ABSTRACT:
In this paper, a modified cascaded H-bridge multilevel
inverter (MLI) is proposed and designed for solar applications. Generally, as
the level of conventional multilevel inverter increases, the required number of
switches and size increases. The proposed topology is cascade of unit stages
which involves 5 switches and two voltage source; moreover a unit stage is
capable of generating 5 levels. Also, the detailed analysis of cascaded
multilevel inverter is discussed which incorporates three different
methodologies involving less number of power devices in order to generate
maximum number of levels. This results into reduction in gate drive circuitry
and less switching losses. The proposed MLI is designed for power 1.5kW and
Inphase level shifting SPWM technique has been incorporated in which 5kHz
carrier wave is compared with 50Hz of sinusoidal wave with a modulation index
of 0.8. As a result, total harmonic distortion (THD) is achieved as 4.71% with
LC-filter for above mentioned multilevel inverter. The circuits are modeled and
simulated with the help of MATLAB/SIMULINK.
KEYWORDS:
1.
Modified
cascaded H-bridge MLI
2.
Solar
3.
SPWM
techniques
4.
Total Harmonic
Distortions
In
this paper, a new topology of modified cascaded H bridge MLI is designed for
solar high power application. The three different methodologies have been
analyzed and 9-level, 13-level and 17-level output is observed in the
respective methodology. The number of switches used in the topology is less
which in turn reduced the corresponding gate driving circuitry and made the
circuit compact in size. The circuits of proposed MLI are simulated in
MATLAB/SIMULINK and total harmonic distortions for the three methodologies are obtained
by using FFT analysis window. The lowest THD observed with LC-filter is 4.71%.
The proposed MLI is designed for power 1.5kW and In-Phase level shifting method
is followed for the pulse generation for all three methodologies.
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