The more electric aircraft concept aims to improve the fuel consumption, the weight and both the maintenance and operating costs of the aircraft, by promoting the use of electric power in actuation systems. According to this scenario, electromechanical actuators for flight control systems represent an important technology in next generation aircraft. The paper presents a linear geared electromechanical actuator for secondary flight control systems, where the safety and availability requirements are fulfilled by replicating the electric drive acting on the drivetrain. Indeed, the architecture considered consists of two power converters feeding as many electrical machines coupled to the same mechanical system. The design of both the permanent magnet synchronous machine and the power converter are addressed. Preliminary results on the electric drive prototype are also provided and compared to the design requirements. Finally, the electromechanical actuator performance at system-level is evaluated in Dymola environment, analyzing different operating modes.

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The more electric aircraft (MEA) initiative aims to improve weight, fuel consumption and maintenance costs of the aircraft, by increasing the use of electric power in actuation systems. Considering this scenario, electromechanical actuators (EMAs) for flight control (FC) systems represent a key technology in future aircraft. The paper presents a linear geared EMA for secondary FC systems, where the safety and availability requirements are fulfilled by duplicating the electric drive acting on the EMA drive-train (i.e. two power converters feeding as many electrical machines coupled to the same mechanical system). The design of the permanent magnet synchronous machine (PMSM) integrated into the EMA is addressed. Preliminary results on the PMSM prototype are also provided and compared to the finite element (FE) outcomes obtained at the design stage. The EMA performance at system-level is evaluated in Dymola environment, analyzing three operating modes, such as active-active, active-standby and active-shorted. Finally, some thermal considerations regarding the active-shorted configuration are outlined.

In the design processes of Switched Reluctance Machines that operate in wide constant power speed ranges, the maximum power available at maximum speed must be evaluated for every machine candidate. This is critical to ensure compliance with the power requirement. Important parameters to include in the design routine are the duration of the energizing period and the advance of the turn-on instant, i.e. advance angle. The latter is highly related to the machine geometry and is usually evaluated through time-consuming finite-element-based iterative methods. In this paper, a simple, yet novel analytical model is proposed to cater for the torquemaximising advance angle in a closed-form analytical expression, directly from the machine geometry. The goal is to provide a non-iterative design tool that speeds up the design process. Successful validations against finite element analyses and experimental results on an SR machine prototype are reported. The main outcome of this paper is shown by the improvement in computation time, without any significant loss of accuracy.

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Investigations in the modelling and control of a medium voltage hybrid inverter system that uses a low voltage /low power rated auxiliary current source inverter. IEEE Journal of Emerging and Selected Topics in Power Electronics, 4 (1). pp. 126-140. ISSN 2168-6785 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/32220/1/Investigations%20in%20the%20Modelling%20and %20Control%20of%20a%20Medium%20Voltage%20Hybrid%20Inverter%20System_final %20%282%29.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the University of Nottingham End User licence and may be reused according to the conditions of the licence. For more details see: http://eprints.nottingham.ac.uk/end_user_agreement.pdf A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk  Abstract-Hybrid converters consist of a main inverter processing the bulk of the power with poor waveform performance and a fast and versatile auxiliary inverter to correct the distortion. In this paper, the main converter is a medium voltage NPC inverter and the auxiliary inverter is a low-voltage and low-current rated current source inverter (CSI), with series capacitor being used to minimize the CSI voltage stress. The result is a high output current quality which is obtained with a very low switching stress in the main converter and a very small added installed power (<4%) in the CSI. This paper expands this concept by investigating the hybridization of a medium voltage inverter with an existing LCL filter and investigates the additional challenges related to resonances and proposes a solution for stable operation. Experimental validation of active ripple cancellation has been provided at 3kW. Index Terms-Active filters, Noise cancellation, Nonlinear filtersI. INTRODUCTION onversion of DC into AC at medium and high voltage levels has become a very important research topic now when the need to transfer very large amounts of power (GW) over long distances favour HVDC transmission systems. In the medium term it is predicted that the distribution system will remain AC which will require the use of high voltage DC/AC inverters to interface the transmission and distribution systems. Standard two-level inverters built using series connected devices were initially used in the first generation of forced commutated HVDC systems for their simplicity and the easiness to embed redundancy by adding additional devices in series; however, difficulties in achieving static and more importantly dynamic voltage sharing during switching meant that the harmonic performance of su...