PROJECT TITLE :

Improved Elimination Scheme of Current Zero-Crossing Distortion in Unipolar Hysteresis Current Controlled Grid-Connected Inverter

ABSTRACT:

In this paper, the generation reason and therefore the improved elimination theme of this zero-crossing distortion (ZCD) of single-phase grid-connected inverter controlled by unipolar hysteresis current control containing band are investigated well. A current ZCD elimination scheme by exchanging the management signal of low-frequency leg of inverter prior the zero-crossing points of grid voltage is proposed. The result of the variation of the amplitude and frequency of tied grid and also the filter inductor on the optimal leading exchanging phase angle (LEPA) is analyzed. One-phase hybrid filter-based mostly enhanced section-locked loop is proposed to estimate accurately the data of the grid, even under nonideal input conditions. Then, an on-line filter inductor estimation scheme is proposed to get the correct actual inductor price. The former estimated parameters are used to calculate the precise optimal LEPA on-line to improve the performance of the present ZCD elimination scheme. Comprehensive experimental results are represented to verify the accuracy and feasibility of the theoretical analysis and the proposed improvement.