PROJECT TITLE :

Dynamic Model, Control and Stability Analysis of MMC in HVDC Transmission Systems - 2017

ABSTRACT:

A management technique is proposed in this paper for control of modular multilevel converters (MMC) in high-voltage direct current (HVDC) transmission systems. Six freelance dynamical state variables are thought of within the proposed management technique, together with two ac currents, three circulating currents, and therefore the dc-link voltage, for effectively attaining the switching state functions of MMCs, and for an accurate control of the circulating currents. Many analytical expressions are derived based mostly on the reference values of the state variables for getting the MMC switching functions below steady state operating conditions. Likewise, dynamic elements of the switching functions are accomplished by the direct Lyapunov method to guarantee stable operation of the proposed technique for control of MMCs in HVDC systems. Moreover, the capability curve of MMC is developed to validate maximum power injection from MMCs into the facility grid and/or masses. The impacts of the variations of MMC output and dc-link currents on the steadiness of dc-link voltage are also evaluated intimately by little-signal analysis.