Research On Key Technologies Of 400Hz Utilities Based Aircraft Ground Power Supplies

The independent ground power unit(GPU)is adopted as the external power supply of the airciraft now.There is no influence among the power supplies and aircrafts in an airport.But,there are a lot of disadvantages for this power supply architecture such as the large quantity of GPUs,the large volume and weight of the system,the difficulty management and maintenance,the high cost as well as the low rate of equipment utilization.In this disseration,a centralized external power supply architecture for aircrafts is proposed based on both the 400 Hz electric power system and the power electronics technology.The centralized power supply architecture adopts the centralized power converter for the frequency conversion.Then the power is transmited to each power supply terminal by the ac bus.With the voltage correcting at the power supply terminal,the power quality can meet the requirements of the external power supply for aircrafts.The power demand of the power supply system is decreased by using the proposed architecture and both the power supply distance and the power capacity are satisfied for the airport by using the 400 Hz electric power system.And,the cost performance and the flexibility are improved.So,it is a high cost performance scheme of centralized aircrafts external power supply for the airport.The key technologies of the proposed power supply scheme are researched in this disseration,including the structure and parameters analysis,the power quality of the power supply terminal,the high power inverter technology,the simnulation and experimental platforms for the demonstration system.In the part of the system and parameters analysis the architecture of the 400 Hz electric power system is analyzed first,including the design and the function allocation of the 400 Hz power station,the 400 Hz power distribution network and the 400 Hz power supply terminal.Second,the voltage level of the power distribution network is determined by both the design objective and the existing public power utilities.Then,several power distribution network schemes are proposed according to both the system equivalent circuit analysis and the load distribution analysis.The operation parameters are received based on the power flow calculation and the optimized power distribution scheme is selected.Taking the terminal 1 at shanghai pudong international airport for example,the proposed centralized power supply scheme is designed and analysed and the feasibility of the centralized power supply scheme based on 400 Hz electric power system is verified preliminarily by the simulation results.To control the power quality control at 400 Hz power supply terminal,a dymanic voltage corrector(DVC)with the function of short-circuit fault isolation is proposed,which satidfies both the voltage amplitude correction and the load short circuit fault isolation.The topology selection and operation principle of the DVC are analyzed.The correction ranges of both the voltage sag and the voltage swell are researched.The main circuit parameters and the closed-loop control parameters are designed.A 3kVA DVC prototype is developped.The DVC has the ability of continuous correction in conditions of both the voltage drop and the voltage rise.Meanwhile,the fault isolution of the load short-circuit is verified.The waveform quality of the compensated voltage is good.The size and weight of the device are small.So it is suitable for installing at the 400 Hz power supply terminal.The simulation and experimental results under the different loads,the load step changes and the load short circuit verified the correction of the theoretical analyses.A high power inverter scheme with low frequency-modulation-ratio(FMR)is proposed for the 400 Hz power station.The topology of the hybrid asymmetric cascaded(HAC)and the modulation strategy of the phase shift and selective harmonic elimination pulse width modulation(SHEPWM)are used.The scheme possesses the superior elimination ability of the low order harmonics under the low FMR control.On this basis,the molulation strategy of the modular structure converter is further researched.A modulation technique of the multi-variable combination is proposed,which combinates the pulse width modulation(PWM),the pulse shift modulation(PSM)and the pulse amplitude modulation(PAM).The multi-variable combination modulation scheme has good abilities of both the harmonics elimination and the output voltage regulation.The modulation scheme is also suitable for the typical multi-module-cascaded inverter topologies.The simulation and experimental results verify the effect of the low order harmonics elimination.Based on the analysis of the above key technologies,a verification platform of the 400 Hz electric power system is developed through simplifying the terminal 1 at shanghai pudong international airport.According to the verification platform,the feasibility of the 400 Hz electric power system is verified.The 400 Hz electric power system is characteristiced as the high utility factor,the low construction and maintenance costs,the small size and weight as well as the flexible power supply mode.It promises good application prospect as the 400 Hz power supply for the airport instead of the traditional independent architecture.The researches are based on both the power electronics technology and the electric power system theory.The theoretical basis and technical solutions are investigated for solving the key issues of 400 Hz electric power system,which lay a foundation for its application in the aircraft service.