The embodiment of the invention provides a signal acquisition device, method, and system, and belongs to the technical field of power electronic equipment. The signal acquisition device comprises a power module, a conversion module and at least two signal acquisition modules. The power module is coupled to the conversion module and each signal acquisition module. Each signal acquisition module is coupled to the conversion module. The conversion module is used to be coupled to a sampling control device. Through the data signal acquisition by the at least two signal acquisition modules, and through the cooperation of the at least two signal acquisition modules and the conversion module, the sampling rate of the data acquisition processing is improved.