Analysis and Experimental Verification of a Variable Speed Turbo Air Centrifugal Compressor System for Energy Saving

Abstract

Conventional constant speed turbo air centrifugal compressor systems (TACCSs) consist of an electric motor driven at the constant speed and an inlet guide vane (IGV) for pressure control. TACCSs with an inverter for a variable speed drive (VSD) of the electric motor are more efficient than the conventional constant speed TACCS because they have a wide operating range and can minimize the power consumption. Therefore, this paper proposes a quadratic V/f control and VSD to reduce electrical and mechanical energy losses. To verify the energy saving effect of the TACCS with the proposed controls, this paper analyzes the performances of an electric motor drive system (EMDS) using the proposed quadratic V/f control considering load conditions of the turbo air centrifugal compressor (TACC) to reduce electrical energy losses. Furthermore, the performances of the conventional constant speed drive (CSD) using the IGV control and the proposed VSD were compared and analyzed in the test bench that represented an actual factory environment. As a result, the proposed quadratic V/f control and VSD experimentally verified energy savings of 4.44% and 23.37% compared to conventional controls. In addition, the economic feasibility of the proposed VSD was verified in the TACCS by analyzing the recovery period of the initial investment due to the addition of the inverter.