Collaborative Predictive Control Algorithm For Optimizing The Charging And Discharging Process Of Capacitor Banks

With the advancement of science and technology and the improvement of productivity,the demand for power systems is also increasing.Capacitors,as energy storage devices,are widely used in new energy vehicles,photovoltaic systems,and electric fish barriers systems due to their advantages such as large capacitance,long charge,and discharge life,and fast charge and discharge.However,with the increasing complexity of various distributed power systems,the difficulty of control has gradually increased,and charging safety incidents have occurred from time to time.These safety accidents will not only cause damage to the equipment itself,but also cause huge economic losses to the family and society in severe cases,and even endanger personal safety.Therefore,ensuring the stability and safety of the charging process of the capacitor bank in the distributed power system has important application value and practical significance.As a new type of fishery aquaculture technology,the electric fish barriers system is not only portable,convenient to install,but also environmentally friendly and energy-saving.It is in line with the concept of sustainable development.However,at present,there are few studies on electric fish barriers charging systems.In order to ensure the electricity demand and safety of electric fish barriers systems,it is necessary to design a safe,reliable,flexible and stable charging system.There are two main problems of the charging system of the electric fish barriers system: 1)In the constant voltage charging mode,inrush current,which may damage the system hardware,will occur at the start-up of charging.And the charging current is very high,which may cause economic loss and even endanger life;2)To meet the power demand of the electric fish barriers system,single-module power system is expensive,inflexible,and severe fever during long working hours.Therefore,multi-module power system is applied in this paper.However,current imbalance problem,which may reduce performance of the power system and cause accident.In order to solve the tow problems mentioned above,the charging process of the electric fish barriers system is optimized from two aspects of predictive scheduling control for distributed capacitor group nodes and current sharing control,turning engineering application problems into optimization calculation problems in academic theory,and carried out in-depth scientific research work.The main research contents of this paper are as follows:Firstly,in order to avoid high start-up inrush current and reduce the current of mains power supply lines in constant voltage charging mode,a novel receding horizon optimal scheduling algorithm is presented.Based on the analysis of system structure,a linear system model is established to describe the dynamic process.Subsequently,the discrete input of switch scheduling is added to obtain the system’s nonlinear charging model.Furthermore,a discrete predictive model is established.A nonlinear current reference trajectory is designed through comprehensive considering with the charging time,current amplitude and rate of current change,simultaneously.The objective function is designed to minimize the variance of the predicted current and the reference current.Receding horizon optimal method is used to obtain the scheduling strategy.Performances of the system with the proposed receding horizon optimal method are verified by simulation results.Secondly,to address the problem of unbalanced output current of a multi-module power system,a distribute cooperative charging protocol of multi-module charging system is proposed,in which input constrains,state constrains,and steady-state error are considered.In our method,the multi-module charging system is modeled by using the state-space averaging method and graph theory.A cooperative consensus tracking control protocol is designed by using leader-follower consensus algorithm.In our protocol,input constrains,and system states are considered,and a sliding mode item is designed to eliminate the steady-state error and improve the system dynamic performance.The stability of closed-loop system is proved by using Lyapunov theory.Simulation results show that the proposed protocol effectively suppresses the imbalance of the charging system and achieves reliable dynamic performance.