Active Common-Mode Filter for Ground Leakage Current Reduction in Grid-Connected PV Converters Operating With Arbitrary Power Factor

This paper proposes a solution for reducing the
ground leakage current in transformerless single-phase gridconnected
photovoltaic converters. This is obtained with the
introduction of an active common-mode filter able to compensate
for variations of the output common-mode voltage of the
power converter. The active common-mode filter is applied to a
widespread and efficient full-bridge driven by a three-level pulse
width modulation, allowing the power converter to operate with
low ground leakage current and with an arbitrary power factor.
After showing the desired voltage waveform for common-mode
voltage compensation, this paper presents the design guidelines
for the needed additional magnetic component together with the
power loss considerations for all the devices added for the proposed
solution. Experimental results show the performance of the
proposed solution in terms of ground leakage current reduction,
effectiveness of dead-time compensation, total harmonic distortion
of the injected grid current, and power losses.