MTPA Control of Double Inverter Fed Wound Rotor Induction Motor Drive

This article presents the Maximum Torque Per Ampere (MTPA) control for the Double-Inverter fed Wound Rotor Induction Machine (DI-WRIM). The MTPA control, in general, is investigated using variable-sweeping and mathematical optimization methods. However, owing to the complexity of the variable sweeping strategy, an MTPA control with the mathematical optimization method is a pressing priority. This article proposes an MTPA control based on the mathematical optimization method for a speed-controlled DI-WRIM. This MTPA control emphasizes the various Regions of Operation (ROPs), described in terms of control variable limitations and system constraints, and covers the wide-speed operation of DI-WRIM, i.e., below the base speed region and the flux weakening region (FWR). The flux weakening is particularly emphasized for DI-WRIM, as it has received little attention in the literature. A thorough graphical representation of the trajectories for various operational variables, e.g., machine voltages and currents in the synchronous d-q plane, is also provided for better understanding. The efficacy of the MTPA control and associated analysis are validated on two design configurations of WRIMs, namely, Design-I and Design-II WRIMs, with suitable simulation and experimental results.