A Real-Time Real-Power DSCC-Based Emulator Capable of Reproducing Both Bending and Torsional Vibrations of a Motor and Load

This paper provides an experimental discussion on a real-time real-power emulator for a medium-voltage, high-power, high-speed motor drive. This emulator is characterized by integrating mechanical dynamics of both motor and load into it. The power-electronic circuit of the emulator consists of a three-phase modular multilevel double-star chopper-cell (DSCC) rectifier, three inductors, and a single two-winding common-mode inductor. This paper designs, builds, and tests a 400-Vdc 10-kW downscaled test bench in which a three-phase DSCC inverter under test is connected in front-to-front (FTF) with the emulator. The DSCC inverter is the same in circuit configuration as the DSCC rectifier. Experimental waveforms obtained from the downscaled test bench lead to the following conclusion: The emulator can reproduce both electrical and mechanical dynamics of a three-phase 200-V, 10-kW, four-pole, 9 000-r/min induction motor coupled with a centrifugal compressor.