In the context of hybrid electric and full electric powertrains for future less-pollutant aircrafts, this paper focuses on the multidisciplinary design optimization (MDO) of the actuation system, including a surface-mounted PMSM in order to maximize the power density of the device: this study is a preliminary approach before integrating the whole powertrain. After an introduction of the MDO context, the analytical model of the electric motor is detailed. It integrates multi-physical aspects (electric, magnetic, mechanical, thermal, partial discharges and insulation, control and flight mission) and takes several heterogeneous design constraints into account. The optimization method involves a genetic algorithm allowing the reduction of the actuation weight with regard to a wide set of constraints. The results show the crucial sensitivity of the electro-thermal coupling, especially the importance of transient modes during flight sequences due to thermal capacitance effects. Another major point is related to the performance of the thermal cooling, which requires the introduction of an “internal cooling” in the stator slots in addition to the “base cooling” for stator and rotor. Gathering these analyses, the MDO leads to high power density actuators beyond 15 kW/kg with high-voltage–high-speed solutions, satisfying all design constraints (insulation, thermal, magnet demagnetization) over the flight mission.
This paper focuses on the analysis, the modeling and the control of a linear-switched reluctance motor. The application under consideration is medical, and the actuator is to be used as a left ventricular assist device. The actuator has a cylindrical or tubular shape, with a mechanical unidirectional valve placed inside the mover, which provides a pulsatile flow of blood. The analytical expression of the effort based on the linear behavior of the actuator is given. The identification of the characteristics of the prototype actuator and the principle of position control is performed. A modeling of the actuator is proposed, taking into account the variation of inductance with respect to the position. The closed-loop position control of the actuator is performed by simulation. A controller with integral action and anticipatory action is implemented in order to compensate the effects of disturbing efforts and tracking deviations. Moreover, a magic switch is performed in the controller to avoid overshoots. The results show that the closed-loop response of the actuator is satisfactory
In order to choose electric machines for transport applications, i.e. automotive, aerospace, railway and naval, a tool that can make quick tradeolfs of high specific torque electric motors has been developed. The level of the different technologies involved in an electrical machine can be quantifi ed using the loadability concepts developed by experienced designers. After recalling these concepts, magnetic, electric and thermaJ balances are used to calculate the main sizes of an electric motor according to some targets. Specific power or specifi c torque can then be quickly assessed. The proposed approach is validated by applying the tool to some known high torque industrial motors.
A linear tubular switched reluctance motor is presented. This actuator is devoted to be used as a left ventricular assist device (LVAD). In order to avoid thrombosis, this actuator includes pump and valve functions. By using a St. Jude Medical mechanical valve inside the tubular mover, a pulsatile flow is created in the descending aorta. A linear model of a basic pattern of the actuator based on a reluctance network is developed. Then, a two dimensions finite element method analysis is performed in order to check the analytically calculated performances. Relying on these both models, specific requirements for the design of this kind of motor are discussed.
A simulation model of an ironless Axial-Flux Permanent-Magnet (AFPM) machines is presented. Indeed as accurate analytical methods do not yet exist for ironless AFPM, 3D Finite Element Analysis (FEA) is required at each time of an operating point. The purpose of this article is to show that for any operating point of the motor, the torque can be calculated from the distribution of the axial magnetic flux density obtained from only one 3D FEA. The proposed simulation model is validated by using a prototype of an AFPM ironless whose nonactive parts are additively manufactured. This first step through the 3D printing technology is simplified by the use of cylindrical magnets and plastic mechanical supports.
The Lorentz force law is proposed as an alternative to the Maxwell stress tensor to calculate the torque of an ironless AFPM motor. This alternative allows calculating only the magnetic field produced by magnets. A model of this field based on the field produced by one magnet, the superposition principle and geometric transformations is proposed. The method is validated by full 3D FEA simulations and experimental measurements performed on a test bench.
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