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.

The fast and stable current inner loop in the permanent-magnet synchronous motor (PMSM) control system is the key factor that ensures the torque control performance of the motor. The deadbeat model predictive control strategy can achieve fast dynamic response, but it depended on the accurate mathematical model of the motor. When the model parameter in the predictive controller has mismatched with real system, the static error or oscillations will occur in the steady state. Therefore, a novel current predictive control based on the fuzzy algorithm is proposed in this paper. The novel control strategy contained a predictive controller, a proportional-integral (PI) compensation link, a magnetic flux observer, and a fuzzy controller. According to the operation state of the motor and the model parameter mismatch of the controller, the fuzzy algorithm can adjust the effect of compensation link by weight coefficient in real time. The dynamic performance of the proposed method is guaranteed compared with the traditional deadbeat predictive current control based on the space vector pulsewidth modulation (SVPWM). When the model parameter mismatch of controller is occurred, the weight of the PI compensation link is enhanced, and the static error or oscillation of the motor system can be eliminated.

There is a certain amount of current harmonics in interior permanent magnet synchronous motor. In order to accurately control the current harmonic, this article focuses on three aspects: establishing current harmonic calculation model, extracting current harmonic, and designing current harmonic regulator. A current harmonic calculation model, which considers the effect of voltage harmonics induced by current controllers and digital control delay on the initial phase angle of voltage harmonics, is established for the first time. With the help of multiple synchronous rotating frame transformation, a current harmonic extraction method more suitable for motor drive field, which aims to extract the current harmonic characteristics of d -axis and q -axis currents, is proposed. On this basis, the controlled quantity and control quantity are unified in d–q coordinate frame for analyzing the coupling relationship of current harmonic characteristics. And then a PI current harmonic regulator, including current harmonic decoupling and voltage harmonic initial phase angle compensation, is constructed, so as to realize the effective control of current harmonics. Finally, the effectiveness and superiority of the proposed method are verified by simulation and experiments.

In the control of permanent magnet synchronous motors, the active disturbance rejection control (ADRC) has attracted considerable attention due to its intrinsic ability for disturbance rejection. However, the existing ADRC methods have the problem of coupling the reference tracking performance and disturbance suppression performance. To simultaneously improve the current control's dynamic response speed and steady-state control accuracy, a two-degree-of-freedom ADRC current control method based on the improved extended state observer (IESO) is proposed in this article. First, the designed IESO cancels the error correction term in the observed current update law to realize the complete decoupling of the reference tracking performance and disturbance suppression performance. Under the decoupling structure, the observed disturbance update law of the IESO is designed as a proportional-integral-repetitive control structure to suppress periodic and aperiodic disturbances. Then, the system stability is proved by analyzing the distribution of characteristic roots, and a two-step parameter tuning guideline of the IESO is provided. The proposed method realizes the complete decoupling of the reference tracking performance and disturbance suppression performance, reducing the complexity of the controller parameter selection and facilitating the realization of the high-performance current control. Finally, the effectiveness of the proposed method is validated by experimental results.

To solve the issue of neutral-point (NP) balancing in the three-level NP-clamed inverter, a novel carrier-based pulsewidth modulation (CPWM) strategy of double modulation waveforms is proposed in this paper. By combining the injection of zero-sequence voltage with the decomposition of modulation waveform organically, NP balancing is achieved over full range of inverter output voltages and load angles for linear loads. Furthermore, the switching frequency of power devices is significantly reduced as an optimal selection method of zero-sequence voltage is applied for the proposed strategy, which is equal to that for the CPWM strategy of single modulation waveform. Effectiveness of the proposed strategy is validated by both theoretical derivation and experimental results.