The large-scale and heterogeneous loads with large capacity are continuously connected to the distribution network, and the traditional distribution transformers are no longer capable to satisfy the rapid and stepless requirements of voltage regulation of the existing distribution network. It shows that researching new distribution transformers and voltage control technologies has become an urgent need. Therefore, this paper proposes a new topology for distribution transformers and derives the equivalent circuit diagram of the topology. Based on the equivalent circuit, the working principle of voltage regulation of the transformer is analyzed in detail, and the accurate mathematical models for the internal converter as well as transformer are established. According to the mathematical models, the strategies for internal loop control, fixed DC voltage control and active voltage regulation control of converters are proposed. The simulation analyses are conducted by utilizing PSCAD/EMTDC software. The simulation results show that the proposed strategy can achieve the target of voltage regulation within 100 ms and the steady-state control deviation is about zero. The proposed strategy could be applied to practical distribution network engineering to solve voltage stability control problems during load disturbances and meet the fast and stepless requirements of voltage regulation.