Online Loss-Minimization-Based Adaptive Flux Observer for Direct Torque and Flux Control of PMSM Drive

This paper presents a novel adaptive flux observer based direct torque and flux control (DTFC) of a permanent magnet synchronous motor (PMSM) drive. An online loss minimization algorithm (LMA) is developed to estimate the air-gap flux so that the motor operates at minimum loss condition while taking the general advantages of the DTFC scheme over the conventional vector control scheme. The proposed DTFC-based PMSM drive incorporating the LMA-based flux observer is implemented in real time using the DSP board DS1104 for a laboratory 5-hp motor. The performance of the proposed LMA-based DTFC control of the PMSM drive is tested in both simulation and experiment at different operating conditions.