Real-Time Finite-Element Simulation of Electromagnetic Transients of Transformer on FPGA

The computation of the electromagnetic transients in a power transformer with nonlinear material using the finite element method (FEM) is so dense that the traditional nonlinear solver employing the Newton-Raphson method can hardly execute in real time. In this paper, we emulate the finite-element computation of electromagnetic transients of a transformer in real time for the first time. The transmission line modeling (TLM) method employed in the FEM successfully decoupled the nonlinear elements from the linear network so the nonlinearities could be solved individually, which is perfect for parallel processing. The parallelism of the TLM-FE solution is sufficiently explored and realized on a field-programmable gate array with deep data pipelining, and the implementation can execute in real time and provide detailed field information of the transformer during the transients. The proposed noniterative field-circuit coupling enabled the transformer to interface with an external network and the comparison with commercial FEM software proved the accuracy and computational efficiency of the real-time FE model.