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Implementation and Design of Advanced DC/AC
Inverter for Renewable Energy
Ergun Ercelebi and Abubakir Aziz Shikhan Electrical and Electronic Engineering, Gaziantep University, Turkey
Email: ergun.ercelebi, [email protected]
Abstract—An inverter is a major component of standalone
solar photovoltaic (PV) system for combining with photo
voltaic or battery. In this paper 600W high efficiency (%95)
advanced inverter relevant to PV system has been designed
and implemented. the system consist of two parts; the first is
the synchronous DC-DC boost converter with variable input
voltage from 9V to 60V and constant DC voltage of 80V,and
second is a DC-AC inverter (voltage source inverter). The
sinusoidal bipolar SPWM is used for triggering the gates of
the inverter bridge. The dsPIC16F877A microcontroller
type is used for the implementation of the inverter system.
The MATLAB Simulink environment is used for simulation
the system. The simulation and experimental results show
the stable operation and the results obtained satisfy the
system.
Index Terms—MATLAB Simulink, converter, dc/ac inverter
I. INTRODUCTION
The classical power systems such as big power
generation plants are located at sufficient geographical
locale produce most of the electrical power, which is then
transferred to large consumption centres’ over long
distance transmission lines. The system control centres’
observe and regulate the power system continuously to
ensure the quality of the power, rated voltage and
frequency. But, now the complete power system is
changing, a large number of generation units, including
both non-renewable and renewable sources such as wind
turbines, wave generators, photovoltaic (PV) generators,
are being developed, and installed. A wide-spread use of
renewable energy sources in distribution networks and a
high breakthrough level will be seen in the near future
many places [1]. The dc-ac converter, also called as the
inverter, converts dc source to ac source at desired output
voltage and frequency according the system. The dc
power input to the inverter is obtained from a present
power supply network or from a rotating alternator
through a rectifier or a battery fuel cell, photovoltaic
array, or magneto hydrodynamic generator [2], [3]. PWM
control is the robust technique that offers a simple
process for controlling of analog systems with the
processor’s digital output. With the availability of
minimum cost high performance DSP chips characterized
by the execution of most instructions in one instruction
cycle, intricate control algorithms can be executed with
Manuscript received January 11, 2015; revised May 8, 2015.
fast speed, making very high sampling rate possible for
digitally-controlled inverters [4]. The AC output voltage
could be constant or variable frequency and voltage. This
conversion can be achieved either by controlled turn on
and turn off electronic switch (e.g. MOSFET, IGBT and
BJT, etc.) or by forced commutated thyristors, depending
on application. In the ideal inverter the output voltage
waveform of should be sinusoidal [5]. Fig. 1 is over all
diagram of synchronous dc-ac inverter. The related works;
Have used a Matlab Simulink model of a single-phase
full bridge 2kVA Voltage Controlled Voltage Source
Inverter in [6]. Development of control circuit for single
phase inverter using ATMEL microcontroller Proposed in
[3]. A new dc to dc boost converter using closed loop
control proportional Integral (PI) and Derivative (D)
mechanism for photovoltaic (PV) standalone high voltage
applications presented in [7]. Designed a boost converter
that was able to boost up a variable DC voltages to a
controlled DC voltage with desired output voltage value
proposed in [8]. A multi-input single-phase grid-
connected inverter for a hybrid photovoltaic (PV)/wind
power system Proposed in [9]. In this paper I designed,
simulated and implemented experimentally a 600W DC-
AC converter, which take from a photovoltaic solar panel
model vary from (9-60) Volt and constant output voltage
of according set point reference (Vref) from (24-80) Volt.
Figure 1. Over all diagram of synchronous dc-ac inverter
II. DC-DC BOOST CONVERTER
The synchronous boos DC-DC converter is used to
obtain a constant output voltage with variable input
voltage. It’s mainly used to the stabilization dc power
supplies. The average output voltage of converter is
always larger than the input voltage. The switching duty
cycle controlled the output voltage of converter. When
the switch is ON, the diode is reverse biased, and hence
isolates the output stage of converter. During the switch
ON the inductor gets the energy from the source and
International Journal of Electrical Energy, Vol. 3, No. 1, March 2015
©2015 International Journal of Electrical Energy 32doi: 10.12720/ijoee.3.1.32-36
stores it. During switch OFF case, the diode is forward
biased and the output side receives the storage energy
from the inductor as well as the input. Thus the energy
transferred to the output from input is always greater in a
given switching cycle. The ratio of output voltage to
input voltage is given by;
1
1
O
I
V
V D
(1)
where, Vin and Vo are the input and output voltages of the
boost converter, respectively, and D is the duty ratio and
defined as the ratio of the on time of the switch to the
total switching period [10], [11].
The Maximum duty cycle
(min)1
VinD
Vout
(2)
where, VIN (min), VOUT, and, η are the minimum input and
output voltages and η is efficiency of the converter
estimated 95%. The Inductor Ripple Current Estimation:
out(max)(0.2 0.4) ILVout
I toVin
(3)
where, D, fs, ΔIL, IOUT(max) are duty cycle, minimum
switching frequency of the converter, inductor ripple
current and maximum output current necessary
respectively. The maximum switch current:
out(max)I(max)
2 1
ILIsw
D
(4)
Inductor Calculation: (L is selected inductor value):
out )Vin (V Vin
L Fs VoutL
I
(5)
Output Capacitor Selection, The maximum output
voltage ripple ΔVOUT, (ΔVout=desired output voltage
ripple) [12].
0.01Vout Vout (6)
(min)Iout(max)
outD
FsC
Vout
(7)
A. Simulation Model for Boost Converter
The converter is designed using one MOSFET, anti-
parallel diode, rectifier diode, inductor and capacitor with
the PI feedback control in Simulink. The MATLAB
Simulation of synchronous DC-DC boost converter is
shown in Fig. 2. The inductance and capacitance are
42µH and 940μF respectively.
Figure 2. MATLAB simulation synchronous boost converter
Control design for a boost PWM converter involves
two steps: choice of modulation strategy, which
corresponds to an open-loop boost converter control, and
design of dynamic closed loop control. The instantaneous
voltage control scheme is applied to the proposed circuit.
The block diagram is shown in Fig. 3, of the control
circuit. The output voltage is compared with a reference
voltage Vr. Hence, the control scheme is simple
compared with others.
The classic PI (proportional-integral) controller has
been used in many industrial control systems, mainly due
to its simple structure that can be easily understood and
implemented in practice, and its excellent flexibility
made possible by adjustment of the coefficients KP, and
KI [6], [7].
Figure 3. MATLAB simulation PI controller feedback and set point
(a)
International Journal of Electrical Energy, Vol. 3, No. 1, March 2015
©2015 International Journal of Electrical Energy 33
(b) Figure 4. Overall diagram dc-dc converter
B. The Implemental DC-DC Booster
The schematic diagrams for the Prototype synchronous
dc-dc boost converter circuit shown in Fig. 4a and Fig. 4b
respectively. The feedback controller concludes UC3843
used current mode controller and LM358 operation
amplifier, and output port 6 of UC3843 fed the MOSFET.
In the power circuit of Fig. 4, the input capacitor 1000μF
and output capacitor tow 470μF connected in parallel to
decrease the ESR (equivalent series resistance). The
prototype synchronous boost converter is shown in Fig. 5.
Figure 5. Photograph DC-DC synchronous boost converter
Table I lists the recorded output voltage. The dc output
voltage is measured by Voltmeter, with varying input
voltage and is found to be constant according set point.
TABLE I. SHOWS THE RECORDED OUTPUT VOLTAGE WITH VARY
REFERENCE VOLTAGE (SET POINT)
Vin Vrf Vo Vin Vrf Vo Vin Vrf Vo
9 24 24 12 48 48 12 60 60
12 24 24 18 48 48 18 60 60
14 24 24 24 48 48 25 60 60
18 24 24 28 48 48 35 60 60
20 24 24 30 48 48 40 60 60
22 24 24 35 48 48 50 60 60
III. THE INVERTER
A. Simulation Model of PWM Inverter
The single-phase full bridge inverter is constructed
using 4 IGBT switches and 4 anti-parallel diodes in
Simulink. In the model, sinusoidal wave at 50-Hz and
carrier wave are compared to generate PWM signals.
PWM inverter uses self-commutating IGBT solid-state
power electronic switches. The switching frequency of
the inverter is 2KHz. The single-phase inverter is fed
from 48Vsynchronous boost converter. LC filter blocks
high frequency harmonics caused by DC to AC
conversion to reduce distortion in the output harmonic.
The inductance and capacitance of the filter is 5mH and
470μF respectively and non-leaner load 12Ω 5mH is used.
The Simulink model is shown in Fig. 6.
Figure 6. The simulation model full bridge inverter
International Journal of Electrical Energy, Vol. 3, No. 1, March 2015
©2015 International Journal of Electrical Energy 34
B. The Experimental Implement of The PWM Inverter
The schematic diagrams for inverter, as shown in Fig.
7, which is consist of power circuit and control circuit.
The PIC microcontroller16F877A is used to generate the
required SPWM signals to drive and switch the full-
bridge IGBTs switches, SPWM and output ports are used
for the implementation. The four PWM signals have been
fed to the optocoupler (NPN 4N25) for the isolation of
gate drivers. Four discrete IGBTs (G4PC30UD) are used
as switching devices.
Figure 7. The implementation full bridge inverter
IV. SIMULATION AND EXPERIMENTAL RESULTS
The simulation results obtain from the Matlab
Simulink DC-DC converter and DC-AC inverter model
developed and that were compared with experimental
results for the 600W inverter are shown Fig. 8-Fig. 11.
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.997547.995
48
48.005Vout
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99750
0.5
1
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99752.0868
2.087
2.0872
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99755
10
15
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.997511
12
13
Time sec
Vin
Vo
MOSFET Triguring
Io
Iin
Figure 8a. Vin 12 set point voltage 48
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.997547.998
48
48.002Vout
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99750
0.5
1
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99752.0868
2.087
2.0872
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99750
5
10
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.997523
24
25
Time sec
Vo
MOSFET Trigering
Io
Iin
Vo
Figure 8b. Vin 24 set point voltage 48
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.997547.998
48
48.002Vout
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99750
0.5
1
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99752.0868
2.0869
2.087
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.99750
5
10
0.9965 0.9966 0.9967 0.9968 0.9969 0.997 0.9971 0.9972 0.9973 0.9974 0.997535
36
37
Time sec
Vo
MOSFET Trigering
Io
Iin
Vin
Figure 8c. Vin 36V set point voltage 48
Figure 9. Vin 12V set point voltage 48
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04-50
0
50V inverter
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04-5
0
5
Time sec
I load
Figure 10. Dc-Ac inverter without fillter inMATLAB simulation
Figure 11. Dc-Ac inverter without fillter practical
Fig. 8a, Fig. 8b and Fig. 8c show the output voltage,
pulses, output current and input current for input voltage
24V, 36V, 48V respectively. Fig. 9 shows the
experimental result. Fig. 10 and Fig. 11 show the output
voltage and current of the inverter for the simulation
result and experimental result without the filter and Fig.
12 and Fig. 13 show the output voltage and current with
LC filter.
International Journal of Electrical Energy, Vol. 3, No. 1, March 2015
©2015 International Journal of Electrical Energy 35
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05-50
0
50Vo
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05-10
-5
0
5
10
Time
I load
Figure 12. Dc
Figure 13. Dc-Ac inverter with LC fillter practical
V. CONCLUSION
This paper presented the simulation model using
Simulink-Matlab and an implementation experimental
design prototype for DC-AC converter. The simulation
results show the ability of the controller to obtain the
constant output voltage for boost converter at different
input voltage. Also the inverter simulation shows that the
AC voltage obtained is approximately sinusoidal
waveform. The experimental results and simulation
results are very close to the others.
REFERENCES
[1] IOV, et al., “Power electronics and control of renewable energy
systems,” in Proc. 7th International Conference on Power Electronics and Drive Systems, 2007, pp. 6-28.
[2] P. Bhangale, P. Sonare, and S. Suralkar, “Design and
implementation of carrier based sinusoidal PWM inverter,” International Journal of Advanced Research in Electrical,
Electronics and Instrumentation Engineering, vol. 1, no. 4, Oct.
2012. [3] B. Ismail, et al., “Development of control circuit for single phase
inverter using Atmel microcontroller,” in Proc. International
Conference on Man-Machine System, 2006.
[4] M. Tümay, K. Ç. Bayindir, M. U. Cuma, and A. Teke. (2004). Experimental setup for a DSP based single-phase PWM inverter.
[Online]. Available:
http://emo.org.tr/ekler/4c76e43c96a0124_ek.pdf. [5] R. Senthilkumar and M. Singaaravelu. “Design of single phase
inverter using dspic30f4013,” International Journal of
Engineering Science and Technology, vol. 2, no. 11, pp. 6500-6506, 2010.
[6] A. B. Sankar and R. Seyezhai, “MATLAB simulation of power
electronic converter for PMSG based wind energy conversion system,” International Journal of Innovative Research in
Electrical, Electronics, Instrumentation and Control Engineering,
vol. 1, no. 8, Nov. 2013. [7] D. S. Karanjkar, et al., “Performance analysis of fractional order
cascade controller for boost converter in solar photo-voltaic
system,” in Proc. International Conference on Engineering, Dec. 2012, pp. 1-6.
[8] J. Faiz and G. Shahgholian, “Modeling and simulation of a three-
phase inverter with rectifier-type nonlinear loads,” Armenian Journal of Physics., vol. 2, no. 4, pp. 307-316, Sep. 2009.
[9] R. Arulmurugan and N. S. Vanitha, “Optimal design of DC to DC
boost converter with closed loop control PID mechanism for high voltage photovoltaic application,” International Journal of Power
Electronics and Drive Systems (IJPEDS), vol. 2, no. 4, pp. 434-
444, Dec. 2012. [10] K. H. Mohamed, T. B. Ibrahim, and N. B. Saad, “Boost converter
design with stable output voltage for wave energy conversion
system,” International Journal of Information Technology and Electrical Engineering, vol. 2, no. 1, Feb. 2013.
[11] Y. Yang, et al., “Multi-Input single-phase grid-connected inverter for hybrid PV/wind power system,” International Journal of
Renewable and Sustainable Energy, vol. 3, no. 2, pp. 35-42, Feb.
2014. [12] B. Hauke. Basic calculation of a boost converter’s power stage.
[Online]. Available:
http://www.ti.com/lit/an/slva372c/slva372c.pdf
Ergun Ercelebi received B.S. degree in
Electrical and Electronics Engineering from METU, Gaziantep, Turkey in 1990 and M.S.
and Ph.D. degrees in Electrical and Electronics
Engineering from University of Gaziantep in 1992 and 1999 respectively. He was the head
of Computer Engineering, University of
Gaziantep between 2003 and 2004. He is presently Professor and head of dept of
electrical electronics department, University of
Gaziantep. His research interests include speech processing, image processing, adaptive filters, neural networks,
statistical signal processing wavelet.
Abubakir Aziz Shikhan received B.Sc.
degrees in Electrical Engineering from
Technical College, MOSUL, IRAQ, in 2003
and 2007, now master student in electric and
Electronic Engineering Gaziantep University. During 2007-2013, he stayed in machine and
power electronics Laboratory, electric
department in technology institute, Ministry of higher education and scientific research of
Erbil, Iraq.
International Journal of Electrical Energy, Vol. 3, No. 1, March 2015
©2015 International Journal of Electrical Energy 36
-Ac inverter with LC fillter in MATLAB simulation