THE INFLUENCE OF PULSATIONS OF AN AUTONOMOUS VOLTAGE INVERTER ON THE PHASE OF THE OPERATING ORGAN OF THE ON-BOARD AVIATION FOLLOWING SYSTEM
Authors:   Chernihiv Polytechnic National University, Denisov Yuri , Skuhariev Vitalii ,   Chernihiv Polytechnic National University
Published: May 2024

On board an aircraft, an automatic control system ensures optimal aircraft engine operation. Its functions are related to monitoring the current parameters of the aircraft engine operating modes, their indication and control of individual working bodies that provide fuel, air and ignition supply according to the commands of the onboard computer. These commands are executed by automated low-power electric drives that are part of the systems of the relevant executive bodies that monitor the parameters of the engine's operating modes. Modern on-board electric drives are based on brushless motors that operate in DC mode, or in synchronous mode as an AC machine. These electric drives follow the specified laws of change of certain parameters, such as the phase position of the working bodies, which ensure the specified operating modes of the aircraft engine. The on-board electric drive of the tracking system is powered by the battery through an autonomous voltage inverter if the collectorless electric machine operates in synchronous mode, or in collector mode if it operates as a DC machine.The accuracy of the implementation of the specified tracking laws is the main indicator of such systems. This indicator is influenced by many factors, one of the main ones being the supply voltage fluctuations, which are a consequence of the discrete mode in the inverter operation, which raises the urgent problem of analysing their impact on the accuracy of the tracking laws. Given the significant impact of the inverter output voltage fluctuations on the accuracy of the tracking process by the executing electric drive, there is anurgent problem of assessing the level of its influence and finding ways to minimise it. An analysis of modern publications on the subject of the study has shown that in the process of developing tracking electric drives, their main accuracy indicator is estimated by the fundamental harmonic of the supply voltage without taking into account its actual shape. This approach greatly simplifies the analysis of the processes of the AC drive system powered by an inverter. However, the real rectangularshape of the motor supply voltage affects the smoothness of its rotor rotation, which worsens the accuracy of the tracking process as a result of the appearance of a pulsating torque. The reason for this is the result of the interaction of the fundamental harmonic field with the fields of higher harmonic currents; the largest amplitude of the pulsating torque is created by the currents of the fifth and seventh harmonics, and in general, the largest amplitude of torque pulsation in the rated load zoneis up to 10% of the rated torque.This raises the urgent problem of studying the effect of voltage fluctuations at the inverter output on the error of the electric drive following the law of change of the corresponding parameter in the aircraft engine operation mode control system. The main purpose of the publication is to analyse the error of tracking the law of phase change of the actuator in the aircraft engine control system and to find ways to minimise it. As a result of the study, a comparative assessment of the tracking error was obtained, taking into account the real form of the motor supply voltage and taking into account only the fundamental harmonicthe system was set up for a finite duration process. The comparison result showed a significant negative impact of the real supply voltage waveform on the tracking error.