717 publications from this institution
This paper describes a hybrid active filter intended for mitigating the line-side harmonic currents of a three-phase 12-pulse diode rectifier used as the front end of a medium-voltage high-power motor drive. This hybrid filter is characterized by series connection of a simple LC filter and a small-rated active filter. This circuit configuration brings low cost, small size, and light weight to the hybrid filter. A three-phase experimental system rated at 400 V and 15 kW is designed, constructed, and tested, which is a downscaled model of the medium-voltage motor drive system. In this experiment, the LC filter is tuned to the 11th-harmonic frequency, and the active filter is based on a three-level neutral-point-clamped pulsewidth modulation converter (NPC PWM) with a dc capacitor voltage as low as 28 V. This hybrid filter is connected on either first or fourth winding of a line-frequency transformer with a first Δ-winding voltage of 400 V in the primary, and a second Δ-winding voltage of 220 V, a third Y-winding voltage of 220 V, and a fourth Δ-winding voltage of 400 V in the secondary. Experimental results show that the hybrid filter performs satisfactory filtering in a range from no-load to full-load conditions.
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.
