DC-FAULT TOLERANT MODULAR MULTILEVEL HVDC CONVERTER USING SWITCHED CAPACITOR SUBMODULE
Advisor:
Mr. Mustafeezul Hassan
Abstract:
Renewable Electric Power Generation is becoming popular these days, as it is environmental
friendly. These sources produce DC Voltages that are required to be transmitted over long
distances across different countries to transmit bulk power to load centers, with the help of
HVDC transmission lines. As, most of the load operates on AC so the DC must be converted to
AC near the Load Centers. Modular Multilevel Converters (MMC) are amongst the most popular
techniques for high voltage DC-AC conversion. A new Switched Capacitor Submodule (SCSM)
has been proposed for the converter that will be capable of blocking any kind of DC side fault,
increasing the system reliability and there is no need of High Voltage DC Circuit Breakers. Each
submodule is capable of producing three level voltage by switching the MOSFETs in defined
sequence with the help of Pulse Width Modulated (PWM) Signals. Moreover, the voltage
balancing is done with half the number of voltage sensors, compared to other MMC topologies,
thus making the implementation of the control system simpler.