Power Electronics

Power Electronics Education Needs A System View

Several design trends are shaping developments in the power electronics industry. The power consumption of processors is rising toward a few hundred watts, while dc power rails are dropping below 1 V. The feature sizes of very large scale integrated (VLSI) circuits and systems on chip (SoC) are dropping toward 65 nm and lower, making transients a more serious concern. With embedded software and memories proliferating, power-quality issues are affecting overall system reliability.

Meanwhile, battery, supercapacitor and fuel-cell technologies are playing a significant role in the ever-increasing number of portable systems. Other trends include “green” design concepts, the quest for improved energy and power efficiencies, and the need to alleviate electromagnetic compatibility problems. All these trends will have a significant effect on the future introduction of new commercial products and systems.

Young engineers entering the field of power electronics (PE) must have the know-how to address all of these design issues when they begin their careers. But, are engineering students receiving the necessary training? Are we achieving the delicate balance of PE subjects in our university and college courses? Given the many design trends at play, should the topic of “power converters” be expanded to “power converters and power management” in PE curricula?

It may be worth comparing the traditional PE topics with more industry-oriented topics. Modern PE systems may contain the following incomplete list of subtopics:

  • Ac-dc power sources (rectifiers and power factor corrected rectifiers)

  • Dc-dc converters (the heart of switched-mode power supplies and battery chargers)

  • Ac-ac power sources such as power conditioners, protection systems and UPSs

  • Battery management systems

  • Electronic lighting and home control systems

  • Automotive systems including the new 42-V standard

  • Motor drives and adjustable speed drives

  • Electronically controlled heating/welding systems

  • Electric utility-related power electronics

  • Electric transportation systems

  • Audio amplifiers and laser drives.

If one considers how dc-dc converter power densities are now surpassing 100 W/in3, then it becomes apparent that the following packaging design and manufacturing topics also should be considered in any industry-oriented PE curriculum:

  • Fundamentals of packaging for power-supply designers

  • Power-supply layout and design to minimize EMI

  • Thermal management and design

  • Selection of capacitors and magnetics for smaller footprint power supplies

  • Power-supply manufacturability

  • Integration of the power supply into the system.

Beyond the individual topics, are we emphasizing the need to treat the PE subsystems as holistic groups of complex analog elements? Is there a need to place a serious emphasis on alternative energy-storage systems? Can we introduce discussions on the parasitic effects of magnetic components and capacitors at megahertz frequencies and the ever-growing complexities of heat removal?

These ideas are on my mind at a time when I am developing and coordinating a final-year PE course for a university. Am I to think beyond the dc-dc converters, electromagnetics, motor drives, power semis, single- and three-phase inverters, and even the state-of-the-art digital control? A good start may be to look at the PE block diagram of a laptop and appreciate the industry's continual struggle to optimize run time from the cell phone battery pack by mixing switchers and LDOs.

PE students also need to learn which product specs are critical and which noncritical ones can be dropped during the design stage. Given the short product life cycles and the movement of assembly lines to Asia, this type of focused approach to design may be necessary. I invite readers of this magazine to share their ideas for improving PE education worldwide.

Nihal Kularatna is a former CEO of the Arthur C Clarke Institute for Modern Technologies in Sri Lanka. With 30 years of experience in industrial and power electronic research, he is presently a senior lecturer in the Department of Physics and Electronic Engineering at The University of Waikato in New Zealand. From 2002 to 2005, he was a senior lecturer at the University of Auckland.

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