The invention relates to a DES (distributed energy storage) power electronic transformer, and a control method therefor. The transformer comprises a power unit and an output module, wherein the power unit comprise an H bridge module, an energy storage module, and an isolation module. The energy storage module comprises a Buck-Boost converter, a filter inductor, and a storage battery. The storage battery is connected with the Buck-Boost converter through the filter inductor. According to the invention, the transformer employs the DES technology, guarantees enough energy under special working conditions, saves a large-capacity battery, and improves the operation stability. The energy storage battery employs an IAI interface, and achieves the decoupling of active power with DC side energy.