Mathematical model of an electromechanical actuator using flux state variables applied to reluctance motor

Abstract

Purpose

Aims to present a new approach for formulating state‐space equations of an electromechanical actuator using magnetic flux linkages as state variables.

Design/methodology/approach

The model is based on employment of discrete databases and their interpolation. The algorithm of determination of databases defining the flux/current characteristics of an actuator is described. Graphical interpretation of variable transformation is presented. A simplified, two‐axis model of reluctance motor is used to illustrate the application of the proposed modelling technique. Comparison with the classical model of the motor is used to verify the validity of the method. Analysis is focused on determination of saturation phenomenon influence on formulation methodology and on correctness of obtained results.

Findings

A very good agreement is observed between reference dq model and the proposed model. The main problem of the presented method is the existence of undefined entries in databases. Sufficiently dense databases can be used to overcome the problem.

Research limitations/implications

The model is limited to actuators in which eddy currents and hysteresis phenomenon can be neglected. Future research will be concentrated on evaluation of different interpolation strategies of databases used in the model for realistic saturation conditions.

Practical implications

The model can be used as a library block for testing various control strategies for actuators without standard simplifying assumptions (e.g. sinusoidal winding distribution). It can be implemented in any simulational software (e.g. SIMULINK) as its block diagram is simple and no numerical differentiation is necessary in derivation of the model data.

Originality/value

Presents an extension of state‐space model of an actuator based on database discretised description of variables to two or more state variables.

Citation

Burlikowski, W. (2006), "Mathematical model of an electromechanical actuator using flux state variables applied to reluctance motor", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 25 No. 1, pp. 169-180. https://doi.org/10.1108/03321640610634425