A quasi-static modeling approach of electromechanical actuators

Abstract

This paper presents a suggested modelling approach of an electromechanical actuator, where the performance of involved semiconductor devices and tentative motors as PM, transversal, torus, and switched reluctance electrical machines are condensed into look-up tables. Current and voltages are then described in form of quasi-static rms values quantities, and the actuator mechanical outputs in momentary forces and velocities. The proposed modelling approach is considered to be one ingredient in future build-up of models of entire MEA aircrafts. Design of the electric power systems of a More Electric Aircraft (MEA) comprises dimensioning of several electromechanical actuator systems. During flight the effective mechanical outputs of the actuators vary considerably slower than the voltages and currents in the corresponding electrical machines and semiconductor devices. To facilitate modelling of the whole system and decrease simulation time it is feasible to separate the high and low frequency behaviour of these components [1]. According to a general electromagnetic transducer model For a general transducer T em = T me = BB 0 l , where B 0 B is the effective magnetic flux density and l is the effective length of the winding wire subjected to B 0 . The fundamental feeding angular frequency ω e is assumed to be considerably higher than the mechanical angular frequencies. This means that one can regard time varying rms values of voltages and currents on the electrical side and related time varying torque and angular values on the mechanical side. The torque and counter EMF constants are t = r 2 T me and e = r 1 T me , respectively, and are normally specified by the electrical machine producer. An equivalent circuit can now be drawn according to Fig. 1.