Low‐leakage current two‐stage transformerless grid‐connected converter for residential PV application. Issue 5 (1st May 2019)

• Record Type: Journal Article
• Authors: Farswan, Rajesh S.; Datta, Abhijit
• Is Part Of: IET power electronics. Volume 12:Issue 5(2019)
• Page Start: 1043
• Page End: 1052
• Publication Date: 2019-05-01
• Subjects: power grids -- DC‐DC power convertors -- photovoltaic power systems -- invertors -- leakage currents; low‐leakage -- two‐stage transformerless grid‐connected converter -- residential PV application -- conventional PV‐fed three‐level DC–DC converter -- greater leakage current -- common mode voltage -- galvanic isolation -- on‐grid inverters -- residential application -- two‐stage single‐phase -- on‐grid PV system -- single‐phase inverter topology -- PV inverter system -- three‐level converter -- three‐level inverter -- measured leakage current -- current 10.0 mA; Power electronics -- Periodicals; 621.31705
• DOI: 10.1049/iet-pel.2018.5363
• Languages: English
• ISSNs: 1755-4535

Abstract

Abstract : Conventional PV‐fed three‐level DC–DC converter has greater leakage current due to varying common mode (CM) voltage, and thus requires galvanic isolation if interfaced with on‐grid inverters. To reduce the leakage current and eliminate the requirement of galvanic isolation, a low‐leakage three‐level DC–DC converter is proposed for residential application. Efficacy of the converter is demonstrated by proposing a two‐stage single‐phase on‐grid PV system by interfacing with a three‐level transformerless single‐phase inverter topology. The DC–DC converter has reduced leakage current, which decreases the overall leakage current in the PV inverter system. In addition, smaller filter magnetics are required for both the three‐level converter and three‐level inverter. The CM analysis of the proposed system is presented. The proposed system is simulated using PSCAD and a laboratory prototype is developed for experimental evaluation. The experimental results show a part‐load efficiency of >96% for the overall system. Furthermore, the measured leakage current in the proposed system is <10 mA, which is below the prescribed RMS limit, as specified in German DIN VDE 0126‐1‐1 standard.