Comparison of ElectroMagnetic Emissions & Harmonic Analysis of 20 HP Motor Controlled by 3L NPC Inverter

In this paper, thirteen experiments are performed to measure the conducted electromagnetic emissions namely common mode and differential mode noises along with time-varying spectra. These emissions are generated by switching IGBTs of three phase three level inverter whose switching pulse width modulated frequency is varied at twelve frequencies from 8 kHz to 120 kHZ. Two equipments under test (EUT) are simultaneously measured for emissions using CE102 of MIL-STD-461G standard with line impedance stabilization network (LISN) and spectrum analyzer. The EUTs are inverter and asynchronous machine, where the inverter is nonlinear space vector modulated three-phase three-level diode neutral point clamped inverter, and the asynchronous machine is non-linear rotating machine, 20HP (15 kW), 400V, 50Hz, Y-winding, squirrel-cage induction motor. The harmonic distortion measurements namely total harmonic distortion(THD), THD in percentage, signal-to-noise ratio(SNR), signal-to-noise and distortion ratio(SINAD) and spurious-free dynamic range(SFDR) are calculated, tabulated and plotted at 15 harmonics resulting from the emissions. The time varying spectra is captured using Welch’s method and Short-time Fourier transform and is also submitted as dataset for each phase of the asynchronous machine and the inverter.