What factors shall be considered when designing a harmonic filter? Most modern variable frequency drives (VFD) have so high power quality that they comply with the corresponding standards without the need for additional harmonic filtering. Nevertheless, there are cases where a filter is recommended or necessary. The consequent questions are: Read more…
How does a grid harmonic filter work? Recently we got a question in our chat group: How does a grid harmonic filter work? It sounds like a very basic question. However, since many people struggle to imagine the flow of harmonics in the system (it is fairly abstract thing) it Read more…
KYDS: Know Your Drive System KYDS -Know Your Drive System – is our new program where you learn more about variable speed drive system and the most important system components (transformer, VFD, electric motor, cooling system, harmonic filter). Scope of KYDS The scope of the Know Your Drive System program Read more…
LCI versus VSI:60 MW case study Introduction In this post we share some results of a case study comparing load-commutated inverter (LCI) and voltage source inverter (VSI) for a 60 MW variable speed drive system. Due to confidentiality some quantities are only presented as relative values in percentage instead of Read more…
Harmonic filters The continuation of our “Network harmonics” series [1] presents an article about AC harmonic filters. We explain the purpose of harmonic filter. Different types of harmonic filters are shown. Several design considerations are discussed. Main items are illustrated with figures and pictures. Grid side filters are covered in Read more…
Network harmonics: Mitigation methods Today’s post focuses on harmonic mitigation methods. Let us review the most common, well proven methods of minimization of harmonic distortion on the grid side. Previous articles presented a general view on harmonics, their origin and effects [1]. The grid side harmonic spectrum of VFDs had Read more…