (r = 0.98). The error between actual and estimated TAB levels, based on turbidity, was within 8 %. These results suggest that real-time monitoring of turbidity can be applied to the water supply control system to maintain the cleaning effect of salted Chinese cabbages.

Current Control of EAST Fast Control Power Supply Based on Improved Grey Prediction Variable Gain PI

Current Control of EAST Fast Control Power Supply Based on Improved Grey Prediction Variable Gain PI

Improving the air supply and hydrogen dilution control of a fuel cell electric vehicle with explicit model predictive control

This study demonstrates the applicability of an explicit model predictive controller (ExMPC) to the air mass flow control in a fuel cell electric vehicle. The two control tasks comprise the supply of air to the fuel cell stack for the electrochemical reaction as well as the dilution of hydrogen in the outlet gas flow of the cathode subsystem. With the aim of achieving zero control deviation for steady states, the linear model in the state observer is extended with two perturbations. During the experimental validation of the proposed controller, fast dynamics are achieved with the ExMPC, which generally exploits the limits of the control variables. After the calibration of the ExMPC, the final comparison to a set of reference PI controllers reveals a significant improvement in the closed-loop behavior of the cathode subsystem during step changes in the controller setpoints.

Control of isolated hydrogen generation power supply for the DC power grid

The utilization of water electrolysis hydrogen in DC power grids can effectively improve the absorption and utilization of renewable energy, and hydrogen production power supply is a key equipment. This article designs an isolated DC hydrogen production power supply, which adopts a bidirectional active H-bridge topology and power modular design. In the process of hydrogen production, the use of constant current and constant voltage control, the development of control strategies for the hydrogen production process but the input current ripple of the electrolytic cell is heavy, so the driving pulse interleaving phase shift between power modules is adopted. The hydrogen production power supply can achieve a hydrogen production process with a small current ripple, and the feasibility and effectiveness of the hydrogen preparation power supply control strategy have been verified through simulation and experiments.

Design of Solar Endurance Control for Unmanned Aerial Vehicles based on Schmidt Trigger Control

In order to improve the endurance of unmanned aerial vehicles (UAVs), a power supply controller with automatic switching between solar energy and battery was designed. The controller is mainly composed of an AT89C51 single chip microcomputer. By collecting ambient light intensity and comparing it with the preset light intensity of the system, the controller completes automatic switching of the power supply for solar unmanned aerial vehicles, thereby achieving continuous and stable power supply for solar unmanned aerial vehicles. In addition, the implementation method of the single-chip microcomputer program in the controller is also introduced. The control core is to use Schmidt de shake control to switch between solar energy and battery, and to test the various functions of the controller through the flight experiment of a small solar powered unmanned aerial vehicle. Tests have found that solar powered drones using this controller can navigate for a long time in weather with varying light intensity, and the device operates well, effectively improving the power stability of solar powered drones.

A framework to formulate and aggregate performance indicators to quantify building energy flexibility

Building energy flexibility is being considered an emerging strategy allowing the demand side actively support the operation and control of variable resources-based energy supply. This study presents the development of a framework to formulate and aggregate energy flexibility indicators (EFIs) to evaluate building energy flexibility. EFIs were developed/selected using the important characteristics of building energy flexible sources, performance factors linked with flexibility services and penalty factors posed by the grid. A multicriteria decision analysis method was then used to develop an Aggregated Energy Flexibility Potential (AEFP) function that can consider the interactions between the power grid, buildings and building energy systems to represent the building's overall energy flexibility potential with a single dimensionless value. AEFP can help determine cost-effective energy flexible sources and solutions for increased energy flexibility. The performance of the EFIs and AEFP developed was evaluated via a case study with two distinct scenarios through simulations. The photovoltaic system provided a peak power demand reduction of 94%, emissions reduction of 46% and energy cost reduction of 54% to the building with an AEFP value of 0.74 (i.e. 74%), whereas a thermal energy storage system coupled with an air conditioning system helped reduce peak power demand by 56.4%, CO2 emissions by 14.5% and energy cost by 32% with an AEFP value of 0.54 (i.e. 54%). Both scenarios verified the effectiveness of the developed EFIs and AEFP for evaluating building energy flexibility.

Совместная оптимизация конструктивных параметров индуктора и алгоритмов управления процессом нагрева под поверхностную закалку

The paper considers an approach for solving the joint optimization problem of design solutions and modes 
 of inductor functioning in the process of heating steel parts of L-shaped form for surface hardening. The first stage solves the problem of optimizing the design of the coils of the inductor and the parameters of the power supply control algorithm, ensuring the maximum uniform heating of the quenched layer to a given temperature above the Curie point in 
 a fixed time. In the second step, a phase limitation is considered, which is a technological requirement to ensure, throughout the heating stage, a temperature not exceeding the limit value. In case of violation of the specified limit, the problem of finding the control algorithm on a special interval within which the maximum temperature in the hardened layer exceeded the maximum permissible value is solved. In the third step, the problem of joint optimization is solved with the found control algorithm at a specific interval of motion on the phase restriction. The described steps can be repeated if necessary. There is presented a test example of the application of the developed strategy for the considered class of technology induction heating for the surface hardening of metal blanks with an angle zone. For the numerical solution in the MATLAB application package developed a software complex, in which integrated two-dimensional nonlinear problem-oriented model of the induction heating process, developed in ANSYS Mechanical APDL. The algorithm for solving the joint optimization problem is based on an alternate method of parametric optimization of systems with distributed parameters. Developed strategy tested on a verified model of interconnected electromagnetic and temperature fields, it is possible to obtain a uniform temperature distribution along the boundary of the hardened layer of steel semi-finished products of complex geometric shape without local overheating throughout the heating stage.

Система природопользования в решениях общественных сходов кочевых инородцев

The subject of the research of this article is the social sentences adopted at the gatherings of nomadic peoples, on the example of the Kalmyks of the Astrakhan province in the last third of the XIX — early XX century, reflecting the rational behavior of nomads in relation to the environment. The basis of the source base was documentary materials from the collections of the National Archive of the Republic of Kalmykia. The research methodology is based on the use of problem-chronological and comparative methods of scientific research. In the course of the study, the author focuses on three areas: land use, water supply and rodent control. In conclusion, it is concluded that respect for the environment is a legacy of traditions developed over several generations and fixed by the norms of customary law, and subsequently approved by imperial legislation. However, practical experience shows that not all areas of activity of the imperial government aroused the interest of the nomadic population and did not always correspond to rational behavior, which was more subject to the norms of customary law

Application Of Consumption Method With Eoq, Mmsl Forecasting And Abc-Ven Analysis In Pharmaceutical Briefing Management In Hospitals General Royal Prima Marelan

Hospitals should plan for drug needs using accountable methods to avoid empty drugs. Good drug planning can improve pharmaceutical stock control in hospitals. The purpose of this study was to find out about the application of consumption methods with EOQ, MMSL and ABC-VEN forecasting in the management of pharmaceutical supplies in hospitals. This study used retrospective mix-method data, quantitative data and qualitative primary data. The research was conducted at RSU Royal Prima Marelan. The results showed that drug supply control using the EOQ method of getting drugs reordered: cefixime 200MG ordered at 447, ondacetron 4MG 740, gabapentin 300MG 706, ranitidine 25MG 1467, novorapid flexpen / 5" 42. In the SS method, the number of drugs available at delivery, cefixime 200MG should be 627 drugs at the time of shipment, ondacetron 4MG should be 522, gabapentin 300MG should be 470, ranitidine 25MG should be 940, and novorapid flexpen/5" should be 26. In the ROP method the drug was reordered at cefixime 200MG it was reordered when the stock was 447 and the quantity ordered was 12027, ondacetron 4MG 740 and 10000, gabapentin 300MG 706 and 9020, ranitidine 25MG 1467 and 18040, novorapid flexpen 42 and 502. In the ABC method, group A as many as 59 types 70.59% with a total investment of 70.59% drug use and an investment value of IDR 606,511,106, group B 64 drug investment 20.33% investment 20.33% drug use investment 174,722,327, group C 146 types (9.08%) investment 9.08% drug use and investment 78,028,263.

Harmonic Injection Strategy Considering Multiplane Iron Loss Impact With Optimal Magnetizing Flux Distribution for Multiphase Induction Machines

Lagging orientation error detuning induced by iron losses for multi-planes of multiphase IM under non-sinusoidal supply control triggers error in determination of calculated harmonic, fundamental air-gap flux advance angles and harmonic slip frequency. This in-turn leads to inaccurate harmonic injected currents, which are dependent on harmonic multiple of frequency for the corresponding plane with respect to fundamental plane frequency. This paper proposes the novel harmonic injection strategy considering the detuned impact of iron losses by keeping in view the complete iron loss modeling for both harmonic magnetizing flux orientation control (MFOC) and fundamental rotor flux orientation control (RFOC) planes. Furthermore, satisfaction of complete optimal flux distribution constraints for multiphase IM are taken into account which results in preserving optimal flux patterns throughout the mechanical loading particularly at low and medium load conditions. Contrary to other traditional orientation schemes, this paper adopts the MFOC and RFOC for harmonic and fundamental plane respectively for acquiring the aligned and synchronized control of harmonic and fundamental air-gap flux distribution. Detailed experimental results incorporating seven phase induction machine as prototype are utilized to evaluate the harmonic injected currents, advance angles, slip frequencies and induced EMF waveforms which validate the effectiveness of proposed scheme.

Математическая модель теплоснабжения помещения как объекта динамического управления температурой

Energy saving issue in the process of administrative buildings heating is an important one. Dynamic control of room temperature depending on the schedule of its usage gives great opportunities. Dynamic control should meet the criteria of energy efficiency and ensure air temperature in the rooms at time intervals of their usage at the required level in terms of external impact on the building. Obviously, such control can only be implemented by an automatic system. To synthesize such a system, we need mathematical models of room heating as control objects. Consequently, the problem under consideration is relevant. Experimental data and numerical simulation methods are used to obtain mathematical models. Mathematical models are obtained in the state space and in the form of transfer functions for controlling and disturbing influences based on the equations of the dynamic heat balance of the room. Two types of mathematical model of the room are defined. They make it possible to synthesize the laws of qualitative and quantitative control of the heat supply of the building with a given accuracy and to determine schedules of temperature changes depending on the schedule of its use, optimal in terms of minimum energy consumption.

Comparison of the treatment results of humerus diaphysis post-traumatic false joints using vascularized bone grafts with and without a monitor skin flap: Retrospective cohort study

BACKGROUND: The use of the microvascular flap in reconstructive surgery of complicated nonunions of the diaphysis of the humerus is highly valuable. Flaps with compromised blood supply are possible in up to 10% of cases and often lead to the failure of vascularized reconstruction. The combined skin + bone graft is a simple, useful, and reliable option for flap vitality control with a high success rate.
 OBJECTIVE: To compare microvascular grafting with versus without monitoring the skin flap.
 MATERIALS AND METHODS: Forty-one microvascular grafting was performed from 2010 to 2017 in patients with humeral non-union and bone defects in the Department of Microsurgery and Trauma of the Hand of Priorov National Medical Research Center of Traumatology and Orthopedics. A combined skin bone flap was used in 23 (56%) patients, and in 18 (44%) patients, grafting was performed without monitoring the skin flap Computed tomography and X-ray imaging were used to monitor non-union healing. The use of a signal skin flap is an effective way to control blood flow in the graft and improves treatment results.
 RESULTS: In the group without monitoring of the skin flap, non-union healing was documented in 14 (77%) cases. In the group with monitoring of the skin flap, nonunion healing occurred in 22 (96%) cases.
 CONCLUSION: Monitoring the skin flap is an effective option to ensure microvascular flap blood supply control and improves the outcomes in humeral nonunion healing.

Numerical analysis and control technology of gas accumulation in a large-scale specially-shaped tunnel passing through coal bearing strata

To solve the construction ventilation problem of super long (length greater than 10000 m) tunnel passing through discrete lenticular gas bag tunnel under complex working conditions in carbonaceous shale stratum, relying on the construction of Banzhulin tunnel of the new Xuyong-Bijie Railway (Sichuan-Yunnan). Using the finite element analysis software, the flow field distribution of the tunnel return air flow in the case of simultaneous excavation of multiple working faces is simulated, and the formation position and influence range of the vortex area which is easy to form gas accumulation are analyzed. On this basis, the technical team developed the PLC uninterruptible self starting ventilation power supply control program. By comparing the changes in the time required for ventilation power supply failure before and after the adoption of this technology, and the comparison of the gas concentration in the return air flow within a relatively short time of the failure, it is proved that this technology reduces the fault response time to 15.74% of the original time, and can well avoid gas accumulation within the failure time, It provides some reference for similar engineering construction.

Real-Time Control of Gas Supply System for a PEMFC Cold-Start Based on the MADDPG Algorithm

During the cold-start process of a PEMFC, the supply of air and hydrogen in the gas supply system has a great influence on the cold-start performance. The cold-start of a PEMFC is a complex nonlinear coupling process, and the traditional control strategy is not sensitive to the real-time characteristics of the system. Inspired by the strong perception and decision-making abilities of deep reinforcement learning, this paper proposes a cold-start control strategy for a gas supply system based on the MADDPG algorithm, and designs an air supply controller and a hydrogen supply controller based on this algorithm. The proposed strategy can optimize the control parameters of the gas supply system in real time according to the temperature rise rate of the stack during the cold-start process, the fluctuation of the OER, and the voltage output characteristics. After the strategy is trained offline according to the designed reward function, the detailed in-loop simulation experiment results are given and compared with the traditional control strategy for the gas supply system. From the results, it can be seen that the proposed MADDPG control strategy has a more effective coordination control effect.

An Operational Attributes of Sri Lanka's Small and Medium Enterprises (SMEs) and India's MSME Sectors in the Perspectives of Digital Transformation and Its Emergence in a Developing Economy

In Sri Lanka, over 75% of enterprises are small and medium-sized enterprises (SMEs), and they generate 52% of the country's GDP and are essential to the country's economy (Kulasinghe et al., 2018). Cutting-edge competition, limited supply and price control, and resource constraints are just a few of the challenges Sri Lankan SMEs face in developing and expanding. Due to their lack of access barriers, cost reduction efforts, and rigid customer and supplier relationships, SMEs find acquiring traditional competitive advantages like differentiation or pricing challenging. To adapt their business models and strategies in response, many companies are experiencing a digital transformation. This article examines how SMEs might use digital transformation as a strategic effort to meet these issues. The report outlines the potential advantages of digital transformation for SMEs in Sri Lanka and indicates areas that need more study through a thorough literature analysis. The study uses a concept paper format, focuses on empirical data, and mainly analyzes Sri Lanka's SME market. The article's conclusion outlines potential paths for study and research in this area.

Milling with Feed Control on a Computer Numerical Control Machine-tools

The process of contour milling is characterized by a change in cutting conditions along the form-formingtrajectory even with an equidistant allowance. Therefore, researching the possibilities of feed control in order to stabilizethe cutting process during milling is an urgent task. The results of experimental studies of end milling on the XYZ VMC1010 machine are presented. Milling of a specially prepared workpiece was performed when the allowance along thecutting path was changed from 0 to 6 mm in depth with a milling width of 30 mm. Milling was performed with a constantfeed in the cutting mode offered by the tool manufacturer and according to a specially designed feed control law. The feedcontrol law was formed automatically when modeling the allowance removal process based on its main characteristic –materials removal rate (MRR). The results convincingly proved the effectiveness of the proposed supply control. The powerof the process was significantly leveled along the milling path regardless of the change in depth of cut, and the machiningtime was reduced by 35%.