International Rectifier Announces Technology Breakthrough in Power Electronics Systems For Automotive Alternators

EL SEGUNDO, Calif. - International Rectifier, IRŪ (NYSE: IRF) announces the production of the first Active Integrated Rectifier Regulator (AIRR) for automotive alternators. The AIRR has been designed by IR to Delphi Corporation's specifications for the alternator of the recently introduced DaimlerChrysler Maybach luxury vehicle.

The AIRR can generate substantially higher power levels in a smaller outline than traditional passive rectifiers and alternator regulators. This technology breakthrough opens the path for future power electronics development for next generation starter-alternators.

The AIRR combines a voltage regulator, which controls the output voltage of the alternator, with an active rectifier in one and the same module. The rectifier converts the alternating current generated by the alternator into the direct current required by the car electrical loads and battery. Simply put, active rectification is the replacement of passive diodes with active FETs to dramatically reduce power losses and increase fuel economy.


In the last decade, the automotive industry has seen a dramatic rise in demand for electrical energy, especially in light vehicles. More and more formerly purely mechanical functions are replaced by electrical and electronic systems to increase fuel mileage, reliability and safety.

"The development in electrical power generation in vehicles has been struggling to keep up with electrical power demand. The transition to new technologies for power generation has so far been too challenging to allow a widespread adoption," says Peter Sommerfeld, Director of Engineering, Power Generation Systems, Automotive Business Unit, at International Rectifier. "Active rectification has been discussed for a long time. We are the first to develop the technology to the point where it can be implemented in a production vehicle."

Bringing the AIRR to production is a milestone in the technology roadmap for automotive electrical power generation. The performance of active rectifiers with state-of-the-art power MOSFETs can improve the output power of today's standard alternators by up to 25% at idle speed, where most generation systems are underpowered. As the automotive electrical power requirements continue to increase from hundreds of watts today to several kilowatts in the near future, alternator technology itself will change, moving to belt-driven or crankshaft-mounted starter alternators. The new power generation architecture will require a new set of expertise for implementation of the power electronics sub-system.

To develop the AIRR, IR combined its complete set of expertise in power systems design and manufacturing. Leveraging its leadership in power semiconductors and power ICs, IR has developed its extensive skills in electromechanical design, packaging technology, analog and digital control, testing capabilities and quality systems. This unique skill set puts IR in a premier position to deliver the complex electronics sub-systems that will be required by future starter alternators.

"Electrical power generation will require new thinking in power electronics," added Sommerfeld. "IR has strategically chosen to invest in this market where our unique set of skills will enable customers to cost-effectively implement future power generation technology."

Technical Information

The first production AIRR has been designed for a very large alternator with 350A output at 6000 revolutions per minute (rpm) at cold temperature, and above 200A output at idle. The module is capable of handling 525A for 20 seconds. The AIRR has passed specified qualification testing as required by the customer.

IR's AIRR can be provided with standard regulation with internal temperature compensation, load response control regulation, or intelligent regulation with bi-directional communication to the engine control unit (ECU).

For more information:

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