This paper provides a review of the state-of-the-art in aircraft electrical propulsion (AEP). Initially, the limitations of on-board energy storage devices are highlighted and contextualised. The definitions of useful measures for determining the suitability of motor design, namely specific power and motor torque per unit rotor volume (TRW), are discussed and relevant examples are provided. The classifications of motors used for terrestrial vehicle applications are reviewed and their limitations highlighted regarding their suitability to AEP applications. A discussion on motor configurations for aerospace applications is provided which includes: synchronous motor stator winding configurations; axial flux motor configurations and the causes of energy losses. Additionally, the topologies and performance characteristics of existing aerospace motor technologies are examined. It was concluded that electrical motors provide an ideal means for achieving aircraft propulsion and that higher motor speeds are likely to be required for future commercial aircraft motor designs.

This paper proposes a high-performance speed measurement method for variable speed electric drives using incremental encoders. It is based on the well-known constant elapse time (CET) method. However, the principle of speed estimation is changed from event driven to ready on demand. This helps to remove the jitter effect, caused by the asynchronous nature of the CET method, and make the speed estimation time constant regardless of the current speed. The proposed method can be implemented on modern motion control microcontrollers. Experimental results using a vector controlled Permanent Magnet Synchronous Motor (PMSM) are provided to confirm the performance of the proposed algorithm and the improvements with respect to conventional methods. Synchronous CET method of speed estimation allows to double the accuracy compared to the original CET method for the same behavior of the speed loop, or to increase the speed response time twice for the same accuracy.

The need to develop and deploy Beyond Visual Line of Sight (BVLOS) aerial vehicles has intensified over the last decade. As the demand for Unmanned Aircraft Systems (UAS) has increased, so too has the regulations that surrounds the industry. Strict regulations are currently in place but differ from country to country. Due to these regulations BVLOS innovators have been posed the task of exploring the means of operating flight missions with the UAV out of the sight of the pilot. Autonomous flight capability is not only fundamental to BVLOS operations for UAS but also likely to have a significant impact on the future development of passenger carrying autonomous aircraft. This review explores the technologies that have been developed to date that enable BVLOS applications. BVLOS flight operations have the potential to open a huge area of commercial opportunity however, there remain many concerns about the current capabilities of UAS to detect and avoid manned and unmanned airborne hazards that may pose a significant safety risk.

This paper proposes an adaptive maximum torque per ampere (MTPA) control algorithm for interior permanent magnet synchronous motor (IPMSM) drives. This algorithm is insensitive to motor parameters variation due to operating conditions that is important for systems, which prioritizes reliability and efficiency. The proposed algorithm is designed to improve conventional control schemes, where the output of the speed controller is the commanded quadrature current and direct current is calculated using an MTPA equation. However, in distinction from the conventional MTPA approach, the proposed algorithm does not use any motor parameters. It implements a seeking technique and continuously varies the stator current phase angle while trying to minimize the magnitude of the current. The main contribution of this paper is the development of the method to overcome the main disadvantage of seeking algorithms – the necessity of stable disturbances at the consecutive measurement intervals. This paper adopts the seeking technique for the operation with the load torque varying over mechanical revolution, which is typical for many applications such as compressors, washing machines, robots, mechanical manipulators, servodrives, etc., The feasibility of the proposed algorithm is proven with experimental results shown and described in the corresponding section.

This paper presents a review of the state-of-the-art in aircraft electrical propulsion technology. A comparison is provided of differing propulsion mechanisms such as propellers, open fans, ducted fans, multi-stage rim driven fans and distributed thrust designs and their suitability to particular flight profiles and mission applications. Electrical motor architectures are also reviewed with particular attention being given to synchronous machines, such as Brushless Direct Current (BLDC) and Switched Reluctance Motor (SRM) technologies, and the recent advances that have been made in solid-state switching and High Temperature Superconducting (HTS) material applications. Present day electrical power generation, storage and control technologies are also reviewed including hybrid and fuel cell technologies and regeneration techniques. Electrical storage capabilities with regard to specific power and energy characteristics are discussed and the extent to which existing system technology can be integrated onto a Hybrid-electric and an All Electric Aircraft (AEA) is also investigated. Finally, a conclusion is provided highlighting the current technological challenges facing the development of commercial aircraft in terms of performance, airframe configuration and legislative and operational infrastructural requirements.