eNewsletter

May 2009

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To power up all the auxiliary electronics inside the mild-hybrid cars, a 1.5 kW to 3 kW dc-dc converter is used. This converter must isolate the 14 VDC voltage output from the high voltage 400 V batteries to protect users from electric discharges. The key element to perform this task is the high power transformer. This transformer must withstand a 3,000 V isolation level during one minute in a 20 square centimeter converter size. Also the current passing through this inductor is very high, from 90 to 200 A, with minimum power losses, no more than 30 W. With these restrictions, old inductive wire wound manufacturing technologies are obsolete, and here is where PREMO offers the new HPT series.

The HPT series has been developed with this target in mind, the auxiliary dc-dc converter that power up all the electronics in the car. In a profile size of only 33 mm and with encapsulation technology that assures the highest isolation level (up to 5 kV), the HPT transformer is able to perform with very high efficiency, typical 99 percent. Against the efficiency of the classic wire wound technology, this means in the life of a medium-level car a 20 percent less of petrol wasted per year and same level of CO2 emissions savings to the atmosphere.

“The way of making this HPT series is totally different from traditional wire wound windings. Instead of using a plastic bobbin, we use several layers of copper sheets and multilayer PCB's. We make a stack with this before integrating it with the core,” said Claudio Cañete Cabeza, global automotive division manager, PREMO Group. “The complete trafo is molded with special resin to increase the thermal performances and electrical isolation level.”

In the micro-hybrid implementations or start/stop systems, a smaller dc-dc converter, uses the energy from the current batteries (14 V) to charge a capacitor and power up an electric motor integrated in the transmission belt. The system stops the gas engine automatically in the traffic lights or short-stops of the car, reducing the gas consumption and CO2 emissions. The power level is up to 750 W (12 V / 65 amp) using different kinds of topologies (boost, buck, cuk, push-pull, etc).

This converter has a very high restriction in EMC efficiency. Due to high switching frequency operation (greater than 200 kHz), no switching noise can came out from the converter to the rest of the car, to protect the rest of the electronics in the vehicle from disturbances and interferences that may affect safety. Therefore, it is mandatory to include high current differential inductors at the converter output in order to filter the switching frequency harmonics. The inductance value needed is from 1 to 4uH with saturation levels up to 70 amps.

Again, size and weight limitations are high, inductors with current levels of around 70 A must fit in profiles of 25 mm. This means 11 A by square centimeter. New ideas and developments are needed to perform this filtering task. PREMO develops these kind of filtering chokes totally custom made to fit in small dimensions (25 mm by 25 mm by 25 mm), 35 grams of weight and lowest DC resistance (0.5 mOhm) with the best EMC performance due totally close magnetic field construction, avoiding to generate any noise outside the converter.

Vishay's New Throttle Position Sensor Features Hall Effect Technology for Applications in Harsh Environments
Vishay Intertechnology Inc. has released a new throttle position sensor in hollow- and D-shaft versions that features Hall effect technology for applications in harsh environments.

The Hall effect technology of the new 981 HE gives it the ability to perform in conditions involving high-frequency vibrations up to 20 G and shocks up to 50 G over a temperature range of 45°C to 125°C, providing a strong advantage over other technologies.

The sensor is optimized for foot pedal position sensors, throttle position sensors, steering position sensors, drive-by-wire, lift and shuttle position sensors, tilt control and tilt positioning feedback and suspension system position sensors in marine, avionics, fork lift trucks, farm equipment, cranes, and automotive applications.

With all electrical angles available up to 360° with no dead band, the device features accurate linearity down to ±0.5 percent. The sensor offers a long life greater than 10 million cycles for the D-shaft version, and greater than 5 million cycles for the hollow-shaft version. The 981 HE provides continuous performance for the life of the device with no drift of linearity. Spring-loaded versions of the device are also available.

The sensor offers a supply voltage of 5 V ±10 percent, with other values available upon request. The device features a typical supply current of 10 mA, and 16 mA for PWM output. The 981 HE offers 20 V over voltage protection and 10 V reverse voltage protection. The recommended load resistance is 1 kΩ for analog output and PWM output. Redundant output signals are available upon request.

Samples of the 981 HE are available now. Production quantities will be available in Q1 2009, with lead times of 12 weeks for large orders. US market pricing for a purchase order based on a volume of 100-piece quantities, the unit price is between $13 and $19, depending on the chosen version.

New Family of Linear Voice Coil Actuators Feature Patented Magnetic Technology, Providing High Safety and Improved Service Life
BEI Kimco Magnetics has introduced a new family of Linear Voice Coil Actuators that provides increased safety and long service life. The new family features two patented spring designs based on magnetic, rather than mechanical technology. This technology ensures constant and precise valve position in either the open or closed setting when electrical power is off. OEMs designing products for safety-critical applications such as medical apparatus and other equipment that depend on maintaining a constant valve setting, will find the new actuators an ideal, low-cost solution.

“Traditionally, mechanical springs have been used to provide a measure of safety for assuring valve position,” said Mikhail Godkin, BEI Kimco engineering manager. “Over time, these mechanical-type springs exhibit wear and tear, resulting in a reduced spring constant that causes undesirable performance deviations.”

The new magnetic designs make use of a mechanical spring unnecessary. Each actuator incorporates either a magnetic ‘extension’ or a magnetic ‘compression’ spring inside a coil assembly. In effect, the entire actuator can be described as a controllable electromagnetic spring whereby the “electromagnetic spring” is controlled by the current in the winding. Both magnetic spring designs also include stops, which limit the position of the moving coil when it is not energized. When the coil is de-energized, it remains in a set, fixed position.

BEI Kimco’s magnetic spring technologies provide “contact-less” actuators, which utilize fewer parts and have no additional friction, eliminating problems associated with wear-related performance while providing better repeatability and longer live. To best meet individual application needs, customers can specify actuator size, stroke force, stall force, peak force, and other key performance requirements, providing an actuator that is completely customized for the end product.

Allegro MicroSystems has Released a New Addition to their Family of Current Sensors
Allegro MicroSystems has released a new addition to their family of current sensors. The ACS758 is a thermally enhanced, high-current, Hall-effect-based linear current sensor that provides an economical and precise solution for AC or DC current sensing. This device offers considerably higher bandwidth and reduced output noise when compared to Allegro’s older generation current sensor products. Typical applications include motor control, load detection and management, power supply and DC-to-DC converter control, inverter control and over-current fault detection.

The device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near the Hall sensor die. Applied current flowing through this copper conduction path generates a magnetic field, which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer, and through the integration of a high performance ferromagnetic core into Allegro’s custom CB package. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory.

The high level immunity to current conductor dV/dt signals and stray electric fields, offered by Allegro proprietary integrated shield technology, guarantees low output ripple and low offset drift in high-side, high voltage applications. The internal resistance of this conductive path is 100  typical, providing low power loss. The terminals of the conductive path are electrically isolated from the sensor leads (pins 1 through 3). This allows the ACS758 family of sensors to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

The ACS758 family is lead (Pb) free. All leads are plated with 100 percent matte tin, and there is no Pb inside the package. The heavy gauge lead-frame is made of oxygen-free copper. It is priced at $3.49 in quantities of 1,000 and has a six to eight week lead-time to market.

austriamicrosystems Introduces AS5311, the First Integrated Linear Hall Encoder to Break into the Submicron Resolution Range
austriamicrosystems, a designer and manufacturer of high performance analog ICs for communications, industrial, medical and automotive applications, has introduced AS5311, the first Hall-effect sensor based linear magnetic encoder to offer submicron resolution.

This integrated linear Hall encoder can be used as an alternative to optical encoders. For linear motion sensing, a multi-pole magnetic strip is used and for rotary motion sensing the magnetic strip is replaced by a multi-pole magnetic ring. For applications like this, an incremental output with a resolution of 10 bit per pole pair and a travelling speed up to 650 mm per second is available. Using for example a multi-pole magnetic ring with a diameter of 41.7 mm, a resolution of 16 bit (65.536 steps per revolution) can be achieved.

In conjunction with a 2 mm pole-pair magnetic strip, the AS5311 provides a 1.95 micrometer resolution signal at its incremental output and a 488 nanometer resolution signal at its serial output.

“austriamicrosystems’ AS5311 together with the magnetic strip are the only two components required to build a robust submicron-resolution position feedback system,” said Josef Janisch, Encoder Product manager at austriamicrosystems. “This small form factor allows AS5311 to be integrated in autofocus, zoom and vibration reduction systems in cameras, switching systems in fiber optics or other micro-positioning applications where tight space is a concern and high resolution is demanded.”

“The AS5311 is the first linear magnetic encoder with submicron resolution, based on our successful integrated Hall sensor technology,” said Matjaz Novak, director of Marketing Industry & Medical at austriamicrosystems. “It offers an attractive solution for applications where cost, high precision and small form factor are the constraints. With the AS5311, we want to offer a device which will allow system designers to implement position sensing solutions meeting all these constraints at the same time.”

austriamicrosystems’ encoder chip also provides extended diagnostic features that constantly monitor the placement of the magnet above the device. These features allow early detection of mechanical systems failures. In addition, the device compensates for the adverse effects of unwanted external magnetic fields thus ensuring additional safety and robustness of the system.

The AS5311 can be operated with either 3.3 V or 5 V supply voltage and is available in a 20-lead TSSOP-package. The device is specified for an ambient temperature range from -40° to 125°C.

Eriez Model HFP Drum in Housing with Feed Protection Offers Powerful Separation for Superior Product Purity
Eriez has introduced the advanced Model HFP Drum in Housing with feed protection, part of the company’s line of drum separators. The Model HFP Drum is specifically designed to provide increased efficiency of separation by regulating material flow to the face of the Drum. It also prevents material from plunging directly onto the drum shell, reducing the possibility of physical damage caused by impinging heavy material or heavy tramp iron.

The HFP Drum features exceptional controlled feed as well as discharge features. This equipment has a nonmagnetic stainless steel portion to prevent the hopper from being magnetically induced. Eriez’ exclusive hinged, telescoping, fully-adjustable stainless steel drum splitter allows the end user to fine tune the separation efficiency of the drum compared to other commercially available units.

Other features include three inspection panels that allow the user to view the critical areas of operation inside the housing while the unit is in operation. For ease of connection to duct work, all input and output openings are flanged.

Additional options include heavy-duty designs, explosion-proof motors, liners and special circuit designs for high temperature applications.

All Eriez Drum Separators employ a powerful Erium 3000 magnetic circuit to allow automatic separation of ferrous contaminants and to provide the highest level of product purity for a wide range of dry bulk materials.

Share your knowledge at next year’s conference!
Call for presentations deadline is July 31st. For more information visit the conference Web site or contact Heather Krier.

To learn more about the 2010 Motor, Drive & Automation Systems Conference, click here.

2009 Magnetics Conference Proceedings Now Available
Did you miss the 2009 Magnetics Conference? The conference proceedings from the 2009 Magnetics Conference held in Chicago, Ill. on April 15-16, are available on CD-ROM and include audio and video of select presentations.

Click Here to Order!

Metal Powder Trade Association Names President
Richard Pfingstler, president of Atlas Pressed Metals, DuBois, Pa., was named president of the Powder Metallurgy Parts Association (PMPA). A member of the Metal Powder Industries Federation (MPIF) in Princeton, N.J., PMPA represents major international manufacturers of precision metal parts made from metal powders.

Pfingstler has been active in the powder metallurgy (PM) industry, serving on the MPIF finance committee and board of directors of PMPA. He is a CPA and has a B.S. in accounting from Gannon University. He joined Atlas in 1980 and is the principal owner.

PMPA activities include market development, statistics, government relations, materials standards, professional education, industry safety & health, e-learning and technology transfer. “The association serves to promote the wider use of PM parts and improve the quality of our products,” Pfingstler said. “It is the champion of the industry rather than one company.”

PM parts are used in a variety of products such as lock hardware, garden tractors, snowmobiles, power tools, appliances, cell phones, sporting arms, oil and gas drilling equipment, aircraft engines, and surgical equipment. The average US-built vehicle contains more than 42 pounds of PM parts.

LMS Virtual.Lab Makes the World’s First Maglev Simulation a Reality
By Joris De Cuyper, Product Line Manager, Virtual.Lab Motion LMS International

With soaring oil prices and increasing pollution, the heat is literally on governments and transportation authorities to explore alternative options. The case for maglev technology is clear. Running on electricity, maglev trains can carry people and freight cheaper, faster, quieter and cleaner than trucks and planes. With dedicated guideways, the system does not contribute to urban congestion and the vehicle and track life span lasts 50 years or more with minimal maintenance - much longer than a truck or airplane.

Read full article here.

5/4 - 5/8
INTERMAG 2009
Sacramento, CA

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ISSUE INCLUDES:

• Research & Development
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• New Magnetics Products / Technology
• Industry News

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