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Permanent magnet (PM) electrical machine has far-reaching impacts in aviation electrification due to the continuous development in high power density and high efficiency electrical drives. The primary barrier to acceptance of permanent magnet machines for safety-critical starter-generator systems is its low fault-tolerance capability and low reliability (for the conventional designs). This article investigates a modular triple three-phase PM starter-generator comprehensively, including the tradeoff of fault-tolerant topology, optimization design process, analysis of electromagnetic (highlight the post-fault analysis) and thermal behavior, respectively. The triple three-phase segmented topology proposed meet the fault-tolerant requirement along with complete electrical, magnetic, and thermal isolation. There would be cost penalty on the proposed topology, but it gets offset by the ease of manufacturing of coils and their insertion.

The Global Navigation Satellite System (GNSS) alone cannot provide high-precision and continuous positioning information for vehicles. The integration of GNSS with Inertial Navigation Systems (INS) has now been very intensively developed and widely applied in high precision positioning of vehicle and provide continuous position, velocity and attitude. However, the overall performance of low-cost GNSS/MEMS IMU frequently degrades in urban shaded environments. Traditional constraints GNSS/MIMU algorithm based on zero-velocity detection can effectively increase the accuracy of the navigation system, but easily influenced by external factors to false detection. This article aims to introduce a multi-dynamic constraints model as accurate update source for EKF to improve the accuracy of navigation solutions of a vehicle during satellites signal blockages. Firstly, we present a tightly coupled strategy to integrate GPS/BDS and INS by applying extended Kalman filter with 27-states.

Thrust vectoring is an interesting propulsion solution in aeronautic applications due to its fast response, improving aircraft's performance for take-off, landing and flight, and enabling Short/Vertical Take-Off and Landing (S/VTOL). In this context, an attempt to design a radically new concept of thrust vectoring nozzle is in current development. This novel nozzle, called ACHEON, bases the jet deviation control on the interaction of two primary jets of different velocities, where the one with higher velocity entrains the one with lower velocity. Two cylindrical walls are positioned after the two air jets mixing. If the inlet conditions are not symmetric, the Coanda effect on the walls forces the resulting air jet to divert from the symmetry axis. This paper shows the experimental pressure distribution along the Coanda wall for different inlet.

This paper aims to develop a general functional model of multi-pulse Auto-Transformer Rectifier Units (ATRUs) for More-Electric Aircraft (MEA) applications. The ATRU is seen as the most reliable way readily to be applied in the MEA. Interestingly, there is no model of ATRUs suitable for unbalanced or faulty conditions at the moment. This paper is aimed to fill this gap and develop functional models suitable for both balanced and unbalanced conditions. Using the fact that the DC voltage and current are strongly related to the voltage and current vectors at the AC terminals of ATRUs, a generic functional model has been developed for both symmetric and asymmetric ATRUs. The developed functional models are validated through simulation and experiment. The efficiency of the developed model is also demonstrated by comparing with corresponding detailed switching models. The developed functional model shows significant improvement of simulation efficiency, especially under balanced conditions.

The paper reports the control design for an aircraft electric starter-generator system based-on high-speed permanent magnet machine operated in a flux-weakening mode and controlled by an active front-end rectifier. The proposed system utilizes advances of modern power electronics allowing the use of novel machine types and the introduction of controlled power electronics into the main path of energy flow. The paper focuses on control design for such system and includes development of flux weakening control of high-speed permanent magnet machine and droop control of the system output dc-link current. The achieved analytical design results and the expected system performance are confirmed by time-domain simulations.

As future commercial aircraft incorporates more EMAs, the aircraft electrical power system architecture will become a complex electrical distribution system with increased numbers of power electronic converters (PEC) and electrical loads. The overall system performance and the power management for on-board electrical loads are therefore key issues that need to be addressed. In order to understand these issues and identify high pay-off technologies that would enable a major improvement of the overall system performance, it is necessary to study the aircraft EPS at the system level. Due to the switching behaviour of power electronic devices, it is very time-consuming and even impractical to simulate a large-scale EPS with some non-linear and time-varying models. The dynamic phasor (DP) technique is one way to solve that problem.

The paper deals with the development of active front-end rectifier model based on dynamic phasors concept. The model addresses the functional modeling level as defined by the multi-layer modeling paradigm and is suitable for accelerated simulation studies of the electric power systems under normal, unbalanced and line fault conditions. The performance and effectiveness of the developed model have been demonstrated by comparison against time-domain models in three-phase and synchronous space-vector representations. The experimental verification of the dynamic phasor model is also reported. The prime purpose of the model is for the simulation studies of more-electric aircraft power architectures at system level; however it can be directly applied for simulation study of any other electrical power system interfacing with active front-end rectifiers.

The more-electric aircraft (MEA) is the major trend for airplanes in the next generation. Comparing with traditional airplanes, a significant increase of on-board electrical and electronic devices in MEAs has been recognized and resulted in new challenges for electrical power system (EPS) designers. The design of EPS essentially involves in extensive simulation work in order to ensure the availability, stability and performance of the EPS under all possible operation conditions. Due to the switching behavior of power electronic devices, it is very time-consuming and even impractical to simulate a large-scale EPS with some non-linear and time-varying models. The functional models in the dq0 frame have shown great performance under balanced conditions but these models become very time-consuming under unbalanced conditions, due to the second harmonics in d and q axes. The dynamic phasor (DP) technique has been proposed to solve that problem.

This paper summarizes recent activities undertaken in the University of Nottingham towards development of simulation tools for accelerated simulation studies of complex aircraft electric power systems. The more-electric aircraft (MEA) is a major trend in aircraft electric power system (EPS) engineering that results in a significantly increased number of power electronic driven loads onboard. Development and assessment of EPS architectures, ensuring system integrity, stability and quality performance under normal and abnormal scenarios requires extensive simulation activity. Increased power electronics can make the simulation of a total EPS impractical due to large computation time or even numerical non-convergence due to the model complexity. Hence there is a demand for accurate but time-efficient modeling techniques for MEA EPS simulations.

The aim of this paper is to derive the methodology for planning an optimal accelerated life test with the consideration of type-I censoring. In a typical industrial setting, the total duration of ALT tests must be controlled as failure times are random in nature. The generalized linear model approach allows optimal designs to be found using iteratively weighted least squares solution without directly calculating the expected Fisher information matrix, which is often intractable in the case of censoring. This approach is demonstrated with an assumed Weibull distribution. We discuss both D-optimal design, where the determinant of variance-covariance matrix of model parameters is minimized, and UC-optimal design, where the prediction variance of lifetime at a product's use condition is minimized.