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.

In recent years, the power, torque, speed, and other performance of interior permanent magnet synchronous motor (IPMSM) for electric vehicles have improved. The temperature rise is an important factor limiting the performance of the motors. In this article, a novel hollow shaft oil injection cooling structure is proposed. The cooling oil is passed in from one end of the hollow shaft and enters the permanent magnet cavity through the radial oil channel. The centrifugal force generated by the rotation of the rotor causes the oil to be sprayed from the oil injection holes on the end caps at both ends of the rotor, and the winding ends and the stator are directly cooled, which reduces the internal temperature of the motor. The Taguchi method is used to analyze the influence of the novel hollow shaft oil injection cooling structure on the average temperature of the winding and the difference in the injection flow rate at both ends of the motor. Considering various operating conditions, the optimization scheme of the cooling structure is determined. Finally, the reliability of the structure is verified by stress calculation and modal analysis.

The high-frequency (HF) square-wave voltage injection sensorless control method will bring additional HF torque ripple to interior permanent magnet synchronous motor (IPMSM). Focused on this problem, this paper analyzes the relationship between the HF response current and the HF torque ripple resulting from HF square-wave voltage injection. It is concluded that when the fluctuation direction of HF response current is vertical to the stator current vector direction at the maximum torque per ampere (MTPA) operating point, the resulting HF torque ripple reaches its the minimum. Based on this conclusion, a novel HF square-wave voltage injection sensorless control method is proposed in this paper, which can realize the sensorless control and minimize the HF torque ripple at the same time. The injection angle of HF square-wave voltage in the estimated synchronous rotating reference frame (SRF) is adjusted in real time according to the operating conditions, so that the HF response current always fluctuates along the vertical direction of the stator current vector at the MTPA operating point. Besides, the corresponding demodulation method of the rotor position estimation error is illustrated. Finally, the experiments are performed on a 20kW IPMSM platform and the results verify the effectiveness of the proposed method.

This paper proposes a new single-current-sensor (SCS) control method for a permanent-magnet synchronous motor (PMSM) driven by a quasi-Z-source inverter (qZSI). In this method, the sum of two branch currents in the inverter is sampled by an SCS twice for one control period, under actions of two different shoot-through voltage vectors. Then, the three-phase currents of the motor can be reconstructed by these two sample values and can be later used for the current closed-loop control of the PMSM. In this paper, the feasibility of the SCS control method is analyzed thoroughly and a corresponding modulation strategy is given for the qZSI. Compared with the traditional SCS control methods, the new method fully eliminates the measurement dead-zone problem without any additional compensation strategy. The operation range of the PMSM extends and utilization rate of the input voltage improves. In conclusion, the proposed method is easy and convenient to implement, which makes itself a promising application in electrical vehicles.

A novel sensorless control strategy for the brushless dc motor (BLDCM) is proposed in this paper. The proposed strategy is realized by employing new flux-linkage functions and can be applied to drive the sensorless BLDCM in the high-speed and low-speed ranges with highly accurate and reliable commutation. Another attractive feature is that the jumping edges of the flux-linkage functions are utilized to determine the commutation points, so there is no threshold needed as compared with other sensorless control methods. In addition, the three-phase current control method is adopted, and terminal voltages in flux-linkage function expressions can be easily obtained by calculation. By this way, the sample delay and the influence of the floating phase voltage can be eliminated, which can improve the accuracy and reliability of the sensorless control strategy. The effectiveness of the proposed strategy is verified by experimental results.