On Semiconductor Debuts Two Power Modules for Traction Inverters in EVs

December 17, 2019 by Gary Elinoff

ON Semiconductor has rolled out the first two devices in its VE-Trac family of power modules for traction inverter designs.

ON Semiconductors has released the first devices in its VE-Trac family of power modules for traction inverter designs. 


VE-Trac Dual.

VE-Trac Dual. Image from ON Semiconductor

The new power integrated module (PIM) devices are geared for automotive reliability in plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV), and full hybrid vehicles (HEV).


What are Traction Inverters?

Traction inverters convert the DC current from an EV’s battery into the AC current required by the vehicle’s motor. Inverters operate at either 400V (HVL1) or 800V (HVL2) levels, the latter being more popular in the latest designs.

For a safety margin, these devices need power semiconductor devices rated in the 600V to 750V or the 900V to 1200V ranges. In addition, current levels at up to 1000A must be accommodated.

Traction inverters can be built by paralleling discrete devices, or, as of late, from power integrated modules (PIM).

The First Two Members of the VE-Trac Family

ON Semiconductor offers two design platforms from which they will roll out the new traction inverters: VE-Trac Dual and VE-Trac Direct.

VE-Trac Dual will consist of Dual Side Cool (DSC) half-bridge modules. ON Semiconductor intends for them to be stackable and scalable with compact footprints for traction applications. The first member of this sub-family is the NVG800A75L4DSC


VE-Trac Dual NVG800A75L4DSC.

VE-Trac Dual NVG800A75L4DSC. Image from ON Semiconductor

VE-Trac Direct devices will be designed to offer direct cooling for better thermal performance. The devices will be housed in the popular six-pack configuration. The first member of this sub-family is the (PDF) NVH820S75L4SPB, which is AQG-324 qualified.


VE-Trac Direct Module NVH820S75L4SPB.

VE-Trac Direct Module NVH820S75L4SPB. Image from ON Semiconductor

Commonalities Between the New Traction Inverters

Both members of the VE-Trac family include direct bonded copper (DBC) substrates for thermal conductivity and both offer 4.2kV isolation. 

The devices also offer ultra-low stray inductance and low collector-to-emitter saturation voltages.

While ON Semiconductor intends for the devices to be most applicable in electric vehicle applications, they may also be an appropriate option for high-powered DC-DC converters.

These units are said to operate continuously at 175°C and are Pb-free and RoHS compliant. 


The NVG800A75L4DSC

The (PDF) NVG800A75L4DSC is part of a family of power modules designed with compact footprints, dual-side cooling, chip-level current, and temperature sensing. 

The 750V, 800A unit consists of two-field stop 4 (FS4), narrow mesa IGBTs, which are arranged in a half−bridge configuration.


Block diagram of NVG800A75L4DSC

Block diagram for the NVG800A75L4DSC. Image from ON Semiconductor

For easier implementation of the module, ON Semiconductor offers an inverter kit—the NVG800A75L4DSC−EVK—along with a dual-side liquid cooling heat sink reference design.


The NVH820S75L4SBP

This device is a power module set in what ON Semiconductor describes as an "industry-standard footprint" for easy deployment into EV and HEV tractor inverter applications.

The (PDF) NVH820S75L4SBP module incorporates its 750V FS4 IGBTs into a 6-pack configuration. This arrangement is intended to provide high-current density, increased blocking voltage, and solid short circuit protection. The device is also built to lower power losses during lighter loads, which would save power in automotive applications.


Block diagram of the NVH820S75L4SBP

Block diagram of the NVH820S75L4SBP. Image from ON Semiconductor


In order to increase reliability and to simplify assembly, ON Semiconductor incorporated press-fit pins into the power module signal terminals. To this same end, the module deploys an optimized pin-fin heatsink in the baseplate.

Looking beyond these first two devices, Asif Jakwani, ON Semiconductor's VP & GM of the high power division of the power solutions group, commented that  "Future announcements will include devices with higher and lower voltage capability than the initial two devices.” 


Evaluation and Support Tools

The VE-Trac Dual EZ Kit for the NVG800A75L4DSC—the NVG800A75L4DSC-EVK—comes with three NVG800A75L4DSC modules mounted on dual-side cooling heatsinks and a 6-channel gate driver board.



NVG800A75L4DSC-EVK. Image from ON Semiconductor

It also includes a DC-link capacitor and external hall-effect current sense feedback for motor control. 

The VE-Trac Direct EZ Kit for the NVH820A75L4SPB—the NVH820S75L4SPB-EVK— includes one single NVH820A75L4SPB direct power module mounted in a cooling jacket.



NVH820S75L4SPB-EVK. Image from ON Semiconductor

In a similar manner to the VE-Trac Dual Evaluation Kit, this tool aims to help customers evaluate the power module’s performances in the early stages of development.