This paper proposes a nonlinear flux linkage observer for the PMSM speed controls without motion sensors, introducing the deviation among the real stator flux linkage and an estimated stator flux linkage to suppress feedback and integral flux drift. In the position detection of an interior PMSM without a speed sensor, the traditional back EMF integration method uses a pure integrator, or LPF, to estimate the stator flux. Its inherent defects inevitably lead to inaccurate flux estimation, which directly affects the estimation of the motor mover position, resulting in the decline in motor control operation and the distortion of phase current. This paper uses an improved integrator with adaptive compensation. The projected value of the stator flux linkage has been derived from the estimated value of the rotor permanent magnetic flux linkage position angle and the algebraic model (m-model) of the stator flux linkage, along with a synchronous coordinate system. The IPMSM stator coil flux linkage obtained from the stator coil current and integral voltage models in the static coordinate system is compared to form a feedback closed-loop to suppress the integral drift, and using the cross-product approach of the actual and estimated flux linkage yields the projected value of the IPMSM rotor speed and position through a PLL. Compared with the existing motion-sensorless observers, the methodology proposed in this article is simple and exhibits better dynamic and static estimation performance. Extensive and comprehensive MATLAB computer simulation and experimental findings validate the proposed motion-sensorless control mechanism.

The elimination of position sensors allows sensorless control to minimizing the size, cost, and additional layers of the permanent magnet synchronous motor (PMSM). In this work, a new flux estimator with an active disturbance rejection controller (ADRC) drift-elimination capability is developed in order to accomplish precise flux estimation. The ESO integrated into the ADRC is capable of detecting and compensating each of the inner model’s fluctuation along with external loads disturbances, enabling a control system with a more effective dynamic response and robust regulations. As a result, the drift issue is greatly mitigated, and the stator flux is accurately predicted throughout a broad range of speeds. The proposed flux observer is validated via sensorless speed vector control of a 15 kW IPMSM motor.

Interior Permanent Magnet Synchronous Motor (IPMSM) motion-sensorless speed control necessitates precise knowledge of rotor flux, speed, and position. Due to numerous non-ideal aspects, such as converter nonlinearities, detection errors, integral initial value, and parameter mismatches, the conventional first-order integrator’s estimated rotor flux experiences a DC offset (Doff). Low-pass filters (LPF) with a constant cut-off frequency yield accurate estimates only in the medium- and high-speed range; however, at the low-speed area, both magnitude and phase estimates are inaccurate. The presented technique resolves the aforementioned issue for a broad speed range. In order to achieve precise flux estimation, this article presents an improved technique of flux estimator with two distinct drift mitigation strategies for the motion-sensorless field-oriented control (FOC) system of IPMSM. Using the orthogonality of the $\mathrm{\alpha }\text{-}$ and $\mathrm{\beta }$-axes, the proposed drift elimination system can estimate drift in different situations while maintaining a high level of dynamic performance. The stator flux linkage (SFL) computation in the synchronous coordinate is established from the estimation of the rotating shaft’s permanent magnetic flux linkage orientation and the statistical equations model of the SFL. By comparing the calculated SFL vector to the SFL vector derived from the stator winding voltage and currents integral model with a drift PI compensation loop, a feedback loop is formed to neutralize integral drift, and the rotational speed and position of an IPMSM is estimated utilizing the vector product of the two flux linkages in a phase-locked loop. Theoretical interpretation is presented, and Matlab Simulink simulations, as well as experimental outcomes, consistently demonstrate that the suggested estimation techniques can eliminate the phenomenon of flux drift.

An interior Permanent magnet synchronous motor (IPMSM) drive employing sensorless control strategies offers to simplify the design of servo systems, reduce costs, and improve reliability, thus attracting significant research attention from both academic and industrial sectors for decades. The straightforward configuration and decreased application prerequisites make model-based sensorless control approaches highly popular. Notably, the conventional first-order integrator flux observer technique exhibits remarkable robustness owing to its minimal reliance on motor parameters. However, the conventional first-order integrator experiences a DC drift and harmonics in the estimated rotor flux as a result of non-ideal factors, such as detection errors, integral initial value, converter nonlinearities, and parameter mismatches. In this paper, an improved ADRC-based integral flux observer capable of eliminating drift is developed to achieve high-accuracy flux estimation. The efficiency of the proposed technique in eliminating the drift from the estimated flux, as evidenced by theoretical analysis, has no detrimental effect on the amplitude or phase angle of the fundamental waveform. The validity of the proposed improved ADRC-based integral flux observer is verified by sensorless vector control of a 7.5 [kW] three-phase IPMSM motor via extensive numerical simulation.