Graduate students win best paper awards at IEEE COMPEL

ECE ILLINOIS graduate students Nathan Charles Brooks and Zichao Ye, both advised by associate professor Robert Pilawa-Podgurski, each received a best paper award at the 2017 IEEE Workshop on Control and Modeling for Power Electronics (COMPEL) hosted by Stanford University.

IEEE COMPEL is a four-day program consisting of keynote speeches, workshops, and lectures with 198 individual submissions, and it is highly esteemed for its quality submission and presentation process as well as the general attendance of renowned researchers in the field of power electronics. A total of five best paper awards were selected, with Illinois walking away with two of them.

Brooks’ paper, “Control Design of an Active Power Pulsation Buffer Using an Equivalent Series-Resonant Impedance Model”, co-authored by Shibin Qin, derives and validates a new AC to DC power converter control method, which results in higher efficiency and smaller size. His findings can have a significant impact on the performance on power converters, in applications ranging from datacenters and electric vehicles, to LED lighting. Brooks’ research goal is to improve the system efficiency and power density of AC to DC converters by investigating active twice-line frequency buffers. He acknowledges “[the] research process of designing, investigating fundamental ideas in mathematics and science, fabricating physical hardware, and producing a successful result is challenging yet still immensely gratifying. Promising results can have a profound impact on the research community through presentation and literature, and the conference exemplified this sentiment.”

Brooks received his electrical engineering BS from the Rose-Hulman Institute of Technology in 2016, and now pursues his PhD in electrical engineering while finishing his second year at Illinois. He enjoys engineering as a practice in the practical application of science on real-world problems and his pursuit of power electronics “constantly satiates his desire to explore and learn diverse and challenging ideas”. After presenting for the first time at a conference, Brooks was pleasantly surprised to find his efforts so well received by his peers and hopes to continue sharing his research contributions in the future.

Ye’s paper, “Investigation of Capacitor Voltage Balancing in Practical Implementations of Flying Capacitor Multilevel Converters”, co-authored by Yutian Lei and Zitao Liao, investigates the capacitor voltage imbalance issue of the popular multi-level power converter topology. “This topology has recently received a lot of attention in both academia and industry because of its potential to achieve dramatic performance improvement over conventional solutions. However, adequate capacitor balancing is a still a prevalent reliability challenge that can lead to system failure,” said Ye.

Ye discovered several practical factors can cause capacitor voltage to deviate which are not captured in the traditional mathematical model. “It is quite common to make assumptions and approximations when developing mathematical modeling, yet the actual hardware is always more complicated,” said Ye. His prized paper both analytically and experimentally demonstrates the causes of capacitor imbalance, and proposes solutions with minimum hardware overhead. “I am very excited to see my work get recognized by the world leading exports in power electronics, and I am confident that my work will have practical impact in the commercialization of multilevel converters”, said Ye. Key applications that will benefit from Ye’s research discoveries are power converters for electric vehicles such as cars and future aircraft, along with high efficiency datacenters.

Ye received his bachelor’s degree in 2014 from ECE ILLINOIS and is now in his fourth year pursuing his PhD in electrical engineering. Ye likes the subject of power electronics because of its interdisciplinary nature and hands-on approach to engineering. He asserts, “the world is always going to have continued power needs, and power electronics is a subject that requires very broad understanding and intersects many disciplinary areas. Knowledge of circuit design, control, electromagnetics, and thermal management are just some of many fields necessary to address power electronics design from a system perspective.”

Brooks and Ye express their gratitude for their advisor, Professor Pilawa-Podgurski. Brooks said, “we get the chance to work on some exciting projects realizing and improving the design of electric aircraft, data center power delivery, and solar-photovoltaics amongst others, which even now begin to dramatically affect people’s lives”. Ye added, “It is my great pleasure to work in this amazing research group. You can always learn something new every day, from the brilliant minds around you, and as everyone is so hard-working, you will never find the labs uninhabited.”

Professor Pilawa-Podgurski was equally thrilled to see his students’ hard work recognized. He concludes, “COMPEL is the top power electronics control conference in the world, and it is a great opportunity for the students to share the results of their work with the leaders of our field. Nathan and Zichao worked very hard to not only perform research at the highest level, but were also able to clearly present their results in both written and oral communication. It is always great when such efforts are noticed by our peers, and it encourages us to keep pushing for excellence in research.”