The document is a final report on a boost converter module designed using a microcontroller for PWM control. It was created by three students for their Industrial Electrical Engineering lecture. The report includes an introduction to boost converters and their operating principles. It then details the design of the specific boost converter module including calculating component values like the inductor, MOSFET, diode and capacitor based on the design parameters of input voltage range, output voltage, current, and switching frequency.
1. FINAL REPORT
BOOST CONVERTER MODULE : MICROCONTROLLER
PWM
Group Members:
1. Abdillah Aziz Munthasir (1310161018)
2. Mohammad Agung Dirmawan (1310161024)
3. Gilang Andaru Trinanda (1310161027)
Class :
3-D4 ELIN A
Lecture :
Ir. Moh. Zaenal Effendi, M.T.
INDUSTRIAL ELECTRICAL ENGINEERING
ELECTRO DEPARTEMENT
ELECTRONICS ENGINEERING POLYTECHNIC INSTITUTE OF
SURABAYA
2019
2. 1. Introduction
A boost converter (step-up converter) is a DC-to-DC power converter that steps up
voltage (while stepping down current) from its input (supply) to its output (load). It is a class
of switched-mode power supply (SMPS) containing at least two semiconductors (a diode
and a transistor) and at least one energy storage element: a capacitor, inductor, or the two in
combination. To reduce voltage ripple, filters made of capacitors (sometimes in combination
with inductors) are normally added to such a converter's output (load-side filter) and input
(supply-side filter).
Figure 1.1. Boost Converter Schematic
Operation
The key principle that drives the boost converter is the tendency of an inductor to resist
changes in current by creating and destroying a magnetic field. In a boost converter, the
output voltage is always higher than the input voltage. A schematic of a boost power stage
is shown in Figure 1.
a. When the switch is closed, current flows through the inductor in clockwise direction
and the inductor stores some energy by generating a magnetic field. Polarity of the
left side of the inductor is positive.
b. When the switch is opened, current will be reduced as the impedance is higher. The
magnetic field previously created will be destroyed to maintain the current towards
the load. Thus the polarity will be reversed (meaning the left side of the inductor will
become negative). As a result, two sources will be in series causing a higher voltage
to charge the capacitor through the diode D.
If the switch is cycled fast enough, the inductor will not discharge fully in between
charging stages, and the load will always see a voltage greater than that of the input source
alone when the switch is opened. Also while the switch is opened, the capacitor in parallel
with the load is charged to this combined voltage. When the switch is then closed and the
right hand side is shorted out from the left hand side, the capacitor is therefore able to provide
the voltage and energy to the load. During this time, the blocking diode prevents the
3. capacitor from discharging through the switch. The switch must of course be opened again
fast enough to prevent the capacitor from discharging too much.
Figure 1.2 The two current paths of a boost converter, depending on the state of the switch S.
The basic principle of a Boost converter consists of 2 distinct states (see figure 2):
ο· in the On-state, the switch S (see figure 1) is closed, resulting in an increase in the
inductor current;
ο· in the Off-state, the switch is open and the only path offered to inductor current is
through the flyback diode D, the capacitor C and the load R. This results in
transferring the energy accumulated during the On-state into the capacitor.
ο· The input current is the same as the inductor current as can be seen in figure 2. So it
is not discontinuous as in the buck converter and the requirements on the input filter
are relaxed compared to a buck converter.
ο· When switch S is ON
When switch in ON the diode will be open circuited since the n side of diode is at
higher voltage compared to p side which is shorted to ground through the switch. Hence the
boost converter can be redrawn as follows.During this state the inductor charges and the
inductor current increases. The current through the inductor is given as
πΌπΏ = (
1
πΏ
)β« π ππ‘
Assume that prior to the opening of switch the inductor current is IβL, off. Since the input
voltage is constant
4. πΌπΏ.πππ = (
1
πΏ
)β«( πππ) ππ‘ + πΌβ²
πΏ,πππ
Assume the switch is open for ton seconds which is given by D π₯ ππ where D is duty cycle
and Ts is switching time period. The current through the inductor at the end of switch on
state is given as
πΌπΏ.ππ = (
1
πΏ
) π₯ ππ π π₯ π· π₯ ππ + πΌβ²
πΏ,ππ (equation 1); Hence ΞπΌπΏ = (
1
πΏ
) π₯ πππ π₯ π· π₯ ππ.
ο· When switch is off
When switch in OFF the diode will be short circuited and the boost converter circuit
can be redrawn as follows. The inductor now discharges through the diode and RC
combination. Assume that prior to the closing of switch the inductor current is IββL, off. The
current through the inductor is given as
πΌβ²β²β²
πΏ,πππ = β(
1
πΏ
) β«( πππ β πππ’π‘ ) ππ‘ + πΌβ²β²
πΏ,πππ
Note the negative sign signifies that the inductor is discharging. Assume the switch is open
for toff seconds which is given by (1-D) ππ where D is duty cycle and Ts is switching time
period. The current through the inductor at the end of switch off state is given as
πΌβ²β²β²
πΏ,πππ = β (
1
πΏ
)( πππ β πππ’π‘ )(1 β π·) ππ + πΌβ²β²
πΏ,πππ (equation 2)
In steady state condition as the current through the inductor does not change abruptly, the
current at the end of switch on state and the current at the end of switch off state should be
equal. Also the currents at the start of switch off state should be equal to current at the end
of switch on state. Hence
πΌβ²β²β²
πΏ,πππ = πΌπΏ,ππ , also πΌβ²β²
πΏ,πππ = πΌβ²β²
πΏ,πππ
Using the equations 1 and 2 we get
(
1
πΏ
) π₯ πππ π₯ π· π₯ ππ = β(
1
πΏ
) π₯ ( πππ β πππ’π‘ ) π₯ (1β π·) ππ
πππ π₯ π· = β( πππ β πππ’π‘ ) π₯ (1β π·)
πππ π₯ (π· β 1 + π·) = πππ’π‘ π₯ (1 β π·)
πππ
πππ’π‘
=
1
1 β π·
5. Since D < 1 πππ’π‘ > πππ. Assuming no losses in the circuit and applying the law of
conservation of energy : πππ’π‘ π₯ πΌππ’π‘ = πππ π₯ πΌππ
This implies πΌππ’π‘ /πΌππ = (1-D), Thus πΌππ’π‘ < πΌππ. As the duty cycle increases the output voltage
increases and output current decreases. But due to parasitic elements in the lumped elements
resistor, inductor, capacitor the step up ratio Vout/Vin decreases at higher duty cycles and
approaches zero at unit duty cycle.
2. Inductor
Inductors are components that are simple in their construction, consisting of coils of
insulated copper wire wound around a former that will have some type of core at its centre.
This core might be a metal such as iron that can be easily magnetised; or in high frequency
inductors, it will more likely to be just air.
Inductors depend for their action on the magnetic field that is present around any
conductor when it is carrying a current. If the wire coil is wound around a core made of a
material that is easily magnetised, such as iron, then the magnetic field around the coil is
concentrated within the core; this greatly increases the efficiency of the inductor.
An inductor is characterized by its inductance, which is the ratio of the voltage to the
rate of change of current. In the International System of Units (SI), the unit of inductance is
the henry (H) named for 19th century American scientist Joseph Henry. In the measurement
of magnetic circuits, it is equivalent to weber/ampere. Inductors have values that typically
range from 1 Β΅H (10β6 H) to 20 H. Many inductors have a magnetic core made of iron or
ferrite inside the coil, which serves to increase the magnetic field and thus the inductance.
Along with capacitors and resistors, inductors are one of the three passive linear circuit
elements that make up electronic circuits. Inductors are widely used in alternating current
(AC) electronic equipment, particularly in radio equipment. They are used to block AC while
allowing DC to pass; inductors designed for this purpose are called chokes.
A choke is an inductor designed specifically for blocking high-frequency alternating
current (AC) in an electrical circuit, while allowing DC or low-frequency signals to pass. It
usually consists of a coil of insulated wire wound on a magnetic core, although some consist
of a donut-shaped "bead" of ferrite material strung on a wire. Like other inductors, chokes
resist changes in current passing through them increasingly with frequency. The difference
between chokes and other inductors is that chokes do not require the high Q factor
construction techniques that are used to reduce the resistance in inductors used in tuned
circuits.
6. 3. Design of Boost Converter Module
Design of Boost Converter based on calculate some parameters and reference of data
sheet component like diode, MOSFET, capacitor, resistor etc.
The boost converter has following parameters :
ππ (πππ₯) = 30 Volt
ππ (πππ) = 24 Volt
ππ = 60 Volt
πΌπ = 2.5 Ampere
Switching Frequency (ππ ) = 40 kHz
Components :
Q : MOSFET IRF460
D : MUR 1560 (Ultra Fast Recovery Diode)
Inductor (L) : Ferrit core PQ 3535 with Cross sectional are (π΄ π = 1.96 ππ2
);
Bobbin diameter ( π· πππ = 17 ππ)
π π : Snubber resistor (..... Ohm, 5 β 10 watt)
πΆπ : Snubber resistor (..... nF, 1 kVolt)
π· π : Snubber diode (FR3017)
οΌ Duty Cycle :
π· = 1 β (
π π (πππ )
ππ
)
π· = 1 β (
24
60
)
π· = 1 β (
2
5
) 0.6 = 60%
11. 5. Experimental Result
οΌ Inductor Test
Inductance of inductor β 290 ππ»
Quality factor (Q) = 368,2
Figure 5.1. Inductance of Design Inductor
Figure 5.2. Quality Factor of Design Inductor
Winding Steps :
1. Firstly, decide the parameters of boost converter like Vs, Vo, Is, Io, frequency
switching etc. Then calculate value of duty cycle, inductor, capacitor, resistor,
snubber circuit etc.
2. To design the inductor, we must calculate the winding and decide split of inductor.
In laboratory, we got ferrit core PQ 35/35 with cross sectional are (π΄ π = 1.96 ππ2
)
and bobbin diameter ( π· πππ = 17 ππ).
3. After calculate the winding and decide split of inductor, determine the lenght of wire
that we need for design boost converter.
4. Take the wire and roll on wire rolling.
5. Next step, divide of the wire based on number of split. Wire must on strained
condition when we divide it. At the same time, get a message of wire use Majun.
6. After that, use wire roll to rolling wire into bobbin.
12. 7. Give isolated (gap) for eash stack (layer). When we roll the wire must be carefull,
because email of wire (laminated) easy get peeled off.
8. For the last stack (layer) give black isolated on the surface.
9. Next, remove email of wire (laminated) for each strand of wire. Make sure that no
email left on strand wire.
10. Wire direction set to the foot of bobbin in same side entered and exit then soldered
wire.
11. Then take the core (ferrit) into bobbin and give air gap by using clear isolate (tape) .
Addition of isolated (tape) until we got the value of design inductor for boost
converter. To check the inductance value use LCR meter.
12. After we got inductance value for design inductor, checking of quality factor (Q) use
quality factor meter.
13. Record the value of inductance and quality factor of design inductor.
οΌ PWM Test
Figure 5.3. Pulse Width Modulation (PMW) Test
PWM Test Steps
1. Make circuit of PWM used Microcontroller STM32F4 as in the schematic PWM.
2. After that, start testing circuit of PWM. First, prepare the equipment needed such as
DC power supply 2 units, one for supply microcontroller 5 VDC and 12 VDC for driver
PWM, oscilloscope, multimeter digital, power cable and probe cable.
3. Then connect input terminal PTR 1 to the DC power supply, inject DC power supply
5VDC.
4. Then connect input terminal PTR 2 to the DC power supply, inject DC power supply
12VDC.
5. Then put in the potensiometer 50K and 100K to terminal PTR 3 and PTR 4.
13. 6. Then connect output terminal PTR 5 to the probe cable of oscilloscope.
7. Next set potensiometer 50K until wave picture in oscilloscope show frequency 40
KHz with time/div 5 Β΅s. Then set potensiometer 100K to change duty cycle.
8. List data result of PWM Microcontroller testing and take a picture VGS wave that
show in oscilloscope.
Table 5.1. Various Duty Cycle
Frequency Duty Cycle PWM
40 Khz 30%
40 Khz 50%
40Khz 70%
14. οΌ Functional Test
Figure 5.4. Functional Boost Converter Test
Functional Test Steps
1. Connecting Boost converter, PWM microcontroller module and other component to
the acrylic.
2. Then, install connection of cable PWM microcontroller and Boost converter for good
connection, PWM microcontroller modul on side acrylic and Boost converter in side
acrylic.
3. After that, start testing, connect the boost converter module microcontroller cable to
input 220 VAC. Push on switch on the module when the PWM switch is OFF and DC
power supply is also OFF.
4. Turn OFF the PWM switch and put the oscilloscope probe to test point PWM to view
VPULSE wave. Set the frequency 40 KHz and PWM duty cycle 30%.
5. Turn ON the PWM switch and put the oscilloscope probe to view VGS. DC power
supply is also OFF.
6. Then connect series ampermeter DC analog with load (lamp).
7. Turn ON DC power supply, set value of DC power supply into VIN = 5 VDC. Put the
oscilloscope probe to view VDS wave.
8. Measure the VIN, IIN, VOUT, IOUT and view wave using oscilloscope.
9. Repeat step 2 until until 8 for another duty cycle and input voltage.
17. Capability Test Steps
1. First, start testing. Connect the boost converter microcontroller module cable to input
220 V, push on switch in the module when the PWM switch is OFF and DC power
supply is also OFF.
2. Turn OFF the PWM switch and put the oscilloscope probe to test point PWM to view
VPULSE. Set the frequency into 40 KHz and PWM duty cycle into 50%.
3. Turn ON the PWM switch and put the oscilloscope probe to Gate and Source point
test to view VGS. DC power supply is also OFF. Then connect series ampermeter DC
analog with variable resistor load.
4. Turn ON DC power supply. Set value of DC power supply VIN into 24 VDC to the
module. Put the oscilloscope probe to Drain and Source test point to check the VDS.
5. Then change the variable resistor load until ampermeter DC analog show the output
current is 0,5 A.
6. Measure the VIN, IIN, VOUT, IOUT , then put the oscilloscope probe to the load to check
the Vout.
7. Repeate step 3-6 with same input voltage, until output current maximal (2,5 A).
8. If the output current cannot reach output current maximum, donβt continued.Because,
if shows that the reability of your modul only reaches that value.
Table 5.3. Experimental Data of Boost Converter
Duty cycle
(%)
Vs
(Volt)
Is
(Ampere)
Vout
(Volt)
Vout cal
(Volt)
Io
(Ampere)
Efficiency (%)
50 24,03 1,03 46,4 48 0,5 93,73
50 24,09 2,17 44,8 48 1 85,7
50 24 3,05 36,45 48 1,5 74,69
πβπππ βΆ πΈπππππππππ¦ =
π ππ’π‘
π ππ
Γ 100%
18. 6. Analysis
In this project, we make boost converter with PWM microcotroller STM32F4. The
boost converter is DC-DC converter use to increase output voltage. It is called a boost
converter because the output voltage is lager than the input voltage. The boost converter that
operates by periodically switching components that is MOSFET. In this project we use
MOSFET IRFP460 to operate switching on high frequency. Design of boost converter based
on calculate some parameters and reference of data sheet component like diode, MOSFET,
capacitor, resistor etc. The boost converter has following parameters :
ππ (πππ₯) = 30 Volt
ππ (πππ) = 24 Volt
ππ = 60 Volt
πΌπ = 2.5 Ampere
Switching Frequency (ππ ) = 40 kHz
After get the parameters of boost converter, calculate the duty cycle, inductor,
capacitor, resistor, snubber circuit, winding etc. To design the boost converter, choose
Vs(min) to get lager rasio output voltage. After the calculate value some components choose
value larger than value of design or suitable in the value generally components, for example
C calculate = 6.25Γ 10β4
πΉ = 625 ππΉ πππ πβπππ π πΆ β 1000 ππΉ, 100 ππππ‘ .
To design the inductor, we must calculate the winding and decide split of inductor.
In laboratory, we got ferrit core PQ 35/35 with cross sectional are (π΄ π = 1.96 ππ2
) and
bobbin diameter ( π· πππ = 17 ππ). To check the inductance value use LCR meter and to
check of quality factor (Q) use quality factor meter. After that, we got value of design
inductor that is Inductance of inductor β 290 ππ» and Quality factor (Q) = 368,2.
Pulse Width modulation or also called PWM is a method of reducing the average
power delivered by an electrical signal, by effectively chopping it up into discrete parts. In
this project, microcontroller STM32-F4 using to created the PWM. For test this design of
PWM, setting frequency on 40 Khz and duty 30%,50% and 70%. Then check manual by
look the duty on oscilloscope.
To complate this project, boost converter must be checking by functional test and
capability test. On functionl test , source voltage setting by 5V, 10V, and 24V with duty
cycle 30%, 50% and 60%. Based on functional test, error output volatge reach 15,5% on
duty cycle 50% with Vs 5 volt and efficiency reach 80,12% β 94,4%. The output voltage,
error, and efficiency can be calculate from this formula :
ππ = (
ππ (πππ)
1 β π·
) ; %πππππ = |
ππ πππππ β ππ ππππ
ππ πππππ
|Γ 100% ; πΈππ =
π ππ’π‘
π ππ
Γ 100%
19. Based on capability test, this converter can endure until 1,5 A. If this boost convereter give
current more than 1,5 A MOSFET canβt be able to switching, this case can demaged
MOSFET. Based on this test, efficiency of this converter reach 93,73% when 0,5A and
74,69% on 1,5A.
7. Conclusion
From the experiment we can get a conclusion :
1. To use PWM with microcontroller STM32F4, this micro must be update to able
create PWM and using optocopler FOD 3182.
2. The quality factor (Q) of design inductor is 368,2 because in design use more split,
so resistance bigger than inductance.
3. Based on functional test, error output volatge reach 15,5% on duty cycle 50% with
Vs 5 volt and efficiency reach 80,12% β 94,4%.
4. Based on capability test, efficiency of this converter reach 93,73% when 0,5A and
74,69% on 1,5A.
5. This module (Boost Converter) is capable to operate until 1,5A.
8. Suggestion
In this section, we will give some suggestion to design boost converter using ARM
STM32 F4 Microcontroller:
1. Using a good isolation of winding the inductor is like your design to get a same value
and best quality factor of inductor.
2. Design the boost converter with mathematic calculation and you should know your
component design and cost based o general market.
3. Read a datasheet of every component correctly to operate it, to take a data of
experiment, please do as SOP.
4. To have very good perform of module, make sure that all components are on circuit
is good and ready to use. Because not good condition of components can cause a big
error of result.
20. 9. Reference
1. http://www.learnabout-electronics.org/ac_theory/inductors.php
2. https://en.wikipedia.org/wiki/Inductor
3. http://www.electronoobs.com/eng_circuitos_tut10_1.php
4. https://en.wikipedia.org/wiki/Boost_converter
5. http://ecetutorials.com/electrical/boost-converter-principle-of-operation-
applications/
6. Hart, Daniel W, Power Electronics, New York : The McGraw-Hill Comparison,
inc, 2011.
7. Rashid, Muhammad H, Power Electronics Handbook :Devices, Circuits, and
Apllications Handbook, Burlington : Elsevier inc, 2011.