Power Electronics

Data Points

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Battery Technology Will Dominate Portable Power for Next Decade

According to a report from NanoMarkets, battery technology — particularly Li-ion and Li-polymer — will continue to have the greatest market share of portable power applications into the near term. The report, “Micro Power Sources: Opportunities from Fuel Cells and Batteries for Mobile Applications,” notes that fuel cell technology continues to advance and is expected to surpass the capabilities of battery technology. However, technological and economic barriers are pushing the eventual displacement of battery technology by fuel cells well into the next decade. The graph below shows market share and growth for the two technologies into 2012.

The great market potential of fuel cells combined with their delayed market penetration has spawned a variety of business strategies. Some companies have stopped fuel cell research and development altogether. Others have developed long-term strategies to develop specific fuel cell technology for use in future applications where battery technology is expected to be inadequate. Still others have brought fuel cell technology into the marketplace by targeting usage models where the performance advantages of fuel cells outweigh the cost advantages of existing battery technology. These markets are mostly military, though there are some high-end commercial and consumer products with fuel cell technology.

For the near term, battery technology will continue to dominate the portable power market. In the NanoMarkets report, it is observed that a transition of Li-ion to Li-polymer technology is anticipated, but neither of these technologies is expected to significantly grow in capability. However, low-cost and low-maintenance requirements will keep batteries as the most common source of power for portable applications for some time. Other battery technologies, such as nanostructures and thin films, will improve certain aspects of battery performance, according to the report.

Batteries also can complement rather than compete against fuel cell technology. The emerging practical application where these technologies are combined is in notebook computers. Fuel cells can provide longer run times than batteries, and batteries respond much better than fuel cells to large power transients. Prototypes of fuel cell notebook computers have been developed.

The NanoMarkets report describes various battery and fuel cell technologies, as well as vendors, their timelines, and their strategies and partnerships. Also discussed are potential benefits and obstacles facing each technology, in addition to market forecasts projecting into 2012. For more information, see www.nanomarkets.net.

IC Further Simplifies Cell-Phone Chargers

With the introduction of its LinkSwitch-LP, Power Integrations continues to develop its off-line switching technology for new segments of the ac adapter market. Like the original LinkSwitch product line, the LP family targets low-cost linear ac adapters with a more efficient switch-mode power supply design. However, the LP models provide an even more loosely regulated constant voltage/constant current (CV/CC) output than the original LinkSwitch ICs. This loosening of output regulation still exceeds that of the linear transformer-based adapters that LinkSwitch-LP replaces, while allowing the use of control techniques that reduce the number of external components needed for complete adapter designs with up to 3 W of output power.

LinkSwitch-LP uses primary-side control of output voltage and current, allowing CV/CC control without an optocoupler. Although no optocoupler was required with the original LinkSwitch chips, those devices required a resistor-capacitor-diode (RCD) clamp to limit ringing (caused by transformer leakage inductance) that could damage the IC. With LinkSwitch-LP, the company's clampless design methodology reduces the ringing by applying proprietary IC trimming technology — to trim the current limit — and innovative transformer construction techniques. The total components count, including the chip, for a LinkSwitch-LP CV/CC design is 14 parts. That's three less than would be required using the original LinkSwitch chips.

Another innovative feature of the LP models is the use of frequency jitter and a unique Filterfuse input stage, which achieves EMI filtering with just a single capacitor. In addition, the E-Shield transformer design eliminates the need for a Y capacitor.

LinkSwitch-LP features a 700-V power MOSFET integrated with control and fault-protection circuitry on a single silicon chip. The ICs operate across the universal input range of 85 Vac to 265 Vac and achieve a no-load power consumption of less than 150 mW at 265 Vac. Parts are available in 8-pin DIPs and SMDs. Pricing in 1000-piece quantities for the LNK562PN, a 1.9-W part in a DIP8 package, is $0.45 each. The LNK564PN, a 3-W part, is priced at $0.49 each. For more information, see www.powerint.com.

Power Supplies Implement Digital Control

Astec Power's iMP Series of modular, switching power supplies features sophisticated digital management capabilities, allowing users to monitor and program a variety of parameters over an I2C bus. The series also enables a high degree of customization since it encompasses a range of hardware modules with single, dual and triple outputs in 600-W to 1500-W ratings. Modules can be configured in a selection of four customizable MP cases accepting inputs from 85 Vac to 264 Vac or 120 Vdc to 350 Vdc. Cases can accommodate up to seven individual modules with a choice of dc outputs ranging from 2 V to 60 V.

Astec product marketing director Chris Jones explains, “The easy-to-use microprocessor interface allows designers to make adjustments to a host of parameters including: voltage, current, fan speed, sequencing, power-factor correction, inrush and more. In spite of the advanced feature set, designers should find that this new digital generation of intelligent switching power supplies be priced competitive with existing technology,” according to Jones.

Samples will be available in the fourth quarter of 2005 with prices starting at $320 for a single-output 600-W configuration. Because the modular design enables more than 200 million combinations, pricing will vary based on configuration. For more details, see www.astecpower.com.

Power Modules Can Be Tuned for Transient Response

The second generation of Texas Instruments' (TI's) PTH line of nonisolated power modules provides a variety of performance improvements such as the ability to tune the converter for fast transient response. Other enhancements include a new synchronization feature, a wide input-voltage range, higher current ratings and POLA compatibility.

The new T2 power modules feature TI's TurboTrans technology, which allows a power supply designer to dynamically “tune” the modules using a single external resistor to meet a specific transient load requirement. According to the company, this capability achieves faster transient response with 40% less output-voltage deviation and a five to eight times reduction in output capacitance. In addition, system stability is enhanced when using ultralow ESR polymer tantalum or ceramic capacitors.

The modules also incorporate a SmartSync function that allows the designer to synchronize the switching frequencies of multiple T2 devices to maximize power efficiency and minimize EMI.

Whereas most synchronization schemes sync up to the highest frequency, SmartSync allows adjustment of switching frequencies either up or down.

T2 series of power modules.
Model Input voltage (V) Output current (A) VOUT adjust range (V)
PTH08T230W 4.5 to 14 6 0.7 to 5.5
PTH08T240W 4.5 to 14 10 0.7 to 5.5
PTH08T220W 4.5 to 14 16 0.7 to 5.5
PTH08T210W 5.5 to 14 30 0.7 to 3.6
PTH05T210W 4.5 to 5.5 30 0.7 to 3.6
PTV08T250W 8 to 14 50 0.8 to 3.6

While the first generation of PTH devices required three models to cover 3.3-V, 5-V and 12-V inputs, the new models feature a 4.5-V to 14-V input range. This wider range enables the power converters to operate directly from converters with quasi-regulated outputs. Current ratings also are raised in the second generation. The new series delivers 30 A in a form factor that previously was rated for 15 A; 16 A in a form factor that previously provided 10 A; and 10 A in a form factor that previously gave 6 A. The company is also introducing 50-A and 60-A models in the T2 series.

Other features include adjustable outputs down to 0.7 V, a 1.5% output voltage regulation, TI's Auto-Track sequencing, and pre-bias startup capabilities. The T2 power modules are now available in sample quantities and TI is accepting orders for volume production. In quantities of 1000, unit pricing ranges from $7.90 for the 6-A module up to $36 for the 50-A module.

Latest Spin on Flywheel Power System Increases Power Output

VSS DC+ is the next generation of Pentadyne's Voltage Support Solution (VSS) DC flywheel power system, which improves overall UPS system reliability by replacing lead-acid batteries completely or by extending battery life. The new flywheel power system comes in the same size cabinet as the original VSS DC but offers higher power and an extended warranty. The VSS DC+ delivers 190 kW versus 120 kW for the VSS DC. And rather than the industry-standard one-year warranty that was offered on the original product, the new model comes with a five-year warranty.

The increased power output translates to lower cost in applications requiring higher power levels. For instance, with the new flywheel power system, it's only necessary to parallel four VSS DC+ units to supply backup power to a 750-kVA UPS for 17 seconds. To achieve that level of backup with the original power system, seven units would have been required.

The higher power output of the VSS DC+ was achieved by two means. One was a lengthening of the carbon fiber flywheel by about 20%, which produced a 30% increase in its output power. Another change was an improvement in the efficiency of the synchronous reluctance motor that converts the flywheel's mechanical energy to electrical energy.

The VSS DC+ integrates equally well with medium and large power UPS systems. At 100% UPS output power, a single VSS DC+ unit provides up to 25 seconds in a 130-kVA UPS and 40 seconds in an 80-kVA UPS. For large power UPS systems, as many VSS DC+ systems as desired can be paralleled together for higher power, longer run-time or redundancy without requiring any communication links.

When integrated with a UPS, the flyhweel power system can provide ride-through protection for safe system shutdown or provide ride-through to generator. And when used in parallel with UPS batteries, the VSS DC+ can extend battery life by handling short-duration power disturbances.

In standby operation, total system power averages about 300 W and the unit features quiet operation, producing -45 dBA of noise at 1 m. Designed for a 20-year service life before major service is required, the compact, self-contained VSS DC+ weighs around 1300 lbs and is housed in a steel cabinet that can be rolled into place and that occupies less than 6 sq ft of floor space. The VSS DC+ requires no air conditioning or safety systems, contrary to lead-acid batteries. For more information, see www.pentadyne.com.

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