Electric Power Institute
# The classic one would be shooting up an electrolytic capacitor to the ceiling... This definitely taught me a lesson to respect electricity more, and to be extracareful dealing with polarized capacitors #
How did you get into electronics/engineering and when did you start?
It wasn’t until my senior year in high school. Back then I lived near the seaport district of Jakarta known as Tanjung Priok and went to this public high school called SMA 13. As part of the high school curriculum at the time, we were introduced to basic circuit components and analysis. I hope they are still doing this these days because that was what really got me interested in engineering.
As for the electronics, I was very much interested in the subject, but the coverage was scant, which motivated me to choose electrical engineering as my major when I came to the U.S. to study. Now I have been teaching electrical engineering at Cal Poly since 1999, and it has been an honor and great pleasure to be able to teach the very subject that I am passionate about.
What are your favorite hardware tools that you use?
I like to use the Frequency Response Analyzer which is a great tool for analysis, measurement, and design of feedback loops in dc-dc converters. The one I have in the power electronics lab at Cal Poly State University is the Venable Frequency Response Analyzer which has been used to help students’ understanding in feedback compensator design.
What are your favorite software tools that you use?
MathCAD. It is an awesome tool for design calculations. I’ve used it in all my consulting work and in design and problem examples I have in my lecture notes. The software really helps streamline long and complex design calculations, and its handling of units provides a convenient way to quickly troubleshoot your design equations. As for circuit simulation, I’ve come to like LTSpice developed by Linear Technology Corporation. It is completely free to download and extremely fast when simulating switching regulators compared to normal Spice simulators.
What is the hardest/trickiest bug you have ever fixed?
Minimizing noises in highfrequency switching dc-dc converter circuits have always been tricky to me.
What is on your bookshelf?
Being a faculty in a primarily undergraduate institution, I have been assigned to teach various electrical engineering courses (lectures and labs). However, courses that I mainly teach almost every year are circuits, control systems, power electronics, power systems, and machines. As a result, my bookshelf is filled with textbooks and my own lecture notes on these subjects. Although since my main interest is in power electronics, two rows of my bookshelf are actually filled with text and reference books on power
electronics. My bookshelf is also where I stock up on quite a few selections of power components such as power MOSFETs, diodes, inductors, and pwm controller chips. These components come in handy for my students to conduct their senior design and master’s thesis projects.
Do you have any tricks up your sleeve?
Not tricks, but perhaps teaching undergraduate students a simpler way to analyze and perform basic
design of dc-dc converter circuits. This is what I hope to share some day in the near future through an
undergraduate level textbook on power electronics, which I have been planning to write.
What has been your favorite project?
Several years ago my students and I were involved in the investigation and development of new topologies for Voltage Regulator Modules (VRMs) to power future microprocessors. As the number of transistors on a microprocessor increases, the power supply to these microprocessors, VRMs, must be able to supply the increase in current demand while maintaining their high efficiency. This becomes especially challenging considering the relatively low voltage operation of these microprocessors.
Consider an example from Intel who announced recently the world’s first 2-billion transistor microprocessor code-named Tukwila. With the massive amount of transistors in the new processor, even higher output current supply will be in demand, and hence more challenging for VRMs. Another example is the current Intel Core i7-980x which has a thermal design power of 130W. However, according to it actually pull as much power as 180W at 1.263VDC. Again, this means the VRMs have to be able to supply high output current with relatively low voltage. There are other processors out on the market that demand the VRM to supply upwards of 400W. The bottom line is, when output power is this high while the output voltage is kept low, the task for designing an efficient VRM for these microprocessors becomes very challenging. Hence, the use of conventional multiphase buck topology would no longer suffice and meet the efficiency requirement.
Our project was then aimed to prove that our proposed new topologies offer benefits in terms of improved efficiency and performance compared to the traditional multiphase buck at high power output and low output voltage. Two variations of the new topologies were designed, built, and tested here in the power electronics lab at Cal Poly. The new topologies are unique in that they employ passive storage components to achieve improvements in performance and efficiency rather than introducing more converter stages or more active switches. Consequently, the new topologies are much less complex to design compared to approaches using additional converter stage or additional active switches. Combined with the use of interleaving technique, we found that the proposed new topologies are able to maintain the high efficiency comparable to or better than those measured from VRMs currently available in the market. Other performances of the new topologies were also tested and evaluated exhibiting the very tight line and load regulations, very small output voltage ripple at full load, and fast dynamic response. These new topologies recently received a patent from the USPTO.
Although the project has been completed, we are currently planning to further test the capability of the new topologies with even much higher output currents (> 200A). In addition, we plan to develop the soft-switching version of these topologies for even higher overall VRM efficiency.
Do you have any noteworthy engineering experiences?
The classic one would be shooting up an electrolytic capacitor to the ceiling. This happened in my first circuit lab back when I was in college. I accidentally placed the capacitor on my circuit with the wrong polarity. This definitely taught me a lesson to respect electricity more, and to be extra careful dealing with polarized capacitors.
What are you currently working on?
These days I’ve been involved in several projects, all in the area of power electronics. The main one is the design and development of DC House to help people get access to electricity. It is currently being studied and eventually developed at Cal Poly to provide electricity to those without it by taking advantage of renewable energy sources and other creative ways of generating power. The project is open access and is still in its initial phase. I welcome anyone to participate and any ideas are greatly appreciated. The website for the project is http://www.calpoly.edu/~taufik/dchouse/
Other projects I’ve been working on are wind-energy harvesting for urban areas, isolated one-stage power factor correction, and improved inverter for Photovoltaic system.
Off campus, I have been an engineering consultant for Enerpro Inc. where I’ve mostly performed transformer designs. I am also assisting a university halfway around the world with getting its international accreditation. [EEWebPULSE/Electrical Engineering Community Magz. Issue 10/September 6, 2011]