Dead Time Analysis of a Power-Hardware-in-the-Loop Emulator for Induction Machines

The power-hardware-in-the-loop (PHIL)-based machine emulator systems use controlled power converters to mimic machine behavior. This testing method allows testing of the drive inverter and drive controller prior to the manufacture of an electric motor prototype. In this paper, a PHIL-based machine emulation system is used to mimic the behavior of a three phase induction machine (IM) which is connected to the grid. However, it is essential for the emulator inverter to have a dead time between the upper and lower switches. This dead time in the emulator inverter leads to lower order harmonics which deteriorate the motor emulation accuracy. Thus, it is important to investigate and analyze the effect of dead time in emulation. A detailed analysis of the dead time effect on motor emulation is presented. Experimental results are obtained from the emulator system and from a squirrel cage induction motor to validate the proposed emulator with various dead times.