1) The document proposes two circuits for fast charging of electric vehicles: a dual inverter drive circuit and a pulse current charging circuit. 2) The dual inverter drive circuit uses two inverters to double the motor voltage and reduce current ripple for more efficient fast charging. 3) The pulse current charging circuit provides discontinuous current pulses to the battery to allow for cooling between pulses and prevent issues caused by constant current charging.

1. High performance fast charging of
Electric Vehicles
Prepared by:
Abdul Azeem
M.Tech(Power System & Drives)
16EEPM015
Department of Electrical Engineering
Aligarh Muslim University, Aligarh 202002

2. Contents
• Introduction
• Existing System
-Circuits using for EV charging
• A new proposed circuit using Dual inverter drive
-Circuit diagram
-Control diagram
-Result
• A charging method based on pulse current charging
-Circuit diagram and result
• Conclusion
• References

3. Introduction
Performance of Electric Vehicles is mainly dependent on the
Charging strategy of its battery. The consumer want fast
charging with the long range drive and good acceleration.
There are various types of battery charging topologies. Each
topology has own merits and demerits.
Various charging techniques are using now a days but still
research is going on to find the more optimum and reliable
topology.

4. Existing System
The existing charging system can be broadly
classified into three types:
1-Level 1 charging
2-Level 2 charging
3-Level-2 or Fast DC charging

5. Level-1 Charging
• Level-1 charging provides charging through a 120V
AC 16-20 Amps and produced the least amount of
stress on battery.
• Charging time takes 8 to 12 hours to completely
charge a fully depleted battery.
• The most common place for level-1 charging is the
owner’s home and typically conducted overnight.

6. Level-2 Charging
• Level-2 equipment offers charging through a 240 V
AC plug.These units require a dedicated 40 Amps
circuit.
• Level-2 charging system takes 4 to 6 hours to
completely charge a fully depleted battety.
• The most common place for level-2 charging is public
parking areas,place of employement and in
residendial settings.

7. Level-3 or Fast DC charging
• Level-3 charging provides 480 V, DC plug.
• It can provide 80% charge approximately in 30
minutes only.
• It uses CHAdeMO technology.
• It is off-board charging.

8. Example of Level-3 charging
• Tesla supercharger
providing half a charge
in approximately 20
minutes.
• But it is compatable
with Tasla Model S.

9. Some circuits for EV charging
Multiphase integrated charger Boost charger

10. Proposed circuit using Dual Inverter
Drive
• The proposed circuit
has n number of battery
string.
• Each string has same
number of cells,
maintaining the same
nominal voltage.
• Common Input DC
source is connected to
both inverter.

11. Cont’d
• The AC side is connected to the open-ended winding of the
electric motor such that the machine leakage inductance is
shared between two switch networks.
• Power can be fed directly from a DC microgrid without a
DC/DC intermediate stage.
• The dual battery pack enables doubling of motor voltage.
• Benefit of utilizing the two traction inverter is current ripple
reduction.
• The motor leakage inductance Ls is limited by the EV motor, it
is beneficial to minimize the high ripple component .
• Power transfer between the DC input and battery unit is
achieved by regulating the inductor current.

12. Working (Brief)
from the figure
• V1i = d1iV1
• V2i = d2iV2
• where i = f(a, b, c) for 3
interleaved dc/dc stages.
• Apply kvl in any pahse,we get
• Vdc = V1d1i + V2d2i
• Assuming d1i=d2i=d
• Vdc = (V1 + V2)d
• From above equation, we have
• (V1 + V2)/Vdc= 1/d
• Conversion ratio is similar to a
boost operation.
Average model

13. Control strategy
In Fig. 8, the voltage balancing
controller takes the voltage
difference and outputs d, which is
then subtracted from d1i and
added to d2i. Therefore, if the DC
source in the upper module is
overcharged relative to the lower,
then the lower one will be
inserted more frequently. Both
sources are charged
simultaneously but with an offset
to shift the power distribution. To
ensure this offset does not
exceed the operating limits of the
converter, a limiter is
implemented at the output
of the voltage balancing controller.
Full control diagram

14. Result
Simulated parameter

15. Cont’d

16. Pulse current charging
• As the name employee instead of continuous current we
provide discontinuous pulse of current to the battery.
• Pulse current technique normalizes ion concentration and
prevents the bad consequences caused by constant current
technique.
• High current charging causes high temperature rise inside the
battery.
• In pulse current technique battery get enough time to cool
between pulses.

17. Circuit diagram

18. Cont’d
• The figure show power
electronics topology of the
proposed circuit.
• Left time of the DC link is called
DC-AC stage, it comprises
uncontrolled 3-phase rectifier.
• DC-DC stage is the Buck
converter.
• Buck converter comprises one or
more IGBT legs.
• More IGBT legs allow the
designer to share the desired
inductor current.

19. Result(simulated)
Battery current in each port
Input battery power at each port
Prototype implemented model

20. Cont’d(practical)

21. Cont’d
• From the figure two ports are providing fast charging services
for the battery packs with different terminal voltages 7.5 V
and 19.5 V.
• It is step down chopper and only inject the current to the low
voltage side, the DC link voltage has been adjusted at 24 V
battery.

22. Conclusion
• Dual converter has a quality to perform the two operation, one is
converter mode in charging and second inverter mode in traction.
• The two inverter double the motor voltage, hence more power.
• The switching scheme attenuate significant harmonics which give the
more efficient operation, and ability to charge at the rated power of the
traction system ideal for electric vehicle fast charging.
• The pulse current charging giving a better performance of battery and
enhancing its life, also it is a better option in future.

23. Reference
• Ruoyun Shi, sepehr Semsar and Peter W. Lehn,”Constant current fast
charging of electric vehicles via DC grid using dual inverter drive,”IEEE
Transaction on Industrial Electronics , January 7th 2017.
• Mahdi Bayati, Mehrdad Abedi and Gevork B. Gharehpetian,”A new
electrical vehicle charging station based on pulse current charging
mathod,” 25th Iranian Conference on Electrical Engineering(ICEE2017).
• Farag Sallabi,Khaled Suhaib and Mahmoud Alahmad,”Online scheduling
scheme for smart electric vehicle charging infrastructure,” IEEE conference
2017.