An Investigation of Power-Hardware-in-the-Loop- Based Electric Machine Emulation for Driving Inverter Open-Circuit Faults

Power-hardware-in-the-loop (PHIL) simulations, in the form of machine emulation, are gaining popularity for electric drive system testing in transportation applications. Since there is a reduced chance of equipment damage with PHIL simulations, they are particularly suited for the testing of electric drive systems, for drive inverter faults. This article investigates PHIL simulations to emulate machine behavior in the event of drive inverter faults resulting due to a gate-drive failure of one or more switches. Modifications are proposed to the closed-loop current control of the machine emulator system. These modifications ensure that various lower order harmonics in the emulated machine currents, resulting due to the drive inverter faults, are accurately emulated. Drive inverter damages resulting due to machine behavior emulation in fault conditions are avoided by proposing appropriate emulator control structure modifications. Experimental results are obtained for the emulation of machine behavior for various drive inverter gate-drive faults. These experimental results are compared with that obtained from a faulty drive inverter feeding a prototype machine. A close match between the two results is shown to prove the sufficiency and utility of the proposed controller modifications in the developed PHIL-based machine emulation system.