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International Journal of Electronics

ISSN: 0020-7217 (Print) 1362-3060 (Online) Journal homepage: http://www.tandfonline.com/loi/tetn20

Development of High Performance SolarPhotovoltaic Inverter with Reduced HarmonicDistortions

Albert Alexander

To cite this article:Albert Alexander (2016): Development of High Performance Solar

Photovoltaic Inverter with Reduced Harmonic Distortions, International Journal of Electronics,DOI: 10.1080/00207217.2016.1196746

To link to this article: http://dx.doi.org/10.1080/00207217.2016.1196746

Accepted author version posted online: 08Jun 2016.Published online: 08 Jun 2016.

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Publisher: Taylor & Francis

Journal:International Journal of Electronics

DOI: 10.1080/00207217.2016.1196746

Development of High Performance SolarPhotovoltaic Inverter with Reduced Harmonic

Distortions

1Abstract In addition to the focus towards growing demand on electrical energy due to the increase in population,

industries, consumer loads etc., the need for improving the quality of electrical power also need to be considered. The design

and development of solar Photo Voltaic (PV) inverter with reduced harmonic distortions is proposed. Unlike the

conventional solar PV inverters, the proposed inverter provides the advantages of reduced harmonic distortions thereby

intend towards the improvement in power quality. This inverter comprises of multiple stages which provides the required

230VRMS, 50Hz inspite of variations in solar PV due to temperature and irradiance. The reduction of harmonics is governed

by applying proper switching sequences required for the inverter switches. The detailed analysis is carried out by employing

different switching techniques and observing its performance. With a separate mathematical model for a solar PV

simulations are performed in MATLAB software. To show the advantage of the system proposed, a 3kWp photovoltaic plant

coupled with multilevel inverter is demonstrated in hardware. The novelty resides in the design of a single chip controller

which can provide the switching sequence based on the requirement and application. As per the results obtained, the solar

fed multi stage inverter improves the quality of power which makes this inverter suitable for both standalone and grid

connected systems.

Key words- Harmonics, Multilevel systems, Modulation strategy, Photovoltaic systems, Power Quality.

I.

INTRODUCTION

In the present scenario, development of an individual and society is basically depends on the

availability of electrical energy. In India, providing electrical power to all the consumers without

interruption is a major issue. To overcome this, many power plants are installed and proposed in

meeting the demand. For the construction of a power plant it requires thousands of crores as the

investment and also consumes more number of years for its debut power generation. Inspite of this, the

power demand is not met for the growing population.

In the conventional power generation system, it causes problems in terms of fossil fuel

1This work was supported in part by the Department of Science and Technology, Government of India under Technology System Development SchemeGrant (Ref. No.DST/TSG/NTS/2009/98).


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exhaustion and drastic effects in environment. To overcome these problems, renewable energy sources

are in high demand. It has been estimated by Cecati, Ciancetta, and Siano (2010) that the energy

generated by non conventional energy sources is estimated to quantify 50% of the total power demand

in 2050. But quality of power from these sources has to be improved to protect the loads connected in

the system and also to enable the continuity of supply to the consumers without any disturbances. Power

quality refers to maintaining near sinusoidal voltage to a bus at rated voltage and frequency. In addition

to the focus towards growing demand on electrical energy due to the increase in population, industries

and consumer loads, the need for improving the quality of electrical power also to be considered

seriously.

There are major considerations over the deviation of voltage, current and frequency in an

electrical system when connected to the load and also to the grid. This affects the entire system and

possesses major problems in connecting the non conventional energy sources towards the common grid.

It is not only the technical problem, it also exhibits financial problem. In USA, poor quality of power

results in economic loss of $120 billion/year as estimated by Electric Power Research Institute (EPRI,

2004). Hence the combination of power quality and power quantity will certainly result in providing

clean power from green energy sources. The discrimination of POWER QUANTITY or POWER

QUALITY results in acceptance of both the parameters. In Indian sub continent, power quality is a

major issue which needs to be addressed in creating a healthy and reliable power grid and utility

enhancing productivity and Gross Domestic Product (GDP) growth.

The proposed work enlists both the extremes such that the solar Photo Voltaic (PV) postulated

towards quantity and the inverter design with switching sequence controller approximated with quality.

To meet the objective, a power electronic interface with harmonic reduction capability needs to be

connected between the source and load. Unlike conventional inverters, the Multi Level Inverter (MLI)

is recommended by Rahim, Mohamed Elias, and Hew (2013) as the high quality outputs obtained from

the multilevel inverter overcomes the system size and filter requirements. The proposed inverter

provides the advantage of reduced harmonic distortions which intend towards the improvement in

power quality. This inverter comprises of multiple stages which provides the required 230VRMS, 50Hz

inspite of variations in solar PV due to temperature and irradiance. The switching sequence for the MLI

is controlled by single chip controller which enables the power quality. The input source considered is

solar PV which intends the power quantity. It is much convenient to both power quality and power

generation in the same system as mulled by Cavalcanti, Farias, Oliveira, Neves, and Afonsa (2012).

Pertaining to power quality, harmonics appear as the waveform distortion of the voltage or

current. The presence of harmonics in inverter output will lead to power supply failure and other system

components. Hence MLIs when compared to conventional two level inverters can be used in diverseapplications which require the quality of electrical power needs to be improved as claimed by Zambra,

Rech, and Pinheiro (2010).


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Alexander and Manigandan (2014) compared the various structures of MLI and found Cascaded

Multilevel Inverters (CMLI) utilizes minimum number of switching devices in ahead of other types of

MLIs. In CMLI, each DC link can be fed by an isolated sources hence it does not possess a voltage

unbalance problem as pointed by Kouro et al. (2010). Due to these merits the CMLI based structure can

be used as power conversion unit in renewable energy sources like solar PV as considered by Rahim

and Selvaraj (2010) and fuel cell by Babaei, Alilu, and Laali (2014).

This paper vindicates the performance improvement in CMLI and also addresses the challenges

of it. By eliminating harmonics, utilizing suitable control algorithms and adopting new multilevel

structures the performance can be improved as experimented by Abu-Rub, Holtz, Rodriguez, and

Baoming (2010). Reducing switching frequency and improving quality of power are the challenges of

MLIas pointed byGovindaraju and Baskaran (2011). For eliminating harmonics, the step modulation

proposed by Liu, Hong, and Huang (2009) computes the gating signals but this method cannot be used

for solar PV applications as this method intend towards equal DC sources. Newton Raphson (NR) based

iterative methods depend on the guess value and possess certain discrepancy when the inverter levels

are increased which was analysed by Fei, Du, and Wu (2010). Chiasson, Tolbert, McKenzie, and Du

(2005) found that resultant theory is much complicated and consumes more time which is capable to

calculate only three switching angles for asymmetrical DC and six switching angles for symmetrical DC

sources. For increasing the inverter levels it requires a new expression.

In this paper, a detailed analysis is carried out by employing different switching techniques and

observing its performance. MATLAB/Simulink is used to perform the simulation studies.The paper is

organised as: Section II formulates the problem design considerations and Section III describes the

various modulation strategies. Section IV describes simulation and its corresponding results. Section V

illustrates experimental outcome and some final discussions.

II. PROBLEMFORMULATION

In CMLI H Bridge each cells are referred as stages. The increase in the number of stages

increases the number of levels at the inverter output whose shape approximates near sinusoidal

waveform. It is henceforth considered that the increase in levels intend towards the reduction in Total

Harmonic Distortion (THD) which is the measure that quantifies how close the waveform is to pure

sine. Figure 1 shows the power circuit of a solar PV fed seven stage inverter to achieve a fifteen level

output.

Figure 1 Solar PV fed fifteen level inverter

Figure 1 also shows the phase voltage waveform of a cascaded fifteen level inverter with seven

PV array inputs. The phase voltage is synthesized by the sum of seven inverter outputs given by the

relation: van = va1+va2+va3+va4+va5+va6+va7. Each inverter level can generate three different voltage


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outputs, +Vdc, 0 and Vdc by connecting the PV array source to the AC output side by different

combinations of the four switches in the individual inverter stage. As a case, in the first stage of the

inverter, turning switches 1 and 4 ON yields the output +Vdcand turning switches 2 and 3 ON yields the

output Vdc. Turning OFF all the switches provides the output 0. Similarly, the AC output at each level

can be obtained in the same manner. If Nsis the number of input PV sources, the output phase voltage

level is m= 2Ns+1. Thus, a fifteen level cascaded inverter needs seven separate DC sources and seven

full bridges. Controlling the switching angles at different inverter stages can minimize the harmonic

distortion of the output voltage which in turn improves the power quality.

In India, the consumer loads operate at the input supply of 230VRMS (Root Mean Square) with

frequency 50Hz. To achieve this, the design procedure is started from the solar cell modelling. The

system considered is single phase standalone PV system with battery storage which enables it to operate

even during weak weather conditions. The proposed system is application specific especially intended

towards rural areas where there is less concentration of utility grid. Each solar cell of specification

Voc=0.5V, Isc=7A is chosen based on the data sheet of the commercial solar PV specifications. Solar

cells of 24 numbers are connected in series/parallel combinations at standard test conditions (1000W/m2

and 250C) to develop a 12V, 7A which constitutes a single solar module. Solar modules are connected

appropriately to achieve 48V, 7A solar PV array or panel. The series connection of the module is the

same as that of cell. This 48V, 7A solar PV serves as the input source for the single inverter stage. In

the proposed work, seven numbers of such input sources are utilized to power the seven inverter stages,

thereby a fifteen level output waveform is obtained. The following relations given in Equations (1) and

(2) hold for the desired design requirement:

V3367V48Vpeak == (1)

V59.2372

336VRMS == (2)

In order to extend the system for making it suitable for grid connected system, the condition

given in Equation (3) has to meet as indicated by Rahim, Chaniago, and Selvaraj (2011).

dc gridV > 2V (3)

In the proposed design, the total Vdc=336V is greater than the square root of the grid voltage

(230VRMS) as per the condition given in the Equation (3). As the design made for Standard Test

Conditions (STC), it produces the fixed DC output from solar panel without any variations. Most of the

models in various literature deals with the fixed output supply panels. Hence the PV panel model which


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exhibits the variations occurring due to temperature and irradiance is required to adhere the real time

specifications. In order to achieve this, a detailed analytical study on temperature and irradiance

variations is undertaken throughout the year by solar PV observatory for the geographic location where

the experiment is conducted. The radiation measurements used are beam and diffuse horizontal surface

radiation gathered with a PV pyranometer. Figures 2 and 3 shows the analysis which depicts the

irradiation and temperature levels measured for the months of January and November. Based on the

analysis it is found that the irradiance varies from 0W/m2to nearly 900W/m2.

The Solectric 9000 model is taken into consideration for modelling which provides 115W of

nominal maximum power and it has 24 numbers of series connected polycrystalline silicon cells for a

single module. It consists of two bypass diodes each of which is connected in antiparallel with 12 series

connected PV cells to protect them against hot spots. For providing a PV array input, 96 series

connected cells are used for modelling. Figure 4 shows the characteristics of modelled solar PV array

which serves as the inverter input.

Figure 2 Solar data for the month of January (Min: 0W/m2, Max: 892W/m2)Figure 3 Solar data for the month of November (Min: 0W/m2, Max: 887W/m2)

Figure 4 (a) V-I and (b) V-P characteristics of solar PV array

III.

MODULATIONSTRATEGIESIn order to improve the modular characteristics and performance of MLIs, unique modulation

techniques, control and protection features are required. A high number of power electronic devices and

switching redundancies bring a higher level of complexity compared with the two level inverters. This

complexity could be used to add additional capabilities to the modulation techniques by reducing the

switching frequency (fs), minimizing the Common Mode Voltage (CMV) and balancing the DC

voltages as studied by Malinowski, Gopakumar, Rodriguez, and Prez (2010).

By using Sinusoidal Pulse Width Modulation (SPWM) techniques, the inverters fundamental

voltage can be controlled and the harmonics will be attenuated. In this method, a carrier signal at the

desired frequency is generated and compared with the modulating voltage signal to generate gating

signals for the switching devices. When the modulating signal is above the carrier, the upper switch is

ON and when below the carrier, the lower switch is ON. Unlike the single carrier used in the SPWM

approach for the two level inverters, multiple carriers PWM with various sequence modifications are

proposed to improve power quality in solar PV fed CMLI. Multiple carrier based PWM has several

triangle carrier signals which can be modified in phase and/or vertical position in order to reduce the

output voltage harmonic content. The frequency of the triangular signal establishes the switching


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frequency of the switches and the frequency of the modulating signal determines the inverter output

frequency.

The multiple carrier modulation is classified into vertical and horizontal distribution; in which

vertical distribution of carriers does not increase the equivalent carrier frequency. This technique is

further classified into Alternate Phase Opposition Disposition (APOD), Phase Opposition Disposition

(POD) and Phase Disposition (PD). Mei, Xiao, Shen, Tolbert, and Zheng (2013) found that PD PWM

has voltage balance capability and better output voltage harmonic profile than phase shift PWM.Cougo,

Gateau, Meynard, Rafal, and Cousineau (2012) shown POD is better in terms of differential mode of

phase currents. Figure 5 shows the carrier arrangements for PD, POD and APOD considering a five

level inverter in normal case with equal distribution of carriers without any modification in frequency or

amplitude. The novelty of the work is in achieving all these modulations in a single chip with

movement of carriers above and below the zero reference for solar PV applications.

Figure 5 Carrier arrangements of (a) PD (b) POD and (c) APOD

For an m level inverter, these level shifted modulation schemes require (m-1) triangle carriers,

all having the same frequency and peak to peak amplitude. The (m-1) carriers are vertically disposed

such that the bands they occupy are contiguous. The frequency modulation index (m f) and amplitude

modulation index (ma) are given in Equations (4) and (5).

m

crf

f

f

m = (4)

)1m(V

V2m

cr

ma

= (5)

where fcr and fmare the frequencies of the carrier and modulating signals respectively. Vcr is the peak

amplitude of the modulating signal and Vm is the peak amplitude of each carrier signal.The value of ma

is between 0 to 1, beyond which it is termed as over modulation region which has to be avoided to

achieve better results.

IV.

PROBLEMSTATEMENT

The paper aims at design and implementation of a solar PV fed cascaded fifteen level inverter

with various modulation strategies in order to reduce the harmonic distortions. This includes the

multiple carrier PWM techniques such as APOD, PD and POD along with the SPWM techniques. The

modifications were made in both carrier and reference arrangements to provide the best suited strategy

for solar PV applications in spite of variations in the solar PV input. Appropriate modulation technique

with the choice of various parameters such as modulation index, switching frequency and signal

arrangement will certainly improve the power quality by reducing the harmonics in the system. The


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methods considered for each of the multicarrier PWM topologies and analysed from single stage three

level inverter to seven stage fifteen level inverter are: a) Multiple carrier with sinusoidal reference,

b) Multiple carrier of variable frequency, c) Multiple carrier of variable amplitude, d) Multiple carrier

with modified sinusoidal reference, e) Multiple carrier with Trapezoidal Amalgamated Reference

(TAR), f) Phase Shifted Carrier (PSC) and g) Unipolar and bipolar modulations.

SIMULATION AND RESULTS

MATLAB/Simulink software R2010b is used for simulation of all the modulation strategies. The

modelled solar PV panel with the input 48V, 7A depicts as the input for the separate inverter stages of

CMLI. For simulations, parameters used are, amplitude modulation index ma=1, switching frequency

fs=1000Hz as considered by Kouro, Roboelledo, and Rodriguez (2010), inverter output frequency=

50Hz and frequency modulation index mf=20. Zhang, Jouanne, Dai, Wallace, and Wang (2000) have

prescribed that the switching frequency of 1 kHz will be much appropriate for PWM inverters to reduce

the losses which was also analysed by Zhang, Jouanne, Dai, Wallace, and Wang (2000). The load

considered is RL whose values are R=100and L=10mH. For a fifteen level inverter, 14 carrier signals

are required to generate the switching pulses in which seven carriers each are placed above the zero

reference and the remaining seven carriers are positioned below the zero reference. Figure 6 shows the

multi carrier arrangements for APOD, POD, PD, PSC (each carrier signals are phase shifted by 25.71 0),

unipolar modulation (with bias at 3.2V) and inverted sine reference with TAR. Figure 7 shows the

carrier arrangements for APOD in which the modifications are made in frequency and amplitude. The

similar modifications are also considered for POD and PD whose results are given in Figure 8.

Figure 6 Multi carrier arrangements for solar PV fed fifteen level inverter

Figure 7 Modified multi carrier arrangements for solar PV fed fifteen level inverter

The comparisons given in Figure 8 (a) to (h) illustrates the resultant THD obtained from solarPV fed single stage inverter to seven stage inverter with aid of various approaches such as normal,

variable amplitude, variable frequency and modified reference. Based on the results it infers that by

increasing the levels, the harmonic distortions are summarily reduced to a great extent.

Figure 8 Comparison of THD for various modulation strategies

A minimum THD is achieved when the inverter output level reaches fifteen. Further increase in

levels can also be made, but as the design procedures suitable for Indian sub continent is developed for

the fifteen levels, it gets limited with this level. While comparing the THD for the multiple carrier PWM

methods, the lesser THD values are obtained at APOD, PD and POD in variable frequency modes and

PSC in unipolar mode.


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V. EXPERIMENTALRESULTS

A 3kWpsolar PV power supply unit is designed and implemented for the seven stage fifteen level

solar fed CMLI with multiple carrier PWM generation in a single chip. Table 1 shows the rating of the

individual solar PV module. Solar panels are connected to the loads in any of three divisions: direct,

standalone and grid connected. For application oriented, the first one is not applicable. In the proposed

set up, stand alone type is used which can also be extended to grid connected systems.

Table 2 reveals the specifications of the entire hardware setup. Figure 9 shows the 3kWp solar

PV plant and Figure 10 shows the complete hardware setup of the proposed CMLI. Here the notation

INV specifies the individual inverter stage. Gu et al. (2013) postulated the necessary to utilize

MOSFETs as a switching device.

The DSP controller is utilized for the generation of switching pulses for the MOSFET switches

based on POD, APOD and PD schemes. The carrier signals are generated and level shifted above and

and below the zero reference to produce the desired pulses. A change over switch is included which will

subsequently make the choice for any of the three schemes.

Table 1 Solar PV panel specifications Table 2 Specifications of experimental set up

Figure 9 Solar PV plant of 3kWp with 28 modules

Figure 10 Experimental setup of the proposed solar fed fifteen level inverter

These carrier signals are level shifted above and below the zero reference as per the program to

achieve PD, POD and APOD signals. Figures 11 to 13 show the carrier arrangements generated by the

controller pertaining to APOD, PD and POD modulation schemes. A DSP based processor for PV

system with tuning parameters for filter design is given by Zhang, Tang, and Yae (2015). Unlike DSP,

an analogue based circuit design for switching function generation in boost converters is investigated by

Cho, Kwak, and Lee (2015). Figure 14 shows output voltage waveform of the proposed solar inverter.

Figure 11 APOD based carrier arrangement

Figure 12 POD based carrier arrangement

Figure 13 PD based carrier arrangementFigure 14 Fifteen level inverter output voltage waveform

Table 3 shows the harmonic analysis conducted for each modulation strategies using Power

Quality Analyser (PQA) WT3000 which depicts both voltage and current THD values. WT3000 is a

high precision analyser which can display 20 parameters along with the THD and the magnitude of

harmonic orders. Based on the results it is found that inspite of variations in solar PV, by using CMLI

the required output of 230VRMS, 50Hz is achieved.

Table 3 Harmonic analysis for APOD, POD and PD

The experimental setup developed for a 3kWp solar PV inverter comprising 28 panels of each

115Wp in a standalone mode, the harmonic measurements are undertaken. The different modulations


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given in Figures 11 to 13 are thus obtained based on the shifting mechanism of carrier waveforms above

and below the zero reference with an aid of DSP processor. High care should be ensured that the carrier

shifting remain same for all the stages in both its amplitude and frequency. Deviations if any will results

in the abnormal waveforms across the inverter output. This is due to the consideration that the

comparison of carrier and reference signals will not be the same for all the three methodologies which

can be clearly viewed for the lower modulation index. The detailed information on harmonic analysis

for the proposed inverter is shown in Table 4.

Table 4. Detailed information on harmonic analysis

Voltage regulation is the process of obtaining the required output voltage in closed loop system.

The actual voltage obtained at the CMLI output in aid of solar PV variations is compared with the

required 230V. The error thus obtained is utilized as modulating signal for POD and compared with its

respective carriers. By adopting this technique, the THD is also reduced and adhere to the IEEE

standard 519-1992.

Table 5 shows the comparison of results .Table 6 shows the comparison of results obtained

from other methods in literature with the aid of resultant THD and the number of levels considered.

Table 5 Comparison between simulation and experimental results

Table 6 Comparison with the other methods

The results thus obtained thus indicate that by the appropriate choice of switching schemes will

eventually improves the power quality by reducing the value of THD. Of the three schemes investigates,

POD provides the lesser THD when compared to its counterparts APOD and PD. When comparing withother methods listed in various literatures, much of the methods are proposed for lesser number of

inverter levels and the implementation is not considered for solar PV applications. For the method

proposed, higher number of levels with reduced harmonic distortion is achieved and a single chip

controller for all the modulating strategies for level shifting makes the method unique when compared

to other methods listed in Table 5.

VI. CONCLUSION

A solar fed cascaded fifteen level inverter for power quality improvement is developed. The

multiple carrier PWM techniques are eminently suggested for the reduction of THD in a solar fed

CMLI. In the multiple carriers, the variations are made in both carrier and reference signals and their

performance is analysed from three level to fifteen level solar PV fed inverters. Based on the results, it

is found that POD method provides the least THD when compared to its counterparts. All the methods

considered for comparison deal with low power systems and uses DC power supply as its input source.

An experimental investigation is carried out for a 3kWp solar PV system with DSP based controller ingenerating the switching signals to the MLI. As per the results obtained, the solar fed multi stage

inverter improves the quality of power which makes it inverter suitable for all the systems.


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ACKNOWLEDGEMENT

The authors acknowledge and thank the Department of Science and Technology (Government of

India) for sanctioning the research grant for the project titled, DESIGN AND DEVELOPMENT OF

MULTILEVEL INVERTERS FOR POWER QUALITY IMPROVEMENT IN RENEWABLE

ENERGY SOURCES (Ref.No.DST/TSG/NTS/2009/98) under Technology Systems Development

Scheme for completing this work.

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with New Method of Capacitor Voltage Balancing. IEEE Transactions on Industrial Electronics.60, 8, 2943-2956.doi: 10.1109/TIE.2012.2200213

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Asymmetrical Multilevel Inverters. IEEE Transactions on Industrial Electronics. 57,7, 2297-2306.doi:10.1109/TIE.2010.2040561

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Figure 1 Solar PV fed fifteen level inverter


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Figure 2 Solar data for the month of January (Min: 0W/m2, Max: 892W/m2)

Figure 3 Solar data for the month of November (Min: 0W/m2, Max: 887W/m2)

(a) (b)

Figure 4 (a) V-I and (b) V-P characteristics of solar PV array

.

(a) (b) (c)

Figure 5 Carrier arrangements of (a) PD (b) POD and (c) APOD


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(a) APOD (b) POD

(c) PD (d) PSC

(e) Unipolar with bias (f) TAR

Figure 6 Multi carrier arrangements for solar PV fed fifteen level inverter

(a) Variable amplitude (b) Variable frequency


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(a) Modified reference

Figure 7 Modified multi carrier arrangements for solar PV fed fifteen level inverter

(a) APOD: Comparison for voltage THD (b) APOD: Comparison for current THD

(c) POD: Comparison for voltage THD (d) POD: Comparison for current THD

(e) PD: Comparison for voltage THD (f) PD: Comparison for current THD


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(g) PSC: Comparion of voltage and current THD (h) Dual reference and TAR: Comparison

Figure 8 Comparison of THD for various modulation strategies

Figure 9 Solar PV plant of 3kWp with 28 modules


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Figure 11 APOD based carrier arrangement

Figure 12 POD based carrier arrangement


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Figure 13 PD based carrier arrangement

Figure 14 Fifteen level inverter output voltage waveform


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Table 1 Solar PV panel specifications Table 2 Specifications of experimental set up

Table 2 Specifications of experimental set up

Parameter Value

Model Solectric 9000

Pmpp 115Wp

Voc 21.2V

Isc 7.4A

Vpm 16.5V

Ipm 6.95A

Max system voltage 540V

Tolerance at peak power 5%

Number of panels 28

Total power 3220Wp

Parameter Rating

Charge Controllers (CC)

Make Sukaam

V-I Rating 48V,10A

Number of CC 7

Battery bank

Make & Model EXIDE 6LMS100L

Rating 12V, 100Ah

Number of batteries 28

Power circuit

Semiconductor devices MOSFET IRF 840

Number of devices 28

Switching sequences APOD, POD, PD

Control circuit

Controller DSP - TMS320F2812

Measuring Instruments

Power quality analyser Yokogawa WT3000

Oscilloscope Tektronix

Logic Analyser 0+ LOGIC CUBE 32128


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Table 3. Harmonic analysis for APOD, POD and PD

Method VRMS IRMS P1 S1 Q1 VTHD ITHD PTHD

APOD 229.05 2.140 439.419 439.429 0.873 8.813 7.740 2.168

POD 229.45 2.294 439.524 439.534 0.871 7.955 7.851 2.206

PD 229.95 2.619 495.398 415.391 0.713 9.514 9.526 2.400

Table 4.Detailed information on harmonic analysis

Or. U1 [V] hdf[%] I1 [A] hdf [%]

Tot. 230.611 2.843

dc --------------- ----------------- ---------------- -----------------

1 228.488 99.079 1.247 99.092

2 0.127 0.055 0.136 0.079

3 27.670 1.999 0.606 1.922

4 0.207 0.090 0.145 0.084

5 10.994 0.767 8.153 0.717

6 0.176 0.076 0.136 0.0797 7.289 0.161 5.422 0.137

8 0.369 0.160 0.238 0.137

9 1.433 0.621 1.063 0.615

10 0.120 0.052 0.087 0.050

11 3.566 1.546 2.649 1.533

12 0.410 0.178 0.292 0.169

13 1.795 0.779 1.316 0.761

14 0.917 0.398 0.673 0.389

15 0.536 0.232 0.369 0.213

16 0.395 0.171 0.294 0.170

17 0.877 0.380 0.648 0.375

18 0.176 0.076 0.141 0.081

19 1.556 0.675 1.152 0.66620 0.360 0.156 0.240 0.139

Table 5 Comparison between simulation and experimental results

S.No. ModulationSimulation Experimental

VTHD (%) ITHD (%) VTHD (%) ITHD (%)

1. APOD 8.98 7.23 8.813 7.740

2. POD 7.84 5.63 7.955 7.851

3. PD 8.04 5.96 9.514 9.526

Table 6 Comparison with the other methodsAuthors Levels Methodology THD (%) Application to solar PV

Zhao, He, and Zhao (2010). 5 PD 38.73

Malinowski, Gopakumar,

Rodriguez, and Prez (2010)

5

5

7

PSC

Bipolar

Bipolar

30.2

29.9

21.8

Gupta, Ghosh, and Joshi (2010) 5 Multiband 27.0

Zambra, Rech, and Pinheiro

(2010)

9 PD 8.29

Proposed 15 POD 7.9

PLL U1

Freq 49.667 Hz

U1 230.611 V

I1 2.843 A

P1 639.8497W

S1 639.8548 VA

Q1 -0.6372 var

1 0.99987

1 D 0.916Uthd1 3.539%

Ithd1 3.445%

Pthd1 1.805%

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