针对具有固定转动惯量的常规光伏储能虚拟同步发电机并网发电系统容易出现功率振荡以及频率超调等问题,提出光储并网系统的虚拟同步发电机(virtual synchronous generator,VSG)自适应控制策略。首先,搭建虚拟同步发电机控制的光伏储能...针对具有固定转动惯量的常规光伏储能虚拟同步发电机并网发电系统容易出现功率振荡以及频率超调等问题,提出光储并网系统的虚拟同步发电机(virtual synchronous generator,VSG)自适应控制策略。首先,搭建虚拟同步发电机控制的光伏储能并网发电系统模型,系统前级采用光伏最大功率点跟踪(maximum power point tracking,MTTP)控制以及储能控制策略;然后,根据功角特性和转子角频率特性曲线分析转动惯量对VSG动态特性的影响,将RBF神经网络应用到VSG中,对转动惯量进行自适应调整,同时,在固定阻尼比的基础上,随着转动惯量的变化自适应调整阻尼系数;在MATLAB/SIMULINK上建立光储并网系统的VSG自适应控制仿真模型,验证此控制策略的可行性;最后,将自适应转动惯量阻尼控制策略与其他控制策略进行对比,仿真结果表明:采用此控制策略能够使光储并网系统的有功功率振荡得到抑制,改善转子角频率超调。展开更多
In this paper,the distributed fuzzy fault-tolerant tracking consensus problem of leader-follower multi-agent systems(MASs)is studied.The objective system includes actuator faults,mismatched parameter uncertainties,non...In this paper,the distributed fuzzy fault-tolerant tracking consensus problem of leader-follower multi-agent systems(MASs)is studied.The objective system includes actuator faults,mismatched parameter uncertainties,nonlinear functions,and exogenous disturbances under switching communication topologies.To solve this problem,a distributed fuzzy fault-tolerant controller is proposed for each follower by adaptive mechanisms to track the state of the leader.Furthermore,the fuzzy logic system is utilized to approximate the unknown nonlinear dynamics.An error estimator is introduced between the mismatched parameter matrix and the input matrix.Then,a selective adaptive law with relative state information is adopted and applied.When calculating the Lyapunov function’s derivative,the coupling terms related to consensus error and mismatched parameter uncertainties can be eliminated.Finally,a numerical simulation is given to validate the effectiveness of the proposed protocol.展开更多
探讨了氧化铝对水体中硅酸的吸附去除潜力、影响因素及机理。结果表明,pH 4~8时吸附量随pH、吸附剂投加量的增大而增加,说明氧化铝具有吸附去除硅酸的能力。吸附过程符合Langmuir吸附等温模式,最大吸附量达39.82 mg/g。结合27Al MAS NMR...探讨了氧化铝对水体中硅酸的吸附去除潜力、影响因素及机理。结果表明,pH 4~8时吸附量随pH、吸附剂投加量的增大而增加,说明氧化铝具有吸附去除硅酸的能力。吸附过程符合Langmuir吸附等温模式,最大吸附量达39.82 mg/g。结合27Al MAS NMR与SEM-EDX分析,氧化铝吸附硅酸的机理是通过硅酸分子与氧化铝中4配位的铝发生化学反应,硅原子取代原来Al—O—Al键上的铝原子形成Al—O—Si键而被固定在氧化铝表面。展开更多
Modeling a system in engineering applications is a time-consuming and labor-intensive task,as system parameters may change with temperature,component aging,etc.In this paper,a novel data-driven model-free optimal cont...Modeling a system in engineering applications is a time-consuming and labor-intensive task,as system parameters may change with temperature,component aging,etc.In this paper,a novel data-driven model-free optimal controller based on deep deterministic policy gradient(DDPG)is proposed to address the problem of continuous-time leader-following multi-agent consensus.To deal with the problem of the dimensional explosion of state space and action space,two different types of neural nets are utilized to fit them instead of the time-consuming state iteration process.With minimal energy consumption,the proposed controller achieves consensus only based on the consensus error and does not require any initial admissible policies.Besides,the controller is self-learning,which means it can achieve optimal control by learning in real time as the system parameters change.Finally,the proofs of convergence and stability,as well as some simulation experiments,are provided to verify the algorithm’s effectiveness.展开更多
文摘针对具有固定转动惯量的常规光伏储能虚拟同步发电机并网发电系统容易出现功率振荡以及频率超调等问题,提出光储并网系统的虚拟同步发电机(virtual synchronous generator,VSG)自适应控制策略。首先,搭建虚拟同步发电机控制的光伏储能并网发电系统模型,系统前级采用光伏最大功率点跟踪(maximum power point tracking,MTTP)控制以及储能控制策略;然后,根据功角特性和转子角频率特性曲线分析转动惯量对VSG动态特性的影响,将RBF神经网络应用到VSG中,对转动惯量进行自适应调整,同时,在固定阻尼比的基础上,随着转动惯量的变化自适应调整阻尼系数;在MATLAB/SIMULINK上建立光储并网系统的VSG自适应控制仿真模型,验证此控制策略的可行性;最后,将自适应转动惯量阻尼控制策略与其他控制策略进行对比,仿真结果表明:采用此控制策略能够使光储并网系统的有功功率振荡得到抑制,改善转子角频率超调。
基金This work was supported by Tianjin Natural Science Foundation of China(20JCYBJC01060,20JCQNJC01450)the National Natural Science Foundation of China(61973175)Tianjin Postgraduate Scientific Research and Innovation Project(2020YJSZXB03,2020YJSZXB12).
文摘In this paper,the distributed fuzzy fault-tolerant tracking consensus problem of leader-follower multi-agent systems(MASs)is studied.The objective system includes actuator faults,mismatched parameter uncertainties,nonlinear functions,and exogenous disturbances under switching communication topologies.To solve this problem,a distributed fuzzy fault-tolerant controller is proposed for each follower by adaptive mechanisms to track the state of the leader.Furthermore,the fuzzy logic system is utilized to approximate the unknown nonlinear dynamics.An error estimator is introduced between the mismatched parameter matrix and the input matrix.Then,a selective adaptive law with relative state information is adopted and applied.When calculating the Lyapunov function’s derivative,the coupling terms related to consensus error and mismatched parameter uncertainties can be eliminated.Finally,a numerical simulation is given to validate the effectiveness of the proposed protocol.
文摘探讨了氧化铝对水体中硅酸的吸附去除潜力、影响因素及机理。结果表明,pH 4~8时吸附量随pH、吸附剂投加量的增大而增加,说明氧化铝具有吸附去除硅酸的能力。吸附过程符合Langmuir吸附等温模式,最大吸附量达39.82 mg/g。结合27Al MAS NMR与SEM-EDX分析,氧化铝吸附硅酸的机理是通过硅酸分子与氧化铝中4配位的铝发生化学反应,硅原子取代原来Al—O—Al键上的铝原子形成Al—O—Si键而被固定在氧化铝表面。
基金supported by the Tianjin Natural Science Foundation of China(Grant No.20JCYBJC01060)the National Natural Science Foundation of China(Grant Nos.62103203 and 61973175)the Fundamental Research Funds for the Central Universities,Nankai University(Grant No.63221218)。
文摘Modeling a system in engineering applications is a time-consuming and labor-intensive task,as system parameters may change with temperature,component aging,etc.In this paper,a novel data-driven model-free optimal controller based on deep deterministic policy gradient(DDPG)is proposed to address the problem of continuous-time leader-following multi-agent consensus.To deal with the problem of the dimensional explosion of state space and action space,two different types of neural nets are utilized to fit them instead of the time-consuming state iteration process.With minimal energy consumption,the proposed controller achieves consensus only based on the consensus error and does not require any initial admissible policies.Besides,the controller is self-learning,which means it can achieve optimal control by learning in real time as the system parameters change.Finally,the proofs of convergence and stability,as well as some simulation experiments,are provided to verify the algorithm’s effectiveness.
