TAKES CONTROL - International Rectifier

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POWER ELECTRONICS Voltage Tolerance in (mV) 300 250 200 150 100 50 0 Pentium II Pentium III di/dt Tolerance Pentium 4 Future 1997 1998 1999 2000 2001 2002 2003 2004 2005 Lidow argues that if, instead of using ‘all-on or alloff’ electromechanical drives to regulate motion, we turned to variable speed drives, then energy consumption levels would plummet. And this is where our magic figure of 10% comes from. “We could save half of all the motion control energy if everybody converted to variable speed drives,” he said. “So that’s half of [the energy consumed by electric motors], or 25% of all our electricity, which gives us a 10% saving on all the world’s energy.” Indeed, in the US alone, an estimated £77.6bn a year could be saved by switching to variable speed motion. But if the gains are this great, why haven’t industries taken on the technology in truck-loads? The answer appears to lie in the low value we continue to place on energy savings. Lidow believes that if people are going to buy into variable speed motion, it has to be very cheap or offer a more tangible benefit. “We have to deliver variable speed motion in such a way that its cost is offset by the value delivered, excluding the energy savings,” he explains. “Somebody has got to want to buy the technology, not because it saves energy, but because it does something else that is really cool.” INVERTERS WASH WHITER A key application area for variable speed motion drives is appliances or ‘white goods’, including washing machines, refrigerators and air-conditioning units. The power electronics industry first started taking real notice of variable motion control in the 900 800 700 600 500 400 300 200 100 0 di/dt (A/µs) Above: Falling voltage tolerances and shorter current rise times have stoked an increase in the need for on-board power management chips in PCs 1990s. At this time, however, swapping, say, a washing machine’s electromechanical drive for a variable speed version, would have cost thousands of pounds – clearly not a realistic option. But despite the huge expense, the manufacturers of washing machines recognised that more sophisticated motion control could improve the functionality of their products, enabling, for example, gentler washing cycles and higher spin speeds – qualities that consumers would actually want. Recognising the market’s potential, International Rectifier embarked on a mission to drive down the cost of motion control. High voltage integrated circuits – analogue and mixed signal – were developed and new architectures designed. Packaging, resistors, diodes and software were all re-evaluated and improved. And, eventually, the price-point dropped from thousands to only tens of pounds. So today, says Lidow, manufacturers are sitting back and watching sales of their new generation of washing machines hit the roof. The machines deliver energy savings of around 60%, for ‘free’, which, argues Lidow, is why consumers are buying them. “US analyst, Freedonia, forecasts that 26% of all washing machines bought in 2004 will have inverter [variable speed] drives; it’s our fastest growing segment,” he adds. And by 2013, Lidow expects to see 50% of the entire appliance market converted to variable speed motors. The good news for variable speed motors doesn’t stop here. Lidow is adamant that exactly the same principles apply to the automotive industry. He argues that by using exactly the same set of technologies, cars could be manufactured with twice the petrol mileage at no extra cost and with no performance losses. Key applications include integrated starter alternators, hybrid engines and in-car climate control. Over the next 25 years, Lidow is confident that all energyconsuming applications in cars will move to variable speed drive control. ➔ 35 IEE Review | June 2004 | www.iee.org/review
POWER ELECTRONICS 37 ABOUT THE MAN Alex Lidow graduated from the California Institute of Technology in 1975 with a B.S. degree in Applied Physics. He went on to study for a PhD at Stanford University, during which time he says he “was aiming to make the most efficient field effect transistor”. He joined International Rectifier in 1977 as a research and development engineer and went on to become vice president of research and development. By the early nineties he had advanced to executive vice president of operations and was finally named chief executive officer in 1995. A co-inventor of the HEXFET – a power MOSFET architecture – Lidow holds nine patents in power semiconductor technology. SETTING THE STANDARD Use of a single common architecture is central to International Rectifier’s strategy for increasing the take-up of variable speed drives. “The volumes of sales in IT are huge,” explains Lidow. “Around 100 million PCs are made every year, so you can support quite a few microprocessor architectures with this many sales.” This is clearly not the case for appliances and cars, where volumes range from hundreds of thousands to the low millions of units per year. The answer, according to Lidow, is to design a small number of reconfigurable architectures. “It could be really easy to pluck out a digital signal processor used in a mobile phone and make it work in a motor drive,” he says. “But for each motor drive chip [design], you can only expect a few million unit sales a year, so standardising is very important in driving down the cost of these specialised chips.” Lidow sees additional benefits from standardisation. First, many of today’s customers are not specialised motor designers, but are, for example, washing machine experts. Standardisation accelerates the rate at which they can incorporate motor drives into their products. Secondly, the automotive industry – the other key market for variable speed motor control – is risk-adverse and cost-sensitive and, as such, is likely to welcome a common-architecture, low-cost product that has been ‘road tested’ in the harsh, humid conditions of a washing machine. “As long as we adopt common architectures, we can learn a lot from these experiences,” says Lidow. BETTER AND BETTER So what does the future hold for motion control and indeed power management? Is this really going to happen? Can we honestly expect to see the mass-uptake of variable speed drives that power electronics manufacturers are anticipating? Analysts, across the board, are predicting revenue growth in the semiconductor industry over the next two years, which, if you do the maths, is actually good news ABOUT THE COMPANY for power management. Power dissipation per unit area of silicon is on the rise, implying a corresponding rise in demand for power management. Today’s PC, may, on the surface, look similar to the PC of a decade ago, but as clock rates have moved into the GHz range, and variations in on-board voltage levels have proliferated, power management requirements have soared. The first Pentium motherboards of the early 1990s had a mere five chips dedicated to power management. In today’s Prescott generation motherboards, the corresponding figure is, on average, 32. And the PC is just the tip of the iceberg. There are household appliances, automotive and communications devices, all sharing a burgeoning need for power management. As Lidow says: “If you predict electronics are going to do well, then you will think semiconductors are going to do well too. And if you think this, then you will know that power management is going to do even better.” International Rectifier was founded by Lithuanian Eric Lidow in 1947, father of Alex Lidow. Eric Lidow had studied engineering at the Technical University of Berlin during the mid to late 1930s, but moved over to the US in 1937. Based in El Segundo, California, the company was first set up to manufacture selenium rectifiers, but later moved towards the development of discrete component products. Now described as the world’s oldest independent semiconductor company, Alex Lidow has driven the power management business towards IT and communications, energy-efficient motion control, defense and space systems and automotive applications. IEE Review | June 2004 | www.iee.org/review
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