Harmonic generation of variable speed drive under complex-voltage unbalance conditions

Abstract

Efficiency in the industrial sector is a priority when seeking to minimize production costs and reduction in losses. Harmonic generation and associated losses need to be treated carefully with broad implementation of variable speed induction motor applications. The effect of these induced losses can add up to a significant loss. This study uses statistical tools alongside synthesized models to deduce and compare outcomes from regulated and unregulated converters in which harmonics may be triggered by switching algorithm of modern switch-mode power supplies and other inductive loads attached to supply bus system. These harmonics accumulate over time due to losses propagating through connected equipment when changes occur on the bus system. In this regard, results obtained from investigating and comparing three original equipment manufacturer variable speed drives that were exposed to voltage unbalance and complex harmonic conditions are presented in this study. A conclusion accomplished from the investigation and comparison suggests that generation of 6-pulse uncontrolled rectifier losses is negligible. Experimental validation confirms that unregulated 6-pulse converter produces on average more harmonics compared to the regulated converter of standard as recommended in guideline to permissible harmonic tolerance.

Perspective Chapter: Mitigation of Power System Harmonics with the Incorporation of Active Filter for a Radial Distribution System

“…Harmonics, which refer to undesirable voltage or current distortions occurring at frequencies that are integer multiples of the fundamental frequency, can have a notable impact on power quality. The following are several commonly employed power quality indices utilized to evaluate the influence of harmonics [8].…”

Simulation design and analysis 9-level H-bridge single phase stepdown cyclo inverter

“…The first type of topology has an identical source voltage level while the non-symmetrical type has a voltage input with different amplitude, number of switches, and switching sequences so that the topological modularity remains incomplete [15], [16]. On the other hand, harmonic disturbances can occur in the power system when the first AC system is created [17]. The trigger angle of the inverter switch gate requires precise considerations and calculations so that a small THD index can be obtained.…”