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DOE Offers $16 Million for Research In Power Electronics and Motors for PHEVs, HEVs and FCVs

DOE’s National Energy Technology Laboratory (NETL) recently issued a solicitation for the development of power electronics and electric motors for use in plug-in hybrid (PHEV), hybrid (HEV) or fuel-cell (FCV) vehicles.

DOE estimates that $16 million will be available over three or four years to support two to six awards selected in four areas of interest. The projects will be phased, with Phase I consisting of design, modeling, and initial research and development (R&D). Based on evaluation of the concept and a go/no-go assessment, the project may proceed to Phase II for continued development, demonstration and testing and analysis.

The four areas of interest are:

  • High Temperature Three-Phase Inverter for Advanced Hybrid Electric Vehicles (HEV) including Internal Combustion Engine HEV, Plug In HEV (PHEV), and Fuel Cell Vehicle (FCV) Traction Drive Applications.

  • High Speed Motors for Advanced Hybrid Electric Vehicles including Internal Combustion Engine HEV, Plug In HEV (PHEV), and Fuel Cell Vehicle (FCV) Traction Drive Applications.

  • Integrated Traction Drive System for Advanced Hybrid Electric Vehicles including Internal Combustion Engine HEV, Plug In HEV (PHEV), and Fuel Cell Vehicle (FCV) Traction Drive Applications.

  • Bi-directional DC/DC Converter for PHEV Applications.

Inverters. Inverters convert direct-current (DC) battery power into alternating current (AC). The inverters in current hybrids require cooling, which add to the cost of the system. An inverter able to operate at high temperatures would reduce hybrid system costs.

Advanced inverters are needed in all three classes of hybrid vehicle application (plug-in, combustion engine, and fuel-cell). DOE notes that high-temperature inverters are especially important for combustion engine and plug-in hybrid applications because the mid- and long-term paths involve a transition to higher-temperature coolants.

Future availability of advanced, high temperature (together with lower cost, weight, and volume) inverters will advance the marketplace application of highly fuel efficient and environmentally beneficial hybrid vehicles.

Currently, inverters in hybrids use 70° C coolant supplied via a separate cooling loop in the automobile. DOE’s goal is to produce an inverter that can operate reliably using ambient air without mechanical augmentation (e.g., fans, air compressors, etc.) as the cooling fluid.

Among the requirements for the inverters are:

  • Reliable operation for 15 years;
  • Rating of 55 kW peak at the coolant temperature;
  • To be no larger than 4.6 liters in volume and weigh no more than 4.6 kg to enable successful integration into the drive system of an automobile;
  • Total cost not to exceed $275 in large (100,000 units per year) production quantities; and
  • Baseline voltage of 325V nominal, with provision for scaling to higher voltage levels.

High-speed motors. Although DOE says that it favors interior permanent magnet (IPM) motors for hybrid designs in which the electric traction drive system is used for a significant portion of the duty cycle, it will also consider other advanced motor technologies.

The goals for this area of interest are to develop advanced motor technology that achieves reductions in size, weight, and cost compared to current IPM motors. The specific goals are for a brushless DC motor that:

  • Produces 55 kW peak power for 18 seconds and 30 kW of continuous power;
  • Weighs no more than 35 kg;
  • Occupies no more than 9.7 liters in volume;
  • Costs no more than $275 in production volumes of 100,000 units per year;
  • Uses a design that is scalable to 120 kW peak power for 18 seconds and 65 kW continuous;
  • Operates at 325V nominal, with consideration given to operation at higher voltage levels; and
  • Can be driven by a standard three-leg inverter with no additional circuitry.

The most promising method for attaining these targets is to increase the operating speed of the motor. The power level of the motor (at constant torque) is directly proportional to speed. Thus doubling the motor speed produces a motor with double the power. Over the past several years motor speeds have increased from 6,000 rpm to 14,400 rpm. This has resulted in the traction drive motor becoming smaller and lighter. It is anticipated that motor technology developed under this area of interest will leap frog current trends and focus on the development of a brushless dc traction drive motor with an operating speed in excess of 14,000 rpm.

Integrated Drive System. The electric drive system consists of the electric motor, power electronic inverter, and DC/DC converter (if needed. While current electric traction drive systems “are acceptable for the early adopter market...they are too costly, heavy, and bulky to allow the HEV to become a mass market option,” according to DOE.

DOE is seeking an integrated traction drive system that can:

  • Produce 55 kW peak power for 18 seconds and 30 kW of continuous power;
  • Be based on a design that can scale to 120 kW peak power for 18 seconds and 65 kW continuous power to accommodate a variety of automotive platforms;
  • Operate reliably for 15 years;
  • Cost no more than $660 to produce in quantities of 100,000;
  • Weigh less than 46 kg and occupy a total volume of less than 16 liters;
  • Operate with the use of engine coolant at a nominal temperature of 105° C;
  • Offer a system efficiency of greater than 90% at 20% of rated torque over 10% to 100% of maximum speed; and
  • Operate at 325V nominal with consideration to operating at higher voltage levels.

Converters. DC-to-DC converters transfer DC power between a low-voltage battery pack and the high-voltage electronics used in hybrid vehicles, allowing the use of a smaller battery pack that operates at a lower voltage.

DOE is asking that Phase I activity include a systems optimization study to determine the vehicle system tradeoffs associated with higher-voltage operation of the electric traction drive system in a PHEV application. The purpose of this study is to establish the need for and level of voltage boost that should be included in the converter. Phase II work would focus on design and testing of a prototype unit.

The converters should:

  • Be capable of transferring at least 5 kW of power between low- and high-voltage buses and provide the necessary voltage boost to the traction drive system;
  • Cost no more than $75/kW;
  • Have a power density of at least 1.0 kW/liter and a specific power of at least 0.8 kW/kg; and
  • Operate with an inlet coolant temperature of 105° C

Applications are due by 15 November. Full details are in the solicitation on the NETL Web site.


Harvey D.

Why is DOE so specific on the type of technology.

Why not keep to difficult but achievable objectives such as weight/size, power/weight ratio, unit and total efficiency %, cost/KW, life expectancy, life time maintenance cost, recycle possibilities, etc and let the researchers select the specific technology.

A more diversified R & D approach could be more beneficial and end up with competing ways to reach the same objectives.


By the time, DOE finishes this project, Toyota will already have introduced a new Prius which will blow the current Prius and the competition away, including, perhaps, plug in technology. I am sure they are spending far in excess in R&D than this trivial amount of money DOE is spending.

Government should setting mandated goals for private industry to meet. Dicking around with these little R&D projects is a waste of time and money.


This is just "Window Dressing". DOE pisses away more than $16M on paper clips.


If the DOE wants to spend R & D $ to support PHEV development, I'm all for it. Maybe some other car company will come out with a better product in a few years, but what if they don’t? No one is mass producing Plug-In Hybrid cars right now. Government mandates sound nice, but I’m not counting on it.

George K

I’m just not seeing the negativity that some are here??!

We have read that Toyota is talking about future hybrids having smaller and cheaper hybrid parts in order to mass market. When I read this article targeting specific hybrid parts being smaller and cheaper, I thought, “way to go DOE”! Focusing some R&D money on specific areas that need enhancing in hybrid drive trains to sell to the mass market, has to be a good idea.

Rafael Seidl

It's good to see the DOE spending money on R&D for electrc traction, especially since it's not focussed on FCVs to the exclusion of all else. However, I share Harvey D. suspicions about the detailed targets being defined here: exact weight, size, voltage, cost etc.

Government spending ought to focus on longer-term, high risk/high reward research on fundamentals. For PHEVs, that would include investigating policy and technology approaches to prepare the distribution grid for the additional load as well as V2G operation.

Instead, the grants on offer here are focussed on near-term product development, which the private sector is heavily investing in anyhow. It all sounds very much like earmarks narrrowly tailored to funnel taxpayer money to specific contributors to political campaigns, though admittedly I cannot prove that.


Rafael, you hit the nail right on the head. (an American expression :) You got it right. Conservative ideology says "government should not pick winners and losers", but when it comes to funneling public money into private accounts, then you can "throw money at the problem".

George K

“… tailored to funnel taxpayer money to specific contributors to political campaigns, though admittedly I cannot prove that.”.

Rafael, I’m surprised. Usually these types of comments are beneath you.


Rafael, you are correct that the winners of these grants are "pre-selected". But not because of political contributions. Contributors at the national level focus on multi-billion dollar Iraqi logistics awards and such, not piddling million dollar per year R&D grants.

This is pure bureaucrat/contractor collaboration. One or more contractors want funding for a pet PHEV project and found a DOE bureaucrat to sponsor it. The contractors will drop this drive train into a demo vehicle and use it to attract investors and/or customers. What motivates the bureaucrat? It could be a strong belief in PHEVs and/or admiration of the contractors (who may be small, spunky little outfits that have fought the odds for a long time). Perhaps he envisions a podium seat for himself when the President unveils "the solution to our dependence on foreign oil". Maybe he just likes the restaurant (or strip club) the VP of Marketing takes him to each Thursday. Maybe he's nearing 20 years of civil service and has noticed the contractor's record of hiring helpful ex-bureaucrats. Maybe his boss told him: "the Prez keeps speechifying about PHEVS -- bring me something by yearend". Most likely it's a combination of these types of factors.

Lead contractor is probably someone like AC Propulsion, but focused on permanent magnet DC motors instead of AC induction. Any ideas? The DC/DC converter specs are weird. 5kW does no good for traction, and why the need for liquid cooling? Sounds like they've mixed together a traction converter (like the Prius uses) with a secondary converter designed to eliminate the 12V battery. Liquid cooling might make sense for the former, 5kW for the latter.


Any money spent on non Fuel Cell crap is good news to me. This is a product of the PNGV - Freedom Car program, they may have already selected the winners, but the requirements are from the Ford, GM folks who already have a system designed


These specs have been around forever. In fact, one of the freedom car participants pretty much achieved the goals for the motor part of the solicitation, except for missing the efficiency part by almost enough to make mechanical drivetrains attractive. Since this is not in line with the DOE's predictions, money must be spent on a certain technology until the DOE is proven right. Enough DOE bashing, some may find it offensive. Does anyone know who if anyone received an award?

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