A multi-rate parallel real-time simulation method based on FPGA–CPU is studied to realize the asynchronous co-simulation of the converter of doubly fed wind power systems with the wind turbine and external power grid. The doubly fed wind power system is partitioned by simulation step length, and the partitioned small-step-length data are processed using integral homogenization. For large-step data, an improved delay-compensated linear interpolation method combined with Newton interpolation is proposed for processing. The general small time-step (GST) model method is used to implement the FPGA modeling of the small-step converter, and resource optimization is achieved through timing time-division multiplexing. Asynchronous parallel co-simulation of a doubly fed wind power system is implemented on an FPGA–CPU co-simulation platform. Among them, the FPGA realizes the development of the converter HDL with a small step of 1 μs, while the CPU completes the simulation of the wind turbine and power grid synchronously with a large step of 50 μs. Finally, by comparing with MATLAB/Simulink offline simulation and analyzing the error, it is concluded that the simulation accuracy of the improved method in this paper is higher than that of the un-interpolated parallel simulation, which verifies the real-time performance and accuracy of the modeling and improved method in this paper.

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In order to realize grid connection and transient real-time simulation of DFIG, a multi-rate parallel real-time simulation method based on co-simulation of Field Programmable Gate Array (FPGA) and CPU is studied. The switching function method is used to model the “back-to-back” converters in the DFIG and optimize the resources, and the modeling segmentation between systems with different step is completed based on PWM averaging to realize multi-rate parallel simulation. The small-step simulation of the “back-to-back” converter is realized with an operational step of 200 by use of high operational rate and strong parallelism of FGPA. Facing the needs of real-time simulation of active distribution network, the 200ns/50 parallel co-simulation of FPGA and independent parallel real-time simulator UREP is realized. By comparing with the off-line simulation results of Simulink and analyzing FGPA resource consumption rate before and after model optimization in this paper, the real-time capacity and accuracy of research method in the paper are verified, which provide a reliable technical support for grid connection and transient research of all kinds of wind power systems.