High Efficiency and Full MPPT Range Partial Power Processing PV Module-Integrated Converter

Abstract

To increase the energy yield of PV systems in presence of module level power mismatches, Maximum Power Point Tracking (MPPT) should be performed by converters at module level. Using module level converters at the output of the PV panels adds a constant loss even when there is no power mismatch which increases the overall system losses and compromises part of the energy yield improvement. To decrease this constant loss especially when there is no power mismatch, Partial Power Processing (PPP) concept is used in this paper to achieve a new high-frequency and high-efficiency module integrated PV converter, which can achieve full range MPPT and maximum possible efficiency when there is no mismatch. To overcome the challenge of limited MPPT range for partial power converters a special Pulse Density Modulation (PDM) technique is proposed, which preserves the merits of PPP and renders full range MPPT. A 220 W prototype converter is implemented to justify the converter principal of operation and analyses. The proposed converter reached 99.6% to 96.5% efficiency for the power mismatches in the PV module ranging from 0 to 50% of the maximum module power generation capability, respectively. The efficiency drop is shown to be linear with power mismatch level without any abrupt reductions that is commonly observed in conventional PV module integrated converters.