Development Of Satellite Power Distribution Unit Based On Solid-state Power Controller

The improvement of spacecraft functions and the increase of mission difficulty have placed a greater demand on the configuration,management,fault detection and diagnosis,miniaturization design and reliability of the power supply and distribution system.The power supply and distribution protection used on satellite is the traditional “fuse plus relay” mode,which can disconnect the load for load bus protection in case of a short c ircuit /over-current of loa d.But the protection methods cannot power up and down the load after fault occurrence,so that the autonomy,restorability,and real-time performance of this protection mode are weak.It could not satisfy the requirements of intelligent control,fault isolation,and fault recovery.Intelligent power distribution takes advantages of several advanced techniques,such as automatic control,computer,power electronics,etc.,which has strong protection ability and can raise the capability of on-orbit management of spacecraft.Intelligent power distribution is a substitution technology for traditional “fuse plus relay” mode.Therefore,with the support of the National 863 Program of China,this thesis surveys the development of power distribution,and proposes the overall scheme of the satellite power distributor on the basis of solid-state power controller.The strate gy is different from the tra ditiona l mana geme nt mode of ground re mote c ontrol,a nd ca n realize the energy mana ge ment system of satellite in orbit and fault isolation.Besides,it can improve the re liability of the energy syste m a nd its ada ptability to the task and on orbit se lf surviva l a bility.The design of the satellite power distributor adopts the idea of modularization,distributed control,and central management.The external bus adopts RS-422 of dual redundancy.The power distribution path is realized by Solid-state Power Controller,which is capable of over-current and short protection,on-orbit I2 t curve modification,and rated current modification.BIT design realizes the health monitoring of power system.The serial I/O module and the power distribution module are the management center.The serial I/O module is responsible for exchanging information with the external management unit,collecting and uploading data,communicating with other internal units,and controlling other units.The serial I/O module collects the state of the power distribution path and external a nalog signal.It can realize fault isolation according to the state of the path and the load p riority.System reconfiguration can also be accomplished by the serial I/O module through switching external reconfiguration relays.The power distribution module is capable of automatic fault isolation and can be restarted by orders after fault occurrence.The intelligent power distributor can also alter the I2 t protection curve and rated distribution current by computer orders,which raises the adaptability of the distributor.FPGA program of the distributor is written using Verilog,which realizes interface configuration,data framing,UART serial communication,and order distribution through the bus according to the communication protocol.Besides,data acquired by A/D chip are compared with the load priority data table.The fault detection,and the fault isolation and reconfiguration are based on the comparison result.The feasibility of the designed satellite power distributor is verified through both software and hardware debugging,and systematic test.The test results indicate that the designed distributor satisfies the expected performance requirements.Finally,a summary is made for the further improvement and optimization method of the satellite power distributor.