IRJET-Static Voltage Stabilizer

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 05 Issue: 01 | Jan-2018 www.irjet.net p-ISSN: 2395-0072
© 2018, IRJET | Impact Factor value: 6.171 | ISO 9001:2008 Certified Journal | Page 86
Static Voltage Stabilizer
Kapil Mulchandani1, Shubham Bannore1, Shilpa Lambor2, Vrinda Parkhi2, Vikrant Bhalerao3
1Electronics, Vishwakarma Institute of Technology, Pune, India
2 Professor, Dept. of Electronics, Vishwakarma Institute of Technology, Pune, India
3Senior Design Manager, Aarcchor Innovations Pvt. Ltd., Pune India
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Abstract - The forgoing stage of voltage stabilizer used in
industries or for household is Servo Voltage Stabilizer.
Commercially the approved range of their operation is 150V-
240V or 90V-280V. Servo Voltage Stabilizer are also
manufactured and used widely in spite of the fact thattheyare
obsolete and use outdated technology. The lately introduced
technology which excludes this old-fangled, low voltage, high
correction time, high maintenance issues of servo stabilizer is
Static Voltage Stabilizer(SVS). StaticVoltageStabilizerdoesn’t
include any moving parts as in servo voltage stabilizer. The
voltage in SVS is produced with the assistance of electronic
circuits also it has absolute electronics to achievecorrectionin
voltages and time. Therefore, it has extremely high voltage
correction speed than servo voltage stabilizer. Thepaperdeals
with the static voltage stabilizer which is controlled by
TMS320F28069 a DSP based controller and a voltage changes
are accounted with the help of Buck-Boost Transformer.
Key Words: F28069, Power Electronics, Stabilizer,
Static Voltage Stabilizer
1. INTRODUCTION
Stabilizers is an electronic device that stabilize the
voltage from fickle to a desired value. Stabilizer provides a
steady and secure powersupplytoequipment’s,whichneeds
a stable voltage and also protects devices from most of the
problems of the mains. As in UPS, voltage stabilizers also
have proved an asset to the protection of electronic devices.
The major utility of a stabilizer is to make the output voltage
that feeds the equipment’s connected to it as much as
possible equivalent to the ideal electrical power supply,
ensuring that the oscillations in electrical power are offset,
and its output maintain a stable value, precluding themfrom
being experienced by equipment’s and thereby avoiding
their damage. The disparity in stabilizer and regulator is
voltage regulator is normally used in DC applications and
voltage stabilizer on other hand is equipmentthat’stabilizes’
the AC voltage which is usually fluctuating.
Fig -1. Block Diagram of Stabilizer
Voltage stabilizer can be broadly categorized as AC
voltage stabilizer, DC voltage stabilizer and Automatic
voltage stabilizer. This paper deals with Static voltage, an ac
voltage stabilizer. The most usedstabilizerisservostabilizer
and has many limitations in accordance with static voltage
stabilizer.
2. STATIC VOLTAGE STABILIZER
The static voltage stabilizers proffer improvement on
slow servo controlled stabilizer. The basic study of SVR is
with buck-boosttransformer withhighprimarytosecondary
ratio for voltage correction of 25%. The control voltage
which is fed by the IGBT drives of SVS is given to theprimary
and input voltage is imposed to the secondary of the buck
boost transformer. The regulation of voltage with help of
buck and boost is attained electronically without any step
changes in the voltage at the time when system regulates.
This task is proficient through a feedback and a control
system implemented by using a TMS320F28069
microcontroller. The system uses IGBTs as power switches,
direct AC-AC converter circuit improves the overall system
response and fast voltage correction. Also 12.8 KHz ePWM
control operation using high end Piccolo F28069 control
card to achieve correction time of 20 to 30 millisecond.
Fig -2. Block Diagram of Static Voltage Stabilizer
2.1. Major components of SVR
1. Buck Boost Transformer: Secondary of Buck and
boost transformer is connected input and outputterminal of
voltage stabilizer. Neutral betweeninputandoutputofstatic
voltage stabilizer is common hence voltage induced across
secondary of buck boost transformer can add or subtract
with input voltage. Primary of buck boost transformer is
connected to IGBT power stage.

2. IGBT Power Stage: It consists of IGBT Bridge which
is connected to Piccolo F28069 DSP controller. IGBT power
stage is responsible for the generation of appropriate
amount of voltage with help of PWM method. The output of
the IGBT power stage is fed to the primary as it is the control
circuit of the device. As the output of the IGBTs is fed to the
primary of the transformer, it can be inphaseor180degrees
out of phase with the input line voltages. So the voltage
induced across the secondary of Buck-Boost Transformer
can be added or subtracted as per the required voltage
needed at the load.
3. DSP based Control board: The major work of the
DSP based control board is to give PWM to drive the IGBT. It
incessantly senses value of input voltage, output voltage,
load current and IGBT current with help of current
transformer and voltage transformer connected to it. And
this processed information as in feedback gives signal to
IGBT power stage to generate desired voltageanddutycycle
with help of PWM method.
3. PICCOLO TMS320F28069
The F2806x Piccolo (Fig.3) family of microcontrollers
(MCUs) provides the power of the C28x core and CLA
coupled with highly integratedcontrol peripheralsinlowpin
count devices. This family is code-compatible with previous
C28x-based code, and also provides a high level of analog
integration. An internal voltage regulator allows for single
rail operation. Enhancements have been made to the High-
resolution Pulse Width Modulator (HRPWM) module to
allow for dual-edge control (frequency modulation). Analog
comparators with internal 12-bit references have been
added and can be routed directly to control the ePWM
outputs. The ADC converts from 0 to 3.3-V fixed full-scale
range and supports ratio-metric VREFHI/VREFLO
references. The ADC interface has been optimized for low
overhead and latency. Features:
 High-Efficiency 32-Bit CPU (TMS320C28x).
 90 MHz (11.11-ns Cycle Time).
 Harvard Bus Architecture.
 Programmable Control Law Accelerator (CLA).
 Embedded Memory Up to 256KB of Flash, Up to
100KB of RAM, 2KB of One-Time Programmable
(OTP) ROM • Three 32-Bit CPU Timers.
 Up to 8 Enhanced Pulse-Width Modulator (ePWM)
Modules.
 12-Bit Analog-to-Digital Converter (ADC), Dual
Sample and-Hold (S/H).
 Up to 54 Individually Programmable, Multiplexed
General-Purpose Input/output (GPIO) Pins With
Input
 Filtering.
 Code-Efficient (in C/C++ and Assembly).
4. PWM GENERATION
Pulse Width Modulation (PWM) is the method to
produce variable voltages using digital means. Typically,
variable voltages come from analog circuits and digital
circuits that
Fig -3. Piccolo F28069 Experimental Kit
produce only two voltages i.e. high (5v, 3.3v, etc.) or low
(0v). So how likely the digital circuits can produce a voltage
that is between the high and the low voltages, it can be
achieved by bringing the digital signal up and down in a
consistent manner and will get a proportion of the voltage
between the high and low voltage. For an instance if a digital
signal is pulsed high (5v) and low (0v) evenly, considering
that the signal was in the high and low state for 1
microsecond each. Adding a capacitor will smooththesignal
and the voltage would measure 2.5 volts. Now, by changing
the high state for 9 microseconds and in the low state for 1
microsecond, the voltage would measure 90% of 5 volts or
5v x 0.9 = 4.5 volts. The 90% is significant since the duty
cycle is represented as a percentage (%).
PWM is a frequently used technique for controlling
power and is made realistic by modern electronic power
switches. The (transistor) switch flanked by supplyandload
can be used to control the average value of voltage (and
current) fed to the load by switching it on and off at a fast
pace. The longer the (transistor) switch is kept oncompared
to the off periods, the higher the power is supplied to the
load. TMS320F28069 has 8 Enhanced Pulse-Width
Modulator (ePWM) Modules. In all there are 16 PWM
Channels; with minimal CPU overhead or intervention an
efficient PWM peripheral must be able to produce complex
pulse width waveforms. It needs to be highly programmable
and very flexible while being easy to understand and use.
The ePWM unit addresses these necessities by assigning all
needed timing and control resources on a per PWM channel
basis. In this model we have used 2 ePWM modules i.e. 4
PWM channels.
In this application, a continuous up-count mode is used to
generate asynchronous PWM. The timer period value is
calculated as follows:
Where, TBCLK = SYSCLOUT = 11.1ns

Fig -4. Two Complementary PWM waves.
In many power electronicsapplicationslikeStabilizer,
Inverter it is necessary that the turn-on periods of the two
switches must not overlap with each other in order to avoid
a shoot-through fault. Thus, a pair of non-overlapping PWM
output is frequently required to properly turn on and off the
two switches. A dead time (dead-band)ishabituallyinserted
between the turning-off of one transistor along with the
turning- on of the other transistor. This delay allows
complete turning-off of one transistor beforetheturning- on
of the other transistor. In F28069 Dead Band (DB)
submodule takes care of it and generate the dead band
desired by the user. In this application a dead band of 2
microseconds is generated.
Fig -5. Dead band of 2us Between Two PWM’s.
5. WORKING AND ANALYSIS OF SVS
Static Voltage Stabilizer is implemented on Piccolo
F28069 DSP based board. This control board continuously
senses input voltage, output voltage, load current and IGBT
current with help of CTs and VTs. Based on these values
Piccolo F28069 DSP control board will triggerIGBTBridgeto
produce voltage at its output with help of PWM method. The
details of operation of Static voltage regulator in Buck and
Boost mode is mentioned below
5.1. Boost Mode
For explaining Boost Mode consider an example, for a
load of 50kVA, 220V is connected at output of static voltage
stabilizer and suppose low voltage of 180V is available at
input line which needs to be corrected to 220V. When
Piccolo F28069 DSP control board senses values of input
voltage, output voltage, load current and IGBT current, to
correct voltage it will trigger IGBT bridge to generate 40V
(220-180=40V) at its output which is in phase with input
line voltages. It persuades 40V at secondary of buck boost
transformer since both voltage; inputlineandvoltageacross
secondary of buck boost transformer are in phase with each
other , it get added and the output voltage get corrected to
220V.
Fig -6. Boost Mode Operation.
5.1.1. Analysis
Fig -7. Circuit Diagram of single phase SVR.
Vout = Vin + [Vind(1 −d)Vin]n = Vin[1 + (2d− 1)n]
The output voltage, Vout is the sum oftheinputvoltage,
Vin and the transformer voltage which is chopped AC voltage
[= n (2d− 1)Vin]. n is the transformer ratio, d is thedutycycle.
For switching frequency large compared to line frequency,
we can write,
IAv-Q21 = (1/2π) {0∫(π-φ) d Ip sin ωt dωt +
(π-φ)∫π (1-d) Ip sin ωt dωt}
= (Ip / 2π) {1 – cos φ + 2d cos φ}
IRMS-Q212 = (1/2π) {0∫(π-φ) d2 Ip2 sin2 ωt dωt
+ (π- φ)∫π (1-d)2 Ip
2 sin2 ωt dωt}
= (Ip2 / 4π) {d2π+(1 – 2d)[φ + sin
(2φ)/2]}
From the above, we can write,

IAv-D21 = (Ip/π) - IAv-Q21
IRMS-D21
2 = Ip2/4 - IRMS-Q21
2
5.2. Buck Mode
Taking same example into consideration for a load of
50kVA, suppose high voltage of 250V is available at input
line which needs to be corrected to 220V. Whenever Piccolo
F28069 DSP control board measures values of input and
output voltage, load current and IGBT current, to correct
voltage it will trigger IGBT bridge to produce 30V
(250220=30V) at its output which is180degreeoutof phase
with input line voltages. It induces 30V at secondary of buck
boost transformer; input line and voltage across secondary
of buck boost transformer are 180 degree out of phase with
each other and so it gets subtracted and output voltage is
corrected to 220v.
This increase or decrease in voltage according to the
rated voltage the Buck and Boost mode take place and the
desired output is observed.
Fig -8. Buck Mode Operation.
6. SIMULATION
Below Figure shows the simulation model for open
loop Static Voltage Stabilizer. For rectification of AC input, 4
diodes are used and the rectified output is fed to IGBTs. In
this model 4 IGBTs are used which aredrivenusingthepulse
generator. Two IGBTs get the same drive i.e. the positive or
negative pulse. The output of the IGBTs is given to the
primary of the Transformer. And subsequently transformer
is connected to load.
Fig -9. Simulink Simulation Model
Fig -10. Simulink Simulation Result
7. HARDWARE DESCRIPTION
The below figure illustrate DSP controlled KVA single
phase Static Voltage Stabilizer. The research was carried on
Piccolo F28069 (DSP) kit, IGBT driver circuit, rectifier
circuit, Buck-Boost Transformer and DSO. The hardware of
SVS can be alienated into Control circuit and Power circuit.
In control circuit section, TMS320F28069 a C2000 family
microcontroller is coded to drive the IGBTs. IGBTs are
voltage controlled devices anditnecessitatea minimumgate
threshold voltage of about 15-V for determining the rated
collector-to emitter conduction. This constraint makes it
complicated to directly interface an IGBT to DSP. For
appropriate operation of IGBTs, correct power levels are
required (Vge(th)=15 V and Ic= 50 mA). The voltage and
current levels of the Piccolo F28069 DSP based controlled
cannot operate the IGBTs. So the IGBT driver circuit is used
to intensify DSP based control board output signals to the
required levels for activating the IGBTs and segregate the
DSP from the power circuit.
Fig -11. Simulink Simulation Result
8. RESULTS
For the hardware model, the IGBT driver circuit is fed
by the PWM generated by the TMS320F28069. Fig.12 shows
the PWM generated signal.

Fig -12. PWM Generated Signal
Fig.13 shows the output voltage of the Static voltage
stabilizer.
Fig -13. Output of SVR
9. CONCLUSIONS
In this paper an openloopMatlab/Simulink model for
single phase static voltage stabilizer is developed and
simulated. Accordingly, we have implementedthehardware
model for Static Voltage Stabilizer. The PWM signal is
generated using TMS320F28069 and fed to the IGBT driver
circuit. The Output voltage was maintained constant
irrespective of the input voltage with the voltage correction
of ± 25%.
ACKNOWLEDGEMENT
We as authors are immensely grateful to express our
special thanks of gratitude to our mentor Vikrant Bhalerao
(Senior Design Manager) and Atul Gupta (Director) of
Aarcchor Innovations Pvt. Ltd for guiding and incessantly
assisting in this project. We would also like to thank
Vishwakarma Institute of Technology, Pune for providing
such a good platform of learning and Dr. R. Jalnekar for
intercalating a concept of semester long internship for
applying our technical knowledge in the outside world. Also
it wouldn’t have been possible without the guidanceofHead
of ElectronicsDepartmentProf.Dr.V.Gaikwad,hiscontinuous
motivation has made us work consistently.
Our thanks and appreciation also goes to our college
guide Prof. Vrinda Parkhi and Prof. Shilpa Lambor for their
careful and precious guidance which were extremely
valuable for this internship as well as project.
REFERENCES
[1] Texas Instruments Incorporated, Technical
Reference Manual, APPLICATION PORT: SPRA18g.
[2] Texas Instruments Incorporated, TMS320F2806x
Piccolo Microcontrollers, APPLICATION PORT:
SPRA698f.
[3] Texas Instruments Incorporated, C2000 Piccolo
Workshop.
[4] Static Voltage Stabilizer Working
<http://www.stabilizer-regulator.com/voltage-
stabilizer/static-voltageregulator-dubai>
[5] Buck Boost Transformer
<https://1y18vt40uea231dp7l2g1lsiwpengine.netd
nassl.com/wpcontent/uploads/Dongan-Buck-
Boost.pdf>

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