Modelling and Simulation of Battery Charger Li-Ion using

CC-CV PI Method

Munir Rifa’i, Novie Ayub Windarko

and Farid Dwi Murdianto

Electrical Engineering Department, Politeknik Negeri Elektronika Surabaya, Surabaya, Indonesia

Keywords: Battery Charger, Buck Converter, Charging, Constant Current, Constant Voltage, PI Controller, Voltage

Threshold.

Abstract:

Damage to the battery is caused by improper and correct charging methods. So it is necessary to have a

system to maintain battery life time. The method is often used to charge batteries is constant voltage by

providing a constant voltage from initial charging to full charge. Charging with constant voltage can provide

a high charging current at the beginning of charging. High charging currents can be dangerous and reduce

battery lifetime. In this seminar paper, charging Li-Ion batteries using Buck Converter with constant current

constant voltage method, namely by providing a constant current before reaching the voltage threshold and

continuing with a constant voltage to full (charging current 3-5% of the capacity of the battery). PI control is

used in the Buck Converter which serves to maintain the stability of the current (constant current) and the

voltage (constant voltage) by output buck converter. With this method the initial current when charging can

be limited according to the ability of the battery, so that more current does not occur and the battery lifetime

will be longer. The PI control on the buck converter can produce a constant current and a constant voltage at

a battery load, with a current ripple of 12.5% and steady state 4A at a constant current and a voltage ripple

of 0.95% and steady state 42V at a constant voltage.

INTRODUCTION

In this globalization era, many electrical devices

use

batteries as their energy source. The electrical

devices

in question are like laptops, unmanned aircraft

(UAVs),

even electric vehicles use batteries as their

energy

source. Means of transportation that are

currently

returning to the trend are bicycles, because it

functions

as a means of recreation, sports and short

distance

transportation. Seeing this, an electric bicycle

was

developed as a hybrid vehicle that uses human

power

and an electric motor. This vehicle has a number

advantages, including less energy than using human-

powered vehicles, does not consume fuel, does not

cause pollution, is not noisy, low maintenance costs,

does not require special permission to drive and does

not require a large parking area. A battery is a device

that can store electricity. The types of batteries

circulating in the community are as follows Lead Acid,

Ni-CD, Li-Ion, and Li-Po. Overall the batteries

mentioned above, the Li-Ion battery is one of the most

widely used, because Li-Ion batteries have many

advantages such as, large capacity with small

physical size, no memory effect and can supply high

currents up to 20 times its capacity (Thowil and

Ayu, 2015). After the battery is used, it will cause

the battery to decrease

its capacity, to be able to

return to its maximum

capacity the battery must be

charged first. There are

several methods for charging

a battery, one of the

methods is Constant Current

Constant Voltage (CC-

CV), this method is suitable

for Li-Ion batteries

because the age of a Li-Ion

battery is greatly

influenced by overcharging

conditions so that using

this method can extend the

battery's life (Vu and Tran, 2018).

To be able to process the battery charging in

Constant Current Constant Voltage can use Buck

Converter. It is because the buck converter has a

voltage and current output with a small riple (Surya

and Zuhri, 2017). So

it is suitable for use in the

battery charging process.

PI controller is used in

Buck Converter section

which serves to maintain the

stability of the output

current (Constant Current)

and the output voltage

(Constant Voltage) of the

Buck Converter. The

stability of the current released

until the battery

voltage capacity reaches the

voltage threshold.

Furthermore, the stability of the

issued voltage to

full battery capacity with the

current parameter is cut

off.

Rifa’i, M., Windarko, N. and Murdianto, F.

Modelling and Simulation of Battery Charger Li-Ion using CC-CV PI Method.

DOI: 10.5220/0010968000003260

In Proceedings of the 4th International Conference on Applied Science and Technology on Engineer ing Science (iCAST-ES 2021), pages 1501-1506

ISBN: 978-989-758-615-6; ISSN: 2975-8246

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

1501

DESIGN OVERALL SYSTEM

2.1 Battery Charger System

The battery is an electric cell in which an

electrochemical process takes place that can be

reversed so that

in the battery there are two

processes namely the discharge process occurs when

the conversion of

chemical energy into electrical

energy while the

charging process occurs when the

conversion of

electrical energy into chemical energy.

The charging

process can occur by means of

regeneration of the

electrodes in it by providing an

electric current in the

opposite direction in the cell

(Rashid, 2011) and (Ashari, 2017).

Constant Current Constant Voltage, which is to

the battery voltage reaches its maximum voltage

then

it is continued with Constant Voltage until the

current decreases according to the cut-off current.

By using this method the battery charging will be in

Figure 1: Charging of constant current constant voltage.

Figure 4 above shows the process of charging a

battery using the Constant Current Constant Voltage

method. Charging starts with Constant Current and

continues with Constant Voltage until the battery

capacity is fully charged.

Lithium-Ion batteries used in this paper have a

total of 10 series and 3 parallel cells. The battery

charging process is done simultaneously. The

capacity of the Li-Ion battery used is 10.5 Ah. As for

the design of the Li-Ion battery charger can be seen

in table 2. Where for constant current is set at 4 A

current and for constant voltage is set at 42V.

Table 1: Specification of battery charger.

Parameters Value

Constant Current 4 A

Constant Voltage 42 V

Total Cells 10S 3P

Block Diagram System

Block diagram system of battery charger is

shown in

Figure 2.

Figure 2: Block diagram system of battery charger.

Figure 5 explains that the source for this battery

charger uses 220 VAC / 50 Hz PLN electricity, which

will be reduced using a step-down transformer of

220VAC to 48 VAC. Next will be rectified into a DC

voltage (Direct Current) using the Fullwave

Uncontrolled Rectifier to 67.8 VDC. The output

voltage of the rectifier will be varied using Buck

Converter. The voltage sensor and current sensor are

used to read the voltage and

current

from the battery

which will then be

compared to the value of the

setpoint. The result will be an error signal which will

then be processed by Arduino and produce a PWM

control signal. Then the PWM signal will be

strengthened in the mosfet driver so that the mosfet

can switch.

B) The Flowchart of Constant Current Constant

Voltage (CC-CV)

The flowchart battery charger system of constant

current constant voltage shown in Fig. 3.

DOWN

RECTIFIER

BUCK

KONVERTER

SENSOR

VOLTAGE

SETPOINT

STM32F4

KONTROLLER

LI-Ion

BATERRY

CURRENT

SETPOINT

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Figure 3: Flowchart system CC-CV.

2.2 Buck Converter

Functions to reduce voltage. The working principle

of the Buck Converter is to use a switch that works

continuously (ON-OFF). As for the so-called PWM

(Pulse Width Modulation) and Duty Cycle in

controlling the speed (frequency) work of the

switch. The choice of buck converter is based on

high efficiency in changing input power to output

power (Pulungan and Sukardi, 2018) and (Wahyu and

Supriono, 2018).

Figure 4: Equivalent of buck converter circuit.

The rating of inductors and capacitors can be

found by following equation (Hart, 2011):

Vo χ (1-D) (1)

Δ iL χf

ΔV =Vo 0.1% (2)

1 - D 8Lrf 2 (3)

Then the switch is in the ON position, diode reverse

bias. Here the inductor starts to absorb some

of the

power from the power supply (Hart, 2011).

Figure 5: Buck converter is ON condition.

When the switch is at the OFF point. Although

not

connected to the source, at this position the

power is

supplied from the inductor which has

absorbed

power as long as the circuit is connected to

the source

(switch position ON).

Figure 6: Buck converter is OFF condition.

Table 2: buck converter parameters.

2.3 PI Controller

Proportional control functions to strengthen the error

signal of the driver (error signal), so that it will speed

up the system output to the reference point. Integral

Control in principle aims to eliminate the error of

steady state (offset) which is usually generated by

proportional control (Suryatini). However, the use of

P controller alone cannot eliminate the steady state

Vin D C

VIn

D C

Parameters Value

Input Voltage (Vs) 65 V

Output Voltage (Vo) 42 V

Output Current (Io)

4 A

Switching Frekuensi (fs)

100 kHz

Ripple Current(∆iL)

20%

Ripple Voltage (r)

0.1%

Vin

Modelling and Simulation of Battery Charger Li-Ion using CC-CV PI Method

1503

error, therefore a PI controller is needed to eliminate

the steady state error. The use of this PI controller can

also reduce rise time and settling time. Just like the P

controller, increasing the Ki value to a certain value

will also increase the overshoot value

(Temel).

Set

Point

E Controlled

ror

Measured

Sensor

Figure 7: Block diagram of PI controller system.

Table 3: Characteristic of pid controller.

Rise Time

Settling Time

Error Steady

State

Overshoot

Decrease Small Change Decrease Increase

Decrease Increase Eliminate Increase

Small Change Decrease Small Change Decrease

The PI controller that is used in the system is

obtained from the simulation response of the buck

converter which uses the predetermined parameters

(Marian, 2012).

The open-loop transfer function

(OLTF) of the system is shown in equation (4) and the

response of the OLTF

shown in Figure 8 and the closed-

loop transfer function

(CLTF) of the system is shown in

equation (5) and the

response of the CLTF shown in

Figure 9.

F= OLT





.

. 

(4)

F= CLT







. 

(5)

Figure 8: Step response of Open-Loop Transfer Function

(OLTF).

Figure 9: Step response of Close-Loop Transfer Function

(CLTF).

SIMULATION RESULT

Battery charging simulation is done using two modes,

namely constant current and constant voltage modes. The

constant current mode works first by giving a constant

current until the charging voltage

reaches its maximum

value. After the voltage reaches

its maximum value, it

is continued with a constant

voltage mode, which is to

provide a constant voltage

until the current flowing

in the battery reaches its

cut-off value.

PI controller is used to optimize the output

voltage and current to be stable in the setpoint. The

simulation uses Matlab with certain patterns.

Figure 10: PI Controller and switch constant current to

constant voltage.

The simulation results for the battery charging

system using constant current constant voltage are

shown in Figure 11.

4 CONCLUSION

The technical and economic analysis of tracker

based solar power system for remoted islanded has

been presented. The potential of the energy of the

PV system can be generated 3,341 kWh/year. The

test result using three different PV structure

installations - fixed structures, single-axis tracking,

and dual-axis tracking mechanisms, shows that the

Kp +

Ki/s

Buck

Converter

Output

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science

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two-axis tracking system has more profitable in

terms of PV electricity production 3,931 kWh in a

year and had the lowest COE of 0,307 $/kWh. This

system requires less PV module and battery storage,

as well as lowest PV system, cost 2,579 $, and less

space needed for system installation. The analysis of

environmental influence needs to be considered for

future research in order to reduce CO

emission.

Figure 11: Simulation result of constant current (CC)

constant voltage (CV) from: (a) output voltage

response,

(b) output current response.

The controller adjusts the duty cycle value

assigned

to the buck converter to match the setpoint.

controller can reach the setpoint value with a time

0.004s and maintain the charging current

according

to the setpoint. The constant current setpoint is 4A

and the constant voltage setpoint is

42V.

From Table 4, the simulation results of

battery charging using the constant current constant

voltage method, the percentage of charging current

error at CC is obtained by 0.5%. The constant

current (CC) charging process takes place up to 99%

battery SOC. After that, the charging process

switches to CV mode until SOC is 100%. The

simulation is performed with a discrete signal

(sample times is 1e-6) and starting at the 99% SOC

battery condition with a matlab time of 20.

Table 4: Simulation results.

C (%)

Open (V)

(

(A)

(Ω)

30 36.915

37.3 3. 0.11

76 95 67

35 36.930

37.3 4. 0.11

98 00 67

40 36.943

37.4 4. 0.11

12 02 67

45 36.953

37.4 4. 0.11

20 00 67

50 36.962

37.4 4. 0.11

28 00 67

55 36.971

37.4 4. 0.11

38 00 67

60 36.982

37.4 4. 0.11

50 02 67

65 36.999

37.4 3. 0.11

64 99 67

70 37.030

37.4 3. 0.11

97 99 67

75 37.092

37.5 4. 0.11

60 00 67

80 37.224

37.6 4. 0.11

93 02 67

85 37.505

37.9 4. 0.11

72 00 67

90 38.109

38.5 4. 0.11

77 01 67

95 39.415

39.8 3. 0.11

83 99 67

96 39.820

40.2 3. 0.11

87 99 67

97 40.292

40.7 4. 0.11

60 00 67

98 40.844

41.3 4. 0.11

11 00 67

99 41.487

41.9 4. 0.11

55 00 67

99.235 41.532

42.0 3. 0.11

00 00 67

99.5 41.768 42.00 1.97 0.1167

99.6 41.94 42 0.5 0.1167

Table 5: Switching results.

SOC

tart

Switch

CC to CV

Setpoint

Output

Mean

Oscillation

99 %

at SOC

Current 4 A 4.022 A 12.5 %

99.1438

Voltage 42 V 42.014 V 0.95 %

Table 5 shows the process of switching from

constant current (CC) to constant voltage (CV). The

displacement occurs when the SOC of the battery is

99.14% with a charging voltage (Vch) of 42 V and a

charging current (Ich) of 0.5 A. The allowed

charging voltage of the battery is 42 V (according to

the datasheet). With a CC current of 4 A, it lasts

until the charging voltage is 42 V. So that's when the

CC switches to CV. The oscillations that occur

Modelling and Simulation of Battery Charger Li-Ion using CC-CV PI Method

1505

against the current setpoint are 12.5% and the

oscillations that occur against the voltage setpoint are

± 0.95%. Oscillation can be affected by the buck

voltage source (rectifier), PI control value and

switching frequency.

Figure 12: The simulation results of a full battery cut off.

Fig. 12, shows the charging process is

complete (full). The battery will be considered full

when the charging voltage is 42 V and the charging

current drops to <= 0.5 A. The cut off process occurs

when the SOC of the battery in the simulation is

99.6%. Battery voltage when open circuit after

charging process is 41.94 V.

REFERENCES

M. Ashari. (2017). desain konverter elektronika daya.

Informatika Bandung.

F Suryatini, A Firasanti. Journal of Electrical and

Electronics (JREC) P, PI, And PID Control Ii Settings

DC Motor Speed With ZIEGLER-NICHOLS Tuning.

Vol 6 No 1.

D. W. Hart. (2011). Power Electronics New York:

McGraw-Hill.

M. Thowil Afif dan I. Ayu Putri Pratiwi. (2015).

Analisis Perbandingan Baterai Lithium-Ion, Lithium-

Polymer, Lead Acid dan Nickel-Metal

Hydride pada

Penggunaan Mobil Listrik – Review. Jurnal Rekayasa

Mesin, vol. 6, no. 2, hlm. 95–99.

V.-B. Vu, D.-H. Tran, dan W. Choi. (2018).

Implementation of the Constant Current and Constant

Voltage Charge

of Inductive Power Transfer Systems

With the

Double-Sided LCC Compensation Topology

for Electric Vehicle Battery Charge Applications.

IEEE

Transactions on Power Electronics. vol. 33, no.

9, hlm. 7398–7410.

P. P. Surya, D. Irawan, dan M. Zuhri. (2017). Review and

comparison of DC-DC converters for maximum

power point tracking system in standalone

photovoltaic

(PV) module. International

Conference on Advanced

Mechatronics, Intelligent

Manufacture, and Industrial

Automation (ICAMIMIA). Surabaya, hlm. 242–247.

M. H. Rashid, Ed. (2011). Power electronics handbook:

devices, circuits, and applications. 3. ed. Amsterdam:

Elsevier/BH, Butterworth-Heinemann.

A B Pulungan, Sukardi, T Ramadhani. (2018). Jurnal

EECCIS Buck Converter As A Power Flow Regulator

In Regenerative Braking. Vol 12 No 2.

I N Wahyu Satiawan, Supriono, I B Fery Citarsa. (2018).

Buck Converter Design for Battery Charging On

Various Loads. Vol 5 No 1.

S. Temel, S. Yağli, dan S. Gören. P, PD, PI, PID

CONTROLLERS. hlm. 64.

Marian K Kazimierczuk. ( 2012). Pulse-width

Modulated

DC–DC Power Converters (WILEY). pp 189-237.

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