Xiuyun Zhang

To address the parameter uncertainties, external disturbances, and limited dynamic performance caused by fixed weightings in conventional predictive position control for permanent magnet synchronous motor (PMSM), this paper presents a weighting adaptive model predictive position control strategy based on Lyapunov stability. First, an augmented state-space model is established, and a finite-horizon receding-horizon cost function including position tracking error, d-axis current tracking error, and control increment is formulated. Next, a weighting adaptive adjustment mechanism is introduced: leveraging Lyapunov stability theory, an online weighting update law is derived to dynamically tune the weighting matrices in the predictive controller, guaranteeing the consistent ultimate boundedness while enhancing dynamic responsiveness, with corresponding stability proofs provided. Furthermore, an extended Kalman filter (EKF) disturbance observer is integrated to compensate for load-torque perturbations, thereby improving robustness. Experimental results demonstrate that, compared with traditional model predictive control (MPC) using fixed weightings, the proposed method achieves approximately 26% reduction in average position tracking error, 25% reduction in maximum error, and 20% decrease in adjustment time. Furthermore, compared with existing adaptive adjustment methods, the execution time is reduced by approximately 28%. This study offers both theoretical insights and practical guidance for high-precision PMSM position control.

To address the predictive control problem of constrained control variables in practical applications and to avoid the drawbacks of nonlinear optimization numerical solutions, such as high computational burden and slow convergence speed, the constraints on the control variables are analyzed from a geometric perspective. The current and voltage constraints are represented as two circles in the $\boldsymbol{\Delta}$u_dm−$\boldsymbol{\Delta}$u_qm plane. By analyzing the positional relationships between the current limit circle and the voltage limit circle, the feasible regions of the constraints under different positional relationships are identified. Subsequently, the cost function is expressed as a family of equipotential surfaces. In this case, the constrained optimization problem in the optimization space is transformed into the issue of where the elliptical surface is tangent to (or intersects with) the feasible region of the constraints. By calculating the tangency points between the ellipse and the intersecting circular arcs, the optimal solutions $\boldsymbol{\Delta}$u_do and $\boldsymbol{\Delta}$u_qo under the constraints are obtained. The reference voltages u_dref and u_qref in the d–q coordinate are then calculated. Experimental verification indicates that this method not only effectively constrains the motor voltage but also is simple and easy to implement, avoiding the disadvantages of high computational burden and slow convergence speed associated with numerical solution methods.

Model predictive control (MPC) mitigates synchronous error accumulation, dynamic response mismatch, and precision-complexity tradeoff in traditional multimotor system. However, constrained numerical solutions in MPC present significant computational challenges. To address this, this article proposes a predictive position synchronization control strategy based on geometric constraints for dual permanent magnet synchronous motor (PMSM) system. First, an incremental MPC framework is constructed, whose embedded integral action not only effectively compensates for short control horizons but also enables high-precision multistep prediction. Second, a cost function incorporating tracking error, synchronous error and control increment is established to derive the current control increment. To reduce computational complexity, a constrained geometric mapping method is proposed: with control horizon N_c = 1, current and voltage constraints are mapped to a 2D plane to form a feasible region, converting the optimal control increment solution into determining the tangent point between the cost function’s elliptic surface family and this feasible region. Rapidly localizing the tangent via real-time query and calculation of analytical solutions significantly reduces online computational load. Experimental results show the proposed strategy can improve computational efficiency by approximately 47% and dynamic response speed by approximately 57% versus traditional quadratic programming (QP) strategy, resolving the precision-complexity tradeoff in multimotor synchronization while ensuring accuracy.

In order to solve the problem that the contour processing of X-Y motion platform is easily affected by load disturbance, friction disturbance and fluctuation of motor parameters, this paper proposes a linear active disturbance rejection contour control strategy of X-Y motion platform driven by dual permanent magnet synchronous motors. The anti-disturbance performance of the position loop is improved by establishing a linear extended state observer to compensate the disturbance. At the same time, the differential feedforward control is added to improve the rapidity of the system, so that the position loop can ensure a certain anti-disturbance while taking into account the rapidity performance. On this basis, a cross-coupled position synchronous compensator is added to improve the synchronous performance of the system. The stability and anti-disturbance performance of the system are studied by the Bode diagram analysis method in the frequency domain, and the tracking performance and contour performance are analyzed. Finally, the simulation research is carried out to verify the effectiveness of the proposed control algorithm.

An enhanced discrete virtual vector- based direct torque control (DTC) strategy is proposed in this article to improve the steady state performance of permanent magnet synchronous motor (PMSM). Discrete virtual vectors are synthesized to extend the candidate voltage vector set, and a universal method is put forward to take advantage of the extended voltage vector set. Three groups of parallel lines, each group perpendicular to one of the A, B, C axes, are carefully designed to divide the internal region of the vector hexagon into several regular subregions, and each subregion has exactly one voltage vector in the center. Conveniently, if the reference voltage vector is located within a certain subregion, the voltage vector located in the corresponding subregion is selected, and the vector selection table is accordingly established. The proposed strategy maintains the simple control structure and good dynamic performance of DTC, and improves the steady state performance by reducing torque ripple and current distortion compared with the existing DTC methods with discrete space vector modulation. Experiments verified the effectiveness of the proposed DTC strategy.

In this paper, the characteristics of the voltage transfer ratio (VTR) and low-order harmonics of the major modern space vector overmodulation strategies for two-level PWM converters are discussed under different VTRs, and the complexity of the modulation algorithm is subsequently elaborated. First, the principles of these overmodulation strategies are summarized. After that, the accuracy and linearization of the VTR are obtained using the Fourier transform analysis, and the relationship between the main low harmonic components and the VTR is obtained in the same way. All the analysis results are verified through experiments. In addition, the merits and demerits of these overmodulation strategies and applications are revealed by comparing the simplicity of their modulation algorithm, digitization, and other characteristics. Finally, this paper reveals the essence of space vector overmodulation strategies. The results facilitate the design, performance prediction, and development of high-performance overmodulation strategies, as well as the transplantation of space vector overmodulation strategies into different converter topologies.

In order to solve the problem that the position synchronous performance of dual permanent magnet synchronous motor servo system is easily affected by parameter perturbation and load disturbance, an anti-disturbance integrated position synchronous control strategy of dual permanent magnet synchronous motor system is proposed. Firstly, the integral mathematical model of a dual permanent magnet synchronous motor system is established. After that, the third-order linear extended state observer is constructed to observe and compensate for disturbance in order to improve the anti-disturbance performance of the position loop. At the same time, a cross-coupled position synchronous compensator is added to improve the synchronous performance of the system, and through the Bode diagram analysis method in the frequency domain, the system stability and anti-disturbance performance are researched. Finally, the effectiveness of the proposed algorithm is verified by experimental research.