Comprehensive Modeling of Single-Phase Quasi-Z-Source Photovoltaic Inverter to Investigate Low-Frequency Voltage and Current Ripple.

The second harmonic $(2\omega)$ power ripple of single-phase quasi-Z-source (qZS) photovoltaic (PV) inverter highly affects the whole system's design and performance. The topology's $2\omega$ ripple model is very important to analyze qZS PV inverter's $2\omega$ voltage and current ripple. The existing models did not consider the PV-panel dynamic and terminal capacitors, which causes the theoretical results apart from the truth. In this paper, a comprehensive modeling for single-phase qZS-PV inverter is proposed, where the $2\omega$ ripple model of the qZS-PV inverter system with a real PV source is established and discussed without and with a PV terminal capacitor. The influences from qZS inductance and capacitance, and PV-panel terminal capacitance to the $2\omega$ voltage and current ripple are investigated using the built model. The system parameter design method is proposed to mitigate this ripple. Simulation and experimental results validate the proposed $2\omega$ ripple model and parameter design method. [ABSTRACT FROM PUBLISHER]