An Improved Fundamental Current Estimation Algorithm for Traction Drives in Overmodulation Zone

Squirrel Cage Induction Motors (SCIM) are widely used in traction applications. Traction drives are usually op-erated in the overmodulation zone to enhance the utilization of the DC bus voltage. However, the inverter output voltage contains a lower-order harmonic voltages in the overmodulation zone. These harmonic voltages result in lower-order harmonic currents in SCIM, which can deteriorate the performance of the closed-loop drive. Therefore, a suitable fundamental current estimation algorithm is required. The correct motor parameters are necessary to estimate precise fundamental current, which is sometimes difficult to estimate. This article proposes an improved fundamental current estimation algorithm, which estimates the leakage inductance error and updates it in real time. The proposed algorithm is simulated and verified in SIMULINK.