The invention provides a power electronic transformer. The power electronic transformer comprises a first-stage converter, a second-stage converter and a third-stage converter; the first-stage converter comprises a first AC/DC and a second AC/DC; the second-stage converter comprises a first DC/DC and a second DC/DC; the third-stage converter comprises a plurality of converters, wherein at least one of the converters is a BPVB; the first AC/DC converter, the first DC/DC converter and the converters in the third-stage converter are sequentially cascaded; the second AC/DC, the second DC/DC and the converter in the third-stage converter are sequentially cascaded; the second output end of the first AC/DC and the first output end of the second AC/DC are connected in series and grounded, so thata first grounding end can be formed; and the first output end of the first AC/DC, the second output end of the second AC/DC and the first grounding end form a first DC voltage output port. The reliability of the power electronic transformer is improved.