Experimental Verification of Rotating Sliding Mode Control with Composite Reaching Law Approach for Voltage Source Inverters

Abstract

In modern power systems, power electronic interfaces like Voltage Source Inverters (VSIs) uses advanced control strategies to ensure high-quality voltage regulation, significantly enhancing system stability and reliability for various applications. This paper introduces a novel voltage regulation method for VSIs using Sliding Mode Control (SMC) under extreme load variations [1]. Besides robustness, SMC is prone to chattering, causing power losses, reduced efficiency, and compromised transient response. To address chattering, an adaptive sliding surface selection mechanism that utilizes the Rotating Sliding Surface (RSS) technique and a new reaching law based on state variable magnitudes, which dynamically adjusts the control gain is proposed here. This composite reaching law uses exponential, power, and difference functions to achieve rapid convergence and reduce chattering. The sliding surface is chosen with a time-varying slope based on error variables. Tests on a single-phase VSI with varying loads demonstrate that the C-ERL-RSS SMC achieves a well-regulated output voltage with just 0.25% THD, reduced chattering, and minimal tracking time. Additionally, implementing the C-ERL-RSS SMC and PRERL SMC on a two-level three-phase VSI under varying load conditions shows superior efficiency and stability, with a low THD of 1.1%. Experimental evaluation on MicroLabBox-dSPACE 1202 for VSIs under extreme conditions reveals that the proposed technique excels in voltage regulation, offering fast transient response and low THD of 1.12% and 2.1% for single-phase and three-phase VSIs, respectively.