2005

1.

[1]-[2].

, 97[%]

5%

,

, 10 ,

,

.

,

(MPPT:

Maximum Power Point Tracking) [3].

,

MPPT ,

.

(

) MPPT

(5 6 / ) ,

.

.

,

. ,

.

IEEE-standard

[4].

UPQC(Unified Power Quality Conditioner)

. ,

.

( 0.9 , THD: 5% ) , MPPT

, (100%)

.

,

Grid-interactive PV Generation system with High Power Quality

*** *** ** * *(Seong-Ryong LeeChil-Hwan JeonSung-Hun KoAh-Ran ChoDae-Up Kang)

Abstract - In this paper, a grid-interactive photovoltaic (PV) system with high power quality is presented, which

gives first priority to maximum power point tracking (MPPT). The proposed system requires only one current

controlled voltage source inverter (CCVSI), which can control the current flow (MPPT operation) at low total

harmonic distortion (THD) and unity power factor, as well as simultaneously provide reactive power support. The

proposed system operation has been divided into two modes (sunny and night). In night mode, the system

operates to compensate the reactive power demanded by nonlinear or variation in loads. in sunny mode, the

system performs power quality control (PQC) to reduce harmonic current and improve power factor as well as

MPPT to supply active power from the PV arrays simultaneously. It is shown that the proposed system improves

the system utilization factor to 100%, which is generally low for PV system (20%). To verify the proposed

system, a comprehensive evaluation with theoretical analysis, simulation and experimental results are presented.

Key Words : , MPPT, Power quality control, CCVSI

* : ** : *** :

2005

.

(PV array) ( )

(CCVSI: Current

Controlled Voltage Source Inverter) ,

.

(PQC: Power Quality Control)

,

MPPT PQC .

CCVSI

.

(24/ )

.

,

.

2.

MPPT

dc/dc

dc/ac two-stage

[5]-[6]. DC

,

[7].

1 dc/ac

single-stage .

1 Single-stage

Fig. 1 Schematic diagram of a single-stage grid-

interactive PV generation system

Load

loadi

CiQ1

Q4

Q2

Q3

PVV

PV array

PVIgi

gV

C1Lc

1 single-stage

.

( )

.

( )

CCVSI

. CCVSI

[8]. CCVSI

.

.

2.1

2 3

.

MPPT PQC

,

PQC .

2

Fig. 2 The equivalent circuit diagram of the proposed

system

LoadGrid CCVSI

0= gGrid VV 0= cCCVSI VV

Ig Ic

Iload

1 CCVSI

2

. CCVSI

.

.gI PVI

cqI

cI

loadpI gV

loadI

gI

cIloadI

gV

(a) (b)

3 Single-stage

Fig. 3 Schematic diagram of a single-stage grid-

interactive PV generation system

2 (Vg ),

(Vc ) (Vload )

, (Iload ) (Ic )

.

(1)

3 (b) (Pload )

2005

. (I*g )

.

(2)

3 (a)

MPPT

.

(I*g ) .

(3)

, Ppv (Vmpp)

.

(MPP)

.

,

dP/dV=0 . MPPT

P&O (Perturbation and Observation)

IncCond (Incremental Conductance)

[9]-[10]. P&O

. IncCond

P&O

MPP

.

(dP/dV)

MPPT

[7].

one-diode (4)

.

(4)

, Ipv Vpv , Iph

, Isat , Rs Rsh

, q , A p-n , K

(Boltzmann`s constant), T

.

(5) (6)

.

(5)

( )

.

(5)

, dP/dV ( I) ( V)

I+( I+ V)V . dP/dV0

dP/dV 0 .

IncCond

.

MPPT

(I*g ) (I*c )

.

(6)

(2) (8)

PQC

, (7)

(Ipvmax ) (3) (8) MPPT

PQC .

2.2

4

Fig. 4 Control block diagram of proposed system

+

loadi

A CD C

P LLS inw t*

gV

V pv

Ipv

Icq*

Icp*

P Q C

M P P T

P R TIc-re f*

V g

Iload

ci pvi

P W M

p vV

G rid

L oad

PVV SIX c

+

Ic

4

MPPT ,

PQC ,

PRT(Polarized RampTime)

.

. ,

,

(2)

(8) sinwt*

2005

(I*cq ) . PRT

(Ic)

PWM . ,

,

MPPT

(Vref) .

dP/dV=I +( I+ V)V dP/dV0

dP/dV 0 .

dc sinwt*

(I*cp )

. PQC

(I*cq )

(I*c-ref ) .

PRT

PWM .

3.

1

[KVA] ,

1 . LS

GMG 01800 14 . GMG 01800

80[W], 17.6 [V], 21.6[V],

4.55[A], 5[A] .

1

Table 1 Conditions and parameters of the experiment

Parameters Values Parameters Values

Vac 220Vrms Vdc 230[70V]

60Hz 5kHz

5mH DC 1000uF

1: 2 1KVA

5

. 5

(a) PQC , (b) PQC

(CH1),

(CH2), (CH3), (CH4) . 5

PQC

.

1:7

. 6 5 FFT

TDS3054B MATH FFT

, THD Voltech PM3000

.

(a)

(b) PQC

5

Fig. 5 Experimental results of proposed system at

night

mode

(a)

(b) PQC

6 FFT

Fig. 6 FFT waveforms of the grid current at nonlinear

load

2005

6 (a) 5 (a) FFT

THD 25.4[%], 0.94 .

6 (b) 5 (b) FFT THD

3.8[%], 0.99 .

0.99

THD 5[%] . 7

9

(CH1), (CH2),

(CH3), (CH4) . 7

(a) MPPT (

) (b) MPPT PQC (

) .

(a)

(b)

7

Fig. 7 Experimental results at inductive load condition

7 (a) MPPT

(0.86 0.51 )

. 9 (b)

MPPT PQC MPPT

(0.99) . 8 5

( ) (a)

470(W/m2 ), (b) 930(W/m2 )

.

8 (a) 470(W/m2 )

. 8 (b) 890(W/m2 )

.

10

.

MPPT

0.99 , THD 5[%] IEEE

.

(a) : 470(W/m2 )

(b) : 890(W/m2 )

8

Fig. 8 Experimental results of proposed system at

sunny

mode

9

,

. 8 (a) 470

(W/m2 )

.

9 MPPT

Fig. 9 Experimental result of proposed system at

decreasing insolation

2005

9

.

4.

MPPT

,

. ,

MPPT

PQC

.

.

1.

0.99 , THD

3.8[%]

IEEE std-1159 .

2. MPPT

.

3. MPPT

PQC

, ,

.

,

. ,

.

97[%]

.

2006

,

.

[1] W. Wongsaichua, Wei-Jen Lee; S. Oraintara, C.

Kwan, F. Zhang, "Integrated high-speed intelligent

utility tie unit for disbursed/renewable generation

facilities," IEEE Transactions on Industry

Applications, vol. 41, pp. 507 - 513, 2005

[2] A.M. Sharaf and A.R.N.M.R.U. Haque, Low cost

utility interconnected photovoltaic scheme for

residential/ village/ cottage electricity,

Proceedings of the System Theory SSST, vol. 1,

pp. 435-438, March 2005.

[3] J.H.R Enslin, M.S. Wolf, D.B. Snyman and W.

Sweigers,"Integrated photovoltaic maximum power

point tracking converter," IEEE Trans. Ind.

Electron., vol. 44, pp. 769-773, Dec, 1997.

[4] IEEE Std 1159-1995, "IEEE Recommended

Practice for Monitoring Electric Power Quality",

IEEE standards board, June, 1995.

[5] S.J. Chiang, K.T. Chang, and C.Y. Yen,"Residental

energy storage system," IEEE Trans. Ind.

Electron., vol. 45, pp. 385-394, June 1998.

[6] .S. Nonka and y. Neda,"Single phase composite

PWM voltage source in Conf. Rec. IEEE-IAS

Annul. meeting, pp. 761-767, 1994.

[7] Y.C. Kuo, T.J. Liang, and J.F. Chen,"Novel

Maximum-Power-Point-Tracking Controller for

Photovoltaic Energy Conversion System," IEEE

Tran. Ind. Electronics, vol. 48, no. 3, pp.

594-601, June 2001.

[8] S.H. Ko, S.R. Lee, H. Dehbonei and C.V

nayar,"Application of Voltage and Current

Controlled Voltage Source Inverters For

Distributed Generation Systems", IEEE Trans.

Energy Conversion, vol.21, no.13 pp. 782-792,

september, 2006.

[9] B.K. Vose, P.M. Szczeny, and R.L.

Steigerwald,"Microcomputer control of a

residential photovoltaic power conditioning

system," IEEE Trans. Ind. Application, vol. IA-21,

pp. 1182-1191, Sept/Oct. 1985

[10] K.H. Hussein, I. Muta, T. Hoshino, and M.

Osakada,"Maximum photovoltaic power tracking:An

algorithm for rapidly changing atmospheric

conditions," Proc. IEE-Generation, Transmission,

Distribution, vol. 142, no. 1, pp. 59-64, Jan. 1995.