Power Interface Considerations For Proposed IEEE

Recommended Practices For Integrated Power Packages

 

Purpose:

To promote standardization of the power interfaces for integrated power electronic modules. The power interface consists of the power supply (source and return) and load terminations. Standardization will facilitate application of power electronic building blocks into mechatronic systems leading to lower cost and more durable functional units. Commonization is required for example to insure that a power electronic module when installed in the application system meets all applicable regulatory requirements such as IEC 1003-2 and 4, IEC555 and IEEE 519 among others.

 

There will be issues with commonality of the power interface when addressing the integration level of power electronic modules. Physical partitioning will be very crucial to a determination of module content. Integrated modules can range from packaged power devices to power plus gate driver to power stage plus driver stage plus application specific logic circuits. Whether or not bus and device snubber capacitors are integrated is highly application specific. Standardization efforts are aimed at providing guidelines to higher levels of integration.

 

Cost is an overarching criteria to any standardization effort and is especially crucial to integrated power modules developed for automotive and commercial application. Only with the synergistic role of packaging, thermal and control interfaces along with the power interface can commonization efforts succeed.

 

Scope:

The power interface recommendation is intended to cover the main power processing ports - supply and load of all module types specified in the packaging guidelines. A power integrated module processes power according to information content at the control interface and within the confines of the thermal and packaging constraints. Functions covered include, but are not limited to:

 

power supply bus type (such as dc, ac, or resonant)

passive components integrated into the bus (integrated bus capacitors or inductors)

passive components integrated into the load (filter components, dv/dt limiting, harmonic tuning/shunting, RFI limiting etc)

source and load structure (such as current or voltage sourcing with voltage or current sinking/loading respectively)

proximity of energy storage components to the power module

stability constraints of the supply and load ports for a range of application

regulation limits on supply and load ports

emission limits on supply and load ports (conducted and radiated susceptibility)

ground path leakage (includes noise injected into heatsink and capacitively coupled via the load back to the module control circuits)

Recommendations:

It is recommended that the following attributes become common for standard power interfaces. Power interfaces for custom and semi-custom packages are not covered by these recommendations. Also not included in these recommendations are power interfaces for power amplifier classes A, B. AB and C in which power processing elements remain in the active region for prolonged periods of time. The recommendations however are valid for all class D and S type power processors that rely on fast transitions between the conducting and blocking states. For the power interface these recommendations can be grouped into hard switched and resonant mode configurations

 

Hard switched power processing subjects the module internal switching devices to simultaneously high voltage and current stress during both turn on and turn off.

 

Resonant mode power processing limits the module internal switching devices to either current or voltage stress during transitions but not simultaneously.

 

Attributes:

over-voltage at power supply bus, range

short/open circuit at load port

reflected voltage at load port (long cable effects)

harmonic content at supply and load ports

methods of bus and load termination attachments (coordinate with packaging std)

Specific Recommendations:

Whether or not to integrate passive components such as turn ON and turn OFF snubbers into either hard or resonant mode integrated power modules is dependent on the device technology used and the capability of the gate driver stage.

 

Physical partitioning of the integrated power module impacts the power interface and is dependent on the value added by higher integration as a function of power level. Cost is a motivator here, but will not be minimized without commonization.

 

Issues with noise and circuit interactions must be minimized but are strong functions of the thermal interface and control interface specifications. In an ac motor drive the gate driver and device self protection circuitry are best integrated but the PWM function is likely best either a stand alone component or the function is performed by the application processor.

 

JMM 1 1/29/96


 

PAR 1461 POWER INTERFACE

 

Alan R. Gale
PNGV E/E Team


Power Interface IEEE RP1461

Definition of the power interface: Includes the source power port and the processed power or application port. The power module uses control/information at the control port to process power at the application port.

Control Port:

Commands, status, fault (self protection, desat)

Communications (J 1850 - assumes CAN)

Logic power

Source Power Port

Power supply bus type

Mechanical configuration

Transient suppression/mitigation

Stability of source (line lengths)

Regulation characteristics

Leakage paths & isolation requirement

Emissions (conducted & radiated)

Applications Port

Load category (UPS, Electric Machine, Power Converter dc/ac, ac/ac etc)

Modulation attributes (square wave, pulse width modulated, pulse density modulated, pulse burst modulation)

Switch mode category (hard or soft)

Electric machine category (VRM, IM, SPM, IPM, Sync. Rel)

Transients (lone cable effects. dv/dt limits)

Packaging: Stand alone or for direct integration to application

Power Interface IEEE RP1461

Electrical Tests

Coordinated between control port and applications port given specific conditions at source port.

Functional Diagram

Attributes

Specifications

Application will determine power interface termination definition. In the case of power converters or for VRM the power module can be either configured as full controlled H-Bridge drive or as half controlled H-Bridge. In the case of other motor types the m-phase configuration is appropriate.