Literature on Variable Frequency Drives, Power Electronics and related subjects The purpose of this blog is to provide useful information about Variable frequency drives (VFD) and power drive systems that you might appreciate when working in this field (specifying, selecting, purchasing, operating, servicing/retrofitting, researching or developing tasks). The blog intentionally Read more…
Network harmonics:Introduction Apart from the numerous advantages of variable frequency drives, such as precise speed or torque control, smooth motor starting or energy savings, this technology also comes with specific challenges. One of them are the network harmonics. The good news is that there is a solution. Actually, there are Read more…
VFD versus fluid coupling Today we open a topic that might polarize our readers: Comparison between variable frequency drive (VFD) and a fluid (hydrodynamic) coupling. Of course, this blog is dedicated to VFDs. Nevertheless, we intend to provide an objective benchmark as far as possible. Please note that there is Read more…
Encoders in motor drive applications What is the purpose of encoder? When is it needed? What types of encoders are being used? This post shall answer some of these questions. VFDs are used to control the motor speed or motor torque. The actual speed is either estimated (speed sensorless control), Read more…
Solutions for variable speed control: Introduction This post introduces the most common solutions for variable speed control in industrial applications. Before starting with the topic we want to refresh the meaning of some commonly used abbreviations. Variable speed drive (VSD) – A general term for anything that varies the speed 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…
#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…
LCI versus VSIPart 1: Introduction LCI (load-commutated inverter) and VSI (voltage source inverter) are the dominant technologies when it comes to high power medium voltage drives. Each technology has certain advantages as well as drawbacks. Project specific conditions and requirements shall be analyzed before deciding for LCI or VSI. Let’s Read more…