New Method for Current Pulsation Calculation in Induction Machines Driving Reciprocating Compressor

Andrea Fusi, Alessandro Ussi

C.S.T. Compression Service Technology

Francesco Grasso
University of Florence - DINFO
Florent Pasteur
Siemens Product Lifecycle Management Software

With a reciprocating compressor driven by induction motor, large errors in the prediction of current pulsation can occur when the steady-state characteristics are used in the analytical solution. One of the major causes consists in the model used for the induction motor that drives the compressor.

Only recently, the model of induction motor, regarded as a simple inertial mass, has been enhanced by adding the effects of the air-gap torque. This model is more accurate than the traditional one and allows to analyze and simulate the torsional natural behavior of the system more completely.

In this paper, starting from this new model, a new method for current pulsation calculation in reciprocating compressor train, based on air-gap torque effects of electric motor, is presented. The method is validated by simulation of the complete system through the use of LMS AMESim, multi-physics simulation software, that simultaneously solves the shafts rotation and electric motor voltage equation.