The Point Of Load Alliance (POLA) and the Distributed-power Open Standards Alliance (DOSA) have both endorsed Power Management Bus (PMBus), the brainchild of Artesyn and Astec Power. An open architecture for power systems, PMBus employs I2C for digital control and monitoring.
Power-One's Z-One Digital IBA uses I2C with a proprietary chip that talks to Power-One's POLs over a custom interface. PMBus takes a different approach, envisioning an I2C port on each power converter. Both techniques have their advantages. But either way, it's clear that digital control has gained a firm foothold in distributed power systems.
Meanwhile, there will be lots of intriguing panels and seminars at the Applied Power and Electronics Conference (www.apec-conf.org), March 6-10 in Austin, Texas. For example, Sunday afternoon's "Fundamentals of State Plane Analysis of Converters" promises a more physically insightful method for analyzing converters with resonant elements than differential equations.
Also, check out Monday morning's "Hybrid Vehicle Propulsion: Exploring the Electronic CVT (Continuously Variable Transmission)" by John M. Miller of the MIT-Industry Consortium on Advanced Automotive Electrical and Electronic Systems and Components. According to Miller, mechanical CVTs aren't efficient at torque conversion ratios of 6:1 and higher. Also, electronic CVTs consisting of a starter-generator and a motor-generator with an electrical energy storage system (ESS) in the middle are the way to go.
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