MTPA- and FW-Based Robust Nonlinear Speed Control of IPMSM Drive Using Lyapunov Stability Criterion

This paper presents a robust nonlinear control technique for a wide-speed-range operation of interior permanent magnet synchronous motor (IPMSM) based on the use of maximum torque per ampere (MTPA) and flux-weakening (FW) controls. The global asymptotic stability of the drive is demonstrated by Lyapunov stability criterion in conjuncture with Barbalat's lemma. For the proposed nonlinear controller, the MTPA and FW schemes are used to control the d-axis stator current below and above the rated speed, respectively. Control laws are developed based on an adaptive backstepping technique to ensure robust system stability. The system nonlinearities are also accommodated through the online estimation of critical parameters. The control and adaptive backstepping laws have been successfully implemented in a MATLAB/Simulink simulation environment. Simulation results indicate excellent speed response and parametric variation insensitivity. The complete drive system is implemented using the peripheral component interconnect (PCI)-based DS1104 digital signal processor (DSP) board for a 3.7-kW laboratory IPMSM. Both experimental and simulation results have demonstrated excellent drive performance, with an extended-speed-range operation and rejection of load disturbance.