Complex-Variable Design of Voltage Control for Grid-Forming Inverter

The proportional integral (PI) and proportional resonant (PR) controllers are usually adopted for the voltage control for the grid-forming inverter. However, the parameters for both controllers are usually designed separately, this will require more design process and lead to different models. In this paper, first, a complex-variable-based control structure is designed for both PI and PR controllers using state space model, then the same parameters can be applied to both controllers. Consequently, they have identical models and response which is beneficial for the analysis and design of the outer power control. In addition, a dominant pole cancellation method is adopted to design the control parameters and achieve an approximate zero-dynamic response which is a good feature for the power control of the grid-forming inverter. At last, the proposed control is verified by the experimental results.