Traditional product modeling methods mainly aim at physical products. However, with cloud manufacturing, the efficient management and utilization of big data under the support of cloud service platform are a challenge, and establishing a reasonable data model is the core of product life cycle data management for generalized products. Aiming at big data management of generalized product modules, the definition, description, and classification of general modules are given in this paper firstly. Then, modular master structure data models are built, including the composition of the generalized modular master structure, property description of generalized part variables, connection objects among the generalized parts, etc. Thirdly, modular instance structure data models of the generalized product are established, the formation process of the instance structure model is analyzed, and the structure mapping views in different phases of the product life cycle are also presented. Finally, based on the secondary development of a product life cycle management (PLM) system, the generalized product data models and the modular structure models of the transformer are carried out. The traditional integrated product models are enriched and improved so the demand of modular data management of generalized products is satisfied under the environment of cloud manufacturing.