The performance of a standard model predictive controller (MPC) is directly related to its predictive model. If there are unmodeled periodic disturbances in the actual system, MPC will be difficult to suppress the disturbances, thus causing fluctuations of system output. To solve this problem, this paper proposes an improved MPC named predictive-integral-resonant control (PIRC). Compared with the standard MPC, the proposed PIRC could enhance the suppression ability for disturbances by embedding the internal model composing of the integral and resonant loop. Furthermore, this paper applies the proposed PIRC to PMSM drives, and proposes the PMSM control strategy based on the cascaded PIRC, which could suppress periodic disturbances caused by the dead time effects, current sampling errors, and so on. The experimental results show that the PIRC can suppress periodic disturbances in the drive system, thus ensuring good current and speed performance. Meanwhile, the PIRC could maintain the excellent dynamic performance as the standard MPC.

In the motor drive system fed by multilevel inverter, the problems such as the complexity of reference voltage synthesis, high common mode voltage (CMV), and high switching loss are usually the obstacles to the practical application. In order to reduce the computational complexity and improve the performance of permanent magnet synchronous motor (PMSM), a novel space vector pulsewidth modulation scheme, which is practical and independent of level number is proposed for PMSM vector control. First, the space vector plane is redivided, and the coordinates of the nearest three vectors and their duty cycles can be obtained directly by determining the location of reference vector, which simplifies the calculation and does not need any iterative algorithm. Then, the optimal switching state and switching sequence are selected online so as to ensure the minimum switching loss under the premise of minimum CMV. This article provides an original method and new idea for motor drive system fed by multilevel inverter. Finally, the practicability and validity of the proposed method are verified by simulation and experiment.

This paper develops an improved hybrid field model (IHFM) to predict the on-load performance of interior permanent-magnet (IPM) motors considering both iron saturation and slotting effect. It combines the air-gap analytical model based on modified conformal mapping with the reluctance mesh method for stator and rotor. The reluctance mesh method can accurately predict the rotor saturation and tooth-tip saturation even their field distribution is complicated due to armature reaction. Besides, IHFM will significantly accelerate computation speed using analytical model for air-gap region while keeping high accuracy. The finite-element analysis and experimental results of flat-type and V-type IPM motors are demonstrated to verify the effectiveness of the proposed model.

Considering the periodic disturbances caused by non-ideal factors like dead time effect, permanent magnet flux harmonics and current sampling errors in the permanent magnet synchronous motor (PMSM) drives, this paper establishes an augmented state space model (SSM) which contains information of periodic disturbances, and then more accurate description for the PMSM system is achieved. Meanwhile, since the three augmented state variables, related to periodic disturbances in the augmented SSM, cannot be measured directly, a novel periodic disturbance observer (PDO) depending on the Kalman filter is designed to estimate these state variables. On the basis of the augmented SSM and PDO, a linear-quadratic-regulator (LQR)-based state feedback controller, which can achieve a successful suppression of periodic disturbances, is proposed to ensure the PMSM acquires a more smooth speed output. Finally, the proposed PDO-LQR is tested in a 6kW PMSM, and the experimental results show that the proposed controller can efficiently improve the steady-state performance of the PMSM system without sacrificing dynamic-state performance.

In this paper, an improved predictive torque control without weighting factor is proposed for a voltage source inverter-permanent magnet synchronous motor drive system, which possesses good control performance of torque and stator flux. By investigating the relationship among torque, the reference stator flux amplitude, and the phase angle of the stator flux, the reference stator flux vector is constructed. Then, the reference voltage vector is calculated by the reference stator flux vector based on the delay compensation and the deadbeat control. The extended control set is designed and two generalized base vectors that require further screening are determined based on the position of the reference voltage vector to improve the calculation efficiency. And the duty ratios used for the generalized base vectors are calculated, according to the geometric relations between the generalized base vectors and the reference voltage vector. Finally, by the duty cycle control between two generalized base vectors and between each generalized base vector and zero vector, the candidate vectors are gained and substituted into the cost function only with the flux vector error term. Experiment tests were carried out and the results validated the effectiveness of the proposed method.

A method of current reference setting for interior permanent magnet synchronous motor based on virtual constant signal injection is proposed. Unlike traditional methods, the partial derivative of torque to d-aixs, q-axis currents is obtained by injecting a virtual constant signal into d-axis, q-axis currents, then the derivative of torque to current angle is obtained through the full differential equation. A scheme of current reference setting, which is applicable to constant torque region and flux-weakening region, is established by means of the derivative information. The difference between the voltage output by the current controller and the actual voltage applied to the motor is also analyzed. Filters that are essential in the virtual sinusoidal signal injection scheme are avoided. Moreover, the acquisition of partial derivative information avoids the influence of neglecting high-order partial derivative term from which the method of injecting virtual square wave signal along the current angle suffers. This method not only realizes maximum torque per ampere control, accurately, but also guarantees the speed range of constant torque region by the setting of q-axis current reference, which is parameter independent. Meanwhile, the torque output capacity is assured in the flux-weakening region. Finally, the proposed method is verified by experiments.