Research On Passivity And Disturbance Rejection Based Control Theory And Application For Power Electronics Systems

With the rapid development of power electronics technique and control theory,power converters regarded as a main power processing unit have been applied in many applications to achieve the energy transfer and conversion,such as spacecraft,intelligent micro-grid,aircraft,ship,communication network and new energy vehicle.The tradi-tional linear control methods are unable to meet the requirement of high performance control in actual applications since power converter systems are strong coupling nonlin-ear systems and frequently suffer the influence of circuit parameter perturbation,input voltage and load variations and unmodeled dynamics.In recent years,the research and application of the nonlinear control algorithms in power electronics systems have been gained more and more attention.Passivity-based control is considered as an advanced nonlinear control approach,which not only obtains fruitful theoretical results,but also be successfully used in electromechanical systems in the past thirty years.This dissertation focuses on the control problem of output voltage of power elec-tronics with resistance and constant power load in the presence of disturbances and then proposes the passivity and disturbance rejection based control methods to improve the anti-disturbance and tracking performance.The main content of this dissertation is summarized as follows.(1)Research on the adaptive passivity-based control for DC-DC buck converter with unknown constant power load.For the control problem of output voltage of DC-DC buck converter with constant power load,the standard passivity-based controller and dynamic interconnection and damping assignment passivity-based controller are presented,respectively.Meanwhile,the power observer is designed to online estimate the power load on the basis of immersion and invariance theory.Therefore,two kinds of adaptive passivity-based control approaches are proposed.The merit of these two methods lies in that they do not use the local linearizaion technique and proceed with the controller design and stability analysis for the original nonlinear system.This makes the closed-loop system has a bigger domain of attraction at equilibrium,which ensures the nice performance of the system under variable working conditions.The difference between them lies in that the former is to control the inductor current to indirectly achieve the output voltage regulation and the latter is to design a controller to directly stabilize the output voltage.The simulation and experimental results illustrate the the proposed control methods do improve the anti-disturbance and tracking performance.(2)Research on the incremental passivity-based control for DC-DC boost convert-er with time-varying disturbance using generalized proportional integral observer.In view of boost converter described by a second order bilinear system,the influence of time-varying disturbances including the parameter perturbation,load variations and parasitic resistance on the performance of this system is analyzed.A composite in-cremental passivity-based controller and generalized proportional integral observer is proposed.The global asymptotical stability of the closed-loop system is proved strictly.The disturbance rejection performance of the proposed control method is investigated by simulation and experimental results in the case of inductor and capacitance changes,time-varying input voltage and load,respectively.(3)Research on the adaptive interconnection and damping assignment control for the DC-DC boost converter with unknown constant power load.For the boost converter,it is noted that the presence of constant power load adds a new nonlinear behavior to the original bilinear system.The difficulty of the control problem is analyzed.By combining the passivity theory and immersion and invariance technique,an adaptive interconnection and damping assignment controller is presented to stabilize this system.It is proved that the closed-loop system is locally asymptotically stable.It is noted that the proposed controller notably improves the anti-disturbance and tracking performance.The simulation results show the effectiveness of the proposed approach.(4)Research on the adaptive energy shaping control for DC-DC buck-boost con-verter with unknown constant power load.Compared with DC-DC boost converter,DC-DC buck-boost converter with constant power load has a more complicated dynam-ics model.Based on its average model,the difficulty of its control problem is analyzed and an adaptive energy shaping controller,which combines the passivity-based controller and immersion and invariance estimator,is designed.The contribution of this control algorithm is that the controller design and stability analysis proceed for the original nonlinear system.Compared with the traditional PD controller,the closed-loop sys-tem under the proposed controller has a bigger domain of attraction at equilibrium,which not only renders that the nice operation performance is ensured under variable operating conditions,but also suppresses the influence of load power variations on the performance of the system.The superiority of the proposed control approach is validated by the simulation and experimental results.(5)Research on the adaptive double-loop energy shaping control for DC-DC buck-boost converter with unknown constant power load.It is observed from the previous chapter that the solving process of the proposed energy shaping controller is a little complicated.This chapter adopts the change of coordinates and feedback linearization to transform the original system into a simple cascade system,to which an adaptive energy shaping controller is designed.The innovation point of this chapter lies in that based on simplifying the solving process,an outer-loop PI action around the new passive output is added to form the double-loop energy shaping controller,which effectively improves the response speed and disturbance rejection performance.Simulation and experimental results are presented to show the effectiveness of the proposed controller.