Electric Stress in Power Electronics Applications

Abstract

Voltage quality is a major issue for several appliances in today's electric power systems. Distorted voltage waveforms caused by power electronics devices can dramatically reduce the useful life of dielectrics, e.g., filter capacitor banks or power factor correction capacitor banks. This paper aims at investigating how different power electronics control schemes can affect the dielectric ageing and, in doing so, it aims at providing a feasible and sustainable electric stress monitoring framework. The two considered control schemes adopted are the classical SPWM and SPWM with sequential command.

A Practical Solution for Torsional Vibrations Evasion in Variable Speed Drives

“…Thus, it will have the priority in choosing the values of m f ; • T HD T , which is directly proportional to I h , can also be the defining criterion. As discussed in [9], the higher the current harmonics, the higher the dc bus voltage distortions are. As a result the expected life-time of the capacitor dielectric decreases.…”

Performance Comparison between Sequential Command SPWM and MLI-NPC in Multi-MW drives for WECSs

“…An approximated analytical expression for the electromagnetic torque and the dc bus voltage was developed in [3,9], which shows the main harmonics in the torque and the dc voltage along with the dependencies of each harmonic on the shift angle of the carrier signal ψ c µ where µ is the module number (here, µ = 1, 2, 3, 4). Such analytical approximated expression proved to be accurate for estimating both harmonic order and amplitudes for both the torque and dc voltage when compared with results of a Simulink model [3].…”

“…The choice ψ c µ = {0 0 , 90 0 , 180 0 , and 270 0 } cancels the harmonics of the order (h = m f ± 3, 2m f , 3m f ± 3 where m f is the frequency modulation ratio) and the least order harmonics left in the torque and voltage expressions is 4m f . For this reason, such choice of the carriers signals shift achieves a much lower harmonic content than the normal SPWM where the least order harmonic is m f − 3 [9].…”

Forecasting the Reliability of Components Subjected to Harmonics Generated by Power Electronic Converters

“…However, results of aging tests of insulation under distorted voltage are rare in the literature, due to the experimental difficulties in arranging test set-ups for aging of insulation in the presence of distorted voltage. For this reason, attention in the literature of reliability models under harmonic distortion is mainly concentrated on the thermal effect of current harmonics [19][20][21][22][23] although applications relevant to the electrical aging can also be found e.g., in [24][25][26][27][28][29][30].…”