Switched-Capacitor Two-Output Multilevel Inverter (SCMLI) with Common Ground for Photovoltaic Applications

A Switched-Capacitor Multilevel Inverter (SCMLI) is proposed. It concomitantly features: a) a permanent non-zero input current, b) a common line-load ground which eliminates the photovoltaic cell leakage current, c) two outputs, d) a high boost factor, equal to that in a similar no common ground inverter, and e) the smallest number of capacitors and switches per output and per boost factor compared to any available common ground SC inverter. Its basic structure is constituted by two SC sub-circuits. The originality of the proposed inverter allowing these features is due to a novel operation scheme in which one of the two SC sub-circuits supplies the positive half-sinusoid of both outputs, and the other SC sub-circuit supplies the negative half-sinusoid of both outputs. It was conceived as an inverter powered by a solar cell that supplies standalone ac loads of small powers. A real world application is implemented: a micro-inverter supplied by the solar cell of type TSM-DEG15MC.20(II) (with V in in the range 40.2 - 41.5V, P out in the range 390 - 415W) offering two outputs of opposite polarity of 110 Vrms, 60 Hz, according to an industrial requirement.