This study presents a neural network-based model for predicting linear quadratic regulator(LQR)weighting matrices for achieving a target response reduction.Based on the expected weighting matrices,the LQR algorithm is...This study presents a neural network-based model for predicting linear quadratic regulator(LQR)weighting matrices for achieving a target response reduction.Based on the expected weighting matrices,the LQR algorithm is used to determine the various responses of the structure.The responses are determined by numerically analyzing the governing equation of motion using the state-space approach.For training a neural network,four input parameters are considered:the time history of the ground motion,the percentage reduction in lateral displacement,lateral velocity,and lateral acceleration,Output parameters are LQR weighting matrices.To study the effectiveness of an LQR-based neural network(LQRNN),the actual percentage reduction in the responses obtained from using LQRNN is compared with the target percentage reductions.Furthermore,to investigate the efficacy of an active control system using LQRNN,the controlled responses of a system are compared to the corresponding uncontrolled responses.The trained neural network effectively predicts weighting parameters that can provide a percentage reduction in displacement,velocity,and acceleration close to the target percentage reduction.Based on the simulation study,it can be concluded that significant response reductions are observed in the active-controlled system using LQRNN.Moreover,the LQRNN algorithm can replace conventional LQR control with the use of an active control system.展开更多
In this study,aiming at the characteristics of randomness and dynamics in Wearable Audio-oriented BodyNets(WA-BodyNets),stochastic differential game theory is applied to the investigation of the problem of transmitted...In this study,aiming at the characteristics of randomness and dynamics in Wearable Audio-oriented BodyNets(WA-BodyNets),stochastic differential game theory is applied to the investigation of the problem of transmitted power control inconsumer electronic devices.First,astochastic differential game model is proposed for non-cooperative decentralized uplink power control with a wisdom regulation factor over WA-BodyNets with a one-hop star topology.This model aims to minimize the cost associated with the novel payoff function of a player,for which two cost functions are defined:functions of inherent power radiation and accumulated power radiation damage.Second,the feedback Nash equilibrium solution of the proposed model and the constraint of the Quality of Service(QoS) requirement of the player based on the SIR threshold are derived by solving the Fleming-Bellman-Isaacs partial differential equations.Furthermore,the Markov property of the optimal feedback strategies in this model is verified.The simulation results show that the proposed game model is effective and feasible for controlling the transmitted power of WA-BodyNets.展开更多
Conventional control systems used for regulated power supplies,including the proportional integral and derivation(PID)controller,have some serious disadvantages.The PID controller has a delayed feedback associated wit...Conventional control systems used for regulated power supplies,including the proportional integral and derivation(PID)controller,have some serious disadvantages.The PID controller has a delayed feedback associated with the control action and requires a lot of mathematical derivations.This paper presents a novel controlling system based on the artificial neural network(ANN),which can be used to regulate the output voltage of the DC power supply.Using MATLABTM,the designed control system was tested and analyzed with two types of back-propagation algorithms.This paper presents the results of the simulation that includes sum-squared error(SSE)and mean-squared error(MSE),and gives a detailed comparison of these values for the two algorithms.Hardware verification of the new system,using RS232 interface and Microsoft Visual Basic 6.0,was implemented,showing very good consistency with the simulation results.The proposed control system,compared to PID and other conventional controllers,requires less mathematical derivation in design and it is easier to implement.展开更多
Scalable coordination of photovoltaic(PV)inverters,considering the uncertainty in PV and load in distribution networks(DNs),is challenging due to the lack of real-time communications.Decentralized PV inverter setpoint...Scalable coordination of photovoltaic(PV)inverters,considering the uncertainty in PV and load in distribution networks(DNs),is challenging due to the lack of real-time communications.Decentralized PV inverter setpoints can be achieved to address this issue by capitalizing on the abundance of data from smart utility meters and the scalable architecture of artificial neural networks(ANNs).To this end,we first use an offline,centralized data-driven conservative convex approximation of chance-constrained optimal power flow(CVaR-OPF)in which conditional value-at-risk(CVaR)is used to compute reactive power setpoints of PV inverter,taking into account PV and load uncertainties in DNs.Following that,an artificial neural network(ANN)controller is trained for each PV inverter to emulate the optimal behavior of the centralized control setpoints of PV inverter in a decentralized fashion.Additionally,the voltage regulation performance of the developed ANN controllers is compared with other decentralized designs(local controllers)developed using model-based learning(regressionbased controller),optimization(affine feedback controller),and case-based learning(mapping)approaches.Numerical tests using real-world feeders corroborate the effectiveness of ANN controllers in voltage regulation and loss minimization.展开更多
High penetration of solar energy can result in voltage rise in midday,while growth in residential air conditioning is the main contributor of overloading and voltage drop issues during peak demand time.This paper prov...High penetration of solar energy can result in voltage rise in midday,while growth in residential air conditioning is the main contributor of overloading and voltage drop issues during peak demand time.This paper provides a hierarchical control scheme to coordinate multiple groups of aggregated thermostatically controlled loads to regulate network loading and voltage in a distribution network.Considering the limited number of messages that can be exchanged in a realistic communication environment,an event-triggered distributed control strategy is proposed in this paper.Through intermittent on and off toggling of air conditioners,the required active power adjustment is shared among participating aggregators to solve the issue.A case study is conducted and simulation results are presented to demonstrate the performance of the proposed control scheme.展开更多
Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typi...Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typical DC distribution network with multiple voltage levels is considered as a research object.It is proposed that the interface converters between DC buses with different voltage levels be implemented through the series-parallel combination of full-bridge LLC resonant converters.To realize the decentralized self-discipline control of DC voltage under various working conditions,different slack buses are prepared according to the voltage ranges of the DC buses,and the voltage regulation modes of the DC distribution network are divided into main voltage regulation mode,backup voltage regulation mode,and off-grid voltage droop regulation mode.By introducing a voltage coefficient related to DC voltage deviation as a basis for mode switching,the voltage fluctuations caused by slow switching between control modes in the method of traditional voltage margin control is reduced,facilitating fast and smooth switching between different voltage regulation modes.Finally,a simulation model for DC distribution networks is constructed utilizing MATLAB/Simulink.Simulation results verify the effectiveness and feasibility of the proposed voltage regulation modes and switching methods for DC distribution networks.Finally,an experimental platform is also constructed to verify the feasibility of the mode switching method proposed in this paper.展开更多
Simple, efficient and accurate controllable systems for materials are becoming more essential, in response to the explosively growing demands in the fields of chemistry and material science. Herein, tailored hydrogels...Simple, efficient and accurate controllable systems for materials are becoming more essential, in response to the explosively growing demands in the fields of chemistry and material science. Herein, tailored hydrogels are explored depending on synergistic regulation of p H-responsive chemical networks with an "on/off" function and physical networks with dynamic selfoptimized arrangement. Thiol-disulfide exchange reaction endows hydrogels with controlled architectures while hydrogen bondstrengthened 2-ureido-4[1H]-pyrimidinone(UPy) moieties contributes a significant increase in mechanical strengths. The integration of that dual cross-linking(DC) network ensures the hydrogels with customized structure and enhanced mechanical property. Such controllably strategy is universally applicable and will open a new avenue to flexibly fabricate desired hybrid hydrogels with distinctive features and functions for their potential applications.展开更多
为适应配电网多线路的潮流调节需求,进一步提高潮流调控能力和响应速度,文中提出一种新型配电网多线路混合式统一潮流控制器(multi-line hybrid unified power flow controller for distribution network, D-MHUPFC)。D-MHUPFC由Sen变...为适应配电网多线路的潮流调节需求,进一步提高潮流调控能力和响应速度,文中提出一种新型配电网多线路混合式统一潮流控制器(multi-line hybrid unified power flow controller for distribution network, D-MHUPFC)。D-MHUPFC由Sen变压器、统一潮流控制器(unified power flow controller, UPFC)和混合式有载分接开关组成,能够快速调节配电网多线路潮流。相较于传统调节方式,D-MHUPFC具有结构紧凑、响应快速、经济性好和可靠性高等优点。文中结合ZIP负荷模型,推导计及D-MHUPFC的多线路潮流方程,优化其协同控制策略,并搭建10 kV配电网仿真平台验证其可行性。结果显示,D-MHUPFC及其控制策略能在0.15 s内快速调节多线路潮流,转移过载功率,提高断面输电极限。D-MHUPFC能够解耦控制有功功率和无功功率,补偿误差小于1%,具有和UPFC相当的潮流调节能力。展开更多
针对分布式电源接入引起的功率波动与潮流不均衡问题,旋转潮流控制器(rotary power flow controller,RPFC)通过伺服电机调节旋转角的大小,输出幅值与相位连续可调的串联电压,实现有源配电网的功率调控,具有控制方式灵活、调节精度高和...针对分布式电源接入引起的功率波动与潮流不均衡问题,旋转潮流控制器(rotary power flow controller,RPFC)通过伺服电机调节旋转角的大小,输出幅值与相位连续可调的串联电压,实现有源配电网的功率调控,具有控制方式灵活、调节精度高和可靠性强等优点。该文首先根据RPFC的工作原理建立其数学模型。其次,提出RPFC功率解耦控制方法,即根据线路有功与无功功率的目标值分别计算出RPFC输出电压的dq轴分量设定值,实现输出电压对线路功率的闭环解耦控制。接着,针对RPFC接入后存在输出功率周期性震荡的问题,采用旋转角转速自适应的调节方式,即将输出电压dq轴分量合成并转换为两个旋转角的参考值,并根据旋转角偏差,对RPFC伺服电机的占空比进行量化计算,从而对两个旋转角的转速进行协调控制。最后,通过仿真验证该控制方法的正确性,并研制一台40kVA的RPFC装置样机,通过在单回与并行线路场景下的实验验证RPFC在不同工况下功率精确控制和潮流均衡调控的可行性与有效性。展开更多
基金Dean Research&Consultancy under Grant No.Dean (R&C)/2020-21/1155。
文摘This study presents a neural network-based model for predicting linear quadratic regulator(LQR)weighting matrices for achieving a target response reduction.Based on the expected weighting matrices,the LQR algorithm is used to determine the various responses of the structure.The responses are determined by numerically analyzing the governing equation of motion using the state-space approach.For training a neural network,four input parameters are considered:the time history of the ground motion,the percentage reduction in lateral displacement,lateral velocity,and lateral acceleration,Output parameters are LQR weighting matrices.To study the effectiveness of an LQR-based neural network(LQRNN),the actual percentage reduction in the responses obtained from using LQRNN is compared with the target percentage reductions.Furthermore,to investigate the efficacy of an active control system using LQRNN,the controlled responses of a system are compared to the corresponding uncontrolled responses.The trained neural network effectively predicts weighting parameters that can provide a percentage reduction in displacement,velocity,and acceleration close to the target percentage reduction.Based on the simulation study,it can be concluded that significant response reductions are observed in the active-controlled system using LQRNN.Moreover,the LQRNN algorithm can replace conventional LQR control with the use of an active control system.
基金the National Natural Science Foundation of China under Grants No.61272506,No.61170014,the Foundation of Key Program of MOE of China under Grant No.311007,the Natural Science Foundation of Beijing under Grant No.4102041
文摘In this study,aiming at the characteristics of randomness and dynamics in Wearable Audio-oriented BodyNets(WA-BodyNets),stochastic differential game theory is applied to the investigation of the problem of transmitted power control inconsumer electronic devices.First,astochastic differential game model is proposed for non-cooperative decentralized uplink power control with a wisdom regulation factor over WA-BodyNets with a one-hop star topology.This model aims to minimize the cost associated with the novel payoff function of a player,for which two cost functions are defined:functions of inherent power radiation and accumulated power radiation damage.Second,the feedback Nash equilibrium solution of the proposed model and the constraint of the Quality of Service(QoS) requirement of the player based on the SIR threshold are derived by solving the Fleming-Bellman-Isaacs partial differential equations.Furthermore,the Markov property of the optimal feedback strategies in this model is verified.The simulation results show that the proposed game model is effective and feasible for controlling the transmitted power of WA-BodyNets.
文摘Conventional control systems used for regulated power supplies,including the proportional integral and derivation(PID)controller,have some serious disadvantages.The PID controller has a delayed feedback associated with the control action and requires a lot of mathematical derivations.This paper presents a novel controlling system based on the artificial neural network(ANN),which can be used to regulate the output voltage of the DC power supply.Using MATLABTM,the designed control system was tested and analyzed with two types of back-propagation algorithms.This paper presents the results of the simulation that includes sum-squared error(SSE)and mean-squared error(MSE),and gives a detailed comparison of these values for the two algorithms.Hardware verification of the new system,using RS232 interface and Microsoft Visual Basic 6.0,was implemented,showing very good consistency with the simulation results.The proposed control system,compared to PID and other conventional controllers,requires less mathematical derivation in design and it is easier to implement.
基金supported by the National Science Foundation(No.ECCS-1847125,No.2115427)。
文摘Scalable coordination of photovoltaic(PV)inverters,considering the uncertainty in PV and load in distribution networks(DNs),is challenging due to the lack of real-time communications.Decentralized PV inverter setpoints can be achieved to address this issue by capitalizing on the abundance of data from smart utility meters and the scalable architecture of artificial neural networks(ANNs).To this end,we first use an offline,centralized data-driven conservative convex approximation of chance-constrained optimal power flow(CVaR-OPF)in which conditional value-at-risk(CVaR)is used to compute reactive power setpoints of PV inverter,taking into account PV and load uncertainties in DNs.Following that,an artificial neural network(ANN)controller is trained for each PV inverter to emulate the optimal behavior of the centralized control setpoints of PV inverter in a decentralized fashion.Additionally,the voltage regulation performance of the developed ANN controllers is compared with other decentralized designs(local controllers)developed using model-based learning(regressionbased controller),optimization(affine feedback controller),and case-based learning(mapping)approaches.Numerical tests using real-world feeders corroborate the effectiveness of ANN controllers in voltage regulation and loss minimization.
基金supported in part by the National Natural Science Foundation of China under Grant 71331001,71401017funding from mid-career researcher development scheme,the Faculty of Engineering&Information Technologies,The University of Sydneyin part by the 2015 Science and Technology Project of China Southern Power Grid under Grant WYKJ00000027.
文摘High penetration of solar energy can result in voltage rise in midday,while growth in residential air conditioning is the main contributor of overloading and voltage drop issues during peak demand time.This paper provides a hierarchical control scheme to coordinate multiple groups of aggregated thermostatically controlled loads to regulate network loading and voltage in a distribution network.Considering the limited number of messages that can be exchanged in a realistic communication environment,an event-triggered distributed control strategy is proposed in this paper.Through intermittent on and off toggling of air conditioners,the required active power adjustment is shared among participating aggregators to solve the issue.A case study is conducted and simulation results are presented to demonstrate the performance of the proposed control scheme.
基金supported by Fundamental Research Funds for the Central Universities(No.2019JBM057)。
文摘Due to the advantages such as low line cost,low transmission loss,and high power supply reliability,DC distribution networks have become the main development trend for future distribution networks.In this paper,a typical DC distribution network with multiple voltage levels is considered as a research object.It is proposed that the interface converters between DC buses with different voltage levels be implemented through the series-parallel combination of full-bridge LLC resonant converters.To realize the decentralized self-discipline control of DC voltage under various working conditions,different slack buses are prepared according to the voltage ranges of the DC buses,and the voltage regulation modes of the DC distribution network are divided into main voltage regulation mode,backup voltage regulation mode,and off-grid voltage droop regulation mode.By introducing a voltage coefficient related to DC voltage deviation as a basis for mode switching,the voltage fluctuations caused by slow switching between control modes in the method of traditional voltage margin control is reduced,facilitating fast and smooth switching between different voltage regulation modes.Finally,a simulation model for DC distribution networks is constructed utilizing MATLAB/Simulink.Simulation results verify the effectiveness and feasibility of the proposed voltage regulation modes and switching methods for DC distribution networks.Finally,an experimental platform is also constructed to verify the feasibility of the mode switching method proposed in this paper.
基金This work was supported by the National Natural Science Foundation of China(21674120,51973226,21725403).
文摘Simple, efficient and accurate controllable systems for materials are becoming more essential, in response to the explosively growing demands in the fields of chemistry and material science. Herein, tailored hydrogels are explored depending on synergistic regulation of p H-responsive chemical networks with an "on/off" function and physical networks with dynamic selfoptimized arrangement. Thiol-disulfide exchange reaction endows hydrogels with controlled architectures while hydrogen bondstrengthened 2-ureido-4[1H]-pyrimidinone(UPy) moieties contributes a significant increase in mechanical strengths. The integration of that dual cross-linking(DC) network ensures the hydrogels with customized structure and enhanced mechanical property. Such controllably strategy is universally applicable and will open a new avenue to flexibly fabricate desired hybrid hydrogels with distinctive features and functions for their potential applications.
文摘为适应配电网多线路的潮流调节需求,进一步提高潮流调控能力和响应速度,文中提出一种新型配电网多线路混合式统一潮流控制器(multi-line hybrid unified power flow controller for distribution network, D-MHUPFC)。D-MHUPFC由Sen变压器、统一潮流控制器(unified power flow controller, UPFC)和混合式有载分接开关组成,能够快速调节配电网多线路潮流。相较于传统调节方式,D-MHUPFC具有结构紧凑、响应快速、经济性好和可靠性高等优点。文中结合ZIP负荷模型,推导计及D-MHUPFC的多线路潮流方程,优化其协同控制策略,并搭建10 kV配电网仿真平台验证其可行性。结果显示,D-MHUPFC及其控制策略能在0.15 s内快速调节多线路潮流,转移过载功率,提高断面输电极限。D-MHUPFC能够解耦控制有功功率和无功功率,补偿误差小于1%,具有和UPFC相当的潮流调节能力。
文摘针对分布式电源接入引起的功率波动与潮流不均衡问题,旋转潮流控制器(rotary power flow controller,RPFC)通过伺服电机调节旋转角的大小,输出幅值与相位连续可调的串联电压,实现有源配电网的功率调控,具有控制方式灵活、调节精度高和可靠性强等优点。该文首先根据RPFC的工作原理建立其数学模型。其次,提出RPFC功率解耦控制方法,即根据线路有功与无功功率的目标值分别计算出RPFC输出电压的dq轴分量设定值,实现输出电压对线路功率的闭环解耦控制。接着,针对RPFC接入后存在输出功率周期性震荡的问题,采用旋转角转速自适应的调节方式,即将输出电压dq轴分量合成并转换为两个旋转角的参考值,并根据旋转角偏差,对RPFC伺服电机的占空比进行量化计算,从而对两个旋转角的转速进行协调控制。最后,通过仿真验证该控制方法的正确性,并研制一台40kVA的RPFC装置样机,通过在单回与并行线路场景下的实验验证RPFC在不同工况下功率精确控制和潮流均衡调控的可行性与有效性。