Research On 1kVA Aviation Static Inverter

Aeronautical Static Inverter(ASI) is used in aviation power supply.It converts the electrical energy of the aircraft generator or battery to obtain high-quality and stable output AC power for use by airborne equipment.This article takes 1k VA two-stage aviation static converter as the research object,and analyzes the detailed design and implementation of the front and rear stages,the stability of the two-stage converter,the factors affecting the performance of the modular combination,and the conducted EMI.ASI uses two-stage structure.The flyback circuit and the control method is simple and reliable.It can achieve electrical isolation and increase voltage.This paper optimizes the design of the plane transformer to reduce its leakage inductance,and adopts a flyback leakage inductance absorption circuit,which can effectively suppress voltage spikes and feed back the leakage inductance energy to the load,improving the efficiency of the converter.Because the leakage inductance is small,the absorption circuit does not work at light load and does not affect the light load efficiency.The subsequent stage adopts the carrier phase shifting unipolar frequency doubling modulation method,so that the midpoint voltage of the 2H bridge arm is 5 level and the frequency is 4 times the equivalent switching frequency,which can greatly reduce the volume and weight of the filter.And the power unit can be controlled independently,and the control is simple.Based on this,a 1k VA two-stage aviation static converter is developed.Due to the stability problem when two-stage converters are cascaded,firstly,Modeling and frequency sweep verification of the flyback converter considering parasitic parameters.Analyzing and suppressing the power ripple of single-phase inverter,and comparing the stability of resistive load and constant power load.Based on this,the compensation design of the front and rear stage regulators is carried out.When ASI is modularly combined,communication design of the control circuit is required.Because there will be a circulating current when the modules are connected in parallel,and the larger the circulating current,the more severe the current sharing problem.Based on this,the model of the parallel circuit is analyzed,the circulation current expression is derived,and the DC circulation current and the AC circulation current are analyzed and suppressed.Finally,the conducted EMI of the two-stage inverter is analyzed.Firstly,introducing the generation and measurement mechanism of conducted EMI.Secondly,establishing the conducted EMI models of single-tube flyback circuit,single-phase full-bridge inverter and two-stage system.The EMI filter is designed,and the system EMI simulation and experimental verification are carried out.