The Delta Configured Modular Multilevel Converter || 2015 IEEE Project
1. The Delta Configured Modular Multilevel Converter
Presented by
IIS TECHNOLOGIES
No: 40, C-Block,First Floor,HIET Campus,
North Parade Road,St.Thomas Mount,
Chennai, Tamil Nadu 600016.
Landline:044 4263 7391,mob:9952077540.
Email:info@iistechnologies.in,
Web:www.iistechnologies.in
www.iistechnologies.in
Ph: 9952077540
2. Abstract
• The modular multilevel converter (MMC) has become an attractive option for dc/ac conversion in
many power system applications, in particular for HVDC transmission.
• Due to its parallel arrangement of phase legs the MMC is known to be wye configured
architecture. In this project, the equivalent delta formulation of the conventional wye
architecture is introduced.
• The delta configured MMC, enabled by series-stacking phase legs, is an alternative realization to
the wye configured MMC and has significantly different operating characteristics.
• Introduction of the delta MMC enables greater flexibility in converter voltage/current scaling for a
given set of sub modules, and may be an appealing option for dc/ac applications requiring a
power tap-off from a high-voltage dc rail.
• The single-ended and differential delta topologies are derived, with the latter seen as the
preferred topology due to its reduced energy storage requirements.
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4. Existing System
• Modular multilevel cascaded converters employing delta configured SMs have been proposed
they are limited to using isolated dc sources.
• That is, they lack a common dc link as depicted in the family of MMC structures in use a common
dc link only for wye configured SMs).
• These topologies are thus constrained to applications such as reactive compensation (i.e.
statcom), battery energy storage systems and ac motor drives. In differential dc/ac converter
structures employing cascaded SMs have been proposed, however a delta equivalent realization
has not been established.
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5. Proposed System
• The theory of operation of the differential delta MMC is discussed in detail. Unique operating
characteristics of the delta MMC include inherent modulation of line-to-line ac voltages, and the
presence of significant circulating ac currents at the third harmonic.
• A mathematical model is derived to provide additional insight into converter steady-state and
dynamic performance.
• Based on the converter model, a dynamic controller is developed for the differential delta MMC
that regulates grid power injections while suppressing unwanted circulating ac currents.
• A comprehensive switched model of the differential delta MMC is implemented in PLECS.
Presented simulation results validate the operating principle of the differential delta MMC as well
as the developed controls.
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6. TOOLS AND SOFTWARE USED
• MP LAB
• ORCAD/PSPICE
• MATLAB/SIMULINK
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