Model-Matching Control for Low Switching Frequency Converters Unifying Different Performance Requirements

Abstract

This paper presents an active damping control for LCL-filtered grid-connected converters to meet strict grid codes and power quality standards. The control strategy allows unifying into a single design procedure different requirements demanded by system operators. A model-matching approach is used to set the reference tracking and disturbance rejection transfer functions separately, which provides an additional degree of freedom to the converter control design. On the other hand, the measurement stage and digital implementation effects are considered in the control design to maximize the control bandwidth. The proposed control strategy uses a reduced number of sensors and is able to compensate unbalanced and distorted grid voltage conditions; it presents a systematic design and is formulated in the discrete-time domain, enabling a direct digital implementation. Performance assessment and comparison of different control strategies are performed using eigenvalue and transient response analyses. The effectiveness and advantages of the proposed strategy are validated through an experimental setup.