A Comparative Assessment of the Energy Consumption of Induction and Synchronous Reluctance Drives of a Pump Unit Taking into Account Losses in a Frequency Converter

Abstract

This paper presents a comparative analysis of the energy consumption of induction and synchronous reluctance electric drives of low rated power used in the water-supply system of a large building. An induction motor (IM) and synchronous reluctance motor (SynRM) were manufactured using the same motor housing. Test results of the variable speed drive employing an IM and SynRM are presented in a wide range of operating modes. The calculation of motor efficiency at points where there is no experimental data is carried out using polynomial interpolation. The influence of the motor type on the losses in a two-stage frequency converter is investigated using analytical and numerical methods. It is shown that despite a number of theoretical assumptions the analytical method used has a relatively small error. In addition, an alternative approach is proposed for determining values of the current and the power factor of the motor that is needed for calculating the losses in the frequency converter. By considering an example of a 1.1-kW drive, it is shown that using an SynRM can significantly reduce the energy consumption of the pump unit as compared to an IM.