Abstract
Most grid-connected DC/AC inverters use traditional proportional–integral (PI) controllers in a synchronous frame. In addition to poor disturbance rejection capabilities, these PI controllers also exhibit steady-state errors for sinusoidal reference signals. To address these drawbacks, this article investigates the use of a high-order controller in the stationary frame and then compares it with the standard PI controller. The effectiveness of the high-order controller in the stationary frame has been examined by providing an infinite gain at a resonance frequency. In this work, the design of high-order and PI controllers and tuning instructions are given. Furthermore, both high-order and PI current-controlled two-level and three-level neutral point clamped (NPC) inverters are compared. Various operational conditions are used for the comparison. The high-order controller reduced the total harmonic distortion (THD) of the injected current by 1.15% for the two-level inverter in normal conditions as compared to the PI controller and 0.9% for the three-level NPC inverters. Furthermore, it reduced the THD in balanced abnormal conditions by 0.5% for the two-level inverter and 0.18% for the three-level NPC inverters. However, the dq controller has a lower THD during unbalance and short circuit conditions.
Funder
Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia
Subject
Energy (miscellaneous),Energy Engineering and Power Technology,Renewable Energy, Sustainability and the Environment,Electrical and Electronic Engineering,Control and Optimization,Engineering (miscellaneous),Building and Construction