Real-Time HIL Emulation of Faulted Electric Machines Based on Nonlinear MEC Model

In electric machine drive systems, hardware-in-theloop (HIL) emulation provides accurate testing of actual control system prototypes and protection devices interfaced with the electric machine model on a real-time simulator in a non-destructive environment particularly when faults are studied. A compromise between the model accuracy and computational burden makes the magnetic equivalent circuit (MEC) model ideal for real-time simulation of electric machines. However, satisfying the timing constraints of real-time simulation to accommodate internal machine faults is still challenging due to the nonlinearity and rotation of electric machines. In this paper, the transmission line modeling (TLM) method is utilized to keep the MEC coefficient matrix unchanged during nonlinear iterations. Afterward, for the first time, the entire potential of the TLM method for pre-calculation is exploited by proposing an efficient matrix re-ordering combined with the left-looking Gilbert–Peierls algorithm to minimize the computational burden of the sparse MEC matrix LU decomposition required in each time-step due to rotation. Furthermore, the massive hardware architecture of the field programmable gate array is used as the platform for implementation to fully exploit parallelism. With the proposed MEC-based real-time TLM method, the minimum timestep as low as 500 microseconds can be achieved and the results validation with two-dimensional finite element model (FEM) of the commercial Jmag-Designer software shows the accuracy and efficiency of the proposed methodolog