Abbreviations and Definitions This post summarizes and explains some of the most commonly used abbreviations and definitons from the field of variable frequency drives (VFD), drive systems and associated areas, such as power electronics, harmonics and power quality, monitoring, testing… AFE Active Front End Grid side converter (in drives often Read more…
Power converters for pumped storage hydro power plants A while ago we started a series on hydro power generation. Today we invite you to learn about how power converters for hydro applications make the pumped hydro storage more efficient and more attractive while supporting the stability of the power grid Read more…
Comparison of LCI versus VSI Technology: Myths and Truth We have already discussed the comparison of LCI versus VSI technology quite in detail [1]. However, there is an article [2] in the Internet making a similar comparison of above VFD platforms. Unfortunately, in that article, there are certain statements that 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…
#LCI versus VSI:Part 4: Comparison (continue) Our series LCI versus VSI belongs to some of the most popular in this blog. We talk about the main medium voltage high power VFD technologies, Load-commutated Inverter (LCI) and Voltage Source Inverter (VSI), and compare them in various aspects. This post is a Read more…
LCI versus VSI:Part 3: Comparison Figure 1: LCI vs VSI In today’s column we continue our popular series ‘LCI vs VSI’ and look a bit closer at the differences between a load-commutated inverter (LCI) and voltage source inverter (VSI). 1. History and references The history of LCI started in mid Read more…
Input power factor and reactive power consumption The focus in all energy efficiency initiatives is to minimize the losses, improve the system efficiency and reduce overall power consumption. With “power” people usually refer to active power and this is basically correct. Main purpose of VFD is to reduce active power. Read more…
What efficiency can you expect from your drive system? In general, the efficiency of a drive system utilizing VFD is high. The differences come from the VFD topology, dimensioning and technical solution. As discussed in our previous post, the user shall always compare total efficiency of a complete drive system. Read more…
#LCI versus VSIPart 2: Truth and lies about LCI and VSI We continue our series about the high power drive champions LCI and VSI. The introduction [1] last time was a bit longer, but the goal was to provide a good and unbiased overview. There is quite some material regarding Read more…