Research On Three-port Converter Of Integrated Power Supply For Spacecraft

Power system is an essential part of spacecraft.It aims to pursuit highintegration and high reliability by improving the frameworkand the control strategy.So, the new Integrated power control system of spacecraft that meet theserequirements has been proposed. The Research onthe three-port DC/DC converter ofintegrated power supply for aerospace advantages to further reducing the volumeand the weight, and benefits for higher power density.Considering the efficiency and scalability, the paperdiscusses severalboostbuckconverters.The three-port DC/DC converter consists of bidirectional buck converterand two-port converter. In order to analyze the stability of three-port DC/DCconverter, a small signal modeling ofstep-downand step-up mode is build by usingthe average element model method.At the same time, in order to realize the reliablity of the maximum power pointtracking scheme, a selection of most suitable control signals commanding the powercontrol stages in Maximum Power Point Tracking(MPPT) schemes is discussed.Through the comparative analysis, the optimal control schemeis obtained. In orderto achieve a proper and reliable tracking action, dual-closed loop control strategy isdesigned. And the MPPT control scheme is realized by changing the input voltageindirectly according to the output current.The simulation results confirm that thestrategy can reacha good dynamic response and good phase margin.The present paper puts forward the improvement design in view of the topologystructure by the use of magnetic integration technology.The power module iscoupled by inductors for internal while the other inductors connected betweenmodulesarecontrolled by the strategy of phase shifter.This design not only reducesthe weight of power supply controller, improves the power density, but alsocanrealize zero ripple voltage of the busand current of the batteries. So, the battery lifecan be improved. In addition, thepaper also presents the numerical control systembased on FPGA.The analysis is confirmed by simulation and practical tests, showing thatthethree-port DC/DC converter can complete the task of stablingthe bus voltage, nomatter in the shadow region or sunshine area.Furthermore,the modeof MPPT can beswitched smoothly and stability,it indicatesthe control strategy can be feasible andreasonable.