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COMPARATIVE ANALYSIS OF CASCADE H-BRIDGE
MULTILEVEL VOLTAGE SOURCE INVERTER
ABSTRACT
In real time industrial applications, there are many limitations in extracting power from
renewable energy sources. To meet the increasing power demand, multilevel inverter is
widely used to extract power from solar cells. It synthesizes the desired ac output from several dc
sources. This paper presents comparative analysis of different cascaded H-Bridge multilevel
inverter topologies employing low switching frequency devices to reduce thermal stress and
improve conversion efficiency.
The inverter is operated on fundamental frequency switching strategy. The present
topology provides high quality output power due to its more output levels, low thermal stress and
high conversion efficiency. This multilevel topology enables to achieve high quality output
voltages and output currents and also immense availability because of their intrinsic switches
redundancy.
Cascade H-Bridge Multi level inverters also have a feature of high modularity index
because each inverter module will be seems like a module with similar circuit topology,
modulation and, control structure. So, in the case of fault in any one of these modules, it is
possible to replace it with another one quickly and easily. Moreover, with a particular control
strategy, it is possible to bypass and disconnect the faulty module without interrupting the entire
load, bringing an almost continuous overall availability.
This paper presents basics of cascaded H-Bridge multilevel inverters, its working
principle, circuit topologies, control techniques, simulation & comparative analysis in terms of
THD and FFT of different level H Bridge topologies. This paper presents comparative analysis
in terms of THD and FFT of different level topologies. The different Multi level Inverter
Topologies are simulated in PSIM.
Block diagram for proposed system
DESIGNG SOFTWARE AND TOOLS:
MAT LAB /SIMULATION Software and sim power systems tools are used. Mainly control
system tools, power electronics and electrical elements tools are used.