ABSTRACT:
The efficient and compact design of multilevel inverters (MLI) motivates in various applications such as solar PV and electric vehicles (EV). This paper proposes a 53-Level multilevel inverter topology based on a switched capacitor (SC) approach. The number of levels of MLI is designed based on the cascade connection of the number of SC cells. The SC cells are cascaded for implementing 17 and 33 levels of the output voltage. The proposed structure is straightforward and easy to implement for the higher levels. As the number of active switches is less, the driver circuits are reduced. This reduces the device count, cost, and size of the MLI. The solar panels, along with a perturb and observe (P&O) algorithm, provide a stable DC voltage and is boosted over the DC link voltage using a single input and multi-output converter (SIMO). The proposed inverters are tested experimentally under dynamic load variations with sudden load disturbances. This represents an electric vehicle moving on various road conditions. A detailed comparison is made in terms of switches count, gate driver boards, sources count, the number of diodes and capacitor count, and component count factor. For the 17-level, 33-level, and 53-level MLI, simulation results are verified with experimental results, and total harmonic distortion (THD) is observed to be the same and is lower than 5% which is under IEEE standards. A hardware prototype is implemented in the laboratory and verified experimentally under dynamic load variations, whereas the simulations are done in MATLAB/Simulink.
KEYWORDS:
1.
Cascaded
H-bridge inverter
2.
Sinusoidal
pulse-width modulation
3.
Total
harmonic distortion
SOFTWARE: MATLAB/SIMULINK
CONCLUSION:
The proposed switched-capacitor based
53-level MLI topology for electric vehicle applications is designed and implemented
for the solar PV energy system with lesser semiconductor devices to reduce the
cost and size of the inverter, improving efficiency and reliability. P&O
algorithm based MPPT technique is used, the stable output is achieved under all
circumstances. The proposed MLI is implemented with various combinations of SC
connections. A basic two units are cascaded and obtained a 17-level MLI configuration.
The cascade connection of two 17-level MLIs results in the formation of a
33-level MLI, and the proposed 53-level MLI is achieved by cascading three SC
units. All the MLIs are designed and compared with various topologies based on several
parameters like devices count, TSV, THD, and cost function per level count. The
comparative analysis shows that the proposed MLI is more efficient with fewer
power losses. It is noticed that both simulation and experimental THD are 1.41%.
TSVpu is 1.15; efficiency is 94.21%, CF/L values for both values of α are 0.7
and 0.73, which clearly shows the cost is significantly less compared with
various topologies. The proposed MLI is tested under multiple dynamic load variations.
This topology is most suited for renewable energy applications.
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