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 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 sub-sections are sized for the local worst-case scenarios. In the MEA concept, multi-port converters could connect the whole EPDS while guaranteeing the galvanic isolation between buses. Since multi-port 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 paper investigates the input impedance of multiple active bridge (MAB) converters when interfaced to 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 are carried out using both simulation and experimental results.

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The concept of the More Electric Aircraft (MEA) is aimed at electrifying the mechanical, hydraulic, and pneumatic subsystems on aircraft. With increasing usage of power electronics, the architecture of on-board electrical power distribution systems (EPDS) becomes more complicated. Therefore, it is necessary to analyze the stability of the system. This paper firstly presents and validates an impedance model of a permanent magnet synchronous generator (PMSG) as a source and dual active bridge (DAB) 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 sensitivity analysis of a circuit reflects the robustness of this circuit to the relevant parameters. This paper investigates the sensitivity of input impedance of DAB converter, which is widely adopted in solid-state transformer (SST) and dc microgrid on more electric aircraft (MEA). In this paper, an improved impedance-based small-signal averaged model is developed to carry out the sensitivity analysis. Bode plots will be used as main analysis tool. The small signal model is compared to a complete switching model to confirm the validity of the proposed approach.

To increase the reliability and reduce the torque ripple, modular winding structure has been employed in the Permanent Magnet Synchronous Motors (PMSMs). However, the reliability of the motor system depends on the lifetime of the power semiconductor devices. In this paper, an Active Thermal Control (ATC) for modular power converters in PMSM drive is proposed. The power routing method is employed to balance the power in a triple modular winding PMSM system. The Rainflow Counting Algorithm is used to calculate the lifetime of the power converters. To verify the proposed method, a simulation model is established and the simulation results are presented.Index Terms-Active thermal control, multi-phase motor, permanent magnet synchronous motor, modular inverter, motor control.

The concept of multiport dc-dc converter was proposed to reduce the conversion stages of dc microgrid on more electric aircraft (MEA). The structure of multiport dc-dc converter is basically developed from the dual active bridge (DAB) converter because of its galvanic isolation and bidirectional power flow. A power electronics converter as a key element of the electrical power distribution system may cause stability issues. To address these challenges, the impedance characteristic of the multiport converter will be analyzed. In this paper, a transfer function based small signal model is developed and validated with a switching model, to figure out the characteristic of input impedance of triple active bridge (TAB) converter. Preliminary experimental results are presented to be as a support.

The development of power electronics and control technology provides improved performance of the electrical appliances, making them robust to changes in the supply voltage or frequency. However, power electronic converters behave as constant power loads (CPLs), which have negative impedance characteristics, and this non-linear behavior is challenging the stability of the grid. This paper investigates the input impedance of a three-phase low-voltage grid connected ac-dc converter that operating as a CPL when interfaced to a single DC bus and a changeable load. The possibility of adopting a Smart Transformer (ST), a power electronics converter which feeds a low-voltage grid, for the CPL stabilization is also addressed. To analyze the behavior of CPLs, a strategy of impedance modelling is employed. Gain Margin Phase Margin (GMPM) Criterion is referred to judge the stability of the system and verify the stabilization operation for CPLs. Simulation results are presented to be as a support.