IEEE Electrification Magazine - June 2014 - 15

By Khwaja M. Rahman, Sinisa Jurkovic,
Shawn Hawkins, Steven Tarnowsky,
and Peter Savagian

electric systems, such as the Chevrolet spark ev. the spark
ev has been introduced as a key part of gm's overall strategy for powertrain electrification.
many of the spark ev's electrification components, systems, and controls were evolved from existing programs,
including the Chevy volt. most of the vehicle's components and systems were leveraged from the Chevrolet
conventional spark architecture, introduced in north
america in 2012. a new drive unit (du) was designed specifically for an optimum combination of efficiency, performance, reliability, and cost as part of the propulsion
system for the 2014 Chevrolet spark ev. the du is a coaxial
transaxle arrangement that includes a permanent-magnet
(Pm) electric motor (em) and a low-loss single-planetary
transmission and is the sole source of propulsion for the
battery-only ev (Bev) spark. the Pm motor has been
designed by gm and is built in gm's newly developed
motor manufacturing line in Baltimore, maryland. the
spark ev transaxle provides high power density and low
system loss over a wide speed range, resulting in a classleading combination of vehicle performance and vehicle
range on a variety of global drive cycles. the battery pack
was designed with a high cell density to fit within the
allowable packaging volume. the motor and battery control systems are adopted from the Chevrolet volt. the
spark ev shares the traction power inverter module (Pim),
after slight modification, and onboard charger module
with the volt. additionally, the Chevrolet spark offers
options of off-board fast battery charging.

energy Diversification Through
Vehicle electrification
thirty-five percent of the world's energy and 96% of automotive energy comes from petroleum. the price of petroleum is
highly volatile, so a future price prediction is difficult. however,
most world energy forecasts predict a gradual increase in
petroleum prices. hence, the diversification of energy for automotive use is quite critical for sustained growth. on the other
hand, electricity is produced from diversified sources of energy, keeping its price stable. Figure 1 shows the u.s. electrical
energy production gwh. the energy for electricity production
comes from diversified sources at present, and the future projection predicts the same level of diversification. the projected
price of electricity is shown in Figure 2. the price of electricity
is predicted to stay quite stable because of this diversification
of energy sources. hence, an increasing level of electrification
in the automotive industry to displace the amount of petroleum usage with electricity is expected.
automotive electrification options are shown in
Figure 3. the level of electrification ranges from petroleum
conservation by a light level of electrification and/or
improved energy efficiency to an increased level of petroleum or biofuel displacement using a plug-in hybrid,
extended-range ev (erev) to full ev. the higher the level of
electrification, the larger the level of petroleum displacement with electricity. these classifications are further elaborated in Figure 4 with an explanation of the functionality
and description of the drive system. there are several
options in the conventional vehicle to improve vehicle fuel

The Spark EV has been introduced as
a key part of GM's overall strategy
for powertrain electrification.

IEEE Electrific ation Magazine / j une 2 0 1 4

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