Power electronic transformers (PET) are widely used in flexible DC networks and new energy DC converters due to efficient and flexible energy transformation. However

many switching devices and high frequency limit simulation step size. Existing methods use small step length simulation overall

affecting computational efficiency. Multi-rate simulation can use asynchronous lengths for different parts of the system as needed. However

applying the multi-rate method to a single power electronic equipment poses some challenges. In this regard

this paper takes a typical cascaded H-bridge type power electronic transformer (CHB-PET) as an example. According to different circuit frequencies

it is divided. A fast-slow multi-scale interleaving equivalent method is proposed to realize single-device multi-rate simulation and improve efficiency with low accuracy loss. Specifically

CHB-PET is divided at the middle of the two-stage circuit. The cascade H-bridge side is the slow subsystem

and the high-frequency chain isolation stage is the fast subsystem. Then

the information conversion problem of components in the two-stage circuit with different steps is investigated. Secondly

through the staggered equivalence of fast and slow subsystems

a reasonable interaction time is designed to ensure no additional delay in the simulation. Finally

the simulation results of the proposed method are compared with those of PSCAD/EMTDC and the experimental results of the physical prototype to verify the feasibility and rapidity of the method.