1. A power conversion system, comprising: an AC input coupleable to receive AC input power from a power source; a rectifier operative to convert the AC input power to provide a DC output; an inverter operatively coupled with the DC output of the rectifier to provide an AC output; and a filter circuit coupled between the AC input and the rectifier, the filter circuit comprising a plurality of filter capacitors; a controller operative to identify a suspected resonance condition in the filter circuit based at least partially on components of at least one current flowing in the filter circuit in a predetermined frequency band.