Research On Optimization Technology For Quality Parameters Of Aviation Ground Power

With the progress of science and the development of civil aviation industry in China,the replacement of diesel generator and auxiliary power unit by bridge mounted ground power supply and storage ground power supply has been gradually realized,and it is also the trend for the country to vigorously develop new energy industries.At present,the aviation ground power supply is developing in the direction of good electrical performance and integration.However,due to the high fundamental frequency,it is difficult for the technicians to design and develop.The purpose of the optimization of aviation ground power supply is to reduce the harmonics produced by the rectification and inversion process as much as possible,to ensure that highquality power is provided for the aircraft,to minimize the harm of harmonics to the airborne equipment,and to ensure the airborne electrical equipment Safety.In accordance with the current requirements of external characteristic parameters of aviation ground power supplies,the inverter’s main circuit topology,modulation strategy and control strategy are optimized in three aspects.For cut the power loss of switching instrument and the output harmonic content,the multilevel cascaded H-bridge topology is improved to two cell five switch multilevel cascaded H-bridge topology,and the appropriate modulation strategy is matched.The advantage of this topology is that the number of switching devices and switching frequency are reduced,and the number of output voltage levels is more when other conditions are consistent.In order to further optimize the output waveform quality,a simulation model of cascaded H-bridge inverter is built in Simulink,and a modulation method is improved based on the carrier amplitude shift modulation strategy.The main principle is to change the triangular carrier waveform and combine the traditional triangular wave with a straight line to form a combined carrier.This strategy can effectively control the waveform quality,cut down the THD of the output voltage,and make the output voltage waveform smoother and the power quality better within a large range of modulation.Finally,the mathematical model of two unit five switch cascaded H-bridge is deduced to optimize the control strategy.Firstly,the double loop control is analyzed theoretically.Aiming at the topology and modulation strategy of aviation ground power supply,an improved resonant controller is derived to increase the phase margin near the resonant frequency,and the stability of the improved controller is verified under different loads.The simulation results show that the improved two unit five switch inverter topology and the improved control strategy have a positive impact on optimizing the quality of ground power output parameters,making the output voltage waveform better and containing less harmonics.