Performance improvement of reconfiguration strategies in photovoltaic array by replacement of blocking diodes with MOSFETs

ABSTRACT

The power from photovoltaic array (PVA) is affected by temperature, solar irradiation, dust concentration, wind velocity, photovoltaic array configuration (PVAC) and shading pattern. The problem of partial shading (PS) is recognized as a major concern which decreases the PVA output power and represents multiple peak power points in the PV characteristic. Different PVACs respond differently with regard to their mismatch power loss (MPL) and fill factor (FF) under partial shaded condition (PSC). The conventional PVACs, such as SP-diode (Series-Parallel), TCT-diode (Total-Cross-Tied), BL-diode (Bridge-Link) and HC-diode (Honey-Comb), use blocking diodes (B-diodes) to block the reverse current. On the other hand, the proposed PVACs, including SP-MOSFET, TCT-MOSFET, BL-MOSFET and HC-MOSFET, replace the B-diodes with Blocking P-MOSFETs (BP-MOSFETs). The improvement in power output of the PVA is examined for four different configurations with B-diode and BP-MOSFET under changing illumination conditions. It is observed that TCT-MOSFET configuration shows better performance with least power losses and maximum efficiency under PSCs.

KEYWORDS:

• Photovoltaic array configuration
• partial shaded condition
• maximum power point
• blocking diodes and P-MOSFETs
• mismatch power loss
• fill factor

List of symbols

$I_{ph}$	=	Solar generated current of each PV cell
$R_{se}$	=	Series resistance
$R_{sh}$	=	Shunt resistance
$I_c,V_c$	=	PV cell output current and voltage
$I_0$	=	Reverse saturation current of diode
$T$	=	Junction temperature of diode
∝	=	Ideality constant of diode
$q$	=	Electron charge
$k$	=	Boltzmann’s constant
$n_s$, $n_p$	=	Series and parallel connected PV cells
$V_{occ}$, $I_{scc}$	=	PV cell open circuit voltage and short circuit current
$V_{ocp}$, $I_{scp}$	=	PV panel open circuit voltage and short circuit current
$V_p$, $I_p$	=	PV panel voltage and current
$N_s$, $N_p$	=	Number of series and parallel connected PV panels
$V$, $I$	=	PV array voltage and current
$V_{oc}$, $I_{sc}$	=	PV array open circuit voltage and short circuit current
$I_p$	=	PV panel current
$G_{STC}$	=	Irradiance value at STC
$I_{p,STC}$	=	PV panel current at STC
$V_{pn}$	=	PV voltage of $n^{th}$ row of PV array
$P_{mpp}$	=	Global peak power at uniform irradiance
$P_{mpp,ps}$	=	Global peak power under partial shading

List of abbreviations

PV	=	Photovoltaic
PVC	=	PV cell
PVM	=	PV module
PVA	=	PV array
PVAC	=	PVA configuration
PS	=	Partial shading
MPL	=	Mismatch power loss
FF	=	Fill factor
PSC	=	Partial shaded condition
SP	=	Series-parallel
HC	=	Honey-comb
BL	=	Bridge-link
TCT	=	Total-cross-tied
MOSFET	=	Metal-oxide semiconductor field effect transistor
B-diode	=	Blocking diode
B-MOSFET	=	Blocking MOSFET
MPP	=	Maximum Power Point
SBHT	=	SP, BL, HC, TCT
OCV	=	Open circuit voltage
SCC	=	Short circuit current
SC	=	Shading case
GMPP	=	Global MPP

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Swati Gautam

Swati Gautam is pursuing her post-graduation in Power System Engineering from School of Electrical, Electronics and Communication Engineering, Galgotias University, G. Noida. Her research interests include Power Systems and Renewable Energy Technologies.

Gitanjali Mehta

Gitanjali Mehta received her B. Tech degree from IET, Bareilly, M. Tech degree in Power Electronics and ASIC Design from MNNIT Allahabad and Ph.D. degree from Department of Electrical Engineering, Indian Institute of Technology, Roorkee. Presently, she is working as Professor in the Power Electronics Division of School of Electrical, Electronics and Communication Engineering, Galgotias University, G. Noida. Her research interests include Power Electronics, Renewable Energy Technologies, Grid-integration of Distributed Energy Resources etc.

Shahroz Anjum

Shahroz Anjum received her B. Tech degree in Electrical Engineering from College of Engineering, Roorkee and her M. Tech degree in Power Systems from Thapar University. Presently she is pursuing Ph. D from Department of Electrical Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India. Her research interest includes power system optimization and renewable energy technologies.