Flexible Control Method Research Articles

Study on the flexible control method of thermal storage technology participating in the power grid

Study on the flexible control method of thermal storage technology participating in the power grid

A novel heating strategy and its optimization of solar–air source heat pump heating system for rural buildings in northwest China

In the rural areas of Northwest China, the utilization of clean and renewable energy is deemed a crucial measure for reducing building energy consumption and environmental pollutant emissions. This paper focuses on constructing a simulation platform for a solar-assisted air source heat pump heating system. A rural residential building in Yongshou County, Shaanxi Province, serves as an illustrative example. A novel flexible temperature control method with a feedback controller in sub-area and period is proposed in this paper, alongside the selection of three distinct objective functions aimed at optimizing the heating system. The simulation results indicate an average temperature of 17.0 °C throughout the heating cycle, with a peak temperature of 18.7 °C. Moreover, the solar fraction is measured at 25.11%, underscoring the significance of collector area and heat storage tank volume as primary factors in system design. The results also demonstrate that across various optimization objectives, the life cycle cost optimization scheme yields greater economic benefits, while the target building unit heating cost optimization scheme boasts the shortest static payback period and lowest unit heating cost. Conversely, the solar fraction optimization scheme stands out for its superior environmental benefits. These findings offer valuable insights for the design of heating systems tailored to diverse objectives.

Multiple heating loads participate in the system power regulation control strategy

With the addition of a high proportion of new energy and power electronic equipment, the power system has shown characteristics such as low inertia and significant energy output fluctuation, which has brought great challenges to power/frequency regulation and control of the power system. Therefore, this article uses the inertia characteristics of heat energy on the load side and exerts reasonable start-stop control to play a positive and beneficial role in the power regulation of the power system. Firstly, the room temperature variation process was transformed into a lumped parameter equivalent model. A lumped parameter heat transfer model of a single typical load was built in Simulink, and its dynamic characteristics were analyzed by symbolic calculation. Based on this, a time-domain simulation was carried out to explore the influence of the law of system parameters and external input on the change of system state quantity. Based on time domain simulation, the behavior of the heating load is analyzed. Then, the effects of typical and multiple loads on system power regulation at different outdoor temperatures are studied. It is found that when the average outdoor temperature decreases, the sustainable time of system power upturn will increase, and the sustainable time of downturn will decrease. The power curve of multiple loads simultaneously is more stable, and the adjustment ability is stronger. The reasonable and flexible control method of load switch setting, namely the coherent characteristic load power regulation strategy, realizes the sustainable power optimization of the load to the system in the specified period.

A Multi-Objective Optimal Control Method for Navigating Connected and Automated Vehicles at Signalized Intersections Based on Reinforcement Learning

The emergence and application of connected and automated vehicles (CAVs) have played a positive role in improving the efficiency of urban transportation and achieving sustainable development. To improve the traffic efficiency at signalized intersections in a connected environment while simultaneously reducing energy consumption and ensuring a more comfortable driving experience, this study investigates a flexible and real-time control method to navigate the CAVs at signalized intersections utilizing reinforcement learning (RL). Initially, control of CAVs at intersections is formulated as a Markov Decision Process (MDP) based on the vehicles’ motion state and the intersection environment. Subsequently, a comprehensive reward function is formulated considering energy consumption, efficiency, comfort, and safety. Then, based on the established environment and the twin delayed deep deterministic policy gradient (TD3) algorithm, a control algorithm for CAVs is designed. Finally, a simulation study is conducted using SUMO, with Lankershim Boulevard as the research scenario. Results indicate that the proposed methods yield a 13.77% reduction in energy consumption and a notable 18.26% decrease in travel time. Vehicles controlled by the proposed method also exhibit smoother driving trajectories.

Flexible closed-loop control device and control method for distribution network based on hybrid phase shifting transformer

With the increasingly complex structure of the distribution network and the increasing demand for power supply quality from the user side, relying solely on the original grid layout for power supply can no longer meet existing needs. Closed loop power supply can achieve uninterrupted load to improve power supply reliability. This article proposes a flexible loop closing device based on HPST for the case of large voltage phasor differences on both sides of the busbar loop closing point in the distribution network and proposes corresponding flexible loop closing and load transfer strategies based on the characteristics of HPST. Finally, a simulation of loop closure and power control was conducted based on the 10 kV distribution network loop closure scenario, verifying the feasibility of the HPST flexible loop closure device and the effectiveness of the control strategy.

Research on dynamic PI parameter tuning of double-fed wind turbine based on ant colony algorithm

Considering the drawbacks of flexible adjustment of PI controller control parameters in the constant pressure control system of doubly fed fans, a PI controller control parameter flexible adjustment method considering ant colony optimization algorithm (ACO) is proposed. This method uses the proportional coefficient and integration time parameters in the PI controller as the ants in the ant colony optimization algorithm, and the ultimate optimization goal is to control the absolute error integration function. During the control process, the parameters of the PI controller are dynamically adjusted. When the electrified wire netting IR-drop and wind velocity changes, a comparative analysis of the dynamic tuning PI controller parameters and the non-dynamic tuning method was conducted. At last, the simulation studies have shown that the constant voltage control system using the PI parameter Flexible adjustment control method found on ACO can rapidly improve the grid voltage stability of double-fed wind turbines and reduce response time.

Synchronization issue of uncertain time-delay systems based on flexible impulsive control

<p>This paper discusses a synchronization issue of uncertain time-delay systems via flexible delayed impulsive control. A new Razumikhin-type inequality is presented, considering adjustable parameters the $ \varpi(t) $, which relies on flexible impulsive gain. For the uncertain time-delay systems where delay magnitude is not constrained to impulsive intervals, sufficient conditions for global exponential synchronization (GES) are established. Furthermore, based on Lyapunov theory, a new differential inequality and linear matrix inequality design, and a flexible impulsive control method is introduced through using the variable impulsive gain and time-varying delays. It is interesting to find that uncertain time-delay systems can maintain GES by adjusting the impulsive gain and impulsive delay. Finally, two simulations are given to illustrate the effectiveness of the derived results.</p>

Low-Power and Low-Cost AI Processor with Distributed-Aggregated Classification Architecture for Wearable Epilepsy Seizure Detection.

Wearable devices with continuous monitoring capabilities are critical for the daily detection of epileptic seizures, as they provide users with accurate and comprehensible analytical results. However, current AI classifiers rely on a two-stage recognition process for continuous monitoring, which only reduces operation time but remains challenged by the high cost of additional hardware. To address this problem, this article proposes a novel fusion architecture for AI processors, which enables event-triggered cross-paradigm integration and computation. Our method introduces a distributed-aggregated classification architecture (D-ACA) that facilitates the reuse of hardware resources across two-stage recognition, thereby obviating the need for standby hardware and enhancing energy efficiency. Integrating a non-encoding biomedical circuit method based on spiking neural networks (SNNs), the architecture eliminates encoded neurons at the hardware level, significantly optimizing energy consumption and hardware resource utilization. Additionally, we develop a configurable and highly flexible control method that supports various neuron modules, enabling continuous detection of epileptic seizures and activating high-precision recognition upon event detection. Finally, we implement the design on the Xilinx ZCU 102 FPGA board, where the AI processor achieves a high classification accuracy of 98.1% while consuming extremely low classification energy (3.73 μJ per classification).

Load flexible control method for wind and solar energy storage power plant considering the power side demand

Load flexible control method for wind and solar energy storage power plant considering the power side demand

Study on multi-type flexible load control method of active distribution network based on dynamic time-sharing electricity price

Accurate load control is the basis of safe operation and optimal dispatching in active distribution network, and the demand response system of flexible electricity price mechanism and incentive mechanism is the premise of load control. Aiming at the complexity increase of load control caused by the integration of conventional loads, electric vehicles, and micro-grid multi-type user loads in the existing active distribution network, this study comprehensively takes the power consumption willingness of multiple typesof users in active distribution network into account for the first time. This study dominated by the user willingness selects a typical active distribution network load-related data onto a certain area to conduct a calculation example analysis. Firstly, a multi-type user load demand response model of active distribution network is constructed. Then, in order to achieve flexible control of active distribution network loads, a dynamic time-of-use electricity price game model considering the target function and the willingness of multiple usersis proposed, in order to achieve the maximum of user satisfaction and interests of power supply enterprises. Furthermore, the example results are compared with the intrinsic electricity price.Finally, the simulation results show that the time-of-use price established by the multi-type user load game is effective inguiding users to adjust their power consumption habits, making the load curve shift, controlling the electricity load within the maximum power supply limit, and thus alleviating the pressure of power grid expansion.

The Effect of Nationwide Organized Cancer Screening Programs on Gastric Cancer Mortality: A Synthetic Control Study

Nationwide organized gastric cancer (GC) screening programs have been running for decades in South Korea and Japan. This study conducted a quasi-experimental analysis to assess the population impact of these programs on GC mortality. We used the flexible synthetic control method (SCM) to estimate the effect of the screening programs on age-standardized GC mortality and other upper gastrointestinal (UGI) diseases (esophageal cancer and peptic ulcer) among people aged ≥40 years. World Health Organization mortality data and country-level covariates from the World Bank and the Global Burden of Diseases study were used for the analyses. We compared postintervention trends in outcome with the counterfactual trend of the synthetic control and estimated average postintervention rate ratios (RRs) with associated 95% confidence intervals (CIs). A series of sensitivity analyses were conducted. The preintervention fits were acceptable for the analyses of South Korea and Japan's GC mortality but poor for Japan's other UGI disease mortality. The average postintervention RRs were 0.83 (95% CI, 0.71-0.96) for GC mortality and 0.72 (95% CI, 0.57-0.90) for other UGI disease mortality in South Korea. The RR reached 0.59 by the 15th year after the initiation of nationwide screening. For Japan, the average RRs were 0.97 (95% CI, 0.88-1.07) for GC mortality and 0.93 (95% CI, 0.68-1.28) for other UGI disease mortality. Sensitivity analysis reveals the result for Japan may potentially be biased. South Korea's nationwide GC screening has apparent benefits, whereas the Japanese program's effectiveness is uncertain. The experiences of South Korea and Japan could serve as a reference for other countries.

Novel Source-Storage Coordination Strategy Adaptive to Impulsive Generation Characteristic Suitable for Isolated Island Microgrid Scheduling

Wave energy generator (WEG) is a new renewable energy source with prominent advantages and disadvantages. Theoretically, it can move around the sea to harvest wave energy better and will not take up valuable land resources. Normally, WEG collects tiny wave energy continuously and generates electricity intermittently on the minute time-scale to enhance energy harvesting efficiency. Thus, the output of WEG shows prominent impulsive characteristics, which needs to be compensated by the battery energy storage system (BESS) and therefore brings about significant battery life losses. For the purpose of stable and economic operation of the weak power grid connected by WEG, a flexible control method enabling a quantifiable tradeoff between its energy harvesting efficiency and impulsive characteristics is proposed. Then, a novel source-storage coordination strategy and the corresponding energy exchange model of WEG with several optimizable control parameters is formulated to depict the energy flow within the microgrid. Subsequently, an optimization algorithm is proposed to schedule the WEG’s mobile route and optimizable control parameters simultaneously. Simulation results show that the proposed source-storage strategy and the energy management scheme can balance WEG’s energy harvesting and impulsive impact, and utilize its mobility to improve the isolated island microgrid’s operation economy and power quality.

Seismic failure probability of adjacent frame structures retrofitted by flexible control measure

Due to the randomness of earthquake and the difference of dynamic characteristics of adjacent structures, the mechanical behavior of the adjacent structures under earthquake is very complex. A flexible control method using steel strands is proposed, which has little impact on the dynamic characteristics of the adjacent structures. A three-dimensional numerical calculation model of the adjacent frame structures is established by using LS-DYNA. The interstory drift ratios of the single structure, the adjacent uncontrolled structure and the adjacent controlled structure are analyzed by using incremental dynamic analysis (IDA) method. The failure probabilities of different limit states (LS) are studied based on the vulnerability, and the annual average and the design life failure probabilities are further discussed by the probabilistic seismic failure risk analysis. The results show that the maximum interstory drift ratio of the structure is reduced by the flexible control, and the failure probability of the adjacent controlled structure is less than that of the single structure and the adjacent uncontrolled structures. It should be noted that the influence of the flexible control on the failure probability is reduced when the PGA is close to 1.0 g. The four limit states LS1, LS2, LS3 and LS4 represent the slight damage, the moderate damage, the severe damage and the complete damage, respectively. The annual average failure probability from LS1 to LS4 decreases in turn, and the difference is about 10 times. Compared with the adjacent uncontrolled structures, the flexible control reduces the design life failure probabilities of the 10-storey structure and the 8-storey structure by 13.82% and 11.79%, respectively. The proposed control measure is helpful to reduce the failure probability of the adjacent frame structures under earthquake action.

Cooperative distributed MPC via decentralized real-time optimization: Implementation results for robot formations

Distributed model predictive control (DMPC) is a flexible and scalable feedback control method applicable to a wide range of systems. While the stability analysis of DMPC is quite well understood, there exist only limited implementation results for realistic applications involving distributed computation and networked communication. This article approaches formation control of mobile robots via a cooperative DMPC scheme. We discuss the implementation via decentralized optimization algorithms. To this end, we combine the alternating direction method of multipliers with decentralized sequential quadratic programming to solve the underlying optimal control problem in a decentralized fashion with nominal convergence guarantees. Our approach only requires coupled subsystems to communicate and does not rely on a central coordinator. Our experimental results showcase the efficacy of DMPC for formation control and they demonstrate the real-time feasibility of the considered algorithms.

Flexible torque control for wind turbines considering frequency response under wind speed crossing region

The operational range of a wind turbine is typically divided into two regions based on wind speed: below and above the rated wind speed. The turbine switches between these two regions depending on the prevailing wind speed; however, during the transition, the generator may undergo transient shocks in torque, which can negatively impact both the mechanical load of the turbine and the reliability of the power system. This article presents a flexible torque control method for wind turbines, specifically designed to handle the transition between wind speed regions when the turbine is participating in frequency regulation. First, the anomalies in generator torque caused by traditional torque control methods during frequency response scenarios are analyzed. Next, two methods—dynamic deloading and flexible torque control—are developed to address these issues. The developed methods set transition regions based on generator speed, which helps to reduce the impact of transient changes in generator torque. Importantly, the addition of transition regions does not require additional feedback, making the controller easy to implement. The response characteristics of the proposed methods are then analyzed under different deloading factors and wind speeds using model linearization. Simulation studies are presented to verify the effectiveness of the proposed methods. Overall, this study demonstrates the potential value of flexible torque control methods for wind turbines, which can help to mitigate the negative impact of torque shocks and improve the reliability and efficiency of wind power systems.

Load flexible control method for wind and solar energy storage power plant considering the power side demand

Load flexible control method for wind and solar energy storage power plant considering the power side demand

Design and implementation of an S-band transmitter for nanosatellites with new configuration

In this paper, the author presents the design and implementation of an Sband transmitter for nanosatellites. By combining heterostructure field effect transistors (HFET) and laterally diffused metal–oxide–semiconductor (LDMOS) technology and using flexible structure and flexible control method, this research obtained 60 dB gain power when input is -14 dBm, output power is 46 dBm (more than 25 W) in 2,1 GHz -2,3 Ghz frequency; phase noise is -80 dBc/Hz at 100 KHz offset frequency. Unlike other traditional transmitters, this transmitter was designed with multi-stages which have multi-peaks resonance to expand bandwidth to respond to the requirement of generation of the complex signal in wide band. Moreover, the phase locked loop (PLL) in frequency synthesizer makes the frequency conversion more flexible and output frequency more stable; thermal problem in module also was solved by using thermistor and operation mode. Measurement results prove that the design does not only satisfy the requirements of nanosatellites but also can be applied to other satellites together with their ground station because it has open configure with flexible structure and flexible control method.

Voltage stability assessment using TCSC and SVC based FACTS controllers

The Most causes of Voltage instability is the sources of reactive power .In order to protect the total system from voltage instability the reactive loads can be reduced or extra reactive power can be added to reach the Voltage collapse point .The Flexible AC transmission devices(FACTS) have made it flexible and possible to prevent Voltage instability by Fast and Flexible control method . Voltage collapse point is predicted with TCSC and SVC devices and is compared with each other. The Voltage stability Indicator is derived to identify the voltage collapse point. it is concluded that voltage stability index provides a simple means to predict vulnerability of a bus in a Multibus system for voltage collapse.

Digital Twin of Beam Pumping Unit Control and Analysis

The software model of beam pumping unit was built through the physical simulation pumping unit lifting system in the Internet of Things laboratory, and the lifting model was updated after mutual verification to form the digital twin system of oil and gas production lifting. Based on the digital twin of beam pumping unit and the real-time data of oil and gas production, the whole process of oil and gas lifting process production is formed, and a flexible closed-loop control method based on the digital twin is obtained. The method is based on the detailed and in-depth analysis of the whole movement, which selecting the load as the monitoring physical quantity, and improving the system efficiency. The method is to change the maximum and minimum load, reduce the input power and improve the system efficiency under the condition of maintaining a certain output. By comparing and analyzing the indicator diagram of oil well production before and after the flexible control, the flexible control method based on digital twin reduces the loss of mechanical operation and saves the consumption of electric energy, so that the efficiency of the pumping unit’s lifting system reaches the maximum. At the same time, the control and analysis method based on digital twinning is a self-diagnosis, adjustment and control method of intelligent ecology, which is the inevitable trend of the development of intelligent oilfield.

Interrelation between parents’ and children’s cognitive styles in primary school and early adolescence

The study aims to test the following hypothesis: cognitive styles (CS) of a mother and father are selectively associated with the severity of a child’s CS in primary school and early adolescence. As part of research for children’s CS (carried out by the method of longitudinal sections), data was collected on the problem of conjugation between parents’ and children’s style characteris- tics. CS were analyzed: impulsiveness — reflexivity (using the method “Comparison of similar drawings” by J.Kagan), field dependence — field independence (method “Gottschaldt’s Fig- ures”), rigid — flexible cognitive control (method “Verbal-color interference” by J. Stroop), narrow-wide range of equivalence (method “Free sorting of words” by V.Kolga). The sample consisted of 24 full families (48 parents) and their children (12 sons and 12 daughters); the hypothesis was tested using factor analysis of CS indicators. The obtained results indicate that in primary school and junior adolescence a child’s CS impulsiveness — reflexivity maintains a connection with the father’s CS, and in the CS field dependence — field independence in younger adolescence — with the mother’s CS, and in both styles this relationship has a positive character. In CS flexible-rigid cognitive control and in CS narrow — wide range of equivalence at the primary school age, both parents influence the formation of a child’s CS. In regard to CS in early adolescence, children and parents are no longer interconnected. It can be assumed that this indicates a different nature of СS: some styles are basic, and the connection with that this indicates a different nature of СS: some styles are basic, and the connection with the father or mother will, to one degree or another, persist in the future. And other styles are social, and with age their formation will be influenced by their social environment. Thus, this study raises questions about the need to clarify mechanisms for the formation of style behavior in ontogenesis, in particular, the influence of the family microenvironment factor. This factor can expand opportunities in the study of individual characteristics of mental activity, and also be taken into account in practical areas such as education, pedagogy, child psychology, etc.