| With the development of spacecraft power supply and distribution system towards high power,integration and intelligence,the traditional power distribution system has been replaced by the intelligent power distribution system,and the solid state power controller(SSPC)is the key device of the intelligent power distribution system,and its reliability largely determines the reliability of the power distribution system.At present,the research on SSPC mainly focuses on the driving circuit,protection circuit and signal isolation of SiC switching devices with new semiconductor materials.Therefore,this paper combines the development needs of SSPC for high reliability and intelligence,and researches the key technologies of SSPC around the driving circuit of SiC MOSFET,signal isolation technology research,and the inverse time protection behavior model based on I~2T in three aspects,as follows.(i)For the design of SiC MOSFET drive circuit in SSPC,firstly,starting from the basic characteristics of SiC MOSFET,the influence of the parameters of each part on the switching characteristics is quantified,the switching process is analyzed theoretically,and the design requirements of the drive circuit are determined.An overvoltage and overcurrent protection circuit is designed on the driver side to improve the reliability of the driver circuit.Then a circuit structure with invertible gate voltage and gate resistance is proposed,which can improve the problem of turn-off voltage spikes.Finally,the correctness of the designed driver circuit is verified using double-pulse experiments.(ii)For the study of signal isolation in SSPC,firstly,the concept of isolation is introduced,and the advantages and disadvantages of capacitive isolation,optocoupler isolation and transformer isolation are compared and analyzed,and the isolation method of on-chip transformer is determined in SSPC.Then the equivalent circuit model of the on-chip transformer is introduced and the main performance indexes of the on-chip transformer are derived.Finally,the geometry of the on-chip transformer is studied and simulated to design a low-loss,high-coupling on-chip transformer model,and the structured model of the on-chip transformer is successfully generated into a layout.(iii)For the design of I~2T-based inverse time protection behavior model,firstly,the inverse time overcurrent protection curve and its key parameters are analyzed and determined,then the I~2T theory and thermal memory theory are studied and analyzed to obtain the discrete expressions of inverse time protection,and the inverse time protection algorithm is implemented.Finally,the behavior modeling of I~2T inverse time protection is carried out on PSIM software,and the accuracy of the behavior model is verified by online simulation and experimental testing.In summary,this paper analyzes the three key technologies of SSPC through theoretical analysis,combined with simulation of SSPS software and PSIM software simulation verification,and finally tested by SSPC verification version,the results show that:all meet the expected index requirements,and have an important role in promoting the development of SSPC towards high power and integration. |
