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