Fast Responding Fundamental and RMS Discrete Fourier Analysis by LabView HIL Simulation

The paper deals with on-line discrete Fourier analysis for measurement of the true real power of fundamental harmonic of passive RL (or RLC) load under non-harmonic supply. Voltage generated by a voltage-sourced inverter (VSI) is an impulse one, but the shape of the pulses is different from idealized ones used for calculation voltage root-mean-square value and the average value of the active power of fundamental harmonic. It is due to VSI real electronic devices (dead-time, turn on and turn off times, voltage drops, delay of switching on-off circuits, over-voltages, snubber properties). Therefore, we want to know real values of fundamental harmonic output voltage or output power, determination from measured values is needed. Calculation of real fundamental harmonic is provided using hardware-in-loop simulation (NIL) by LabView techniques. To be fundamental U
_lrms
constant the width of voltage pulses should be changed. For single-phase two-pulsed VSI converter the RMS value of output voltage can be calculated (and provided by feedback loop) as a constant value. Worked-out dynamic transient waveforms of voltages and currents of VSI converter are given in the paper.