| With the development of space technology,the load and function of spacecrafts are increasing.The capacity of its power system has increased from 10-2 to 10-1 kW to 1kW or even 10kW.The bus voltage has also increased from traditional 28V and 42V to 100V or even higher.With the emergence of application requirements such as space stations,it is necessary to build large and complex spacecraft system in orbit docking and networking.When many spacecrafts are connected,the power system of the spacecraft is also "Networking"-grid connected power supply,which can expand the power and make comprehensive use of energy,and also can achieve the supplementary supply of energy under the fault,and improve the reliability and robustness of the whole system.Because of its special structure and special application demand,the power supply system of the spacecraft is very different from the grid connected technology of the photovoltaic power supply on the ground.The existing literature and research show that the grid connected power supply technology of spacecraft power system has disadvantages such as low stability of grid connected buses,low system expansion,no grid connection between high-voltage power systems,power loss and weight cost,complex system control and so on.Therefore,considering the rapid development of space technology in China,the problem of grid connected power supply between high-voltage and high-voltage spacecraft is studied systematically.A new scheme of grid connected power supply system is proposed.The system can better realize the fusion control between the grid connected controller and the power control unit(PCU),which is beneficial to the stability of the grid system.In this paper,the key components of the system plan,the grid connected power controller and the PCU technology are deeply studied.A new design scheme of the grid connected power controller and a PCU design scheme adopting the new bus regulation system are put forward.After analyzing the shortcomings of the existing low voltage grid connected power supply technology,this paper first puts forward a scheme of high voltage"current-variable voltage-limited”grid connected power supply system,which has the characteristics of high power and high voltage grid connection,small transformation loss,high reliability and strong expansibility.The bus control strategy and the bus transient characteristics of the grid system are deeply studied.The results of analysis and simulation show that the scheme of high voltage "current-variable voltage-limited"grid connected power supply system can achieve better integration of the output characteristics of the grid connected power controller and the PCU.Compared with the constant voltage control mode,there is no current oscillation,and the transient characteristic of the bus is improved,which is beneficial to the stability of the whole system.The influence of space special environment on power generation power of spacecraft is studied.The energy management strategy of the grid connected system is put forward.The analysis results show that the strategy can achieve the energy controllable transmission of the grid connected system,so as to optimize and optimize the energy utilization of the whole system.The topology research of grid connected power supply system is carried out.The analysis results show that by modularized combination of basic topology of grid connected,the grid connected power supply system can be upgraded flexibly to meet more complex application scenarios.On this basis,one of the key components of the scheme for supporting high voltage grid connected power supply system----the grid connected controller,is carried out.On the basis of analyzing and comparing the topology structure of the existing space power converter,the design scheme of the grid connected controller with input parallel output series(IPOS)four staggered double transistor forward topology is proposed,which solves the problems of the existing power supply technology,such as non adjustable power,no high voltage and high voltage spacecraft,and low grid power.In order to adapt to the high reliability of aerospace power,reduce device stress,increase the availability of key devices and reduce the volume of equipment,an improved dual tube converter circuit is proposed.Compared with the traditional double tube converter,the converter circuit saves the filter inductor and the continuous current diode of the rectifier side.The working mode of the modified topology and the design scheme of key parameters are analyzed.The analysis and test results show that the circuit reduces the use of magnetic components,improves the power density of converters,improves the parasitic oscillation and reverse recovery of rectifier diodes,and is better adapt to the use of space power supply.The design of PWM control,constant current/constant voltage/variable current circuit of the grid connected power controller is studied.A prototype is developed,and the basic functions of the grid connected power controller are tested and verified.The test results show that the interleaved control timing is correct,the load step and mode switching functions are normal,the load dynamic response is good,and the operation requirements are met.The PCU is another key component of the high voltage grid connected power supply system.The integration of PCU and grid connected power controller is the key to realize the stable control of high voltage grid connected power supply system.The PCU bus regulation and control scheme is very important for the control of grid connected power system.After comparing various different PCU schemes on the existing spacecraft,a hybrid fully regulated bus control technology is proposed in this paper.Compared with the traditional non regulation and semi regulation bus control scheme,this technology has the advantage of high stability of the bus voltage.Compared with the fully regulated bus control technology,this technology has the advantages of S3R(Sequential Switching Shunt Regulator)system "with independent battery chargering regulator " and S4R(Sequential Switching Shunt Series Regulator)system "two domain control".At the same time,the technology also has the characteristics of independent configuration of solar array power supply module and charging module,and it is more suitable for low orbit spacecraft frequent charging applications,which is conducive to improving the life and reliability of the system.Several key components of PCU,such as battery discharge regulator,battery charge controller,shunt regulator and main error amplifier(MEA),have been systematically studied.This paper uses battery discharge regulator scheme based on Weinberg topology,battery charging controller scheme based on Superbuck topology,shunt regulator scheme based on frequency limiting sequential switching technology and the main error amplifier scheme based on MEA technology.The analysis and simulation test of each component scheme are carried out.The results show that all the components have high stability margin,good dynamic characteristics and low output impedance.A prototype PCU prototype is developed.The test results show that the voltage of the PCU bus is controlled properly and the different working intervals are switched correctly to meet the requirements of the hybrid fully regulated bus control scheme.In order to verify the correctness of the design scheme,a test platform for grid connected power supply is developed to carry out the system test.A variety of test conditions are designed to test the basic functions and performance of the grid connected power system.The test results show that the grid connected power system has normal function and good load response under different working conditions.The switching function of different control interval is normal,and the design of the "current-variable voltage-limited" grid connected power supply system is correct. 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