IEEE Power Electronics Magazine - September 2023 - 38

We know that charging cables
can be connected to all sides of EV
(front and back; left and right) for
different reasons, and, as a consequence,
various situations may arise
in practice. For example, sometimes
drivers need to route the cable over
the roof or trunk of their car, or
walk-through snow, or untwist the
cable first, to be able to connect it
to the charging point.
Latest trend in the development of city parking lots,
with very few support pillars, presents a problem that
there will be no walls to place wall-boxes for conductive
charging. In addition, for future 100% automated parking
garages, drivers will not have access to the parking spot,
hence will not be able to plug into a conductive charging
wall-box either. For fully-automated ICS, this would be no
problem and, hence, there would be no challenges to the
drivers. The desired features of an automated ICS can be
summarized as:
■ Technologically mature for mass production.
■ Average charging efficiency (depending on vertical and
horizontal alignments) >90%.
■ Charging of all types of passenger vehicles (sport, sedan,
and SUV) with one common GPM.
■ Power transfer through materials (if GPM is buried).
■ Intelligent and safe [to comprise, e.g., foreign object
detection (FOD) and living object protection (LOP)].
■ Working with parking X/Y-axis misalignments of
±75/±100 mm and angle-misalignment (e.g., yaw, pitch,
and roll), respectively.
Inductive Charging System
The era of wireless power transfer started more than a
century ago with the work of Nikola Tesla [9], a Serbian-American
scientist and inventor. However,
research interest in this topic started to increase only
in the last 22 years [10]. Having reviewed 15 review
papers on the topic it was noticed that researchers'
focus was on: power transfer, efficiency increase, coil
design, materials, control, compensation circuits, ancillary
and protection features, standards, etc. [11]. The
only topic that was not covered, in the analyzed literature,
is the auxiliary power supply of the ground
23% drivers in 2021
and 18% drivers
in 2022 were
willing to buy an
automated ICS.
assembly, details of which can be
found in [5], [12], and [13].
The generic high-level block diagram
of the power flow of an ICS is
shown in Figure 2 [11]. It comprises
input filter, power factor correction
(PFC), dc link, inverter, primary
tuning circuit, primary and secondary
coils, secondary tuning circuit,
rectifier, and dc-dc converter. Note
that in BRUSA the term " tuning circuit "
is used, whilst in other sources authors use the
terms " compensation network " or " impedance matching
network. " The power transfer takes place at 85.5 kHz
as defined per standard IEC 61980-3 [14]. The auxiliary
power supply and other ancillary systems are not shown
in Figure 2.
From an engineering perspective, the system complexity
can be classified into six categories:
■ Power electronics hardware
■ Ancillary-functions hardware
■ Coil and magnetics design
CPM parameter
Table 1. CPM specifications.
Value
Ground clearance (full power transfer)
123-224 mm
Battery voltage range, full power transfer 525-825 V
Battery voltage range, power derating
Cooling
470-525 V
Liquid, forced
Table 2. GPM specifications.
GPM parameter
Input power
Value
3.7-11 kVA
DC link voltage range, full power transfer 650-850 V
Ground-car clearance
Ambient temperature range
Cooling
Air, forced
Z1-Z3 height classes
−40°C to 50°C
FIG 2 High-level generic block-diagram of an ICS (power flow
only) [11].
38 IEEE POWER ELECTRONICS MAGAZINE z September 2023
FIG 3 The CPM (upper) and GPM (lower) modules of the first
generation ICS 3.6 kVA. Source: BRUSA Elektronik AG.
IEEE Power Electronics Magazine - September 2023

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