Research on Control Strategy of Three-Phase Inverter Based on Fractional Calculus

Abstract

Three-level inverters has widely used in Medium pressure due to its advantages of low total harmonics, low voltage resistance of power switch tubes and low switching losses. In order to further improve the output voltage waveform quality and optimal control effect of the Three-level inverter, this paper introduces fractional calculus in the control method of the three-level inverter circuit. First, designed a control strategy for the fractional voltage outer loop. Secondly, the use of vector representation simplifies the parameter tuning of fractional-order controller, the optimization process of the parameters of the fractional order PI^λ and integer-order PI is completed by utilizing the ITAE rules. At the same time, the Oustaloup approximation method realizes the fractional integral operator in the controller, thereby achieving the purpose of improving the output voltage of the system. For three-level inverter circuit model, comparative analysis of the control effects of the fractional-order PI^λ and integer-order PI. Finally, simulation results show that fractional-order PI^λ controllers have excellent flexibility, robustness.