Research on open-loop current estimators for current sensor fault compensation in PMSM motor drive

The elimination of current sensors in vector-controlled motor drives, particularly in Permanent Magnet Synchronous Motors (PMSMs) can be motivated by cost, space constraints, and reliability concerns. This paper presents two current sensorless algorithms for estimating stator phase currents in PMSM drives, aimed at enhancing fault-tolerant control (FTC) capabilities. The first estimator employs a classical motor model with constant d-q axis inductances and stator resistance, where parameters are optimized using the Particle Swarm Optimization (PSO) algorithm. The second, approach, utilizes a nonlinear magnetic model based on flux linkage as a function of current, implemented via a Look-Up Table (LUT). Comparative analysis demonstrates that while the classical model offers simplicity and reduced computational requirements, the LUT-based estimator provides superior accuracy across a broader range of operating conditions. Both methods enable drive operation without direct current measurement, contributing to robust FTC strategies. Future work can focus on enhancing the estimation of instantaneous current values for improved dynamic performance.The files contain waveforms of physical quantities recorded in a drive with a PMSM motor.The “NF_AB” file contains data recorded in a drive in which information from current sensors was used to determine the control.The “NF_AB_VCS” file contains data recorded in the drive, in which information from the VCS estimator was used to determine the control.The “NF_AB_VCS_LUT” file contains data recorded in the drive, in which information from the LUTE estimator was used to determine the control.Each file contains the following waveforms: measured speed (speed_mechanical), reference speed (speed_ref), position (position_mechanical), reference load torque (load_torque_Nm), voltage on the voltage inverter bus (uDC), and currents and voltages in the ABC, alpha-beta, and dq systems. Current and voltage measurements are given in amperes and volts, respectively, and the other quantities have the appropriate unit added.The file “FluxMap_dqTheta_MCS_14H15_def_offset.xlsx” contains information about the magnetic model of the PMSM motor.The variables id_ref, iq_ref and Position define the grid of operating points of the drive for which the values of the fluxes FluxD and FluxQ have been determined.