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Active disturbance rejection controller (ADRC) possesses the considerable capability of improving the robustness of the permanent magnet synchronous motor (PMSM) drives. Nevertheless, the traditional linear ADRC (LADRC) and nonlinear ADRC (NLADRC) have their specific characteristic disturbance range of application. To further expand the disturbance range so as to improve the robustness against the disturbances, a novel NLADRC is proposed, which replaces the traditional linear function with a nonlinear function (NLF). And it is applied as the speed regulator for PMSM drives. Considering the accuracy and the dynamic performance of the disturbance estimation at the same time, an NLF is developed, and its describing function is established accordingly. Based on the above analysis, the NLADRC employing a cascaded nonlinear extended state observer is constructed to guarantee the relatively rapid and accurate disturbances estimation and compensation. Then, via the describing function technique, the theoretical frequency-domain analysis for the stability, the disturbance estimation performance, and the stiffness of the proposed NLADRC-based sensorless PMSM drive is given. Finally, the validity of the proposed scheme is verified experimentally on a 2.2-kW PMSM drive platform. [ABSTRACT FROM AUTHOR]

For the purpose of improving the performance of sensorless interior permanent magnet synchronous motor (IPMSM) drives, an enhanced electromotive-force (EMF)-based position observer adopting second-order generalized integrator (SOGI) to eliminate the harmonic error is proposed. The inverter nonlinearities and flux spatial harmonics that give rise to the harmonic error of position estimation are analyzed. A harmonic decoupling network consisting of multiple SOGIs based adaptive filters is adopted to achieve the multiple selective EMF harmonic elimination (MSEHE). The application of the frequency-locked loop ensures the SOGI resonance frequency adaptive, which is critical for the variable-speed operation in IPMSM drive applications. Using the SOGI-MSEHE in the position tracking estimator, the low-order harmonics in the estimated EMF can be effectively eliminated, contributing to cancelling the position estimation harmonic error. The effectiveness of the proposed enhanced position observer is verified by the experimental results at a 2.2-kW IPMSM sensorless drive. [ABSTRACT FROM PUBLISHER]

To improve performance of the field-oriented controlled position sensorless interior permanent magnet synchronous motors (IPMSM) drive, a model-based high-order sliding-mode observer with a software quadrature phase-locked loop (PLL) is proposed. A simplified method of designing the feedback gain matrix of the sliding-mode observer is introduced for easy application. The PLL coefficients are analyzed by considering the expected position estimation error and the operating condition. Compared with the conventional arc-tangent calculation method, the proposed quadrature PLL estimation method can be immune to the influence of the noise and distortion. To achieve the robust high-efficiency operation of the sensorless IPMSM, an enhanced online maximum torque per ampere (MTPA) control strategy without motor parameters dependent is adopted for the vector control drive. The optimal MTPA operation is achieved by searching the optimal current angle online to make the current amplitude be the minimum. The effectiveness of the proposed method is verified with a 2.2-kW IPMSM sensorless drive. [ABSTRACT FROM AUTHOR]