Solar Power Conditioners Using Bidirectional Chopper Circuits Connected in Series.

This paper proposes a new high-efficiency grid-connection inverter suitable for the interface with thin-film solar cells, which is composed of two bidirectional buck converters and an H-bridge PWM converter connected in series. The switching frequencies of the first bidirectional buck converters are equal to the grid frequency, while the second is operated at twice the grid frequency. The combination of these two converters synthesizes an AC rectangular voltage pulse train from the DC input power. The H-bridge PWM converter is operated at 20 kHz with a low DC capacitor voltage to compensate for the harmonic voltage included in the rectangular voltage pulse train. As a result, the proposed grid-connection inverter makes it possible to reduce both switching loss and common mode voltage. Experimental results obtained by a 1-kW single-phase inverter demonstrate a high efficiency of 98% without any common mode voltage. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(2): 51-60, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22379 [ABSTRACT FROM AUTHOR]