Comprehensive control scheme of the interlinking converter in hybrid AC/DC microgrid

Abstract

This paper presents a comprehensive control scheme for the interlinking converter (ILC) in a hybrid AC/DC microgrid consisting of the outer loop flexible power sharing control and the improved robust inner loop control. The outer loop power control of ILC is presented to achieve flexible power sharing of distributed generations (DGs) in the hybrid microgrid, depending on different power management objectives, which is realized based on the deduced balance state equation, and regulating the frequency and DC voltage at the same time. The improved robust inner loop control of ILC is also presented to suppress external disturbance and system model uncertainties with the improved dynamic response. This improved inner loop control which includes a disturbance observer link, can force the converter current to track the reference value with no steady error and improve the dynamic stability of the microgrid. With the proposed outer loop power sharing control and improved inner loop control, the comprehensive control scheme for the ILC is presented. Simulations cases show the effectiveness and superiority of the proposed comprehensive control scheme.