Comparison of air core and iron core choke There are various reasons for installation a choke¹ within a variable frequency drive system – see [1] for an overview. The next question is about the design of such choke. This post Read more…
VFD compliance with voltage and current harmonic limits National and international standards provide guidelines and limits for individual harmonics and total harmonic distortion. But how to assess the situation when the VFD meets the limits for voltage harmonics while current Read more…
When to go for an active front end drive? Abstract Grid side of the VFD can be either Diode Front End (DFE) or Active Front End (AFE). The later one is more expensive but brings several additional options such as Read more…
Ratio between grid short-circuit power and VFD installed power Successful integration of a variable frequency drive (VFD) into the electric grid shall follow certain rules. Moreover, the VFD shall comply with standards related to power quality and harmonics. In case Read more…
VFD layout options Introduction Default VFD layout is normally a straight lineup. The individual cabinets are installed side by side on a common base frame. However, specific site restrictions may require adaptations of the mechanical layout in order to fit Read more…
What is the time constant of a dc link? Introduction Most commercially used variable frequency drives (VFD) belong to the category of indirect frequency converters. The AC power of a fix frequency (usually 50 or 60 Hz) is first rectified Read more…
Fault current considerations for integrated transformer of CHB drive Introduction Cascaded H-bridge (CHB) variable frequency drives (VFD) have the input transformer as an integral part of the VFD. This transformer has high number of secondary windings (equal to the number Read more…
We celebrate 5 years – You benefit MB Drive Services was established in July 2019. Thus, we are celebrating 5 years of existence. These were adventurous years. What started as sort of experiment developed into a popular platform. At the Read more…
How does skin effect impact the drive system? This short article provides a brief description of the skin effect and its impact on a drive system. As it will be explained, the skin effect influences the system in both negative Read more…
DTC in a nutshell Direct torque control, DTC, is a motor control method famous for its superior dynamic properties. Less known is the fact that DTC optimally utilizes the switching frequency to achieve the target: regulation of torque and flux Read more…