International Rectifier's new power modules cut drive design risk

El Segundo, Calif. - Good news for designers and developers of customized motor controls, International Rectifier has raised the bar for intelligent power modules with its new iNTERO family that incorporates 130 components, extra functions, and an optional controller in one compact package.

05/28/2002


El Segundo, Calif. - Good news for designers and developers of customized motor controls, International Rectifier has raised the bar for intelligent power modules with its new iNTERO family that incorporates 130 components, extra functions, and an optional controller in one compact package. The product line targets industrial motor drives that control servo, brushless dc, and ac induction motors up to 15 kW rating.

First member of the iNTERO family is a programmable, isolated intelligent power module (PI-IPM), rated at 50 A and 1,200 V. It's the most integrated device within the family. PI-IPM's core is a complete three-phase inverter in a module dimensionally compatible with the popular "EconoPack."

Besides the power stage, PIIPM50P12B004 incorporates a programmable digital signal processor (DSP) for logic; encoder feedback signal; current sensing; gate driver; isolation; and a power supply. Power stage protection features allow direct interface to the system controller and input stage. "The only additional components needed to make a complete drive are an input stage, brake, and capacitor," said Odile Ronat, director of outbound marketing at International Rectifier (IR), on a recent visit to Control Engineering.

Innovative module

The power module serves as a building block for the iNTERO family, but is a standalone product, as well. In the PI-IPM version, the module is configured with an embedded driver/controller board and a high-voltage gate driver. However, module footprint remains unchanged. Six latest-generation IGBTs (insulated-gate bipolar transistors) are used in the power stage, while the embedded controller contains a 40 Mips DSP. To simplify interfaces and reduce wiring, power pins to motor windings, signal pins, and dc bus connections are incorporated into the basic module package.

"Having the control board within the same compact package is novel," says Ms. Ronat. Ability to place the controller with its DSP atop power-switching IGBTs speaks for the module's thermal and electrical design. The six-layer power module design is said to shield electrical noise and hold down the size of EMI filters. Use of non-punch through type IGBTs, which have lower intrinsic noise, contributes to the solution.

Also novel are the four current sensing resistors integrated into the module. There is one for each drive output phase and one for the dc bus. "This ensures precise current sensing and short-circuit protection, explains Ms. Ronat." The sensors provide undervoltage and overvoltage shut-down protection; and they have a further safety role, because of their ability to detect loss of isolation in the motor winding, or connecting cables, before a forced shutdown occurs.

With its 5 kHz bandwidth current feedback loop, PI-IPM provides the level of control needed for high-performance servo motors-including low torque ripple, especially at low-speed.

Other benefits, future modules

Integrated power module design has become too complex for most motor drive developers to do themselves. Availability of this specialized hardware permits OEMs and end-users to concentrate on software and application aspects of building customized motor controls. Benefits extend to product planning and scheduling, because project risks are reduced through well-defined development costs, 50% faster time to market, and lower costs, says IR.

iNTERO was announced at the PCIM 2002 (Power Electronics, Intelligent Motion, Power Quality) Exhibition and Conference in Nuremberg, Germany, May 14-16. Sample devices are available now and volume production starts in Summer 2002. PIIPM50P12B004 is priced at $500 each in 500-unit lots. Software development tools are available.

Other iNTERO devices are coming. Three device variations-inverter, bridge-brake, and inverter-bridge-brake combination-are planned for later in 2002 with outputs up to 15 kW at 600 V or 1,200 rating, according to International Rectifier.

Control Engineering Daily News Desk
Frank J. Bartos, executive editor
fbartos@cahners.com