Research On 150VA Three-phase Aeronautical Static Inverter

The aeronautical static inverter has the advantages of small weight and volume,high efficiency,stable performance and high power density,and is suitable for using as airborne equipment.It has gradually replaced rotary converters to power instruments and other equipment on aircraft.At the request of an enterprise,this paper mainly develops a 150 VA three-phase aeronautical static inverter.Firstly,this article introduces the research context of the project.By comparing and analyzing the main topological structure of current aeronautical static inverters,we propose to use single-ended flyback converters and three-phase half-bridge inverters as the front and rear stages of this three-phase static inverters.The working principle of the single-ended flyback converter with RCD clamp is analyzed,and its small signal models under CCM and DCM operating modes are established.The stability of the system in the full input and full load range is analyzed.The planar transformer was used to replace the traditional winding transformer,and the Maxwell simulation model of the EI transformer was built.The impact of air gap position and winding arrangement on peripheral circuits and winding losses was analyzed,which provides guidance for the optimal design of planar transformers.Starting from the working principle of the three-phase half-bridge inverter,the small-signal model of the single-phase half-bridge inverter is established,and the mathematical expression of the output voltage of the bridge is derived.For the low-frequency harmonics introduced by the dead zone,the influence of the dead time on the output fundamental wave and THD of the inverter is analyzed providing an optimization direction for the parameter selection of the inverter.What’s more,based on the theoretical analysis and engineering design mentioned above,the prototype of the three-phase aeronautical static inverter is developed and the corresponding case is designed.It is verified through experiments that the prototype can meet electrical requirements in the full input and full load range and has good dynamic performance.In addition,the method of extraction and analysis of conducted EMI is also studied in this paper.The equivalent circuits of conducted EMI noise of the two-stage converter are established.Based on the common-mode equivalent circuit of the flyback converter,a method of adding a capacitor between the primary and secondary sides of the transformer was proposed to suppress common-mode noise,and it is verified by saber simulation and experiments.Basesd on the original noise measured by the three-phase static inverter developed in this paper,an EMI filter is designed and verified through experiments,where both common-mode and differential-mode noise can meet the GJB standard.