IRJET-PV Based Dynamic Voltage Restorer (PV-DVR) With Significant energy Conservation Level

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 02 Issue: 02 | May-2015 www.irjet.net p-ISSN: 2395-0072

2015, IRJET.NET- All Rights Reserved Page 197

PV Based Dynamic Voltage Restorer (PV-DVR) With Significant energy

Conservation Level

N.Jeevagasundaram1, R.Kumar 2

1 PG Scholar, Power System Engineering, Maharaja Prithvi Engineering College, Avinashi-641654

2Assistant Professor/EEE, Maharaja Prithvi Engineering College, Avinashi-641654

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Abstract -Dynamic Voltage Restorer (DVR) can

provide the most cost effective solution to mitigate

voltage sags, voltage swells and outages by

establishing the proper voltage quality level that is

required by the sensitive loads. PV-DVR system has

become a favorable solution for a home or small

industry. Particularly in Tamil Nadu, India, rural

areas that have a substantial amount of insulation

and have more frequent power interruptions on every

day. This may occur in the developing countries,

where the generated electrical power is less than their

demand. Problems facing industries and residences

regarding the power qualities are mainly due to

voltage sag, short duration voltage swell and long

duration power interruptions.The rating and design

of series injection transformer of the DVR is

presented. Many research works have been carried

out on focusing the design and control of DVR. on-line

type DVR has been presented to compensate the

voltage sag in the system. The DVR without PV system,

supported by the super capacitor as energy storage

device for power quality improvement in electrical

distribution system is presented.

Key Words: Dynamic Voltage Restorer, PWM inverter, DCDC converter, MPPT algorithm

1. INTRODUCTION

Dynamic Voltage Restorer (DVR) with the proposed

system consists of a PV array, low step-up DCDC

converter with P&O MPPT algorithm, battery, high step-

up DCDC converter, PWM inverter, series injection

transformer and semiconductor switches S1, S2, S3, R1

and R2.

Fig. 1. Block diagram of the proposed PV-DVR

Table 1 Control signals for S1, S2 and S3.

Supply voltage in % Control signals Mode of operation

S1 S2 S3

100 1 0 1 Idle

100 1 0 0 DVR

0 0 1 0 UPS



Table 2 Battery Charge Control.

PV voltage in volts Control signals Battery charging

unit

R1 R2

>6 0 1 PV array



PWM pulse. The simulink block diagram of the fuzzy

controller based P&O MPPT is shown in Fig. 7. The

inputs and output of fuzzy controller are expressed as a

set of linguistic variables as follows: NB-Negative Big,

NS-Negative Small, Z-Zero, PS-Positive Small and PB-

Positive Big. The output of the fuzzy is chosen from a set

of semantic rules that lead to track the maximum power

point of PV array.

Table 3 Fuzzy rules for MPPT method.

e/De NB NS Z PS PB

NB

NS

Z

PS

PB

Z

Z

PS

NS

NB

Z

Z

Z

NS

NB

PB

PS

Z

NS

NB

PB

PS

Z

Z

Z

PB

PS

NS

Z

Z

2. High step-up DCDC converter

Fig. 4.High step up DCDC converter.

Usually, the output voltage level of the low step-up DC

DC converter and batteries are low. Hence, it is not

sufficient to inject the required amount of voltage to the

load to mitigate deep voltage sags, swells and outages.

For that a high step up DCDC converter is used to step-

up the low voltage DC (24 V) into high voltage DC (230

V). It is connected in between batteries and DC link of

the PWM inverter. Fig.4 shows the circuit diagram of a

high step up DCDC converter.

2.2 DVR controller

Fig. 5 Block diagram of DVR controller.

The control scheme used to maintain a constant

voltage magnitude at the load point, under system

disturbance, is shown in Fig. 5. In the proposed

controller, a discrete single phase PLL is used to track

the phase angle of the source voltage to perform the

parks transformation on the measured single phase

voltage [30]. The measured p.u. value of supply voltage is

converted into |Vs|, and the error is obtained from the

difference of |Vs| and reference voltage (Vref).

The PI controller designed by the Ziegler

Nichols tuning method processes the error and

generates required angle d to drive the error to zero. The

modulating angle d is applied to the reference voltage

generator to generate the Vref for the Sinusoidal Pulse

Width Modulation (SPWM).

The reference voltage calculation is obtained by

the following equation

The generated Vref is utilized to produce switching pulses

for VSI. The basic idea of SPWM is to compare a

sinusoidal control signal (Vref) of normal frequency 50 Hz

with a triangular carrier waveform (Vcarrier) with 20 kHz

signal to produce the PWM pulses.



When the control signal is greater than the carrier

signal, the switches are turned on, and their counter

switches are turned off. The output voltage of the

inverter mitigates the voltage sag, swell and outage.

3. Experimental verification of PV-DVR

In the following section the experimental

verification of the proposed PV-DVR with different

experimental results are presented. The details of the

experimental set-up and experimental results are

presented.

3.1 Experimental setup

The hardware setup was accomplished with a

400 V A DVR prototype to experimentally verify the

feasibility of implementation of the proposed PV-DVR.

This prototype consists of a solar panel, low and high

step-up DCDC converter, batteries, single phase series

injection transformer and a load. The cost of the

proposed PVDVRis about 1.502.40 $/W [31,32]. A

single phase auto transformer with 1 kV A, 0270 V

capacity is used to introduce the voltage sag of 50%,

voltage swell of 110% and outages on the 230 V systems.

The inverter is a standard H-bridge system that is

connected at the 230 V level through a 1 kV A single

phase injection transformer. The DC bus voltage can be

charged up to 230 V using the PV and rectifier output

voltages. For all experiments the line frequency was 50

Hz, the switching frequency was set to 20 kHz and

batteries of two 12 V, 9 A h was used. Once the measured

voltage magnitude dropped/raised from its nominal

value, a voltage sag/swell is detected. A single phase

step-down transformer (230 V/5 V) with the potential

divider arrangement is utilized to sense the supply

voltage variations. Based on the comments received

from the Analog to Digital converter (ADC), the proposed

SPARTAN6 FPGA controller decides the switching logic

of the semiconductor switches S1, S2, S3 and R1, R2,

respectively. The DVR compensates the voltage

sag/swell with a reference generated by the error

between Vref and Vactual. The output voltage measured

by the Digital Storage Oscilloscope (DSO) and Precision

Power Analyzer (PPA) is presented.

Fig. 6. Supply voltage, injected voltage, load voltage and

load current.



Fig. 7. PV array output voltage without and with boost

converter.

Fig. 8. Power generated and obtained from the PV array.

Fig. 9. Discharge characteristics of battery for various

output currents.

Fig. 10.Output voltage of the high step up DCDC

converter.

Fig. 11.Transient response of the proposed DVR.

CONCLUSION

This project presents a novel application of utilizing a

PV solar system as DVR for voltage sag/swell and outage

mitigation at a residence or small industry. A DCDC

converter with fuzzy logic controller based P&O MPPT

algorithm is implemented to track the maximum power

point of the PV array. This novel PV-DVR is designed to

reduce the energy consumption from utility grid by

disconnecting the utility grid from the load through

semiconductor switches, when the PV array generates

equal or excessive real power to meet the load demand.

Further, it reduces the panel tariff and avoids the use of

UPS & stabilizer for the individual equipment at a

residence, small industry and educational institution.

The simulation and experimental results show the

capability of PV-DVR in mitigating the voltage variations.



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IRJET-PV Based Dynamic Voltage Restorer (PV-DVR) With Significant energy Conservation Level

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