Enhancing Power Quality in PV Inverters Using Hysteresis Current Control (HCC) Technique

This manuscript proposed three closed-loop strategies using Hysteresis Current Control (HCC) for PV-inverter application. A string-PV arrangement of parallel and series-PV connection (Np = 6 and Ns = 10) aims for target input voltage of ±400 V, intended for Off-grid PV (OGPV) system. The PV-system design is tested under Standard Test Condition (STC) where the irradiance and temperature are kept constant at 1000 W/m2 and 25˚C, respectively. Full-bridge inverter is chosen as the PV-inverter since it is commonly used inverter for unfolding purposes in the PV application. The proposed PV-inverter with HCC strategy was designed and compared with the PV-inverter using conventional Bipolar Pulse Width Modulation (PWM). These proposed blocks were designed and simulated using MATLAB/Simulink software. Performance improvement of the power quality was measured in terms of current and voltage harmonic percentage, where the PV-inverter with HCC produced slightly lower current harmonic percentage of THDi = 25.45% compared to THDi = 29.19% from the conventional strategy. The proposed HCC technique resulted in a 3.74% improvement in power quality. When combined with an additional LC-filter, the power quality was further enhanced, achieving improvements of 74% in voltage and 82% in current harmonic reduction, respectively.