Abstract:The aircraft environmental control system (ECS) is the second-highest fuel consumer system, behind the propulsion system. To reduce fuel consumption, one research direction intends to replace conventional aircraft with more electric aircraft. Thus, new electric architectures have to be designed for each system, such as for the ECS. In this paper, an electric ECS is modeled and then sized and optimized for different sizing scenarios with the aim of minimizing fuel consumption at the aircraft level. For the syst… Show more
“…Among these solutions, smart transformers, also called power electronic transformers, have been widely applied to interface medium-and low-voltage systems through fully controllable power electronic devices [3]. Similarly, power electronic transformations have played a key role in the onboard systems for transportation applications, aircraft, and shipboard [4,5]. Active rectifiers, as a first stage in those applications, have become the most attractive approaches towards smart power systems.…”
Active front-end (AFE) rectifiers have become widely employed in power systems to achieve unity power factor and harmonic mitigations. The typical modeling approaches applied for AFE rectifiers in the literature mostly relied on two baselines: the detailed model and the time-average model. The former approach deals with the switching element model (SEM), which leads to significant harmonics in currents with distorted waveforms. The latter approach uses the average-value model (AVM) to overcome the currents’ harmonics as well as provide fast responses. However, even the AVM baseline has shown problems during the starting stage (lack of control signals) and over the dead-time periods, which causes serious issues in the implementation process. This paper presents an improved dynamic AVM for AFE rectifiers by precisely considering the issues mentioned above, along with the practical starting procedure and desirable initialization. The studied AFE rectifier is developed using the voltage-oriented control (VOC) technique based on the different modeling methodologies, including SEM, Conventional AVM, and the proposed AVM. The performance of all models is analyzed and compared using simulation results with MATLAB/Simulink R2023a Function blocks for all the algorithm parts and SimScape elements for the electrical circuit model. The simulation results illustrate that the performance of the proposed AVM approach can closely resemble the behavior of the SEM baseline with low harmonic distortion. To evaluate the performance of the proposed model, several case studies are investigated to verify the AFE rectifier operation, regarding mostly the total harmonic distortion (THD) wherein the THD percentages are improved to 4.78 and 2.5 from 5.14 and 2.78 for low- and high-power loads, respectively.
“…Among these solutions, smart transformers, also called power electronic transformers, have been widely applied to interface medium-and low-voltage systems through fully controllable power electronic devices [3]. Similarly, power electronic transformations have played a key role in the onboard systems for transportation applications, aircraft, and shipboard [4,5]. Active rectifiers, as a first stage in those applications, have become the most attractive approaches towards smart power systems.…”
Active front-end (AFE) rectifiers have become widely employed in power systems to achieve unity power factor and harmonic mitigations. The typical modeling approaches applied for AFE rectifiers in the literature mostly relied on two baselines: the detailed model and the time-average model. The former approach deals with the switching element model (SEM), which leads to significant harmonics in currents with distorted waveforms. The latter approach uses the average-value model (AVM) to overcome the currents’ harmonics as well as provide fast responses. However, even the AVM baseline has shown problems during the starting stage (lack of control signals) and over the dead-time periods, which causes serious issues in the implementation process. This paper presents an improved dynamic AVM for AFE rectifiers by precisely considering the issues mentioned above, along with the practical starting procedure and desirable initialization. The studied AFE rectifier is developed using the voltage-oriented control (VOC) technique based on the different modeling methodologies, including SEM, Conventional AVM, and the proposed AVM. The performance of all models is analyzed and compared using simulation results with MATLAB/Simulink R2023a Function blocks for all the algorithm parts and SimScape elements for the electrical circuit model. The simulation results illustrate that the performance of the proposed AVM approach can closely resemble the behavior of the SEM baseline with low harmonic distortion. To evaluate the performance of the proposed model, several case studies are investigated to verify the AFE rectifier operation, regarding mostly the total harmonic distortion (THD) wherein the THD percentages are improved to 4.78 and 2.5 from 5.14 and 2.78 for low- and high-power loads, respectively.
“…A small part of the literature models deals with E-ECS (e.g. [25], [22], [26] but they require detailed input data available only in the later design phases. For instance, these models require the geometry of the heat exchangers, the characteristics of the main system valves and the diameter and length of the secondary flow duct.…”
In present decades, the need for a more efficient air transport system is driving towards more electric aircraft subsystems. Electrified subsystems offer the opportunity to optimize the operational performance of systems by reducing the power required by the propulsion system therefore, reducing the fuel burnt. A considerable advantage can be obtained by electrifying the environmental control system which is the most power demanding aircraft subsystem. The paper presents a simplified model to estimate the main performances of the conventional and electrified environmental control system during the aircraft conceptual and preliminary design phases. Different air cycle machine architectures can be designed. The model is divided in two main modules. The first is dedicated to the estimation of the aircraft thermal loads including the effect of solar radiation, the conduction of external air, the presence of passengers and the avionic systems. With the main result of estimating the cabin airflow required to control the temperature and the air quality within the aircraft's mission profile. The second module of the model designs all major components of the air conditioning pack including the dedicated compressors of the electrified environmental control system. The model requires basic input data that can be easily estimated during the early stages of aircraft design. The model is calibrated using the available data of a conventional system and then applied to the electrified one. The results show the increased efficiency of the electrified system that results from optimizing both pneumatic power generation and the air cycle machine.
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