Feedback Linearization Direct Torque Control With Reduced Torque and Flux Ripples for IPMSM Drives

This paper designs a feedback linearization direct torque control (FL-DTC) based on the space vector modulation (SVM) which can noticeably reduce the electromagnetic torque and stator flux ripples that affect the system efficiency on interior permanent magnet synchronous motor (IPMSM) drives. First, a decoupled linear IPMSM model with two state variables (i.e., the stator flux and electromagnetic torque) is derived to implement the proposed FL-DTC strategy that preserves some advantages such as fast torque control, high torque at low speed, and fast speed response. Also, the proposed technique greatly alleviates the torque and stator flux ripples which are the major concerns of the classical hysteresis-based DTC scheme and have an effect on the stator current distortion. The system stability with the designed FL-DTC method is mathematically analyzed using the Lyapunov stability theory. Finally, the effectiveness of the proposed control law is validated through simulation results with MATLAB/Simulink and experimental results obtained from a prototype 1-HP IPMSM drive with TI TMS320F28335 digital signal processor (DSP). The verification results demonstrate that the proposed FL-DTC scheme achieves faster torque response, smaller torque ripple, and lower stator flux ripple than the conventional SVM-based PI-DTC approach under parameter uncertainties and external disturbances.