40220140505008

International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print),

ISSN 0976 – 6553(Online) Volume 5, Issue 5, May (2014), pp. 74-88 © IAEME

74

SOLAR POWERED SYNCHRONOUS BUCK CONVERTER FOR LOW

VOLTAGE APPLICATIONS

Lopamudra Mitra

Asst. Professor, Dept. of Electrical & Electronics Engineering,

Silicon Institute of Technology, Bhubaneswar, India.

ABSTRACT

The current resurgence of interest in the use of renewable energy is driven by the need to

reduce the high environmental impact of fossil based energy systems. Future sustainability depends

on use of different renewable energy sources. A photovoltaic generation system is becoming one of

the important renewable energy due to absence of fuel cost, low maintenance and environment

friendliness. This paper presents synchronous buck converter based PV energy system for portable

applications; especially low power device applications such as charging mobile phone batteries are

considered. Here, the converter topology used uses soft switching technique to reduce the switching

losses which is found prominently in the conventional buck converter, thus efficiency of the system

is improved and the heating of MOSFETs due to switching losses reduce and the MOSFETs have a

longer life. The DC power extracted from the PV array is directly fed to the synchronous buck

converter to suit the load requirements. The whole system is simulated using MATLAB-Simulink

environment.

Keywords: MOSFET, ZVS, ZCS, Synchronous Buck Converter, PV Module.

I. INTRODUCTION

India imports more than 80% of its oil; hence it has a huge dependency on external sources

for development. With depleting fossil reserves worldwide, there has been a threat to India’s future

energy security. Hence, the government of India is investing huge capital on development of

alternative sources of energy such as solar, small hydroelectric, biogas and wind energy systems

apart from the conventional nuclear and large hydroelectric systems.

For environmental concern and increase of peak power demand PV solar cells has become an

alternative energy source for green and clean power generation. Solar cells are steadily gaining

INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING &

TECHNOLOGY (IJEET)

ISSN 0976 – 6545(Print) ISSN 0976 – 6553(Online) Volume 5, Issue 5, May (2014), pp. 74-88

© IAEME: www.iaeme.com/ijeet.asp Journal Impact Factor (2014): 6.8310 (Calculated by GISI) www.jifactor.com

IJEET

© I A E M E



75

acceptance in our society. These are usually adapted for either grid connected or standalone

applications. It is becoming a boon for the rural community for whom electricity had become only an

imaginary thing. Due to a sudden up rise of mobile usage, and it’s cheaper availability, it has become

an affordable thing to have. But its recharging is cause of concern for the rural counterparts for

whom electricity is not so abundant. These lesser electrical demand can be met with these PV solar

cells.

But these PV cells are not so popular due to their high initial cost. But due to stiff

competition among the manufacturers these cost are also scaling down. After building such an

expensive renewable energy system, the user naturally wants to operate the PV array at its highest

energy conversion output by continuously utilizing the solar power developed by it at different time.

For low voltage applications such as mobile charging and laptop power supply etc, the output of the

PV array should be regulated in order to match the dynamic energy requirement of the load [3]. In

addition, the modulation process should be very efficient so that the system losses can be decreased

considerably. For this efficient regulation of DC voltage, synchronous buck converter is proposed in

the paper.

1.1 PV ENERGY SYSTEMS FOR PORTABLE APPLICATIONS

This energy generation system consists mostly of capacities below 100W. They have a huge

range of applications ranging from powering calculators, educational toys, solar lamps, traffic

signals, mobile chargers, etc. They are usually made up of poly crystalline material of solar cells due

to their higher energy density over a small area and fits in the portable applications. However, this

system is not highly commercialised due to battery technology required to store the power generated

and high cost of poly crystalline silicon solar cells. They generally use lithium ion batteries [4] to

store energy due to its high energy capacity and light in weight. These systems come handy when

power is required on move and has a potential to revolutionise the current era of electronics with free

power on move. The simple mobile charger based on PV energy system consists of a small solar

module generally made of poly crystalline silicon, connected to the electrical load through a

buck/boost converter for regulation of voltage at the load end [5]. This regulation is usually done

using a feedback loop that senses the output voltage and tries to keep it at the desired output voltage

required.[21].

However, higher input voltages and lower output voltages have brought about very low duty

cycles, increasing switching losses and decreasing conversion efficiency. So in this paper, the

efficiency of the synchronous buck converter is optimised by eliminating switching losses using soft

switching technique. The voltage-mode soft-switching method that has attracted most interest in

recent years is the zero voltage transition [1],[2], [4]-[8], [10], [11], [13]-[20], [22]-[24], [26]-[27],

[29].This is because of its low additional conduction losses and because its operation is closest to the

PWM converters. The auxiliary circuit of the ZVT converters is activated just before the main switch

is turned on and ceases after it is accomplished. The auxiliary circuit components in this circuit have

lower ratings than those in the main power circuit because the auxiliary circuit is active for only a

fraction of the switching cycle; this allows a device that can turn on with fewer switching losses than

the main switch to be used as the auxiliary switch.

Various converter topologies have been proposed in the literature [4]-[6]. In the conventional

buck converter usually switching losses are higher due to high switching frequency of

operation of MOSFET and losses in the freewheeling diode is more due to larger forward voltage

drop (0.4V). Consequently, it reduces the overall efficiency of the converter systems (typically less

than 90%). The possible solutions are to increase the efficiency of the converter system is described

as follows. First solution is to replace the freewheeling diode by MOSFET switch. Here MOSFET

acts as a rectifier. So forward voltage drop in the switch can be reduced. Second solution is to

incorporate the auxiliary MOSFET across the main MOSFET along with resonant circuits (Lr& Cr)



76

[7].This combinations constitute a soft switching technique, so that the switching loss can be reduced

in the main switch. The resultant dc-dc converter topology is said to be synchronous buck converter.

Here main MOSFET “s” is switched on and off synchronously with the operation of the MOSFET

switch ‘s2.[24-25]

In this paper an attempt has been taken to analyze such converter for PV energy system based

low power applications especially to charge the batteries used in mobile phones. This converter

topology enables to provide simple and cost effective solution in the charging circuit. This converter

using soft switching technique for low power application [20-25 ] is found in literatures but in this

paper this converter is directly connected to the modelled PV module for low voltage application not

known to be present in literature is presented.

1.2 OPERATION OF A SYNCHRONOUS BUCK CONVERTER

Fig 1: Synchronous Buck Converter.

The operation of synchronous buck converter with ZVS and ZCS technique for reducing the

switching loss of main switch is described as follows [9]

Mode 1: Before starting of this mode diode of S2 was conducting and at time t1, mosfet S1 is

turned on through ZCT which is caused by the current passing through Lr. In this mode Lr and Cr are

resonance with each other and it ends when diode of S2 stops conducting and when current through Lr

reaches I0.

Fig 2: Mode I

Mode2: Lr and Cr continue to resonate. At t1 the synchronous switch S2 is turned on under ZVS.

This mode ends when S2 is switched of and iLr reaches its maximum value.



77

Fig 3: Mode 2

Mode 3: At the starting of this mode, iLr reaches its peak value iLrmax. Since iLr is more than load

current I0, the capacitor Cs will be charged and discharge through body diode of main switch S,

which leads to conduction of body diode. This mode ends when resonant current iLr falls to load current

I0. So current through body diode of main switch S becomes zero which results turned off of body

diode. At the same time the main switch S is turned on under ZVS. The voltage and current

expressions for this mode are:

ILr = I0; VCr = VCr1; VCr is some voltage which can found basing on other modes.

Fig 4: Mode3

Mode 4: In this mode, the main switch is turned on under ZVS. During this mode growth

rate of iS is determined by the resonance between Lr and Cr. The resonance process continues

and iLr starts to decrease. This mode ends when iLr falls to zero and S1 is turned off through

ZCS.

Fig 5: Mode4



78

Mode 5: In the previous mode, S1 is turned off. The body diode of S1 begins to conduct because of

discharging of Cr. The resonant current iLr starts increasing in reverse direction and finally becomes

zero. The mode ends when body diode of S1 is turned off.

Fig 6: Mode 5

Mode 6: Since in the previous mode, body diode of S1 is turned off, the MOSFET S alone carries the

current now. There is no resonance in this mode and circuit operation is same as conventional PWM

buck converter.

Fig 7: Mode 6

Mode 7: At starting of this mode, the main switch S is turned off with ZVS. The schotkey diode D

starts conducting. The resonant energy stored in the capacitor Cr starts discharging to the load

through the high frequency schottky diode DS for a very short period of time, hence body – diode

conduction losses and drop in output voltage is too low. This mode finishes when Cr is fully

discharged.[26]

Fig 8: Mode 7



79

Mode 8: Before starting of this mode, the body diode of switch S2 is conducting. But as soon as

resonant capacitor Cr is fully discharged, the schottky diode is turned off under ZVS.

During this mode, the converter operates like a conventional PWM buck converter until the

switch S1 is turned on in the next switching cycle.

Fig 9: Mode 8

II. MODELLING OF PV ARRAY

The use of equivalent electric circuits makes it possible to model characteristics of a PV cell.

The method used here is implemented in MATLAB Simulink for simulations. The same modeling

technique is also applicable for modeling a PV module.

The simplest model of a PV cell is shown as an equivalent circuit below that consists of an

ideal current source in parallel with an ideal diode. The current source represents the current

generated by photons (often denoted as Iph or IL), and its output is constant under constant

temperature and constant incident radiation of light.

Fig 10: Equivalent Circuit of ideal cell with load

There are two key parameters frequently used to characterize a PV cell. Shorting together the

terminals of the cell, as shown in Figure 5, the photon generated current will follow out of the cell as

a short-circuit current (Isc). Thus, Iph = Isc. As shown in Figure, when there is no connection to the

PV cell (open-circuit), the photon generated current is shunted internally by the intrinsic p-n junction

diode. This gives the open circuit voltage (Voc). The PV module or cell manufacturers usually

provide the values of these parameters in their datasheets.



80

The output current (I) from the PV cell is found by applying the Kirchoff’s current law

(KCL) on the equivalent circuit shown in Figure.10.

I = Isc − Id (1.1)

where: Isc is the short-circuit current that is equal to the photon generated current, and

Id is the current shunted through the intrinsic diode.

The diode current Id is given by the Shockley’s diode equation:

Id = Io exp( qVd /kT −1) (1.2)

where: Io is the reverse saturation current of diode (A),

q is the electron charge (1.602×10-19 C),

Vd is the voltage across the diode (V),

k is the Boltzmann’s constant (1.381×10-23 J/K),

T is the junction temperature in Kelvin (K)

Replacing Id of the equation (1.1) by the equation (1.2) gives the current-voltage relationship of the

PV cell.

Ι = Isc − Io (exp(qV/kT) −1) (1.3)

where: V is the voltage across the PV cell, and I is the output current from the cell.

The reverse saturation current of diode (Io) is constant under the constant temperature and found by

setting the open-circuit condition as shown in Figure 6. Using the equation (1.3),

let I = 0 (no output current) and solve for Io.

0 = I sc − I o(exp (qVsc / kT )−1) (1.4)

I sc= I o(exp (qVsc / kT )−1) (1.5)

I o = I sc/(exp (qVsc / kT )−1) (1.6)

To a very good approximation, the photon generated current, which is equal to Isc, is directly

proportional to the irradiance, the intensity of illumination, to PV cell . Thus, if the value, Isc, is

known from the datasheet, under the standard test condition, Go=1000W/m2 at the air mass (AM) =

1.5, then the photon generated current at any other irradiance, G (W/m2), is given by:

I scIG = (G/Go) I scIGo (1.7)

Figure shows that current and voltage relationship (often called as an I-V curve) of an ideal

PV cell simulated by MATLAB using the simplest equivalent circuit model. The PV cell output is

both limited by the cell current and the cell voltage, and it can only produce a power with any

combinations of current and voltage on the I-V curve. It also shows that the cell current is

proportional to the irradiance.



81

Fig 11: I-V Characteristics of a PV Cell

A single PV cell produces an output voltage less than 1V, about 0.6V for crystalline silicon

(Si) cells, thus a number of PV cells are connected in series to archive a desired output voltage.

When series-connected cells are placed in a frame, it is called as a module. Most of commercially

available PV modules with crystalline-Si cells have either 36 or 72 series-connected cells. A 36-cell

module provides a voltage suitable for charging a 12V battery, and similarly a 72-cell module is

appropriate for a 24V battery. This is because most of PV systems used to have backup batteries,

however today many PV systems do not use batteries; for example, grid-tied systems. Furthermore,

the advent of high efficiency DC-DC converters has alleviated the need for modules with specific

voltages. When the PV cells are wired together in series, the current output is the same as the single

cell, but the voltage output is the sum of each cell voltage, as shown in Figure 12.

Fig 12: PV Cells connected in series to make up a PV Module

Also, multiple modules can be wired together in series or parallel to deliver the voltage and

current level needed. The group of modules is called an array.

III. SIMULATION RESULTS AND DISCUSSIONS

The simple diode equivalent model is take into considered and PV module is modelled and

various effects of temperature and irradiance are shown below.

0 5 10 15 20 25 30 35 40 45 500

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

module voltage

module

current



82

Fig 13: I-V Characteristics with varying Irradiance for G =400 W/m2, 600W/m2 and 1000 W/m2

Fig 14: I-V Characteristics with varying Temperature for T=25ºC, 35ºC and 50 ºC

The following parameters are considered for design:

Vin = 30V ,Vout = 12volts, Iload = 1 amps Fsw = 200 kHz Duty ratio (D) = Vin / Vout = 0.43.

Assume Iripple = 0.3*Iload (typically 30%). The switching frequency is selected at 200 kHz. The

current ripple will be limited to 30% of maximum load.

Fig 15: Simulink model of synchronous buck converter without PV

0 5 10 15 20 25 30 35 40 45 500

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

module voltage

module current

0 5 10 15 20 25 30 35 40 45 500

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

module voltage

module current

International Journal of Electrical Engineering and Technology (IJEET), ISSN 0976

ISSN 0976 – 6553(Online) Volume 5, Issue 5, May (2014), pp.

Fig 16: Output Voltage of synchronous buck converter not connected to PV

Fig 17: Output current

Fig 18

ional Journal of Electrical Engineering and Technology (IJEET), ISSN 0976

6553(Online) Volume 5, Issue 5, May (2014), pp. 74-88 © IAEME

83

age of synchronous buck converter not connected to PV

current of synchronous buck converter not connected to PV

18: Voltage across main switch S

ional Journal of Electrical Engineering and Technology (IJEET), ISSN 0976 – 6545(Print),

age of synchronous buck converter not connected to PV

of synchronous buck converter not connected to PV



Fig

Fig

Fig



84

Fig 19: Current across switch S

Fig 20: Voltage across switch S1

Fig 21: Current across switch S1




Fig

The voltage waveform of MOSFET ‘S’in fig.

which means the MOSFET is switched on when the voltage

zero power loss across MOSFET ‘S’

resonant inductor (Lr) is used as an auxiliary circuit for causing ZVS for MOSFET ‘S’. The

waveforms shown in fig.18 and fig.

indicates the zero current turn off of MOSFET ‘S1’ (ZCT). It is

resonant inductor.

Fig 23: Synchronous buck conv



85

Fig 22: Current across switch S2

of MOSFET ‘S’in fig. reveals the zero voltage switching (ZVS),

the MOSFET is switched on when the voltage across MOSFET is zero, thereby causing

zero power loss across MOSFET ‘S’. The MOSFET ‘S1’along with resonant capacitor (Cr) and


nd fig.19&20 describe the current and voltage across MOSFET ‘S1’

indicates the zero current turn off of MOSFET ‘S1’ (ZCT). It is turned off by ZCT because of

Synchronous buck converter connected with PV.


reveals the zero voltage switching (ZVS),

is zero, thereby causing

The MOSFET ‘S1’along with resonant capacitor (Cr) and


describe the current and voltage across MOSFET ‘S1’

turned off by ZCT because of



Fig 24: Output Current of synchronous buck converter connected with PV

Fig 25: Output voltage of synchronous buck converter connected with PV

IV. CONCLUSION

The waveforms depict the soft switching phenomena. This converter is used as a DC

converter between PV array and load. Since the switching and conduction losses are reduced, the

system can be used as a high efficient portable device. Besides the main switch ZVS turned

turned-off, the auxiliary switch ZCS turned

and turned-off under ZVS. Hence switching losses ar

current stresses on the main devices do not take place, and the

allowable voltage and current values.

connecting the PV module and with connection of the PV module in MATLAB Simulink

environment and for input voltage of 30V the output voltage of 12V is obtained which can be used

for any low power application fed from PV module and in most cases the of PV is around 15V to

40V depending on temperature and irradiance, hence this converter connected with PV can be used

for portable applications.



86

Output Current of synchronous buck converter connected with PV

Output voltage of synchronous buck converter connected with PV

The waveforms depict the soft switching phenomena. This converter is used as a DC

between PV array and load. Since the switching and conduction losses are reduced, the

system can be used as a high efficient portable device. Besides the main switch ZVS turned

off, the auxiliary switch ZCS turned-on and turned-off, the synchronous switch also turned

off under ZVS. Hence switching losses are reduced and the additional voltage and

stresses on the main devices do not take place, and the auxiliary devices are subjected to

es. In this paper the simulation is done for two cases i.e without



power application fed from PV module and in most cases the of PV is around 15V to



Output Current of synchronous buck converter connected with PV

Output voltage of synchronous buck converter connected with PV

The waveforms depict the soft switching phenomena. This converter is used as a DC-DC

between PV array and load. Since the switching and conduction losses are reduced, the

system can be used as a high efficient portable device. Besides the main switch ZVS turned-on and

ronous switch also turned-on

additional voltage and

auxiliary devices are subjected to

In this paper the simulation is done for two cases i.e without



power application fed from PV module and in most cases the of PV is around 15V to




87

REFERENCES

[1]. L.Yang and C.Q.Lee, “Analysis and design of boost zero-voltagetransition PWM

converter,” in Proc. IEEE APEC Conf. 1993, pp.707-713.

[2]. G.Hua, C.S.Leu, Y.Jiang, and F.C.Lee, “Novel zero-voltagetransitionPWM converters,”

IEEE Trans. Power Electron., vol.9, no.2, pp.213-219, Mar.1994.

[3]. A.J.Stratakos, S.R.sanders, and R.W.Broderson, “A low-voltageCMOSdc-dc converter for a

portable battery-operated system,” in Proc. Power Electronics Specialist conf., vol.1, Jun.

1994, pp.619-626.

[4]. A.V.da Costa, C.H.G.Treviso, and L.C.deFreitas, “A new ZCSZVS- PWM boost converter

with unity power factor operation,” in Proc. IEEE APEC Conf., 1994, pp.404-410.

[5]. N.P.Filho, V.J.Farias, and L.C.deFreitas, “A novel family of DCDC PWM converters uses

the self resonance principle,” in Proc.IEEE PESC Conf., 1994, pp.1385-1391.

[6]. G. Moschopoulos, P.Jain, and G.Joos, “A novel zero-voltage switched PWM boost

converter,” in Proc. IEEE PESC Conf.,1995, pp.694-700.

[7]. Elasser and D. A. Torrey, “Soft switching active snubbers for dc/dc converters,” IEEE

Trans. Power Electron., vol. 11, no. 5, pp. 710–722, 1996.

[8]. K.M.Smith and K.M.Smedly, “A comparison of voltage-mode soft switching methods for

PWM converters,” IEEE Trans. Power Electron., vol.12, no.2, pp.376-386, Mar.1997.

[9]. O.Djekic, M.Brkovic, “Synchronous rectifiers vs. schottky diodes in a buck topology for

low voltage applications,” Power Electronics Specialists Conference, 1997. PESC '97

Record, 28th

Annual IEEE, 22- 27 June 1997, vol.2, pp. 1374 – 1380.

[10]. Y.Xi, P.K.Jain, G.Joos, and H.Jin, “A zero voltage switching forward converter topology,”

in Proc. IEEE INTELEC conf.,1997, pp.116-123.

[11]. C.J.Tseng and C.L.Chen, “Novel ZVT-PWM converter with active snubbers,” IEEE Trans.

Power Electron., vol.13, no.5, pp.861-869, Sept.1998.

[12]. O.Djekic, M. Brkovic, A. Roy “High frequency synchronous buck converter for low voltage

applications.” IEEE PESC’98 Record, vol.2, pp. 1248 – 1254.

[13]. G. Moschopoulos, P.Jain, G.Joos, and Y.F.Liu, “Zero voltage switched PWM boost

converter with an energy feedforward auxiliary circuit,” IEEE Trans., Power Electron.,

vol.14, no.4, pp.653-662, Jul.1999.

[14]. T.W.Kim, H.S.Kim, and H.W.Ahn, “An improved ZVT PWM boost converter,” in Proc.

IEEE PESC Conf., 2000, pp.615-619.

[15]. J.H.Kim, D.Y.Lee, H.S.Choi, and B.H.Cho, “High performance boost PFP with an improved

ZVT converter,” in Proc., IEEE APEC Conf., 2001, pp. 337-342.

[16]. N.Jain, P.Jain, and G.Joos, “Analysis of a zero voltage transition boost converter using a soft

switching auxiliary circuit with reduced conduction losses,” in Proc. IEEE PESC Conf.,

2001,pp.1799-1804.

[17]. M.L.Martins, H.A.Grundling, H.Pinheiro, J.R.Pinheiro, and H.L.Hey, “ A ZVT PWM boost

converter using auxiliary resonant source,” in Proc. IEEE APEC Conf., 2002, pp.1101-1107.

[18]. C.M.Wang, “Zero-voltage-transition PWM dc-dc converters using a new zero-voltage

switch cell,” in Proc. IEEE INTELEC Conf., 2003, pp.784-789.

[19]. M.L. Martins, J.L. Russi, H. Pinheiro, H.A. Grundling, H.L. Hey,“ Unified design for ZVT

PWM converters with resonant auxiliary circuit,” Electric power applications, IEE

proceedings, vol.151, issue 3, 8 May 2004, pp. 303-312.

[20]. S. Kaewarsa, C. Prapanavarat, U. Yangyuen, “An improved zerovoltage-transition technique

in a single-phase power factor correction circuit,” International conference on power system

technology – POERCON 2004, 21-24 Nov. 2004, vol.1, pp.678 –683.



88

[21]. M.D.Mulligan, B.Broach, and Thomas H.Lee,” A constantfrequency Method for Improving

light-load efficiency in synchronous buck converters,” IEEE Power Electronics letters, vol.3,

no.1, pp.24-29, March 2005.

[22]. M.L.Martins, J.L.Russi, H.L.Hey, “Zero-voltage transition PWM converters: a classification

methodology,” IEEE proceedings on electric power applications, 4th March 2005, vol.152,

no.2, pp.323– 334.

[23]. W.Huang and G. Moschopoulos, “A new family of zero-voltage transition PWM converters

with dual active auxiliary circuits,” IEEE Trans. Power Electron., vol.21, no.2, pp.370-379,

March2006.

[24]. V.Yousefzadeh and D.Maksimovic, “Sensorless optimization of dead times in dc-dc

converters with synchronous rectifiers,” IEEE Trans. Power Electronics, vol.21, no.4,

pp.994-1002, July 2006.

[25]. A.K. Panda, Aroul.K, “A Novel Technique to reduce the Switching losses in a synchronous

buck converter” IEEE PEDES Conference, 12th-15th Dec2006, IIT, Delhi, pp.1-5.

[26] B.ChittiBabu, S.R.Samantaray, Nikhil Saraogi, M.V. Ashwin Kumar, R. Sriharsha and S,

Karmaker “Synchronous Buck Converter based PV Energy System for Portable

Applications” IEEE Students Symposium, 14th

-16th

January 2011,IIT Delhi, pp1-6.

[27] Jadhav Sumedh Damodhar and Phatale Aruna Prashant, “Microcontroller Based

Photovoltaic Battery Charging System with Buck Converter”, International Journal of

Electrical Engineering & Technology (IJEET), Volume 3, Issue 1, 2012, pp. 123 - 130,

ISSN Print : 0976-6545, ISSN Online: 0976-6553.

[28] Ramjee Prasad Gupta and Dr. Upendra Prasad, “Design of a Pwm Based Buck Boost Dc/Dc

Converter with Parasitic Resistance Suitable for Led Based Underground Coalmines

Lighting System”, International Journal of Electrical Engineering & Technology (IJEET),

Volume 3, Issue 3, 2012, pp. 175 - 186, ISSN Print : 0976-6545, ISSN Online: 0976-6553.

[29] Arun Kumar Pandey, Prof. S. K. Misra snd Sumit Kumar Misra, “Transient Response

Improvement of Buck Converter”, International Journal of Electrical Engineering &

Technology (IJEET), Volume 4, Issue 1, 2013, pp. 131 - 138, ISSN Print : 0976-6545,

ISSN Online: 0976-6553.

40220140505008

Technology

pv energy systems

energy generation system

solar power

use of renewable energy

wind energy systems

pv cells

high energy capacity

important renewable