The frequency control system of the screw unit with a solid rotor

Abstract

This paper examines the features of construction and hardware implementation of the work control system of the screw-type multifunctional energy converter (MFEC). MFEC is an atypical electric machine, which is an induction motor with an external hollow solid rotor. Due to the presence of a ferromagnetic rotor, when power is supplied to the stator winding, the rotor is heated due to eddy currents and simultaneously rotates. In this way, it is possible to combine several functions at the level of the principle of operation in one device. However, such an electric machine as MFEC requires a special approach to management and ensuring the stability of operation. Thus, the task is complicated by the mechanical connection of several MFEC rotors into a single structure. The task of the control system includes not only ensuring a low speed of rotation of the general rotor of the MFEC, but also ensuring the value of the torque at the nominal level without losing the intensity of heating the rotor. Prerequisites for the practical solution of the given problems are preliminary theoretical studies of the authors and simulation modeling. The practical implementation of theoretical developments is considered in detail in this work. In particular, one MFEC module is supposed to be powered by a frequency converter in the mode of maintaining the specified rotation speed. The power supply of the second MFEC module is provided by an unregulated three-phase power source, which creates a torque opposite to that of the first MFEC module. The characteristics of this mode of operation, its purpose and influence on the initial characteristics of the screw unit are explained in detail in the relevant sections of this paper.