In more electric aircraft (MEA) weight reduction and energy efficiency constitute the key figures. Additionally, the safety and continuity of operation of its electrical power distribution system (EPDS) is of critical importance. These sets of desired features are in disagreement with each other, because higher redundancy, needed to guarantee the safety of operation, implies additional weight. In fact, EPDS is usually divided into isolated sections, which need to be sized for the worst-case scenario. Several concepts of EPDS have been investigated, aiming at enabling the power exchange among separate sections, which allows better optimization for power and weight of the whole system. In this paper, an approach based on the widespread use of multi-port power converters for both DC/DC and DC/AC stages is proposed. System integration of these two is proposed as a multiport power conversion system (MPCS), which allows a ring power distribution while galvanic isolation is still maintained, even in fault conditions. Thus, redundancy of MEA is established by no significant weight increase. A machine design analysis shows how the segmented machine could offer superior performance to the traditional one with same weight. Simulation and experimental verifications show the system feasibility in both normal and fault operations.

The increasing prevalence of grid-following (GFL) converters in modern power systems raises concerns about transient stability, mainly stemming from loss of synchronization (LOS). In certain scenarios, grid-forming (GFM) converters are utilized to improve system stability. Existing literature focuses on the transient stability analysis of individual converter types, with limited attention given to hybrid systems incorporating both GFL and GFM converters. Particularly, the interactions between these converter types, concerning transient stability, are seldom discussed, and stability enhancement in such systems remains unexplored. To address this gap, this paper aims to investigate the interaction mechanism of paralleled GFL and GFM converters and propose a control strategy to mitigate the risk of LOS in hybrid systems. The paper presents detailed aggregated models, theoretical analysis, and the control design of the proposed scheme. Theoretical analyses and the proposed method are validated through simulation and experimental results

The concept of the more electric aircraft is aimed at electrifying the mechanical, hydraulic, and pneumatic subsystems on aircraft. With increasing usage of power electronics, the architecture of onboard electrical power distribution systems becomes more complicated. Therefore, it is necessary to analyze the stability of the system. This article, first, presents and validates an impedance model of a permanent magnet synchronous generator as a source and dual active bridge converter as a load. These models are used for the stability analysis of a simple dc power system. In addition, two new control strategies are proposed to enhance the stability of the system. The stabilization effects of the new control strategies are verified with experimental results.

The electrical power distribution system (EPDS) of the more electric aircraft (MEA) is a fundamental component that needs to be efficient and resilient. The commonly considered architectures feature separate buses to achieve separation between different subsections of the EPDS. Although effective, this implies an over design, since all subsections are sized for the local worst case scenarios. In the MEA concept, multiport converters could connect the whole EPDS while guaranteeing the galvanic isolation between buses. Since multiport converters would give rise to a completely different EPDS topology, dominated by power electronics interfaces, the stability of such a system must be assessed. This article investigates the input impedance of multiple active bridge (MAB) converters when interfaced with a single dc bus and multiple resistive loads. A transfer function-based input impedance model of the MAB converter is proposed. To validate the proposed input impedance model, the verification of input impedances of a triple active bridge (TAB) converter and a quadruple active bridge (QAB) converter is carried out using both simulation and experimental results.

The multiport active bridge (MAB) converter has been recently proposed aiming to increase the power density and the availability of electrical power distribution systems. However, the dynamic performance of proportional-integral (PI) controller for MAB voltage control is characterized by a relatively slow response and large overshoot. To address this issue, a power decoupling based configurable control (PDC-MPC) strategy inspired by the model predictive control (MPC) was developed. The proposed control strategy can achieve good transient performance and high control flexibility with good precision to comply to DC voltage regulations. In this paper, the PDC-MPC was investigated and implemented in a triple active bridge (TAB) converter with multi-winding high frequency transformers. The operating principle of the PDC-MPC is divided into two phases: prediction of the DC current through a binary search and decoupling of the desired power of each isolated virtual branch to its phase shift angles under the single phase shift (SPS) modulation strategy. Steady-state and dynamic performances of the proposed PDC-MPC for TAB converters were analysed using modified cost function and predictive models. Simulation and experiments were conducted to validate the theoretical analyses.

Large-scale integration of renewable generation interfaced to the network through power electronic converters has led to drastic changes in power system dynamics. In islanded microgrids or weak grids, different control concepts for the synchronization of converters have been proposed to provide virtual inertia and improve their resilience against transient events, ensuring safe operation without heavy redundant design. The complexity of these power-related control algorithms and their interaction with the inner control loops causes problems in frequency components above the range of traditional studies which calls on modeling techniques with a wider bandwidth. This work aims to provide an outline of modeling methods for grid-connected converter dynamics from subsynchronous to switching sideband frequency range and relevant analyzing tools. The major contributions of this work are: 1. Theoretical foundations and the derivation processes are discussed for each of the modeling methods within the time domain, frequency domain and harmonic domain. 2. Similarities and differences between these methods are highlighted and recommendations are given regarding different grid situations. 3. A case study with an active front end converter is shown and the analysis results are validated by simulation and Hardware-in-the-Loop (HiL) test, illustrating the effectiveness of these methods.