With the development of society and increasing of electrical equipment, the original offgrid type wind power generation systems need expansion in some remote areas. In this paper, a novel cascade rectifier device for offgrid type wind power generation is proposed. Using Common DC bus technology, this device can achieve the parallel operation of two generators at the same time, which increases the system capacity. Furthermore, this device can also achieve the maximal wind energy capture of multimachine operation while allowing the duty cycle of power switch device operate in the reasonable range, improving the performance of the system. The simulation results prove the correctness and effectiveness of the device and the control strategies.