Aircraft Electric Power System Research Articles

Research on dual‐winding permanent magnet generator system with integrated dual‐channel controller

AbstractThis article presents a dual‐winding permanent magnet generator (PMG) system with integrated dual‐channel controller to meet the requirements of high power density, high reliability, and high output performance of aircraft electric power system. The dual‐winding of the PMG are designed to have the same phase spatially, with which the same rotor position can be applied in independent vector control. In addition, a dual‐channel controller is applied to control the two sets of windings, which achieves high‐performance control under normal state and fault‐tolerant control under fault state. The integrated dual‐channel controller integrates two sets of main power circuits into one controller and uses a main control unit, which simplifies the PMG system leading to reduction in the overall volume and weight. Reliability analysis of dual‐winding PMG system is proposed to be compared with that of the single‐winding PMG system. A dual‐winding cooperative control strategy and a fault‐tolerant control strategy are proposed to achieve high‐performance control of DC‐link voltage under normal condition and redundant functions under fault condition. As a result, the reliability of the PMG system is improved. The experimental results validate the effectiveness of the proposed PMG system and the control strategy.

Comparative Analysis of Charging and Discharging Characteristics for Batteries in Aircraft Electric Power Systems

Abstract—This paper presents a comparative analysis of the charging and discharging characteristics of batteries used in aircraft electric power systems. The performance and efficiency of different battery technologies play a crucial role in determining the viability of electric propulsion and power systems in aircraft applications. In this study, we systematically evaluate the charg- ing and discharging behaviors of various battery types, including LiFePO4, Ni-Cd, and lead acid, using Simulink. The simulations encompass state of charge (SOC) dynamics, charging efficiency, discharging profiles, and passive cell balancing technique. By utilizing Simulink, we can accurately model the behavior of different battery technologies under various operating conditions. The results obtained from the simulations provide valuable insights into the performance, efficiency, and overall suitability of battery technologies for aircraft electric power systems. This comparative analysis, serves as a valuable resource for engineers and researchers involved in the design and optimization of battery management systems for aircraft applications, aiding in the informed selection and integration of batteries in aircraft electric power systems. Index Terms—Charging Characteristics, Discharging Charac- teristics, Simulink Simulation, State of Charge (SOC), Passive Cell Balancing

MODELING AND SIMULATION OF AN AIRCRAFT ELECTRICAL POWER SYSTEM

Although recent developments in aircraft electrical technology have had a significant impact on aircraft electrical power systems (EPS), thus reminding the development and production of more electric aircraft (MEA), but also important steps in the development of all-electric aircraft (AEA), still the EPS of the latest aircraft produced by the two big players in the market, the Neo series from Airbus and the NG or Max from Boeing respectively, is completely traditional – a constant speed constant frequency (CSCF) system. Thus, for an alternating current one, it is composed of the power source – the integrated drive generator (IDG), the command and control system – the generator control unit (GCU), the transmission and distribution system, the protection system – the CBs (circuit breaker) and electrical loads. This paper presents the design and simulation of an aircraft EPS using Simulink’s Simscape package, a MATLAB program, and for the first time in the specialized literature, a model of the constant speed drive (CSD) generated with the same program is used to drive the synchronous generator (SG) in the IDG.

A novel pulse multiplication circuit for reducing harmonic distortion of 12 pulse rectifiers in aircraft electrical power systems

AbstractTo improve the performance and reduce the total harmonic distortion (THD) of the autotransformer 12‐pulse rectifier, a novel pulse multiplication circuit (PMC) based on two tapped inter‐phase reactors (TIPRs) is proposed to improve performance and reduce the THD of the autotransformer 12‐pulse rectifier. The proposed rectifier includes a phase‐shifting autotransformer based on a polygon connection, two 6‐pulse diode bridge rectifiers (DBRs), and a PMC. The novel PMC consists of two TIPRs (TIPR1 and TIPR2), an auxiliary single‐phase diode bridge (including four diodes D1 to D4), and two auxiliary diodes D21 and D22, which are connected directly to the output terminal of the DBRs (DBR1 and DBR2). The simulation and experimental results confirm the high capability of the proposed PMC to reduce the harmonic distortion of the input current, so that by using the proposed PMC, the input current is almost sinusoidal and the THD of the input current is less than 3%. Also, the results show that the proposed 12‐pulse rectifier meets the standard requirements of aircraft electrical systems (DO‐160G) without the need for any input and output filters.

Research on the Design and Verification of the Civil Aircraft Battery Integrated Control System

This paper aims to study the integrated control technology of the civil aircraft battery system. The battery system is the backup power supply of the important DC (Direct Current) power equipment on the aircraft. As the last line of defense of the civil aircraft electrical power system, it plays an irreplaceable role in the safety of the aircraft. So, the research on battery system control is particularly important. This paper adopts forward design methods, such as capturing design requirements, functional decomposition, and integrated design, and proposes a relatively advanced battery-integrated control technology. This technology is verified by laboratory tests, on-aircraft ground tests, and flight tests. The test results show that this technology meets the design requirements and better solves the control problem of the battery system. It also has good social benefits and important reference significance for developing subsequent new aircraft types. It is of great significance to promote the rapid commercialization of civil aircraft in our country.

Implementation and performance analysis of a novel sliding mode controller for bidirectional DC to DC converter in aircraft application

Purpose The purpose of this paper is to implement a closed loop regulated bidirectional DC to DC converter for an application in the electric power system of more electric aircraft. To provide a consistent power supply to all of the electronic loads in an aircraft at the desired voltage level, good efficiency and desired transient and steady-state response, a smart and affordable DC to DC converter architecture in closed loop mode is being designed and implemented. Design/methodology/approach The aircraft electric power system (EPS) uses a bidirectional half-bridge DC to DC converter to facilitate the electric power flow from the primary power source – an AC generator installed on the aircraft engine’s shaft – to the load as well as from the secondary power source – a lithium ion battery – to the load. Rechargeable lithium ion batteries are used because they allow the primary power source to continue recharging them whenever the aircraft engine is running smoothly and because, in the event that the aircraft engine becomes overloaded during takeoff or turbulence, the charged secondary power source can step in and supply the load. Findings A novel nonsingular terminal sliding mode voltage controller based on exponential reaching law is used to keep the load voltage constant under any of the aforementioned circumstances, and its performance is contrasted with a tuned PI controller on the basis of their respective transient and steady-state responses. The former gives a faster and better transient and steady-state response as compared to the latter. Originality/value This research gives a novel control scheme for incorporating an auxiliary power source, i.e. rechargeable battery, in more electric aircraft EPS. The battery is so implemented that it can get regeneratively charged when primary power supply is capable of handling an additional load, i.e. the battery. The charging and discharging of the battery is carried out in closed loop mode to ensure constant battery terminal voltage, constant battery current and constant load voltage as per the requirement. A novel sliding mode controller is used to improve transient and steady-state response of the system.

Enhanced Starting Control Scheme for PMM-Based Starter/Generator System for MEA

A control approach for aircraft Starter/Generator (S/G) with Permanent Magnet Machine (PMM) operating in Flux Weakening (FW) mode is presented. The proposed strategy helps the previous approaches which are adopted for the Variable Voltage Bus (VVB) or Voltage Wild Bus (VWB) concept for an aircraft Electric Power System (EPS), to cover a wide speed range in motoring and generation modes. Compared to prior works, the proposed control approach adjusts the q-axis reference voltage with a single current regulator, and the maximum available voltage provided by the converter is used to evaluate the d-axis voltage. By adopting the proposed approach, the DC bus voltage can be fully utilized, increasing aircraft efficiency by allowing the S/G system to operate at a wide range of speeds. The results of the analytical design and the performance of the system were verified by time-domain simulations using MATLAB/Simulink and experiments and compared to the conventional method.

Digital Twins in the Theory and Practices of Aircraft Electrical Power Systems

The article addresses the problem of applying new digital technologies at the aircraft electrical equipment life cycle stages. The features pertinent to the development and application of digital twins in aircraft electrical equipment systems are presented. A unified approach to development of mathematical models for digital twins, called an energy processes mathematical prototyping method, is suggested. This method is based on taking into account the energy potentials and flows occurring inside the system, as well as incoming and outgoing energy flows. It is shown that for particular tasks arising at the products and systems life cycle stages, it is possible to use projections of the full model on the observed and controlled parameters corresponding to these tasks. Such projections are called "digital portraits". In addition, a set of properties of a particular object or system due to which it can perform informational interaction with other objects (systems), and which ones follow from the digital twin full model, is proposed to be called "digital passports".

Components of Electrical Power Systems in More and All-Electric Aircraft: A Review

Even though achieving carbon-free and reduced NOx emission transportation is a prevailing goal, the aviation industry is in its infancy to arrive at passenger class all-electric aircraft (AEA) properly operating over commercial missions. Challenges are mainly associated with the components of the aircraft electric power system (EPS). Considering today’s technologies, power electronics components are not capable to sustain tens of megawatts of required power during the takeoff and meet the aviation limits in terms of size, weight, and cost at the same time. The state-of-the-art electrochemical energy units (EEUs), including battery, fuel cell, and supercapacitor, cannot provide the 25–30-MW thrust power needed for the takeoff, and electrical circuit breakers (CBs) are not able to clear a fault in a large AEA propulsion system, and multimegawatt electric drives/motors can barely be found being able to provide 2–3-MW thrust power, so that they can be employed in a distributed propulsion architecture. Taking mentioned challenges into account, this article aims to tackle challenges associated with protection devices, EEUs, and electric machines in passenger class AEA and present promising solutions using an envisioned medium voltage direct current ±5-kV EPS for an AEA, all-electric NASA N3-X aircraft. Based on findings and discussions made through this article, the authors conclude that although technology advancements are essential in all research areas, high-voltage wide bandgap electrical CBs, Li-air and Li-S batteries with >1000-kW/kg specific power, and multimegawatt superconducting electric machines will turn a commercialized passenger class AEA into reality within the next 20–30 years.

All-Electric NASA N3-X Aircraft Electric Power Systems

In this article, turboelectric NASA N3-X aircraft is fully electrified for the first time; engines are removed and the all-electric NASA N3-X aircraft electric power system (EPS) is introduced, supplied by four electrochemical energy units (EEUs), including batteries, fuel cells, and supercapacitors. In this regard, three medium-voltage direct current (MVdc), ±5 kVdc, bipolar EPS architectures are proposed for the aircraft and discussed and analyzed in detail by a performing power flow (PF) analysis. The proposed architectures are also considered as three-phase ac, 10 kVac, EPSs and discussed and analyzed in detail for comparison. To perform the PF analysis for the proposed MVdc EPSs, two PF solvers for dc networks under constant power generations and loads are also modified and developed. Potential cable conductors are selected and hints are provided to choose final conductors; to assess the performance of selected conductors, dimensions of the aircraft are estimated and cable parameters are calculated based on the presented dimensions. The proposed EPS architectures meet power system planning criteria under normal condition as well as all n −1 contingencies. This article aims to assess newly designed EPSs and, therefore, assumptions are made about EEUs and propulsion motors to the extent whereby PF analysis is affected.

A low‐rating 40‐pulse AC–DC rectifier based on a new passive harmonic mitigation circuit

A novel 40-pulse autotransformer rectifier is proposed to reduce total harmonic distortion (THD) of the input current in aircraft electrical power systems. The 40-pulse rectifier (40PR) includes a passive harmonic reduction circuit (PHMC) with a low kVA rating (about 0.95% of the load power) to enhance the performance of the conventional 40PR. This PHMC is based on 2 harmonic suppression circuits and contains four tapped reactor and 4 auxiliary diodes. 50 Hz simulations of the improved 40PR indicate that THD of the input current and voltage is less than 2%, which meets the IEEE-519 standard. In addition, without using any input and output filters, input current harmonic components at 400–800 Hz are less than the requirements mentioned in the DO-160G and MIL-STD-704F standards. The suggested PHMC can easily be implemented. A prototype is developed to verify the proposed design. A good agreement can be seen in simulation and experimental results.

Multi-Domain Modeling and Simulation of High-Temperature Superconducting Transmission Lines Under Short-Circuit Fault Conditions

Emission reduction in transportation requires advancements in aviation technologies enabling fully electrified propulsion, among which the use of superconducting technologies can provide untapped benefits given their low weight and minimal losses for high-power transmission. However, to enable their use in aircraft electrical power systems, additional considerations for electrical and thermal performance during faults is required in order to meet stringent aircraft safety requirements. In this work, a cryogenically cooled electric aircraft power system is studied under short-circuit conditions for different cooling media. This system consists of a fuel cell, high-temperature superconducting (HTS) transmission line, inverter, and motor, where each of their fault models have been explored. A trade-off study of the impedance of the fuel cell is conducted to identify the values at which the superconducting cable remains thermally stable after a short-circuit fault, as it is crucial that the cable does not experience a thermal runaway.

Hybrid Deep Reinforcement Learning Considering Discrete-Continuous Action Spaces for Real-Time Energy Management in More Electric Aircraft

The increasing number and functional complexity of power electronics in more electric aircraft (MEA) power systems have led to a high degree of complexity in modelling and computation, making real-time energy management a formidable challenge, and the discrete-continuous action space of the MEA system under consideration also poses a challenge to existing DRL algorithms. Therefore, this paper proposes an optimisation strategy for real-time energy management based on hybrid deep reinforcement learning (HDRL). An energy management model of the MEA power system is constructed for the analysis of generators, buses, loads and energy storage system (ESS) characteristics, and the problem is described as a multi-objective optimisation problem with integer and continuous variables. The problem is solved by combining a duelling double deep Q network (D3QN) algorithm with a deep deterministic policy gradient (DDPG) algorithm, where the D3QN algorithm deals with the discrete action space and the DDPG algorithm with the continuous action space. These two algorithms are alternately trained and interact with each other to maximize the long-term payoff of MEA. Finally, the simulation results show that the effectiveness of the method is verified under different generator operating conditions. For different time lengths T, the method always obtains smaller objective function values compared to previous DRL algorithms, is several orders of magnitude faster than commercial solvers, and is always less than 0.2 s, despite a slight shortfall in solution accuracy. In addition, the method has been validated on a hardware-in-the-loop simulation platform.

Load Identification for the More Electric Aircraft Distribution System Based on Intelligent Algorithm

Accurate identification of electrical load working status can provide information support to the remote electrical distribution system (EDS) of more electric aircraft (MEA), which could use it to realize redundant switching and protection. This paper presents a method to automatically identify the load status on the remote power distribution unit (RPDU) of MEA by using an intelligent algorithm. The experimental platform is built in an aircraft Electrical Power System (EPS) distribution large-scale test cabin. Four pieces of typical aviation equipment are installed in the test cabin and powered from RPDU. Voltage and current values under 15 working combinations on the RPDU are measured to extract the steady-state V-I trajectory. In total, 750 group samples were collected in the feature parameter database. A generalized regression neural network (GRNN) identification model was established, and the smoothing factor was calculated by using a conventional cross-validation method to train and reach an optimal value. However, the identification results are not ideal. In order to improve the accuracy, the parameter of GRNN was optimized by genetic algorithms. The proposed model shows great performance as accuracy of all 15 classifications reached 100%. The proposed model has advantages of flexible network structure, high fault tolerance, and robustness. It can realize global approximation optimization, avoid local optimization, effectively improve GRNN fitting accuracy, improve model generalization ability, and reduce model training calculation.

The Architecture Optimization and Energy Management Technology of Aircraft Power Systems: A Review and Future Trends

With the development of More/All-Electric Aircraft, especially the progress of hybrid electrical propulsion or electrical propulsion aircraft, the problem of optimizing the energy system design and operation of the aircraft must be solved regarding the increasing electrical power demand-limited thermal sink capability. The paper overviews the state of the art in architecture optimization and an energy management system for the aircraft power system. The basic design method for power system architecture optimization in aircraft is reviewed from the multi-energy form in this paper. Renewable energy, such as the photo-voltaic battery and the fuel cell, is integrated into the electrical power system onboard which can also make the problem of optimal energy distribution in the aircraft complex because of the uncertainty and power response speed. The basic idea and research progress for the optimization, evaluation technology, and dynamic management control methods of the aircraft power system are analyzed and presented in this paper. The trend in optimization methods of engineering design for the energy system architecture in aircraft was summarized and derived from the multiple objective optimizations within the constraint conditions, such as weight, reliability, safety, efficiency, and characteristics of renewable energy. The cost function, based on the energy efficiency and power quality, was commented on and discussed according to different power flow relationships in the aircraft. The dynamic control strategies of different microgrid architectures in aircraft are compared with other methods in the review paper. Some integrated energy management optimization strategies or methods for electrical propulsion aircraft and more electric aircraft were reviewed. The mathematical consideration and expression of the energy optimization technologies of aircraft were analyzed and compared with some features and solution methods. The thermal and electric energy coupling relationship research field is discussed with the power quality and stability of the aircraft power system with some reference papers. Finally, the future energy interaction optimization problem between the airport microgrid and electric propulsion aircraft power system was also discussed and predicted in this review paper. Based on the state of the art technology development for EMS and architecture optimization, this paper intends to present the industry’s common sense and future trends on aircraft power system electrification and proposes an EMS+TMS+PHM to follow in the electrified aircraft propulsion system architecture selection

Active Power Filters in Aircraft Electric Power Systems: A Comparison Among Conventional and Advanced Compensation Techniques

The world is moving towards more electric aircraft due to its benefits for more efficiency and less dependence on conventional energy. However, as conventional energy has its drawback of reduced total energy efficiency for aircraft, the use of more electronics is accountable for higher losses, unbalance currents, reduced power supply performance, and generation of harmonics. In this paper, a comparison among three conventional control techniques (Synchronous Rotating Frame, Sinusoidal Current Control and Constant Instantaneous Power Control) and advanced control techniques (ANN, fuzzy logic controller, genetic algorithm, adaptive blanket body cover algorithm, the combination of ANN & fuzzy logic controller and ANN with the application of genetic & adaptive blanket body search algorithm) for aircraft shunt active power filter has been proposed. Furthermore, the best control schemes for aircraft active power filters will be proposed to depend upon the THD of source current and voltage and the compensation time (speed).

Fault Diagnosis of Civil Aircraft Electrical Power System Based on Triangular Fuzzy Number and Grey Relational Analysis

Abstract The stable operation of the aircraft electrical power system is closely related to aircraft’s function implementation and safety. Therefore, research on fault diagnosis of aircraft electrical system is important and necessary. This paper proposes a fault diagnosis method of civil aircraft power system based on triangular fuzzy number and grey relational analysis. For the purpose of obtaining complete data, it takes into account single fault symptom and historical data, and keeps the fuzzy feature from initial estimation of diagnosis scheme to the end. The example analysis shows that this method has feasibility and efficiency in practical application.

Simulation Study of Reliability Model and Optimization for Electrical Power System

Abstract An architecture with multi-parallel and multi-standby system of aircraft electrical power system is proposed, simulation study is given. First the reliability model of parallel system is formulated, and total system reliability model is obtained. Parallel subsystem number and standby subsystems number are the two parameters of reliability model. In order to maximize the system MTBF and minimize the purchase cost of each subsystem, a novel redundancy optimization function is proposed. Simulation results are analyzed to study the impact of parameters on the system reliability. Redundancy number and configuration of typical aircraft power system is also discussed from the viewpoint of application practice. Simulation result shows that the architecture is flexible, with the options to increase or decrease subsystems of parallel or standby systems to satisfy reliability and capacity requirement.

Reliability Uncertainty Analysis Method for Aircraft Electrical Power System Design Based on Variance Decomposition

As a safety critical system, affected by cognitive uncertainty and flight environment variability, aircraft electrical power system proves highly uncertain in its failure occurrence and consequences. However, there are few studies on how to reduce the uncertainty in the system design stage, which is of great significance for shortening the development cycle and ensuring flight safety during the operation phrase. For this reason, based on the variance decomposition theory, this paper proposes an importance measure index of the influence of component failure rate uncertainty on the uncertainty of power supply reliability (system reliability). Furthermore, an algorithm to calculate the measure index is proposed by combining with the minimum path set and Monte Carlo simulation method. Finally, the proposed method is applied to a typical series-parallel system and an aircraft electrical power system, and a criteria named as “quantity and degree optimization criteria” is drawn from the case study. Results demonstrate that the proposed method indeed realizes the measurement of the contribution degree of component failure rate uncertainty to system reliability uncertainty, and combined with the criteria, proper solutions can be quickly determined to reduce system reliability uncertainty, which can be a theoretical guidance for aircraft electrical power system reliability design.

A Novel More Electric Aircraft Power System Rectifier Based on a Low-Rating Autotransformer

From a theoretical and practical point of view, to increase rating and decrease the cost and complexity of a multi-pulse rectifier (MPR), its pulse number has to be increased. In many industrial applications, a 20-pulse rectifier is suggested as the practical solution considering its simple structure and low weight. But the 20-pulse rectifiers, suggested in different studies, must use filters to satisfy the DO-160G requirements for 21st and 39th harmonics for ac–dc more electric aircraft (MEA) power systems. To overcome this problem, this article proposes a novel 20-pulse rectifier for the ac–dc MEA power system based on a low-rating autotransformer (LRA). Also, a passive harmonic reduction circuit (PHRC) is used on the dc side of the 20-pulse rectifier to suppress the harmonics up to the 40th order according to DO-160G without using any filter. In this article, simulations are provided to show the merits of this new rectifier over other proposed solutions. Then, an experimental prototype is implemented for evaluating and verifying the simulation results. By investigating the captured outcomes, this article concludes that the introduced design is practical and can simultaneously consider the trade-off among autotransformer structure, pulse number, complexity, rating, and cost.