Reza Tavakoli, Aleksandar Jovicic,Niranjan Chandrappa, Ryan Bohm, and Zeljko Pantic (Assistant Professor)
Utah State University
Design of a Dual-Loop Controller forDynamic Wireless Charging of an Electric Bus
SELECT Annual Meeting and Technology Showcase – Logan, Utah – September 27-28, 2016
MOTIVATION In the past decade, there has been a significant interest toward transportation electrification and more specifically
electrification of roadways.
Limited onboard energy and power storage is identified as the main challenge toward successful implementation of
Electric Vehicles (EVs).
Emerging technology of Dynamic Wireless Power Transfer (DWPT) offers an alternative solution for limited onboard
energy resources through hybridization between vehicles battery storage and the power grid.
This technology not only extends the EV range significantly but also results in the considerable reduction of battery size
and capacity.Retrieved from: http://money.cnn.com/2015/08/18/technology/uk-electric-cars-roads/
PROBLEM STATEMENT
Sec.Comp.
Buck Battery Pack
Pri.Comp.
Inverter 20-100 kHz
AC Main( 60 Hz)
Primary coils
Secondary coil
PrimaryCurrent
Pri
ma
ry S
ide
Seco
nd
ary
Sid
e
• Energize Primary Coils Successively
• Control the primary coil current at the reference value
• Limit the transferred power
SYSTEM OVERVIEW
Current Controller Giv(s)
Power Controller
Gpi(s)PDC
P*
PDC
Err I* IPri,RMS
SS model ofLCC & Primary coil
SS model of LCC & DC link
Err Vinv,f
EVDS signal
Controller System Model
IPri
PIController
Initial Start-up
I*
IPri
Vinv,fPI
Controller
Equation
I*
IPri
P*
PDC
CONTROLLER OPERATION
BatteryCurrent
PrimaryCurrent
BatteryCurrent
PrimaryCurrent
BatteryCurrent
PrimaryCurrent
INITIAL START-UP
Pri
. Cu
rren
t (A
)
RM
S P
ri. C
urr
ent
(A)
Energizing of each primary coil is initiated after EV is detected:
Feedforward loop (6 ms)+Delay (1.5ms)+ PI controller (2.5 ms) = 10 ms
SEGMENTED COIL OPERATION
• When the detection system detects an
EV, the controller automatically
energizes the 1st coil.
• If the PDC is more than the limit (20
kW), the controller reduces the primary
current to keep the transferred power
constant.
• When the power transfer is finished,
the controller turns off the primary coil.
• The controller estimates the EV speed
and energizes the 2nd coil after a
calculated delay.
• This activation scheme can be repeated
for additional coils in the same manner.
ACKNOWLEDGMENTFunding provided by USTAR, the Governor’s Office of Energy Development in Utah, and Utah State
University. The Authors acknowledge research support from the Electric Vehicle and Roadway group
at Utah State University.
