Opelex Project

#11 Interview With Atul Abhyankar

2023-07-22T00:00:00+05:30

Mr. Atul Abhyankar, Practice Head (Power Electronics) at L & T Technology Services Mumbai, talks about design, development and testing of high performance power converters for various industrial applications.

Show Notes

Guest Profile:

Atul Abhyankar, Practice Head, L&T Technology Services, Mumbai

About LTTS
- Power Electronics is a common bond
- Industrial, Automotive Fields, Aerospace
- Telecom Power Supplies, Utilities
- Customers: Industry segments - Drives segments, tier-1 from Automotive, OEMs, Power and Utility Segments
- Emanated from the Electrical Business of L&T
Academics
- Dr. V. Nagaraja, Project on Digital Simulation of Induction Machine and compared with simulation
- Tata Power
- Masters : Dr. Syed Ali Mirbaud (student of Prof. Dewan): Static Power Converter
Black and Decker (Dr. Tomy Sebastian, Mr. Pradeep Bhagwat)
- Corded and Cordless battery charger
- 50KHz inverter
- Drives for Bandsaw application
Aplab
- L.S. Sanabharti
- Resonant switching, Soft switching Active PFC, No SiC diodes!
- Naturally air-cooled rectifier (95% efficiency)
- Reliability: Fans and Electrolytic caps; fan depositing dust on the electronics reduces reliability
- Planar core transformers
HF link Inverters; Asymmetric Half-bridge Fly-forward
Instant to Instant analysis
- “Freeze” the circuit - comes from drawing waveforms
Power electronics is still quite a complex field - need to know multiple domains: magnetics, electromechanical, packaing, electronmagnetics, etc
New graduates:
- Start with a testing project
- First phobia is high voltage - 230v
- Debug skills
Memorable burns:
- IR2110
Mentors:
- Dr Ali Mirbod
- Mr. Pradeep Bhagwat
- Mr.L.S. Sannabhadti
- Dr. Tomy Sebastian
- Mr. P.S. Deodhar
- Mr. Paul Lee

#10 Interview With Girish Kamath

2022-09-15T00:00:00+05:30

An interview about multi-domain engineering design with Dr. Girish Kamath, Senior Design Engineer at Hypertherm, Inc, New Hampshire, USA.

Show Notes

Guest Profile

#9 Interview With Kartik Iyer

2022-08-15T00:00:00+05:30

An interview with Dr. Kartik Iyer, Staff Electronic Design Engineer, Power Electronics at Tesla.

Show Notes

Kartik Iyer (LinkedIn)

Bio

Kartik V. Iyer received the B.Tech. degree from the National Institute of Technology, Surat, India, in 2011, and the M.S. and Ph.D. degrees from the University of Minnesota, Minneapolis, MN, USA, in 2013 and 2017, respectively, all in electrical engineering. He is currently with Tesla, Palo Alto, CA, USA as a Staff Electronics Design Engineer. His research interests include high-frequency magnetics design, multi-level converters, and high-frequency ac-link conversion for renewable energy integration. He has served as a session chair in multiple IEEE conferences and as reviewed papers in premium IEEE journals in the field of Power Electronics.

Education:

Doctor of Philosophy in Electrical Engineering at University of Minnesota, Twin Cities. (2017)
Thesis: Investigation of a High-Frequency Link Single-Stage Asymmetrical Multilevel Converter for Grid Integration of Renewable Energy Systems
Master’s in electrical engineering at University of Minnesota, Twin Cities. (2013)
Thesis: Transformer winding losses with round conductors and foil windings for duty-cycle regulated square waveform followed by winding design and comparison for sinusoidal excitation
Bachelor’s in electrical engineering from NIT, Surat (2011)

Professional Experience

Staff Electronic Design Engineer, Power Electronics at Tesla (2020- Present)
Senior Electronic Design Engineer, Power Electronics at Tesla (2017-2020)
Intern, Power Electronics at Tesla (2016)
Intern, Power Electronics at Cummins Power Generation (2015)

#8 Interview With Jonathan Maisonneuve

2021-09-26T00:00:00+05:30

An interview with Prof. Jonathan Maisonneuve of Oakland University, who works on Membrane Processes, Energy and Water Systems, and Energy Efficient Buildings.

Show Notes

Prof. Jonathan Maisonneuve (Homepage)

Coming soon

#7 Interview With Manoj R

2021-05-15T00:00:00+05:30

Discussions on Power Electronics (and systems design) for space and aeronautical applications with Manoj R of the Indian Space Research Organisation (ISRO).

Show Notes

Manoj R.

Engineer at the power conditioning lab, Inertial Systems Unit (ISU), Indian Space Research Organisation (ISRO)
M.Tech in Electronics Design at Indian Institute of Science
Previous work places: Vikram Sarabhai Space Centre (Trivandrum), ISRO Satellite Centre (Bangalore)
DC/DC converters and their miniaturization
Designing for low SWAP-C (Size, Weight, and Power, Cost)
Powering sensors and acquisition systems with low noise
Power range: 2W to few kW
B.Tech project: Power harmonic distortion measurement using MATLAB: data acquisition on a laptop using the audio-in connector
Importance of learning on the job
Major challenges in space: Environment
- Being within specification in a wide ambient temperature range: -40C to 120C
- Exposure to thermal cycling
- Stringent EMI/EMC requirements because of other critical systems connected to the same DC bus
- Space radiation (ionizing)
  - Launch vehicles are exposed to this for a short duration
  - Geosynchronous space crafts work for >15 years without servicing
- Operation in vacuum: Need tight control over materials used
- Reliability
- Thermal management of power devices: Even 4W of power dissipation in a single device is challenging, conduction is the only mode of taking out heat from the device (no convection in absence of air, not much thermal radiation at lower temperatures owing to Stefan’s law)
- Spacecraft thermal management: Using reflectors, radiators, heaters (when spacecraft is in shade), heat pipes
Solar panels, energy storage (batteries), and energy management on the spacecraft
Transferring space technology to terrestrial applications: renewable-only energy systems, DC-only systems, space crafts and EVs are both essentially battery-based systems with minimum SWAP requirements
“If you look at power, you start imagining the origin of things: How does something really start up? Where is its source of power? Where and how does the power flow? Who needs it? How much is needed? When you look at all this stuff, you start understanding the system much better.”
“When you work in power electronics, you have to interface with almost everyone around – because nobody can work without power. You start interacting with the digital team, communications team, thermal, mechanical, almost everyone.”
“Adoption of wide bandgap (WBG) devices in power electronics is a turning point similar to the introduction of IGBTs in the high power conditioning levels.”
Key skills for working in power electronics: analog electronics, working of semiconductor devices, magnetics design
“Back in my bachelors days, I used to believe that it’s the voltage that you should look at all the time, to know what is actually happening. Slowly with more experience, it was wonderful for me to come to know of current probes. Early in your career, start looking into current waveforms and not just in textbooks. If voltage is the cause, current is the result. If you want to know the result, look at the currents.”
Approach to innovation:
- ISRO works in small strong teams.
- Bottom-up approach: ideas coming from the grassroot level are put into a common pool and reviewed so that the best ones come up and they get funded.
- Problem solving by divide-and-rule: break up a problem into smaller problems and distribute to the people by skillset.
- Special focus on defining interfaces clearly.
ISRO hes university satellites too, accepts students for project work.

#6 Interview With Sheldon Williamson

2021-04-09T00:00:00+05:30

An interview with Prof. Sheldon Williamson of the Ontario Tech University, Canada.

Show Notes

Prof. Sheldon Williamson

Department of Electrical, Computer and Software Engineering, Ontario Tech University, Oshawa, Canada
Research group webpage
Twitter handles: @OT_STEER, @electrifiedshel
Google Scholar Profile

Education:

Bachelors at Father Agnel’s College, University of Mumbai, India. Masters and PhD at Illinois Institute of Technology (IIT), Chicago, USA.

Academic experience: 8 years at Concordia University, Montreal followed by 5 years at Ontario Tech University, Oshawa
Typical day of the professor: Meetings with graduate students and industry partners, administrative meetings, teaching courses, office hours for students, grant proposal writing
Courses taught over the years: Power electronics, Advanced power electronics, Motor drives, Advanced motor drives, Electric machines, Electric vehicles / Electric transportation, Electric energy storage systems.
Future plan on teaching side: Developing a program in transportation electrification and autonomous e-mobility, including all the core power electronics courses, and also courses on control systems, electric machine design.
Emailing North American professors for grad studies: Prof Fang Peng, Michigan State University, Prof Ali Emadi, IIT Chicago (now with McMaster University).
First Discovery Grant (5 years): Research on powertrain efficiency in hybrid electric vehicles.
Present areas of interest: EV charging, Photovoltaics (PV) for charging, Wireless charging, Battery Management Systems (BMS), Traction and electric motor drives
Graduate students who worked on wireless charging: Dr. Kunwar Aditya, Deepak Rozario, Dr. Deepa Vincent, Dr. Phuoc Sang Huynh.
“Engineering research means nothing if it does not produce a product at the end of the tunnel. We are engineers, not scientists.”
Importance of developing products in collaboration with industry
Industrial collaborators: TM4, Opal-RT, InMotive, Linamar, D&V Electronics
“The most fruitful part of engineering research [in academia] is when you see your work being used in the industry. That is an indicator of the impact of your research.”
Looking into the future: “Mobility will completely change. Plugged charging needs human intervention, and hence will have to be replaced by wireless charging.”
Problems in adoption of wireless charging: Standard are not yet mature, power levels need to be scaled up, social acceptance especially with regard to concerns for health effects of the electromagnetic radiation.
Incoming research students: They already have 60% of the skills and learn the remaining 40% through experimentation and failures. One of the key skills is to be able to design a system to specifications.
Revamping of the electrical engineering syllabi and programs is a priority especially in India as many of the curriculums are stuck at older times. New programs required in smart grids and transportation electrification.
Big challenges in the next few decades: autonomous mobility (land, air, sea), vehicle-to-vehicle charging, cybersecurity of power electronic systems.
IEEE Power Electronics Society (PELS) and Industrial Electronics Society (IES)
PELS Digital Media and Education Committee, headed by Prof Prasad Enjeti, Texas A&M University.
The Power Electronics Society Podcast
IEEE Open Journal of Power Electronics

Additional information:

Book by Prof Sheldon Williamson:
Energy Management Strategies for Electric and Plug-in Hybrid Electric Vehicles

#5 Interview With Jemimah Connie

2021-03-08T00:00:00+05:30

This International Women’s Day special episode is an interview Dr. Jemimah Connie Akiror, an electrical engineer working at the Uganda Electricity Generation Company, Kampala.

She shares her diverse experiences in Uganda and Canada, from increasing generation capacity of hydro-generators to managing a broad range of electricity generation assets.

Show Notes

Dr Jemimah Connie Akiror (LinkedIn)

Uganda Electricity Generation Company Limited (UEGCL), Kampala: https://uegcl.com/
Three parts of the electricity sector: Generation, Transmission, Distribution
Education:
- Masters in Materials Engineering and PhD in Electrical Engineering at Concordia University, Montreal, Canada: https://www.concordia.ca/
- PhD Thesis: https://spectrum.library.concordia.ca/982361/
- Bachelors at Makarere University: https://www.mak.ac.ug/
Hydro Quebec Research Institute (IREQ): https://www.hydroquebec.com/innovation/en/research-institute/
Increasing generation capacity (power output and life) of hydro-generators
Core-losses in ferromagnetic materials:
- “For a long time, it was assumed that the flux inside the transformer or electric machine is just pulsating flux. We found that there are some areas in the core where the flux is rotational. The formula for calculating core loss needed a tweak.”
Asset Management:
- Planning for assets, managing risks, decisions on operations and maintenance, life cycle, sustainability.
- Asset management standards: PAS 55, ISO55000
Theory/Science-based vs Project/Applications-based approach to engineering education: Need a combination of both.
Life-cycle costing of renewable energy systems
“Everything that every researcher does is only a tiny bit of the big pie.”
“There used to be an assumption that PhDs are for working in the university. But that is changing. Different companies are now embracing research as a good component of what they do, to improve the services they give.”
Rewarding innovation at the organization level (at UEGCL) at the end of the year.
- “However simple or straight-forward the innovation could look like, as long as it has made people’s lives better, you are recognized for it.”
- Encouraged to participate in international conferences.
Companies, and society in general, could do a lot to support women in engineering. E.g. longer paid maternity leave, reduced working hours for nursing mothers.
Uganda is one of the world leaders in hydro power. Hydel power plants can last a long time—50 to 100 years—if you take care of them.

#4 Interview With Ashwin Khambadkone

2021-02-04T00:00:00+05:30

Lalit and Abhijit talk to Prof. Ashwin Khambadkone who is currently a Professor at the National University of Singapore, and has rich experience in academia as well as industry.

Guest Profile: Prof. Ashwin Khambadkone:
- NUS Homepage
- Experimental Power Grid Center
- PhD at University of Wuppertal, supervised by Prof. Holtz

Change in Air Pollution levels due to Coronavirus (Article from Science Daily)
Renewable Energy Sources are non-dispachable
Traditional power system:
- Generation follows variation in demand for Power Balance
- RES are both variable and uncertain
- Data Analytics, Data Mining, Big Data etc have a lot of potential in providing some prediction and addressing uncertainity.
Non-Technology based solutions:
- behavioral changes
- Time-of-use pricing for EV charging
- “Inconvence fee / factor”: Many regions have some form of demand based pricing for use of cars, (https://en.wikipedia.org/wiki/Congestion_pricing) e.g. London (https://tfl.gov.uk/modes/driving/congestion-charge) and Singapore.
Problems need to be solved beyond purely from technology-basis
Need to keep in mind the humans interacting with the system and the behavioural aspects of these interactions.
More choice is not always necessary:
- e.g. stock market investing is “automated”
- Not just an electronic solution – a system solution
Evolution of technology solutions:
- Old systems relied on “muscle” power and had heavy user interaction
- Evolved into energy self sufficiency
- Evolving into control self sufficiency
Old way of doing engineering is changing – need to be aware of and understand the entire system
“Making engineering more interesting”
How should students of today prepare themselves for the challenges of complex-system thinking in modern jobs?
First year curriculum re-design:
Phasor representations
- Harmonics cannot be shown in conventional phasor diagrams
- Ask questions and connect the dots: link it to your own experience
- Systems thinking: Universal input voltage range
How to ask questions the smart way. Prioritize your questions – we are in an information rich world
How to find answers
- IEEE Spectrum, Electronics Magazines (Bodo, etc) How stuff works.com
- Websites of manufacturers
- Youtube teardown sites
- AmpHour Forum
- Electronics Stackexchange
- Electronics Reddit, r/AskEngineering
Get a layman’s understanding: “You do not really understand something unless you can explain it to your grandmother.” this quote has been attributed to a number of people, not sure of actual origin
Industry projects:
- The most important thing is to understand what the customer needs
- Its not always about just taking the best algorithm
- You need to consider things which no standard textbook will teach, e.g. current limit as a function of thermal loading of devices
- The system you develop should not require a PhD to operate!
- Run the system for an entire day!
Problem definition is key!
Multidisciplinary Approach
The chase of a “Novel Idea”
Closing remarks:
- Identify your priorities first!

#3 Interview With Ned Mohan

2020-12-20T00:00:00+05:30

Lalit and Abhijit chat with Prof. Ned Mohan of the University of Minnesota, Twin Cities. He is a leading researcher and educator in the field of power electronics and renewable energy.

Show notes coming Soon

#2 Interview With L Umanand

2020-11-21T00:00:00+05:30

Lalit and Abhijit interview their PhD advisor and mentor, Prof. L. Umanand of the Department of Electronic Systems Engineering at the Indian Institute of Science Bangalore (DESE, IISc).

Show Notes

Guest Profile:
- Prof L Umanand, Department of Electronic Systems Engineering (DESE), Indian Institute of Science (IISc), Bangalore, India
- Personal webpage
- Google Scholar Profile
- Undergraduate education: B.E. (Bachelor of Engineering)
  - Electronics and communication engineering
  - Using discrete, and then integrated devices, to build transmitters and receivers (ham radio)
  - Fear of power electronics: SCR (Silicon Controlled Rectifier) waveforms
- Masters’ degree: M. Tech.
  - Electronics Design and Technology, IISc, Bangalore
  - Impact of a great teacher on getting attracted to power electronics: Prof Ramesh Bhat
- Areas of present interests: power conversion, DC/DC converters, DC/AC converters (inverters), renewable energy, photovoltaics (PV), motor drives, electric vehicles (EV)
Typical power electronics course at DESE: 2 hours/week theory, >3 hours/week lab
“It is difficult to draw a demarcation line between implementation and research. They are highly coupled, intermingled.”
Masters’ students typically take up closed-form projects that are implementation-oriented and time bound.
PhD (research) students typically take up open-ended problems where the end-time is not always fixed.
Promoting interaction between masters and PhD students through overlap in projects.
Solar desalination project by Dr. Ravinder Kumar
- Problem with earlier approach: Membrane-based desalination needs frequent replacement of membranes.
- Proposed solution: Increase flow rate of distilled water using two-stage distillation and pressure modulation to reduce boiling point of water.
- Modeling of thermal systems using bond graphs.
- Related publications:
  - Ravinder Kumar and L. Umanand, “Dynamic pressure modulation for solar desalination system,” Desalination, vol. 249(1), pp. 90-98, 2009. URL: https://www.sciencedirect.com/science/article/abs/pii/S0011916409007528
  - Ravinder Kumar and L. Umanand, “Modeling of a pressure modulated desalination system using bond graph methodology.” Applied Energy, vol. 86(9), pp. 1654-1666, 2009. URL: https://www.sciencedirect.com/science/article/abs/pii/S0306261909000282
Two domains of knowledge:
- Physics: Dealing with the inanimate
- Life sciences: Dealing with the animate
- “If you look at physics as the mother of all the inanimates, you are domain-free, you lose the fear of domains. That is what an engineer should do.”
Bond graphs vs block diagrams: Thinking in terms of energy transfer, effort variable, flow variable, input impedance, feedback effect, across multiple engineering domains.
- Introductory lecture on bond graphs by Prof Soumitro Banerjee, IIT Kharagpur https://www.youtube.com/watch?v=p9VZ3ONMqJs
Solar cooking project by Dr. Prasanna UR
- Very low flow-rate meter
- Current control in the electrical domain transformed to mechanical domain using bond graphs.
- Related publications:
  - UR Prasanna and L Umanand, “Non-disruptive and null-deflection mass flow measurement by a pressure compensation technique,” Flow Measurement and Instrumentation, vol. 21(1), pp. 54-61, 2010. URL: https://www.sciencedirect.com/science/article/abs/pii/S0955598609000557
  - Prasanna U R and L Umanand, “Flow measurement system and a method thereof”, Indian patent application number: 2112/CHE/2009, August 2009.
Big challenge for next few decades: Prime mover (or electric motor) design for e-mobility—cars, individual transport, 2/3/4 wheelers, locomotives.
- “Permanent magnet (PM) machines, such as the permanent magnet synchronous machine (PMSM), are not the solution. There is only one country which has monopoly on rare-earth PM materials.”
- Non-PM machines will gain importance: synchronous reluctance machines (SRM) with mechanical as well as virtual salient poles, electromagnetic synchronous machines using rotating transformers (non-contact, no slip rings, no brushes).
- Our systems will move more towards automation and robots.
Energy storage:
- Li-ion batteries: popular technology today, high energy density and power density, but limited life.
- Ni-ion batteries: potential to form the backbone (large energy storage) for the electrical grid in presence of intermittent and distributed renewable energy sources. Long life of 15-20 years.
- Thermal power companies in India (e.g. NTPC) which are traditionally coal-based could soon be shifting to renewable energy (wind and PV) with large energy storage.
Advice to bachelors’ students in electrical and electronics engineering: “Focus on implementation. Understand the working of circuits, beyond just passing exams. They should be able to build interfaces. Basically electronics is nothing but building interfaces. On the left hand side, you have something, and on the right hand side, you have something [else]. In between them, you are building an electronic gadget to interface the left to the right. It could be analog, digital, signal, power…”
“A PhD is a kind of meditation, a deep contemplation, it is not just a degree. The output of the PhD process is the mind of the person, the thesis is the vehicle, papers are spin-offs.”
On publications: “Knowledge is for sharing. It is the only thing which increases within you when stolen. Publish your work in whatever way possible, the freer the better. Unfortunately, publications have become a number counting mechanism for career development.”

Additional information:

Online Courses (NPTEL) by Prof L Umanand:
Books by Prof L Umanand:
- Power Electronics: Essentials & Applications
- Design of Magnetic Components for Switched Mode Power Converters