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A MULTI-LEVEL INVERTER FOR SOLAR ENERGY APPLICATIONS
J.Harshavardhan V.Ghouse Basha III B.Tech III B.Tech Department of
EEE Department of EEE SSITS.Rayachoti, A.P, India, SSITS,Rayachoti,
A.P, India, Mobile:+91-8464836628 Mobile:+91-8790060994
E-mail:[email protected]
E-mail:[email protected]
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ABSTRACTA new multi-level inverter topology based on a H-bridge
structure with four switches connected to the dc-link. Based on a
new PWM method which requires only one carrier signal is
suggested.The switching sequence to balance the capacitor
voltage.The proposed topology requires minimum number of component
count to increase the number of voltage level.
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Presentation outlineIntroductionVarious topologies of multilevel
invertersModulating strategies & features of MLICircuit Diagram
& its implementationSimulation implementation & its results
Advantages & ApplicationsConclusionFuture-scope
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INTRODUCTIONMLI produces nearly sinusoidal outputMLI control the
lower order harmonicsMLI introduced by grid connected
systemTopologies of MLINeutral point clamped typeFlying capacitor
type Cascade type
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*VARIOUS TOPOLOGIES OF MULTILEVEL INVERTERS:
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comparisons of components requirements per phase multilevel
inverters
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TYPES OF CONNECTIONS: Diodes protect the circulating current
Capacitor gives the supply to switches
Neutral point clamped (NPC) type:*
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Capacitors are directly connected to the switches capacitors are
used to charging and discharging at unbalance voltages*Flying
capacitor type
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There is no interruption Levels can be increased by cascade
connection*Cascade type:
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Modulation strategies for multilevel inverters:
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Features of Multilevel Inverters:
It may be easier to produce high voltage, high power inverter
with multilevel structure
They can operate with a lower switching frequency
By increasing number of voltage levels the harmonic content of
output voltage waveform decreases
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CIRCUIT DIAGRAM OF THE PROPOSED SYSTEM:Fig.1: Single- phase
MLI*
Output voltage(Vo)Switching conditionTp+Tp-TN +TN -TA+ TB-TA-
TB+VdcONOFFOFFONONOFF0.5VdcOFFONOFFONONOFFONOFFONOFFONOFF0OFFONONOFFONOFFOFFONONOFFOFFON-0.5Vdc
OFFONOFFONOFFONONOFFONOFFOFFON-VdcONOFFOFFONOFFON
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SWITCHING STATESVo= -VdcVo= Vdc*
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Vo=0.5VdcVo=-0.5Vdc*Switching states (contd.)Vo=0Vo=0
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Vo=-0.5VdcVo=0.5Vdc*Switching states(contd.)
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SOLAR INPUT CIRCUIT DIAGRAMFig.2: Single phase inverter system
of solar input*
DC-link voltage200VOutput voltage110 VrmsDC- link capacitor2200
FFilter inductor(Lf)300 HFilter capacitor(Cf)150 FSwitching
frequency(Fsw)5 KHzOutput frequency(fo)60 Hz
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SIMULATION DIAGRAM:*
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SIMULATION DIAGRAM FOR SOLAR INPUT:*
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SIMULATION RESULTS:*Fig.3:Out put voltage and current wave form
for R = 9.3 (R-load)Fig.4:Out put voltage of a 5-level
multi-inverter
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ADVANTAGES:Simple structure Low power Consumption Reduces the
switching lossesOperating at fundamental frequencyMore reliable
APPLICATIONS:Applicable for Solar/wind power generation Hybrid
vehicles Grid energy supply
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CONCLUSION:
Number of devices of the proposed multi-level inverter is fewer
than that of the conventional multi-level inverters. The proposed
system is more reliable and cost effective than the conventional
two-level and multi- level inverters. Switching loss of the four
switches (TA+, TA-, TB+, TB-) is almost negligible. Only one
carrier signal is required to generate the PWM signals for 4
switching devices (TP+, TP-, TN+, TN-).
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FUTURE SCOPE:The proposed topology can be easily extended to
7-level or higher level with minimized active device component
count.
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REFERENCES: Gui- jia su, senior member ,IEEE Multilevel DC-Link
Inverter , IEEE Trans. on Indapplications, vol.41, issue 4,
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senior member Fundamental Frequency Switching Strategies of a Seven
level Hybride Cascaded H-Bridge MultiLEVEL Inverter , IEEE
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References (Contd)
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