Reliability is a fundamental requirement in aircraft safety-critical equipments. Its pursuing involves the adoption of protective design concepts such as fault-tolerant or redundant approaches, aiming to minimize mission failure probabilities. Multi-phase motor drives are gaining a growing interest to this extent, because they permit a boost in torque and power density, allowing the design of very compact high efficiency drives with intrinsic fault-tolerant capabilities. This paper presents a five-phase permanent magnet brushless motor drive developed for an aircraft flap actuator application. The motor is designed to satisfy the load specifications with one or two phases open or with a phase short circuited, while a failure in the rotor position sensors is remedied through a sensorless strategy. Design studies aiming to predict the faulty mode performance in case of different remedial strategies are presented. Experimental tests on the drive prototype are included, which confirm its capability to satisfy the planned degraded modes of operation.

Nowadays energy storage is strongly needed to allow grid safety and stability due to the wide penetration of renewable plants. Mainly economic and technological issues impede a relevant integration of conventional storage devices in the energy system. In this scenario, the hybridization of different storage technologies can be a techno-economic solution useful to overcome these issues and promote their diffusion. Hybridization allows multi-operation modes of the Energy Storage System (ESS), merging the positive features of base-technologies and extending their application ranges. This paper provides a dynamic analysis of a hybrid energy storage system (H-ESS) consisting of a flywheel and a battery pack coupled to a photovoltaic generation plant and a residential load up to 20 kW. A dynamic model of the overall micro-grid (MG) was developed implementing the H-ESS preliminary sizing and a suitable management algorithm. The instantaneous behavior of each component was evaluated. A brief summary of the MG performance at different weather and load conditions was provided together with a characterization of the impact of power fluctuations on the battery current and on the power exchange with the grid.

The demand for high reliability motor drives increases every day, especially in aircraft where traditional, nonelectric systems (hydraulic, pneumatic) are being replaced by electrical actuators following the More Electric Aircraft (MEA) trend. Electric drives for aerospace need a fault-tolerant design approach to achieve reliability objectives with optimized architectures reducing redundancies, over-sizing and costs. The presented work shows how fault tolerant design methodologies can be applied in two motors for typical aircraft application such as a Cart Lift System (CLS) and a Flap Actuator (FA). Analyses and tests are reported to demonstrate how the designed multi-phase motors are able to run at rated torque also with one or two phases faulted.

Development trends in aeronautics involve a better employment of electric motors also in safety critical hazardous applications until now covered by mechanical systems. The electromechanical actuators (EMAs) are gaining a growing interest owing to their force and power density capability and the high dynamical performance by electronic control. Hence, very compact and high-efficiency drives can be designed, with satisfactory characteristics from the reliability point of view. This paper refers to a rotor damper system for helicopter application, using specifically designed permanent-magnet motors as EMAs. Design criteria and details will be presented focused on the integration of the electrical machine inside such specific application. Reports of analyses and tests carried out on the motor prototypes are included to confirm the capabilities and the performances of the proposed solution.

The recent markets crisis imposes the adoption of advanced technical solutions to match the requirements of energy efficiency, promoting a gradual transformation in the field of mechanical actuators for hazardous applications and moving the attention to more electric and efficient systems. Nevertheless the adoption of the electromechanical actuators are still limited in those fields that require a high degree of reliability, especially in the cases that involve huge hazard for peoples and environment or failures in systems characterized by heavy out-of-service or restarting costs. Multi-phase motor drives are gaining a growing interest because they permit a boost in torque and power density, allowing the design of very compact high efficiency drives with good improvement by the reliability point of view. The present paper recalls the basic concepts of multi-phase fault-tolerant design and illustrates their adoption in the development of two different systems for aircraft application such as a flap actuator and a cart lift system. Design details will be presented. Reports of analyses and tests carried out on the drives prototypes will be included to confirm the fault-tolerance capabilities with respect to the lack of one or two phases.

This paper describes requirements and design principles of an electric motor for helicopter tail rotor application. The application demands high specific power and specific torque with little possibility to adopt a liquid cooling solution. The tail rotor shall also comply with severe safety requirements that directly affect the motor design. Volume and weight constraints make the design of the electrical machine challenging. Different solutions have been investigated to propose an effective alternative to the Fenestron ^® mechanical actuation system. In the paper two different permanent magnet motors with external rotor are illustrated and compared.