Enhanced Model Predictive Control For Wireless Power Transfer System

Wireless power transfer system is a more reliable,more flexible and safer power conversion system due to the elimination of physical contacts.In the wireless power transfer system,the parameters of coupling coefficient,load resistance and input voltage may change.The charging current / voltage of the system changes accordingly,so an effective closed loop control strategy is needed to maintain the constant output of the sys tem.In the case of variable parameters,if the dynamic response of the system is slow,the system output will produce large overshoot / undershoot,and the recove ry time is long,which will affect the service life of the load equipment connected to the sy stem,have a great adverse impact on the working conditions of the motor,battery and other electrical equipment,and even damage the equipment.Therefore,in this dissertation,a closed-loop control strategy with high dynamic performance will be studied for wireless power transfer system.In order to optimize the dynamic performance of wireless charging system and make it respond quickly under the conditions of variable load resistance,variable coupling coefficient,variable output current reference value and variable input DC voltage,this paper takes the series / series compensated wireless power transfer system as an example to study model predictive control method.In this dissertation,the mathematical model of the series / series compensation wireless charging system is established,the discrete mathematical model of the system is deduced,and the model predictive control based on the output current predictive value is designed.In this dissertation,moving discrete control set model predictive control and group optimization model predictive control are proposed.Combined with the advantages and disadvantages of the above two control methods,a hybrid model predictive control method is proposed.When the error between the output value and the reference value is small,the moving discrete control set model predictive control is automatically adopted to ensure the high control accuracy of the system.When the error between the output value and the reference value is large,the group optimization model predictive control method is adopted to improve the dynamic performance of the system.This hybrid model predictive control method has the advantages of small amount of calculation,fixed switching frequency,high control precision and fast dynamic response.After the completion of modeling analysis,PI control and model predictive control strategy design and device selection,PSIM simulation software is used to verify the simulation model of series-series compensated wireless power transfer system.Then the proposed control method is experimentally validated on a 24 V / 1.2 A 40 k Hz 30 W wireless power transfer system.The simulation and experimental results verify the feasibility of the scheme.