A hybrid voltage-current compensator using a synchronous reference frame technique for grid-connected microgrid under nonlinear load conditions

Abstract

Power quality is important for the reliable operation of power grids. Unwanted harmonics cause serious degradation of power quality. This problem is more obvious for distributed generations connected to a microgrid. To solve this issue, this paper proposes an improved voltage and current (VI) compensator to collectively suppress voltage and current harmonics in a three-phase hybrid fuel cell and photovoltaic grid-connected inverters using a synchronous reference frame (SRF) based technique in the presence of non-linear loads. It is shown that the proposed compensator can effectively reduce the harmonic contents in voltage and current without any dependence on offset devices such as active and passive filters. Simulations in MATLAB/Simulink show that the proposed control strategy not only reduces the total harmonic distortion to less than 5% (as per the IEEE 519 standard) but also results in the least total harmonic distortion (THD) as compared to existing techniques.