Multivariable Analysis and Control of a VSC Back-to-back Converter Interfacing Two Ac Systems

This work analyses a voltage source back-to-back converter interfacing two alternating current systems from a multivariable perspective. Since the plant is not functionally controllable, frequency-dependent relative gain array analysis is carried out to aid in the choice of the most suitable variables to be controlled in a specific frequency range. This analysis is crucial to choose the low- and high-frequency controllers. A systematic approach is developed to tune a centralized optimal control. Validation of theoretical analysis and proposed multiple-input multiple-output (MIMO) control law is performed through experimental results.