Research On Key Technologies Of Magnetically Integrated Superbuck Converter

In the field of aerospace,more and more researchers pay attention to microsatellite.The power module,which is responsible for providing high-quality power for the satellite modules,is particularly important in the satellite components.Since the weight of power module accounts for a high proportion of the total weight of small satellite,it is necessary to improve the power density of power module.For the power supply with Solar-Battery structure,because the input side of the battery charging regulator is connected to the bus,the input current ripple is expected to be as small as possible,so as to avoid the negative impact on the bus current quality.Therefore,the main research contents of this thesis are: select and optimize the topology of battery charging regulator,improve the power density of the topology,reduce the current ripple of the system,and ensure the stability and rapidity of the system through the design and optimization of the controller.When choosing the topology of battery charging regulator,many high-order DC-DC buck converters whose input current is continuous are considered in this thesis.Because of the continuous input current of the fourth-order converter named Superbuck,and it has the characteristic of no right half plane zero point,the Superbuck converter is chosen as the topology of this thesis.However,Superbuck topology has two inductors,which is disadvantageous to the power density of the system.In order to improve the power density of the topology and further reduce the current ripple,the two inductors can be coupled.However,the zero ripple condition and the right half plane zero limit condition of the coupledinductor Superbuck can not be satisfied at the same time,which limits the reduction of the input current ripple.In order to make the circuit meet the zero ripple condition and avoid the zero point of the right half plane at the same time,a magnetically integrated Superbuck topology with additional coupling branch is proposed in this thesis.The topology uses magnetically integrated technology to ensure the high power density of the system,and the addition of coupling branch makes the topology can meet the zero ripple condition without the appearance of the zero point of the right half plane.When selecting the controller,the stability and rapidity of the system are considered,and the high reliability of the controller is also considered.Because the traditional linear control is designed according to the fixed working point,though it has good stability and high reliability,it is not fast.The nonlinear control module is added to the linear controller in this thesis,and it can be verified that the linear-nonlinear cooperative controller can improve the rapidity of the system in the dynamic process and ensure the stability of the system in the steady process.In this thesis,the traditional Superbuck topology and the novel Superbuck topology are modeled and analyzed,and on the basis of the model,the optimal parameter design and linear controller design are carried out.Through the simulation of the steady-state and dynamic process of the three topologies,the advantages of the novel Superbuck topology are verified.In addition,through the simulation and physical verification of the novel magnetically integrated Superbuck converter with linear-nonlinear cooperative control,it is proved that the dynamic performance of the system can be effectively improved by adding nonlinear control module.