Dynamic sliding mode control of Grid Connected PV system via a series active power filter with a 3-level inverter

Abstract

This paper presents a study of power quality improvement for a single-phase series active power filter under distorted grid conditions, based on a three-level halfbridge inverter topology powered by two photovoltaic sources. A new non-linear control strategy is proposed to: (i) attenuate grid voltage harmonics, (ii) compensate for sudden voltage sags and swells, and (iii) ensure the voltage balancing of the DC bus capacitor. The proposed non-linear controller is designed based on the non-linear model of the system using a dynamic sliding mode technique and Lyapunov stability. The overall performance of the system is analysed using stability analysis tools and validated by numerical simulations in MATLAB/Simulink. A comparison is also made with a classical backstepping controller and the results highlight the superiority of the proposed controller in terms of stability, signal quality and total harmonic distortion, considering different real operating conditions.