ABSTRACT:
KEYWORDS:
1.
Capacitor
Voltage Balancing
2.
Circulating
Current Control
3.
High-Voltage
Direct Current (HVDC) Transmission
4.
Modular
Multilevel Converter (MMC)
5.
Modulation
Techniques
6.
Redundancy
7.
Variable-Speed
Drive Systems
SOFTWARE: MATLAB/SIMULINK
CONCLUSION:
The salient features of the MMC, i.e.,
its modularity and scalability enable it to conceptually meet any voltage level
requirements with superior harmonic performance, reduced rating values of the
converter components and improved efficiency. Over the past few years, the MMC
has become a subject of interest for various medium to high voltage/power system
and industrial applications including HVDC transmission systems, FACTS,
medium-voltage variable-speed drives, and medium/high voltage dc-dc converters.
For power system applications, e.g.,
HVDC systems and FACTS, the MMC has reached a certain level of maturity and
seems to stand as the most promising technology as a number of MMC-HVDC systems
and STATCOMs has been successfully implemented and installed. For
medium-voltage variable-speed drives, there is still a plenty of room for
further development and to address the operational and control issues of the
MMC, specifically under constant-torque low-speed operation. One major problem
that needs to be addressed is to minimize the magnitude of the capacitor voltage
ripple of the converter SMs at low frequencies without sacrificing the
converter efficiency, thereby making a reasonable tradeoff between the
converter size/volume/cost and efficiency.
The introduction of a family of modular
multilevel dc-dc converters, originated from the MMC topology, has opened up a
new avenue on research and development of medium/high voltage dc-dc converters.
To take the full advantage of these converters for various applications,
advanced modulation strategies that enable high voltage conversion ratio, high efficiency
and reduced component stresses are required. With a significant amount of
MMC-derived converter topologies and applications, it is concluded that
development of novel modulation and control strategies will be a major driving
factor to shape the future of MMC applications.
REFERENCES:
[1] G. Ding, G. Tang, Z. He, and M.
Ding, “New technologies of voltage source converter (VSC) for HVDC transmission
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2008, pp. 1–8.
[2] S. Allebrod, R. Hamerski, and R.
Marquardt, “New Transformerless, Scalable Modular Multilevel Converters for
HVDC-Transmission,” in Proc. IEEE Power Electronics Specialists Conf. (PESC),
2008, pp. 174– 179.
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