IEEE Electrification Magazine - June 2014 - 36

model #l-1150, at the Mine expo international, las vegas.
this vehicle has ruggedized power electronics with control
and gate driver circuits designed, developed, qualified to
specification as per design requirements, and manufactured
by John Deere electronics solutions (JDes), formerly known
as Phoenix international. JDes is a business unit of Deere &
company, based in Fargo, north Dakota. the Joy Global vehicle l-1150 carries
an onboard engine with 898-kW power
with a payload of 34,473 kg. the vehicle
propulsion system is based on four
high-efficiency switched-reluctance
(sr) traction motors and one sr generator with reduced maintenance
requirements. the drive system uses
high-power iGBts in a chopper configuration. the vehicle travels at a maximum speed of 12 mi/h in either
direction. the electric drive with
onboard electric braking system
enhances productivity with decreased
fuel consumption while providing the
capability of full stop without the use
of any mechanical brake. Figures 6 and 7 are photos of the
l-1150 machine using sr technology. it is proven that the
electrification of heavy-duty, off-highway construction vehicles could result in a significant savings of fuel and fluid
because of increased efficiency and system simplifications.

John Deere has numerous products in its portfolio, which are
now public knowledge, and the success stories behind some
of these products are narrated in the following sections.
in March 2011, John Deere released its first hybrid wheel
loader, the 644K, at the World of concrete show in las vegas.
the 644K hybrid, which was first previewed at conexpo 2011,
incorporates a John Deere Powertech 6.8-l interim tier 4-emission certified diesel engine and Deere's electric drive technology

for heavy-duty vehicles, which consists of a generator, inverter,
motor, and brake resistor. as per a John Deere press release,
operators will see a 25% fuel savings as compared to the conventional hydraulic powertrain. ruggedized power electronics
parts and systems for the 644K hybrid loader are designed,
manufactured, and qualified by JDes, Fargo. Figure 8 is a photo
of the John Deere 644K hybrid loader.
the hybrid technology used in the
644K hybrid loader enables the engine
to run at a constant speed region, and
this will ultimately reduce the maintenance costs due to the elimination of
wear and tear as the engine ages and
as operating hours are accumulated on
the vehicle. this is quite different as
compared to the conventional hydraulic drivetrain where the engine speed
varies over a wide range while the
loader is handling the payload. therefore, as anticipated, during the design
phase of the hybrid vehicle, it is determined that the electric drivetrain is
proving its abilities to reduce the maintenance costs, significantly reduce the vehicle's downtime,
and increase the productivity and performance due to the
increase in the vehicle's uptime. the increased cost of an
additional Us$53,000 per vehicle did not deter the customers who purchased the electrified 644K loader because of
the fuel savings it would provide in addition to the competitive advantage due to the increased performance and productivity. customers want more hybrid machines of
different sizes, and John Deere is expected to meet these
demands through continuous efforts to improve vehicles'
performance and productivity through its vehicle electrification programs.
For heavy-duty, off-highway vehicles with engine powers of 150 kW and greater, it is pertinent to state that, once
dc voltage bus is available on an electrified vehicle, it could

Figure 6. An L-1150 machine that uses ruggedized power electronics.

on display.

The detection and
accurate diagnosis of
these problems on
the drive system and
vehicle plays an
important role in the
overall robustness of
electric vehicles.

John Deere Construction Vehicles

I E E E E l e c t r i f i c ati o n M agaz ine / j un e 2014

Figure 7. The ruggedized power electronics for the L-1150 machine

Table of Contents for the Digital Edition of IEEE Electrification Magazine - June 2014