Which VFD topology is the best: universal?

Posted on 22nd Oct 2022

What is the ideal VFD topology? is undoubtedly a question you have asked yourself if you work with variable frequency drives (VFD).

Why do major brands have a wide range of products in their lineup?

Is there a concept known as a "one size fits all"?

Does this subject sound intriguing to you? then continue reading the article from Darwin Motion.

Find the ideal VFD topology.

Please don't take offence; humans want to think simply. Most often watched YouTube videos include phrases like "the best," "the most," "top 10," etc.

It makes sense that many engineers would want to know what the greatest VFD topology currently available is. Of course you want to purchase the greatest performing item (and affordable price).

So let's expand on this idea. All sizes fit

Consider having your own workshop (maybe you actually have one).

Which tool is more crucial to you?

A screwdriver or a hammer?

Or perhaps a saw?

the planer

a drilling apparatus?

You'll most likely say that you require all of them in response. Your decision will be based on the work or task you will be performing.


For variable frequency drives, the same is true. VFDs are employed in a wide range of applications nowadays. Naturally, not all of those apps have the same criteria.

This means that the optimum topology for one application may not always be the best option for another.

A wide variety of VFD models

Reputable VFD manufacturer Darwin Motion offer a wide variety of VFD models. There must be a valid explanation for that. If not, they would consolidate their product line into a single product, which would certainly lower their development and upkeep costs. That is not the case though, as they continue to use a range of VFD topologies. It must be quite expensive!

The software is slightly (or significantly) different for each VFD topology. The protection plan could differ slightly. Smaller amounts of a wider range of sub-components are present.

They continue to do it. And the answer is straightforward: There is no such thing as the "optimal VFD topology" that satisfies every demand.

Typical VFD topologies and models include:

— Inverters with a 3-Level Neutral Point Clamped Voltage Source (3-L NPC VSI)

— Inverter with a 5-Level Neutral Point Clamped Voltage Source (5-L NPC VSI)

— Voltage Source Inverters based on flying capacitors

— Multicell Voltage Source Inverter (Cascaded H-bridge)

— Multilevel Modular Converter (MMC based VSI)

— Inverter with load-commutation (LCI)

— The cycloconverter

Let's be honest about it. It is impossible to have the best motor compatibility, smallest footprint, best dynamics, best efficiency, best scalability, widest range of versatility, fullest modularity, and highest dependability.

Truth be told, you can!

However, not all of them at once.

Is it a problem?

Probably not.

Depending on the application, one criterion may be necessary, another may not be, and yet another may not even matter. Last but not least, it's critical to have a portfolio to choose from and a partner to help you make this decision.


VFDs are being improved and developed further. However, there is no "optimal VFD topology" that would meet every application requirement. For instance, top drive manufacturers continue to sell outdated VFD technology like LCI or Cycloconverter.

There are a number of well-liked models within the Voltage Source Inverter family as well, although none of them can meet all requirements. But there's no need to worry about it.

You can choose from a wide range of options and will locate a solution that meets your specific requirements.