Mechanical Improvement of Electrical Interharmonics Damping

Abstract

During operation of compressor trains by a variable speed drive system (VSDS) integer and non-integer harmonics are generated in the inverter. Via the electrical system of inverter and motor a torsional excitation is transferred across the air gap torque into the main mass of the motor. This excitation may cause torsional resonances. However, the main focus of this case study will be on the new electrical damping method to attenuate the torsional excitations induced by an LCI Variable Frequency Drive (VFD). The effectiveness of the proposed electrical damping method will be demonstrated in 2 case studies: Case Study 1: Blocked speed ranges eliminated Case Study 2: High gear vibrations avoided