Induction Machine Emulation under Asymmetric Grid Faults

Machine emulation is the concept of developing a virtual machine in real time with power-hardware-in-the-loop (PHIL) technology. This process of emulation allows testing the variable speed drive or drive inverter or the performance of grid without using a real machine. In this paper, the machine emulated is a three-phase induction motor (IM) fed from the grid. The common asymmetric-grid faults namely unbalanced voltages, line-to-line (L-L) and line-to-neutral (L-N) faults are applied at the input terminals of a virtual induction machine. The main contribution of this paper is a detailed analysis of machine's asymmetric fault behavior and its cause by mathematical derivations and simulations for the process of imitation by a virtual machine. This is being done by corresponding step by step improvement in emulator controller design. The experimental results with the emulator are validated with a real machine and also with Matlab simulation to prove the dynamic performance and accuracy of the proposed novel emulator.