Robust Gain-Scheduling Control Of Buck Converter Based On Polytope LPV System

As the core of switching power supply,DC/DC converter is widely used in various fields of electronic information industry.DC/DC converter is a nonlinear time-varying system,which exists the problem of uncertain parameters in mathematical model.If the traditional control theory is used for modeling and control,the robustness and global stability of the whole system cannot be satisfied,and the current high performance parameters of the DC/DC converter cannot be met.In this paper,the input voltage and output load resistance are selected as system variable parameters,and the state average model of Buck converter is transformed into a polytope linear variable parameter(LPV)system model,obtaining state-space expression models for each vertices of the polytope LPV system.The problem of model parameters uncertainty and nonlinearity of Buck converter is solved by using the convex decomposition technique of LPV system and the vertex characteristics of the polytope model.This paper proposes a set of linear matrix inequality(LMI)constraints that satisfy both closed-loop pole placement and H? robust performance,and translates the controller design problem for Buck converters into a set of LMI solving problems.The advantage of the vertex characteristic of the polytope LPV system is reused,which is the finite vertex of the polytope can describe the entire system.The controller design only needs to solve the limited LMI constraints for the limited vertices of the polytope,which not only reduces the complexity of the controller design,but also can get the gain controller with global characteristics.In this paper,the LMI toolbox of Matlab is used to solve the LMI constraints of the vertices of the polytope LPV system.The state feedback gain matrix of the polytope vertices is obtained off-line.Finally,the robust gain-scheduling state feedback controller with the global characteristics is obtained by combining the state feedback controller of each vertex of the polytope LPV system.The robust gain-scheduling state feedback controller not only satisfies both dynamic performance and H? robust performance,but also guarantees the global stability of the system in theory.This paper analyzes the simulation experiment of robust gain-scheduling control algorithm based on Matlab platform,and verifies the theoretical feasibility of robust gain-scheduling.Based on PSIM and Matlab platform to study the application of robustgain-scheduling control algorithm in Buck converter circuit,the comparison experiment of output response to robust gain-gain control and PID control is completed.The simulation experiment results show that robust variable gain control has better dynamic performance and anti-interference ability,further validate the effectiveness of robust gain-scheduling control algorithms in Buck converter circuit.