Study On Adaptive Model Predictive Control Method For DC Chopper

DC chopper circuit,DC-DC converter,is a power converting circuit.Keeping the output voltage at a given value is the key control problem for DC chopper.The output direct current could be variable or fixed.MPC is a control algorithm which is efficient to deal with multivariate and bounded problem.MPC is a hot spot in control field.Its modeling is simple,and dynamic performance is high.Adaptive MPC includes parameter identification on the basis of MPC,which improves the shortcomings of MPC's lack of system feedback.This paper aims at system feedback,and improves the dynamic and static performance of Boost chopper and Buck chopper under continuous current mode(CCM).The static performance focuses on the output steady error caused by various parasitic parameters of the circuit,and the dynamic performance is to ensure the dynamic response speed of the circuit output under various disturbances.This three algorithms are as follows:At first,for buck chopper circuit,the least squares with forgetting factor algorithm combined with the MPC,monitoring circuit inductance value and the load resistance value.On the basis of anti-saturation,there is an accurate tracking of the output voltage with inaccurate parameter in circuit.Second,for boost chopper circuit,through the introduction of feed-forward compensation online link,we put forward a PI feedforward adaptive MPC algorithm.It realizes fast accurate voltage tracking effect under unknown circumstances of stray resistance and inductance load resistance.Finally,in view of the boost chopper circuit we transform the cost function and do a parameter optimization in order to improve the MPC.Under the condition of unknown input voltage and load resistance,this new algorithm track output voltage well and fast.At the same time,it could eliminate steady-state error and improve the dynamic response speed.All three algorithms are verified by MATLAB/Simulink.The two algorithms of Boost circuits are verified by experiment,and the experiment platform is a hardware-in-the-loop rapid control prototyping system combined with PC and CompactRIO.