Extended electrical equivalent circuit for modelling compound DC motors

Purpose The purpose of this study is to create an extended equivalent circuit model for a compound DC motor, consisting completely of electrical parameters and quantities. Design/methodology/approach The dynamic model of the compound DC motor is obtained by establishing the voltage equations for the armature and excitation circuit and the mechanical equation for the mechanical part. The mechanical parameters in the dynamic model are converted into electrical parameters with an electrical circuit proposed for the mechanical part. By combining the armature and excitation circuits with the electrical circuit created for the mechanical part, the extended equivalent circuit model of the compound DC motor is obtained. Because the proposed extended equivalent model is completely an electrical circuit, simulations can be made in the circuit simulation programme. Simulations of the proposed compound DC motor circuit were carried out, and the accuracy of the proposed circuit was verified by performing experimental studies with an existing compound motor. Findings When comparing speed and current profiles in experiments and simulations, it is seen that compound DC motor can be modelled with the proposed equivalent circuit including completely electrical elements in a simulation programme for the circuits. The results show that the proposed equivalent circuit satisfies the dynamic model of the compound motor. Originality/value In DC machine models, armature and excitation circuits are given as an electrical circuit, and mechanical part of the machine is modelled by only mechanical equations. The originality of this study is converting the dynamic model of an electrical machine consisting of electrical and mechanical equations into a completely electrical circuit. With the proposed method, the dynamic model of many motors can be converted into a completely electrical circuit. In this way, motors can be simulated as an electrical circuit in simulation programmes for the circuits, and the dynamic behaviour of motors can be obtained.