Optimal design methodology for llc resonant converter in battery charging applications based on time weighted average efficiency To Get this projects Call : 9566355386 / 99625 88976 Visit : www.lemenizinfotech.com / www.ieeemaster.com Mail : projects@lemenizinfotech.com

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Optimal Design Methodology for LLC
Resonant Converter in Battery Charging
Applications Based on Time-Weighted
Average Efficiency
Abstract
The problems of storage capacity and weight reduction
represent the challenging issues for many EV applications.
Lithium-ion (Li-ion) batteries are becoming mainstream power
sources of vehicles among various batteries due to their
superiorities such as high energy density, long cycle life, high
voltage, and absence of memory effects. However, with the
improvement of battery performance, charging algorithms of
these batteries keep gaining complexity so as to maximize
battery life and shorten the charging time. Smart battery
chargers with high efficiency and high power density are needed
to implement high capability battery fast charging, which should
also meet the widely variable battery voltage requirements of
charging algorithms. A battery charger usually consists of an ac–
dc converter with power factor correction (PFC) and a followed
isolated dc–dc converter. Conventional pulse-width-modulation
converter with high switching frequency leads to degraded
efficiency, in spite of high power density. Therefore, soft

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36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue,
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switching converters are proposed for high switching frequency
applications, such as phase-shift converter and resonant
converter. Among these converters, LLC resonant converter with
high efficiency and power density is widely used. Zero voltage
switching (ZVS) at primary side and zero current switching
(ZCS) at secondary side are implemented to achieve high
efficiency. Moreover, this converter can operate at a wide output
voltage range with a comparatively small variation of switching
frequency.
Existing system
The LLC resonant converter is receiving a lot of attention
because of its high efficiency through zero voltage switching
(ZVS) and its narrow operating frequency variation under
overall load conditions, despite the fact that designing these
converters is somewhat complicated.
Proposed system
Although LLC converters have been used in many
applications with constant output voltage, the design
requirements of charging applications are significantly different
due to the fact that voltage and conversion efficiency vary with
the state-of-charge (SOC) of batteries during charging process.
To evaluate the efficiency adequately, a new TWAE index is

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LeMeniz Infotech
36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue,
Pondicherry-605 005.
Call: 0413-4205444, +91 9566355386, 99625 88976.
Web : www.lemenizinfotech.com / www.ieeemaster.com
Mail : projects@lemenizinfotech.com
defined to assess the performance of charger, which represents
the average weight of conversion efficiency under different
conditions. Compared to normal applications, a wide operation
range will be achieved and TWAE needs to be optimized in
order to reduce the total energy losses in battery charging
process. A variable-step exhaustive search algorithm is
presented in this paper to optimize the converter parameters for
high TWAE.
Advantages
 High reliabilty
Applications
 Electric vehicle (EV) and plug-in hybrid EV (PHEV).

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LeMeniz Infotech
36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue,
Pondicherry-605 005.
Call: 0413-4205444, +91 9566355386, 99625 88976.
Web : www.lemenizinfotech.com / www.ieeemaster.com
Mail : projects@lemenizinfotech.com
Block diagram
AC INPUT DIODE
BRIDGE
RECTIFIER
BOOST
CONVERTER
FULL BRIDGE INVERTER
WITH RESONANT
CIRCUIT
ISOLATION CIRCUIT
PIC CONTROLLER WITH
BUFFER
5V DC
12V DC
CENTER TAPPED
TRANSFORMER
FILTER
LOAD

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LeMeniz Infotech
36, 100 Feet Road, Natesan Nagar, Near Indira Gandhi Statue,
Pondicherry-605 005.
Call: 0413-4205444, +91 9566355386, 99625 88976.
Web : www.lemenizinfotech.com / www.ieeemaster.com
Mail : projects@lemenizinfotech.com
Tools and software
 MPLAB – microcontroller programming.
 ORCAD – circuit layout.
 MATLAB/Simulink – Simulation.