Power Electronics

Data Points

Battery Monitor Could Help Keep Hybrids on the Road

Scientists at the Department of Energy's Idaho National Laboratory are developing a smart battery-monitoring system that tracks the health of batteries used in hybrid electric vehicles (HEVs) and plug-in HEVs. Working together with researchers at Montana Tech, an engineering school at the University of Montana, and Qualtech Systems (Wethersfield, Conn.), Idaho National Laboratory researchers have created a technique called Impedance Noise Identification (INI), which pulses batteries with pink noise to quickly measure battery impedance. A typical test takes less than 30 seconds. The impedance data can then be used to calculate battery life.

INI offers a potential alternative to existing techniques such as pulse testing and electrochemical impedance spectroscopy. With pulse testing, a high current is applied to the battery and the battery voltage is measured; however, this method takes hours to perform and drains the battery. On the other hand, electrochemical impedance spectroscopy, which applies currents at different frequencies, is a quicker test but needs large and sensitive equipment.

INI is a variation on electrochemical impedance spectroscopy, but it applies a test signal comprised of pink noise rather than applying discrete test frequencies. The equipment needed to perform INI, which is being built at Montana Tech, is roughly as big as a desktop CPU. Eventually, INI could be incorporated into a vehicle to provide more accurate predictions of battery life without draining the battery.

For additional information, see “A Smart Battery Monitor for Hybrid Cars” from the Oct. 6, 2008, DOE Pulse at www.ornl.gov/info/news/pulse.

Researchers Present 20-MHz Micro-inductor at Workshop

Last month in Cork, Ireland, at the inaugural International Workshop on Power Supply on Chip, PwrSoc '08, members of the Micropower team at Tyndall National Institute presented the most recent results from their research on micromagnetics on silicon for power supply-on-chip (PwrSoC) applications.

Dr. Terence O'Donnell presented efficiency data for micro-inductors of more than 90%, operating at 20 MHz and delivering 0.5 A, within a footprint of 5.5 mm2. The Tyndall micro-inductor structure consists of a racetrack of electroplated copper windings encased in a thin-film, electroplated, closed, nickel-iron soft magnetic core.

The micro-inductors were demonstrated with a monolithic “MOSFETs and driver” power-train IC, operating in the 15-MHz to 65-MHz range. This IC was designed by project partner Power Electronics Research Laboratory at University College Cork, which was led by Dr. Ray Foley. Optimization analysis undertaken by the Tyndall team demonstrates that micro-inductor efficiencies as high as 95% can be achieved in a footprint of 3 mm2 at 100 MHz.

“Tyndall's patented technology in this area is the result of more than 50 person-years of research over the last decade, funded by the Irish government, with specific direction from the Irish power electronics industry,” says PwrSoc Workshop Co-chair Dr. Cian Ó Mathúna, also of the Tyndall National Institute.

The presentation by Tyndall's Micropower team was one of many presentations during the two-and-a-half day workshop. Explaining the rationale behind the workshop, Dr. Ó Mathúna noted, “PwrSoC '08 is the first international workshop to address the issue of the development of next-generation, miniaturized switched-mode power-supply product formats for use in future mobile phones, portable electronics and high-performance computing platforms. These multicomponent products can be referred to as power supply-in-package and PwrSoC.

“This concept of integrated power solutions presents a significant disruptive opportunity in power management and warrants an international forum for its discussion and for the elucidation of the key challenges and opportunities that lie ahead,” continued Ó Mathúna.

For more information see, www.powersoc.org.

Labs Collaborate to Create Advanced Solar Testing and Certification Facility

TUV Rheinland Group has joined forces with Arizona State University (ASU) to create TUV Rheinland Photovoltaic Testing Laboratory (PTL), a comprehensive state-of-the-art facility for testing and certification of solar-energy equipment.

A private venture that will be based in Tempe, Ariz., this unique collaboration combines the reputation, technological sophistication, management expertise and international reach of TUV Rheinland — a provider of independent testing and assessment services — with ASU's more than 50 years of research on solar energy and solar testing know-how.

ASU's PTL, established in 1992, is said to be the only lab in the United States accredited for photovoltaic (PV) design qualification and type approval. ASU's legal involvement in this venture was made possible by Arizona Technology Enterprises and its wholly owned subsidiary Commercial PTL Ventures

TUV Rheinland's collaboration will connect ASU's PTL facility to the company's global network. The new company substantially expands PTL's testing capabilities in both volume and scope by adding state-of-the-art test equipment and the capacity to test and certify PV panels and electrical components for Europe, Asia and North America.

In turn, PTL provides TUV Rheinland with its university knowledge base, an immediate entry into the U.S. solar testing market and the lab's experience testing PV panels in both simulated and real outdoor environments.

Furthering the impact of TUV Rheinland PTL is a collaboration between the new company and Arizona's largest electric provider, Arizona Public Service. The utility will provide 5 acres of outdoor testing space at its Solar Test and Research Center for use by the venture to conduct outdoor endurance testing.

“The potent combination of business, university and utility solar test assets will enable TUV Rheinland PTL to be the first in the world to offer full-scale PV testing and certification across the entire component chain of photovoltaic systems,” says Stephan Schmitt, president and CEO of TUV Rheinland North America Holding. For more information, see http://sustainability.asu.edu or www.us.tuv.com.

Infineon Tops Power Semiconductor Rankings for Fifth Year

Infineon Technologies (Munich, Germany) retained its position as the world's largest supplier of power semiconductors (discretes and modules) in 2007 for the fifth consecutive year, according to a recent report by IMS Research (Wellingborough, U.K.). “The Global Market for Power Semiconductor Discretes & Modules” study found that Infineon Technologies not only remained the market leader for the fifth consecutive year, but in fact recorded the largest increase in market share of all suppliers in 2007.

Infineon now commands a 9.7% share of the $13.6 billionmarket, according to IMS Research. “Infineon grew its power discretes and modules business by over 20% in 2007, outpacing the market, which grew at just under 10%, and retained its position as the largest supplier to the market,” said Josh Flood, a co-author of the report.

The study found that the top 10 suppliers to the power semiconductors market experienced mixed performances in 2007, with STMicroelectronics (Geneva, Switzerland) and Fairchild Semiconductor (South Portland, Maine) ranking second and third, respectively. “The future of the market continues to look very positive for power semiconductor suppliers with energy efficiency and energy concerns a major driver of growth,” said Ash Sharma, IMS Research director.

The report contains analyzed sales data from the leading global suppliers to create a detailed assessment of the global market today, and its likely future development.

Voltage Comparators Integrate Pre-Amps and Output Drivers

A series of dual-precision voltage comparators developed by Sunnyvale, Calif.-based Advanced Linear Devices (ALD) combines three functions — precision pre-amp, voltage comparator and voltage driver — in one chip. Offered in 8-pin DIPs and SOPs with industry-standard (LM193) pinouts, the ALD2331/ALD2331A/ALD2331B comparators can sense input signals down to 1 mV and then generate sufficient output to drive 200-Ω loads. Applications for these devices include MOSFET drivers, relay drivers, power-supply voltage monitors, high-speed LED drivers and battery-operated instruments.

The CMOS voltage comparators use the company's EPAD precision-trimming technology to provide low input-offset voltage, low input-bias current and low overdrive voltage in the same comparator. Typical specifications for the A-grade versions include an input offset of 0.02 mV and an input bias of 0.01 pA. Input impedance is 1012 Ω typical, and a response time of 750 ns is achieved with only a 10-mV input step signal. The comparators also feature a low current consumption of 55 µA per comparator and single 5-V or dual ±5-V power-supply operation.

The comparators are available now starting at $1.47 each in quantities of 1000. For additional information, visit www.aldinc.com.

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