| dc.description.abstract | Five-level inverters are widely used in medium-voltage (MV) wind energy and
electric drive systems. However, the use of a large number of components (including passive
and active components) and complex control methods are the major issues in the existing
inverters. Also, some of the inverters are difficult to control using multicarrier modulation
schemes due to the lack of redundancy switching states. In this research work, a new five-level
inverter is introduced for MV applications. The new inverter requires only flying capacitors
and switching devices and has a low total component count. Also, it requires only a flying
capacitor voltage balancing method to achieve a safe and reliable operation. Hence, the new
inverter is cost-effective and has less control complexity compared with the existing inverter
topologies. The flying capacitor's voltage in the new inverter is analysed with the help of
charge-balance theory and established as a theoretical basis for the capacitor voltage balancing
method. Through this analysis, a simple voltage balancing method is developed. The developed
balancing method is further analyzed with the conventional multicarrier modulation schemes
using MATLAB simulations at different operating scenarios. Also, a modified multicarrier
modulation scheme is introduced to handle the new inverter operation at higher load power
factors. Finally, the performance comparison of the conventional and modified multicarrier
modulation schemes is presented. | en_US |
