A lumped power supply circuit for converting an AC signal into a DC signal, the lumped power supply circuit including: a cascaded H-bridge circuit having N H-bridge sub-circuits connected in series between two input terminals of the AC signal, and being configured to convert the AC signal into N first voltage signals, where N is a positive integer greater than or equal to 2; a high-frequency filtering module configured to filter the N first voltage signals, and to generate N second voltage signals; a DC conversion module to receive the N second voltage signals, and to convert the N second voltage signals into at least one third voltage signal; and a lumped power buffer module having an output terminal coupled to a load, and being configured to receive the at least one third voltage signal, and to filter out part of power frequency fluctuations in the third voltage signal.