A multilevel energy buffer and voltage modulator for grid-interfaced micro-inverters

Minjie Chen, Khurram K. Afridi, David J. Perreault

Research output: Chapter in Book/Report/Conference proceedingConference contribution

11 Scopus citations

Abstract

Micro-inverters operating into the single-phase grid from solar photovoltaic (PV) panels or other low-voltage sources must buffer the twice-line-frequency variations between the energy sourced by the PV panel and that required for the grid. Moreover, in addition to operating over wide average power ranges, they inherently operate over a wide range of voltage conversion ratios as the line voltage traverses a cycle. These factors make the design of micro-inverters challenging. This paper presents a multilevel energy buffer and voltage modulator (MEB) that significantly reduces the range of voltage conversion ratios that the dc-ac converter portion of the micro-inverter must operate over by stepping its effective input voltage in pace with the line voltage. The MEB also functions as an active energy buffer to reduce the twice-line-frequency voltage ripple at the output of the solar panel. The small additional loss of the MEB can be compensated by the improved efficiency of the dc-ac converter stage, leading to a higher overall system efficiency. A prototype micro-inverter incorporating a MEB, designed for 27 V to 38 V dc input voltage, 230 V rms ac output voltage, and rated for line cycle average power of 70 W, has been built and tested in grid-connected mode. It is shown that the MEB can successfully enhance the performance of a single-phase grid-interfaced micro-inverter by increasing its efficiency and reducing the total size of the twice-line-frequency energy buffering capacitance.

Original languageEnglish (US)
Title of host publication2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013
Pages3070-3080
Number of pages11
DOIs
StatePublished - Dec 31 2013
Externally publishedYes
Event5th Annual IEEE Energy Conversion Congress and Exhibition, ECCE 2013 - Denver, CO, United States
Duration: Sep 15 2013Sep 19 2013

Publication series

Name2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013

Other

Other5th Annual IEEE Energy Conversion Congress and Exhibition, ECCE 2013
CountryUnited States
CityDenver, CO
Period9/15/139/19/13

All Science Journal Classification (ASJC) codes

  • Energy Engineering and Power Technology
  • Fuel Technology

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    Chen, M., Afridi, K. K., & Perreault, D. J. (2013). A multilevel energy buffer and voltage modulator for grid-interfaced micro-inverters. In 2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013 (pp. 3070-3080). [6647102] (2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013). https://doi.org/10.1109/ECCE.2013.6647102