Archive for June, 2015

Intelligent Stacks need Digital Power Controllers – PCIM 2015 Highlights

Thursday, June 11th, 2015
Intelligent Stacks need Digital Power Controllers

Semikron Slimline SEMIKUBE










PCIM is the show where the large power electronics industry comes together to celebrate and show off.  Three big trends at PCIM in May 2015 are off the shelf IGBT stacks, mature inductors and intelligent IGBT power stacks.  No off the shelf controllers for these stacks were to be seen at the show.


By large converter I mean above 3kW.  PCIM Europe is in Nuremberg, Germany.  Other PCIM shows are in China and South America. When I attended this years PCIM show it was clear that three large trends are occurring in the power electronics market.  With the off the shelf converters and inductors now available it is clear that intelligent stacks need digital power controllers.

Three trends at PCIM

The PCIM show always has significant numbers of new products launched.  This year three trends were very clear.

IGBT Stacks

Firstly there are more and more ready made stacks available.  These are IGBT modules mounted on heatsinks with integrated gate drivers and DC bus capacitors.  In some products there are fans included as does Semkron’s SEMIKUBE SlimLine, while other vendors, like AgileSwitch and Infineon, have left the cooling to the user.  An interesting turn up is the Danfoss semiconductors stack that reportedly is a drop in replacement for the SkiiP product from Semikron.  This might be that this is the result of Danfoss buying Vacon.

Intelligent Stacks need Digital Controllers

Infineon’s MiPaqPro is a new Intellingent IGBT Stack










Semikron also showed a watercolled megawatt converter in a cabinet for large wind and solar applications.  They also had a really effective new parallel power converter system.  Both are very impressive and useful for large grid connected converters.

When the Semikron, Danfoss, AgileSwitch (AgileStack) and Infineon (MiPaqPro) products are stacked up (sorry for the pun) together is it clear that off the shelf power converter stacks and systems are here to stay as all these vendors are truly committed.  It also is clear that buying stacks off the shelf is going to be a valid solution instead of developing your own.  I am not sure what that means for those who are still doing converter development.  Time will tell.  Probably purchasing volume and management commitment to building converters will be the deciding factors internally in the product companies.  One colleague at the show thought that “If you stop developing your own converters you may as well just call it quits”.

Inductors are mature

I recall seven years ago struggling to find an inductor manufacturer that could design reasonable quality and that had a balance sheet that would pass any kind of financial stress test.  And now there are at least three inductor companies who do a good job technically and who do not present too large a financial risk.  Hoganas from Sweden have perhaps the strongest balance sheet of all the vendors at the show.  And their inductors are good.

Intelligent Stacks

Monitoring of the IGBT performance while the stack is running looks like a great feature.  Amantys had gate drives that did this.  That company went by the wayside when they folded at the beginning of the year. .  Two other vendors Infineon and AgileStack have created intelligent stacks and AgileSwitch are doing replacement gate drives for the Amantys part.  Contact Rob at AgileSwitch for their intelligent gate drives.

AgileSwitch - An Intelligent Stacks which needs a Digital Power Controllers

AgileSwitch Power Stack – Intelligence and robust implementation.










These intelligent stacks have microprocessors or FPGAs that can monitor the stack performance and provide data for controller to do condition monitoring and system performance analysis.  The Infineon MiPaqPro has a great water cooled heatsink plate that may become the new high performance low cost standard for heatsinks.  The monitoring for the IGBTs is in the stack and there was a fiber optic interface also.  Fiber optics are a good idea for monitoring as they provide great safety in the event of a fault or failure.  Fiber optic systems are also very robust in highly noisy EM environments.

The AgileSwitch stack is a great little converter.  It has integrated gate drives and has the ability to self monitor and provide digital output for status and current via a digital link.  This link is electrical.  AgileStack do not yet have a fiber optic link for their stack.  Their system is however very flexible and all the external signals are differential which gives higher noise immunity.

The AgileStack system can also come with inbuilt low inductance DC bus capacitors.  It looks to be a great solution.

All you need is a controller – Intelligent Stacks need Digital Power Controllers

The stacks at PCIM all need inductors and capacitors for the grid coupling filters.  There were lots of capacitor and inductor vendors at the show.  The stacks also need controllers to make them switch.  How this controller is implemented is not the concern of the stack manufacturer as all they need is the gate dive signals.  Ensuring that the gate drive signals make the converter do as required is the missing piece in the the three trends at PCIM.

It seems that power electronics companies can now purchase off the shelf power stacks.  By adding inductors and capacitors from other vendors the converter is almost complete.

Then the controller is required.  The stack manufacturers and the inductor manufacturers have solved two thirds of the power converter.  The controller is the missing part of the puzzle.  Get your digital power controller from ELMG Digital Power.

Get the ELMG Digital Power Controller Technology by clicking here