Symmetric and Asymmetric Multilevel Inverter Topologies With Reduced Device Count

 Abstract

In this work, two new topologies of single-phase hybrid multilevel inverters for symmetrical and asymmetrical configurations are presented for use in drives and control of electrical machines and the connection of renewable energy sources. The proposed topology uses 2 dc sources, 12 switches,1 flying capacitor, and 3 diodes to generate boosted 13-levels and 17-levels for symmetric and asymmetric configuration, respectively. Self-voltage balancing of its capacitor voltage regardless of load type, load dynamics, or modulation index is a key advantage of the suggested design. The higher performance of proposed topologies in terms of the total number of switches, TSV, THD, switch stress, and dc sources are demonstrated by comparing those with recently published topologies. In addition, a widely employed nearest level control modulation approach is used to provide output voltage levels with low THD. Finally, experiments were undertaken to validate the performance of the suggested topology.

Keywords

Multilevel inverter (MLI), switched-capacitor, nearest level control (NLC), total standing voltage (TSV).

Proposed Diagram:

Figure 1. Proposed SCMLI Topology.

Expected Simulation Results:

Figure 2. Simulation Results For The Symmetrical Topology. Output Voltage, Output Current, Voltage And Current Across Capacitor C1 For (A) Dynamic Change Of R-Load (B) Dynamic Change Of Rl-Load (C) Change In Frequency Of The Reference Sinusoidal Signal (D) Change In Modulation Index (Mi).

Figure 3. Simulation Results For The Asymmetrical Topology. Output Voltage, Output Current, Voltage And Current Across Capacitor C1 For (A) Dynamic Change Of R-Load (B) Dynamic Change Of Rl-Load (C) Change In Frequency Of The Reference Sinusoidal Signal (D) Change In Modulation Index (Mi).

Conclusion

This paper presented a topology for symmetric and asymmetric configuration, which generates 13 and 17 output levels, respectively, with lesser components. TSV and THD are also quite low. Although it used 2 sources, it generates boosted output voltage for both configurations with the help of a flying capacitor. Utilizing the concept of a dc-link capacitor across the sources, the output levels are increased. All the capacitors are self-balanced without the need for extra control circuitry. The static and dynamic stability of a topology is determined by the findings obtained for various load scenarios. In addition, power loss analysis provides insight into the switch kinetics. On the basis of the comparative analysis, it can be determined that the proposed topology provides greater performance compared to other topologies in the literature that have been compared. The architecture is very efficient and well-suited for renewable energy applications such as solar PV systems that are grid-connected.

References

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