R&D Projects
Topology design
Non-Isolated DC-DC converter topologies are unable to use the inductor efficiently. Comparing a buck or a boost with a topology such as Push-Pull or Bridge really demonstrates the inefficient use of the inductor. Conventionally, the B-H curve for non-isolated topology is used for the followings:
Ensure inductor will not saturate by keeping the flux density, B, below the flux density at the saturation BSAT.
Limit the temperature of the inductor.
Define minor B-H loop for inductor based on current ripple.
These criteria are satisfied just by carful design process. However, the inductor is not fully utilized as you can see that the minor loop does not go to the third quadrant of the B-H graph. If there was a way to flow negative current through the inductor, the inductor size could be minimized while maintaining the same criteria listed above. This topology design looks into different circuit design that would satisfy this hypothesis. Right now, I have a circuit under analysis where I am trying to derive the transfer function and other key equations.
Power electronics control using off-the-shelf microcontroller
Currently, power electronics control requires a custom integrated circuit (IC) to operate converters. However, such integrated circuits could be obscure as the underlying control schemes are hidden behind the manufacturers. Currently there is no open source technology to run controls for power electronics.
This project involves creating control models on Simulink and then coding them using C to impalement on a Arduino Uno. By using the Arduino Uno microcontroller you can go beyond just running a converter’s control but also do extensive instrumentation. Multiple controls schemes are going to be under evaluation such as:
Voltage Mode Control
Current mode Control
Constant On-Time
Automatic Control (fuzzy control)
First iteration of the design has been fabricated. Initial software and Simulink model are completed and ready to integrate with the board. At this point, multiple efforts are made to troubleshoot the custom PCB and reduce BOM cost.
Converter Design python Jupyter Notebook
Many companies run their own excel, python notebook, or other application in order to calculate converters parameters. Creating an open source design tool that helps with component design as well as loop stability is highly necessary. The tool will start by evaluating 3 control types for Buck and Boost converters. I am potentially looking to integrate state-space equations to generate plots and key equations. The python notebook would integrate the Digi-Key API to choose components after the values been chosen.
Master Thesis:
A Multiphase Modified Boost Converter with Reduced Input Current Ripple: Combined Capacitors
ABSTRACT
The delivery of high power and smaller footprints through a non-isolated topology demands for the use of multiphase topology in DC-DC converters. Multiphase reduces the ripple observed on both the input and output waveforms; however, it may not be enough to connect to sensitive power sources such as renewable energy sources. A single-phase modified boost converter demonstrates the ability to acquire very minimal input current ripple by addition of passive components. The expansion to multiphase topology is the next logical step for higher power application while furthering the low input current ripple benefit. In this thesis, the multiphase modified boost topology is compared with the multiphase standard boost topology to explore the benefits and trade-offs of the proposed topology. A 12V input to 19V output at 95W output power multiphase standard and modified boost converters were designed and constructed for the thesis. Results from theoretical calculations, computer simulations, and hardware implementations were then compared to evaluate their performances. Results show that compared to the standard boost, the modified boost yields significantly less input current ripple at 2% under full load condition while maintaining output voltage ripple of 5% and higher than 90% efficiency.
Multidisciplinary Senior Design Project
- OnQ -
This senior project class brought together multidisciplinary majors, such as engineering, business, and design, and broke students into teams in order to start an idea from ideation to prototyping, and eventually startup creation.
Problem OF INTEREST
Students are frustrated with the extensive time loss they experience when waiting in line to speak with a recruiter
Students wait upwards of 45 minutes to talk with one company for a short amount of time
Students feel that the Career Fair is although an important opportunity, it is an unproductive one
Smaller companies are overshadowed by more popular, well-known options
Solution
OnQ is a line management mobile application that allows job-seeking university students to maximize the efficiency of their time at a career fair by organizing their interactions with talent-seeking recruiters.
This involved creating a mobile app for students & recruiters and website interface for university career services to update the app. I worked specifically on the website, integrating a Google Firebase database and creating the front and backend. I was able to produce core functionality for the website in 2 months while learning Javascript and HTML.
Startup Weekend
What the heck is startup weekend?
Startup weekend is a 54-hour long, over the weekend (thus this fancy name), hackathon. Unlike any other hackathon, it involves building a business case as well as a tangible product. This hackathon helped me get involve with the entrepreneurship community as well as help me build friendship that would last a lifetime. Some of the teams I worked with were small and some were large. Sometimes my team received an award and others just amazing bonding experience. Some years, I knew nobody and others I was able to work with my brother and sister. And more importantly, some years I was a participant and others an organizer. This hackathon has influenced the way I see innovations drastically and because of this hackathon I also consider myself a business major. Here some of the ideas I worked on.
Startup Weekend 2014, Twippo was twitter polling service. It allowed users to create a poll on twitter by using special characters when responding to a twitter poll. The idea was to be able to run political or opinion polls and get revenue from companies who want to run such polls.
Startup Weekend 2017, OUTPAC is a breathable, durable neoprene “fanny pack” for surfers. It is designed specifically for surfing essentials: Wax, energy bars, sunscreen, etc. Now days, surfers are unable to carry those essentials with them into the ocean, but with the OUTPAC they can.
Startup Weekend 2015, Paxology was a modular backpack. Now days, you would need multiple backpacks depending on whether you go to school or going camping. Paxology allowed you to modify your backpack to fit all your needs.
Startup Weekend 2018, SPICED. is subscription box that sends you spices from around the world with the story of the spice master. The subscription box comes with 4 spices, a letter from the spice master and some recipes. This was an idea of mine and was able to recruit a team. The idea surfaced from traveling and missing the cultural aspect that cam with spices. My original intent was to be able to make cultural food just like how they tasted on my trip.