Detection and Compensation of Inter-turn Short Circuit in Interior Permanent Magnet Synchronous Machines with 2-level Voltage Source Inverter

This paper evaluates the feasibility of implementing the detection and compensation of an inter-turn short circuit (ISC) in an interior permanent magnet synchronous machine fed by a 2-level voltage source inverter (VSI). The proposed method detects the ISC fault using a current observer capable of detecting a specific disturbance related to the ISC. Once the ISC is detected, the possibility of compensating for an ISC is evaluated. With a 2-level VSI, the options for fault compensation are somewhat limited; however, a significant reduction in the fault current can be achieved by adequately injecting d-axis current to cancel out the magnetic flux from the permanent magnet. In this paper, proof of concept of ISC detection and failure path current reduction with d-axis current injection is shown through experimental measurements. Then, the feasibility of post-fault operation is analyzed using an ISC model validated through FEA.