Archive for the ‘Digital Power Electronics’ Category

Inverter grid synchronisation – Six AC system frequency facts

Thursday, December 9th, 2021

With inverter grid synchronisation the key problem is that the grid frequency can vary.  In fact the frequency of AC systems around the world is different and is constantly changing.

  1. Aircraft AC systems run at 400Hz three phase.  They do this to make the motors lighter with less iron due to the volt second integral being lower.
  2. Some railway locomotive AC systems are 16.7Hz single phase.  These frequencies are chosen to minimise the current needed to charge the capacitance of the overhead line and so minimises the number of substations needed.  The 16.7Hz  is chosen to so as to not be a multiple of 50Hz.  The was made by rotary frequency changers (this is truly what they were called as power engineers often lack imagination) but is now also made by static power electronic frequency changers.  With modern static frequency changers with inverter grid synchronisation 16.7Hz is achieved.
  3. In Switzerland the railway has their own separate distribution grid.
  4. There have been railway frequencies as low as 8Hz and some train locomotives even operate from very low frequency AC with a frequency of zero.  DC is the AC you have when you are not having AC.
  5. Early on GE decided that 40Hz would be good for AC distribution but it did not catch on.
  6. There are aluminium smelters in Australia where they have or had 60Hz, 50Hz, 25Hz and 16 2/3 Hz AC systems and reportedly all at the same time.

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Other useful information for synchronisation.

  • NATO ships are 60 Hz,
  • The Swiss, German, and Austrian rail network reportedly changed to 16.7 Hz from 16 2/3 Hz  in 1995.  This to prevent over heating in rotary converters.
  • Japan has both 50 Hz and 60 Hz with the 50Hz built by the British and the 60Hz by the US after the second world war.  The two systems are linked by HVDC links.
  • 60 Hz is probably a better choice than 50Hz but it is too late now for the 50Hz countries.
  • Reportedly Tesla (not the car company) chose 50Hz first and then 60Hz.
  • There is a power station on the Argentina/Brazil border where half the generators make 60Hz for Brazil and half make 50 Hz for Argentina.
  • Sometimes, in some countries, on some days, 50Hz AC systems will run at 38Hz.  This presents an interesting inverter grid synchronisation problem.

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Grid frequency varies constantly as the mismatch between generator and load power changes.  In most countries the variation is not as large as the change to 38Hz.

Grid connected power converters must track or lock to the grid the grid.  The best way to do this is with a phase locked loop or a frequency locked loop.

Inverter Grid Synchronisation

Phase locked loops to track grid frequency are an essential part of grid connected converters. Click here to ask us about using an ELMG phase locked loop for inverter grid synchronisation.

May 18 Webinar – Basics of Digital Control of Power Electronics

Friday, May 14th, 2021

Our webinar series is back! Grab your lunch or a coffee and join us for this free webinar on the basics of digital control of power electronics.

From the comfort of your own desk you can join ELMG Digital Power for a free webinar to expand your knowledge and expertise about the advantages that digital electronics provides including:

* Flexibility
* Configurability
* Re-tuning the loop for component variation such as Electrolytic capacitor freeze out at low temperatures
* Management of the non-linearity of the converter
* Self-measurement of the loop response in closed and open-loop

and learn about the three key basics of digital control of power electronics these being

1. Limited number of bits.

2. Power converter characteristics including non-linearity

3. Limited PWM timer precision

This webinar will be hosted and presented by Dr. Hamish Laird, ELMG Digital Power’s CTO and a Principal FPGA and Power Electronics Engineer. Hamish has considerable experience in the design and implementation of varied digital control systems and IP for power electronics on FPGA platforms.

The webinar on Basics of Digital Control of Power Electronics: Where to start and what is important will be held May 18, 2021, at 12 Noon PDT on Zoom.

Spaces are limited.  

See you at the webinar.

Click here to register

Xilinx Alliance Program Engineer Re-Certification 2020

Tuesday, October 20th, 2020

ELMG Digital Power Engineers and the Xilinx Alliance Program

ELMG Digital Power Engineers and the Xilinx Alliance Program form an ongoing, valuable, and extremely productive partnership.

When asked about this ELMG Digital Power CTO,  Dr. Laird said

“Maintaining ELMG Digital Power’s commitment to providing exceptional service and products is our key uniqueness. To this end we are pleased to continue in the Xilinx Alliance Program membership.  We see great things happening with Xilinx All Programmable FPGAs and Zynq SoCs, UltraScale devices and the Spartan7.

It is great to see the capability of the Xilinx tools like Vitis and the Vivado Suite continue to allow exceptionally fast, reliable and robust development flows.  We are really pleased to support engineers to maintain competance and capability with Xilinx tools and devices.”

ELMG Digital Power Engineers and the Xilinx Alliance Program

Continuing Training with Xilinx Tools and Devices at ELMG Digital Power

Dr Laird continues

“As always this training opportunity let’s me stay capable and able to create Xilinx based power electronics controllers. Learning about the new improved HLS and Vitis tools is an invaluable capability to offer ELMG Digital Power Customers.”

Contact ELMGDigitalPower now.

ELMG Digital Power and the Xilinx Alliance Program

Xilinx Alliance Member ELMG Digital Power

About the Xilinx Partner Program

The Xilinx Partner Program is a worldwide ecosystem of qualified companies who offer Acceleration solutions, IP cores, Design Services, and Board development and production. Ecosystem Partners help system designers in the rapid integration of Xilinx FPGAs, SoCs, 3DICs, intellectual property, and software-defined solutions. They offer proven products and expert design support from chip level to full turnkey product development, which accelerate time to production of complex electronic systems.

ELMG Xilinx Alliance Partner Listing

Free Webinar – Digital Control of Power Electronics using Zynq

Friday, January 31st, 2020

If you have just sat down at your desk with a coffee, then put that aside for a minute and grab your diary. Review your schedule for Tuesday 4th February and consider this stellar opportunity: on that day ELMG Digital Power will be hosting a FREE webinar on Digital Control of Power Electronics using Zynq.

That’s right, from the comfort of your own desk you can join ELMG Digital Power (Members of the Xilinx Alliance Program) for their Zynq Digital Power Webinar and expand your knowledge and expertise by discovering:

* What is important in digital power, including numeric precision and latency
* Why you would use a FPGA for digital power and why the Zynq SoC in particular
* Key issues in digital controllers in programmable logic, such as the serial-parallel trade-off, fixed or floating point,      choosing sample rates and what precision to use
* Building blocks for digital control with ELMG’s licensable IP cores
* Using the ARM cores in the Zynq to your full advantage.

This webinar will be hosted and presented by Dr. Hamish Laird, ELMG Digital Power’s CTO and a Principal FPGA and Power Electronics Engineer. Hamish has considerable experience the design and implementation of varied digital control systems and IP for power electronics on FPGA platforms.

The webinar on Digital Control of Power Electronics using Zynq, which includes a short Q&A session, will be held on Tuesday 4th Pacific Standard Time at 10am and is available globally.

Spaces are limited.  

See you at the webinar.

Click here to register

Precision Correction for Digital PWM

Friday, August 30th, 2019

Precision Correction in Digital PWM Modulators – Free Webinar

Get the best digital PWM modulator performance.

Register here

Tuesday October 1 at 12 noon PDT (3pm EDT)

Register here

Digital Modulators have precision limits that arise from the limited timer clock rate of microprocessors and digital signal processors.  Possible effects on the control of the power converter includes

  • Poor steady state tracking
  • Limit cycle oscillation from slip-strike 
  • Reduced stability margins and possible instability
Get the best digital PWM modulator performance
Get the best digital PWM modulator performance

Get the best digital PWM modulator performance

In the webinar these topics are explained

  • Timer precision
  • PWM Quantization
  • Variable Period Oscillator Quantization
  • Precision extension as a solution to digital modulator issues
  • Designing the digital modulator

The webinar will explain how to get the best performance from your digital PWM for you converter designs. Take a look at our Power Control IP Blocks

Register here

As always there will be 10 minutes of questions and answers after the webinar.

Register here

Xilinx Alliance Program Re-Certification

Thursday, July 4th, 2019

ELMG Digital Power and the Xilinx Alliance Program

ELMG Digital Power and the Xilinx Alliance Program is an ongoing, valuable and extremely valuable partnership.

When asked about this ELMG Digital Power CTO,  Dr. Laird said

“Maintaining ELMG Digital Power’s commitment to providing exceptional service and products is our key uniqueness. To this end we are pleased to continue in the Xilinx Alliance Program membership.  We see great things happening with Xilinx All Programmable FPGAs and Zynq SoCs, UltraScale devices and the Spartan7.

It is great to see the capability of the Vivado Suite continue to allow exceptionally fast, reliable and robust development flows.  We are really pleased to continue with ELMG Digital Power’s Xilinx Alliance Program commitment and are please to be part of the Xilinx community.”

ELMG Digital Power and the Xilinx Alliance Program

Certification for ELMG Digital Power CTO, Dr Hamish Laird

Dr Laird continues

“For me this training let’s me stay capable and able to create Xilinx based power electronics controllers. Xilinx products are great and the support and capability we can provide to customers is amazing.”

Contact ELMGDigitalPower now.

ELMG Digital Power and the Xilinx Alliance Program

Xilinx Alliance Member ELMG Digital Power