More-electric aircraft (MEA) has become a dominant trend for modern aircraft. On-board MEA, many functions, which are conventionally driven by pneumatic and hydraulic power, are replaced with electrical subsystems. Starting aircraft engines with an electrical motor instead of using pneumatic power from the auxiliary power unit (APU) is one of the major characteristics of future aircraft. This paper presents the development of a novel electric starter-generator system for aircraft applications. The paper describes the main achievements of the project within the key areas including electric machines, power electronic converters, thermal management and overall system control design. The developed prototype has been tested successfully and the test results are presented in this paper.

This paper describes a hybrid control scheme for a permanent magnet machine-based starter-generator (S/G) system. There has been increased usage of electric drive systems in the transportation sector for increased efficiency and reduced emissions. One of the advantages of utilizing suitable electric drives is the capability to operate as a starter or generator. The control design of such a system should be considered due to the operating requirements and fast load changes. Different control approaches should therefore be considered in order to achieve these goals, which are a current trend in the transportation sector. Model predictive control (MPC) is considered due to its very fast dynamic performance. In particular, modulated MPC (M ² PC) was recently introduced and showed significantly better performance than the standard MPC. The control scheme used in this paper utilizes M ² PC for the current inner loop and PI controllers for the outer loop. The use of M ² PC allows very fast transient-current response for the S/G system. The proposed overall control benefits from reduced current ripple when compared with a full cascaded PI control scheme. Simulation analyzes and experimental results show the capability and performance of the designed controller across both starter and generator modes.

The dynamic phasor (DP) concept has been widely used in modeling electrical power systems. So far, the DP concept has been restricted to modeling systems with one single electrical source at a fixed fundamental frequency, either one generator or an ideal three-phase AC source. This paper aims to extend the DP modeling methodology to a wider application area. Two major achievements have been introduced: 1) application of DPs for multi-source, multi-frequency systems; 2) modeling of systems with time-varying frequencies. These two techniques enable the use of DPs to study nearly all types of electrical power systems (EPS). The developed theory is validated using a twin-generator system from the More Open Electrical Technologies (MOET) project. The accuracy and effectiveness of the developed models is confirmed by comparing the simulation results of detailed switching models and DP models under both balanced and unbalanced conditions.

This paper deals with the control design for an aircraft electric starter-generator system that utilizes recent advances in modern power electronics allowing the use of novel machine types together with the introduction of controlled power electronics into the main path of energy flow. The paper describes the developed system and focuses on control design including flux weakening control of high-speed permanent magnet machine and droop control of the system output dc-link current. The analytical design results and the expected system performance are confirmed by time-domain simulations.

It is known that, when tightly regulated, actively controlled power converters behave as constant power loads. These loads can significantly degrade the stability of their feeder system. The loop-cancellation technique has been established as an appropriate methodology to mitigate this issue within DC-DC converters which feed constant power loads. However, this has not yet been applied to uncontrolled rectifier based AC-DC converters. This paper therefore details a new methodology which allows the loop-cancellation technique to be applied to uncontrolled rectifier based AC-DC converters in order to mitigate instability when supplying constant power loads. This technique could be used in both new applications and easily retrofitted into existing applications. Furthermore, the key contribution of this paper is a novel adaptive stabilization technique which eliminates the destabilizing effect of constant power loads for the studied AC-DC power system. An equation, derived from the average system model, is introduced and utilized to calculate the adaptable gain required by the loop-cancelation technique. As a result, the uncontrolled rectifier based AC-DC feeder system is always stable for any level of constant power load. The effectiveness of the proposed adaptive mitigation has been verified by small-signal and large signal stability analysis, simulation, and experimental results

Under certain conditions Electro-Mechanical Actuators are able to regenerate, rather than consume electrical power. Within the More Electric Aircraft this possibility must be carefully considered in order to ensure safe and stable operation of the electrical systems. This paper assesses various strategies for the management of regenerated power in the More Electric Aircraft. A range of options are considered and the advantages/disadvantages of each are discussed. This includes considerations of safety and stability but also weight, component minimization, cost and potential utilization of the regenerated energy. Key aspects which are investigated in this paper are the effect of increased DC bus voltage on the management of regenerated energy and an assessment of the feasibility of returning energy to the engine inertia. It is shown that increased DC link voltage has distinct advantages when employed in combination with current architectures. However if a fundamental change to system architecture is utilized then this brings very significant benefits.