Powerful Circuits: the Future of Power Electronics

David Perreault
Laboratory for Electromagnetic and Electronic Systems, Research Laboratory of Electronics

Addressing the growing energy challenges faced by our society requires advances in how we create, manipulate, store, and utilize electrical energy. Energy-processing circuits – or power electronics – are a key element in each of these areas. Researchers in the Laboratory for Electromagnetic and Electronic Systems (LEES), part of the Research Laboratory since July, 2009, are exploring how power electronics can be better designed and applied to meet the energy needs of our society. For example, ongoing research in the laboratory explores the design of power electronics to better extract energy from solar, mechanical, and thermal sources (e.g., Fig. 1). Likewise, the development of power electronics to improve efficiency and energy utilization is being explored in applications ranging from lighting to computation to communications.

Figure 1 Automotive alternator with embedded switched-mode power electronics. This design, developed by LEES student Armando Mesa, incorporates power electronics and special controls to realize up to 50% increase in power and 20% increase in efficiency over a conventional design of the same size.

Figure 1 Automotive alternator with embedded switched-mode power electronics. This design, developed by LEES student Armando Mesa, incorporates power electronics and special controls to realize up to 50% increase in power and 20% increase in efficiency over a conventional design of the same size.

To meet the needs of future systems, it is important to miniaturize and better integrate power electronic circuits. The size and cost of power conversion circuitry is a major factor preventing improved energy utilization and efficiency in many applications. Moreover, power electronics are not easily integrated with other electronic elements, and often limit the miniaturization of entire systems. Miniaturization and integration of power electronics are difficult because the necessary energy storage components scale down poorly in size and are not well suited to the planar geometries of most integrated fabrication processes.

Researchers in LEES are working to develop power electronics that provide much greater levels of miniaturization and integration. A key focus of this work is the development of system architectures and circuit topologies that permit greatly increased operating frequencies. Higher frequencies are desirable because they reduce energy storage requirements, thereby reducing size and enabling better component integration. However, higher frequencies have traditionally been associated with major practical obstacles, including low efficiency. New circuit designs under development in LEES greatly reduce frequency-dependent losses by recovering energy that is traditionally lost in device switching and gating.

Figure 2 Resonant dc-dc converter for LED lighting developed by LEES graduate student Robert Pilawa. This design operates at a switching frequency of 110 MHz – two orders of magnitude higher than conventional designs – while providing high efficiency (up to 87%) across a wide load range. In this design, passive energy storage is not a limiting size factor, making the design amenable to integration and further miniaturization in a future revision. (photos: David Perreault)

Figure 2 Resonant dc-dc converter for LED lighting developed by LEES graduate student Robert Pilawa. This design operates at a switching frequency of 110 MHz – two orders of magnitude higher than conventional designs – while providing high efficiency (up to 87%) across a wide load range. In this design, passive energy storage is not a limiting size factor, making the design amenable to integration and further miniaturization in a future revision. (photos: David Perreault)

These designs also seek to eliminate fixed loss components that reduce lightload efficiency. Additional research focuses on design of semiconductor devices and passive components that are compatible with these circuits and that operate efficiently at very high frequencies. Together, these approaches enable up to two orders of magnitude increase in operating frequency, with commensurate improvements in energy storage (e.g., Fig. 2). It is anticipated that such design approaches will enable small, highly integrated power controls that benefit size, efficiency and energy utilization in a tremendous range of future systems.

One Response to “Powerful Circuits: the Future of Power Electronics”

  1. eecsnewsletter says:

    Hello, Thank you for your comment and request. We really don’t have direct materials that we can send, but suggest that you check for more websites that originate with the author, Prof. David Perreault. His website is: http://lees.mit.edu/lees/dperreault/index.htm

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