Extended Modulus Optimum Method for Off-Grid Inverter’s Voltage Control System

摘要

Stationary reference frame proportional-resonant (PR) controllers play a significant role in grid-tie and off-grid inverter control because of their ability to achieve zero steady-state error at AC frequency and provide high rejection ratio for undesirable harmonic content with minimum computation burden. While extensive efforts have been put into application-oriented performance optimization for grid-tie application, the off-grid inverter case was barely investigated. This paper proposes an extension of the Modulus Optimum tuning method from a synchronous frame to a stationary frame. The proposed approach is directly applied to the transfer function of the off-grid inverter in a stationary frame. As a result, the structure of the controller with optimized transient and steady-state behaviours is synthesized. The relationship between the proportional and the resonant part of the investigated controller is obtained to achieve the optimum utilization of the presented control bandwidth. The validation of the presented approach was performed by computer simulations and laboratory experiments on the off-grid battery inverter.