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The output voltage distortion of the inverter worsens the performance of the permanent-magnet synchronous motor, therefore, it should be compensated accurately. The inverter output voltage can be measured by the oversampling system, but the measured voltage contains drift and noise. To solve this problem, an adaptive sigmoidal function (S-function) model is first proposed in this article to estimate the voltage distortion. A nonlinear Levenberg–Marquardt regression method with voltage oversampling measurement is employed to identify the initial parameters of the adaptive S-function. During the operation, a recursive least square method is exploited to refresh the parameters of the S-function in realtime. The voltage distortion is accurately obtained by the proposed method, and an accurate compensation scheme is proposed to reduce the current distortion and torque ripple. The effectiveness of the proposed method is validated by experiments.

For many servosystems in electric vehicles (EVs), high-performance controls of permanent magnet synchronous motor (PMSM) drives are widely used due to their high efficiency and low vibration and noise. In order to ensure the high efficiency of the servosystems, some online and offline maximum torque per ampere (MTPA) control strategies are proposed; meanwhile, the vibration and noise of interior PMSMs (IPMSMs) in these servosystems for EVs must be smooth and soft. In this article, the vibration and noise of the IPMSM based on MTPA control algorithms are evaluated and compared. First, the influence of the voltage inverter on the noise of IPMSM is presented in detail and the relationship between the harmonic frequencies of the air gap magnetic force and the vibration frequencies of the IPMSM is investigated. Then, combined with this relationship, the effect principle of the control strategies on the magnetic vibration of the IPMSMs is defined. Based on this definition, the operation process and noise mechanism of different control methods are discussed. Finally, the performance of the vibration and noise under classical field-oriented control, offline MTPA control, and online MTPA control is concluded. With the comprehensive analysis and overview provided in this article, it is significant to guide the selection of a high-performance control method for servosystems in EVs.

This paper provides a detailed investigation of the influence mechanism on vibration and noise of permanent magnet synchronous motors with skewed stators. Several skewed stator structures are researched to show the features of the flux and force. The finite element method is used to analyze the motor vibrations, displacements of deformation, and modals considering the mechanism of skewed stator. The displacements are converted to the sound pressure level which can reveal the characteristics of acoustic noise. The noise performances of motors with different stator skew factors are compared to choose a best stator structure. At last, the testing motor with skewed stator were experimentally demonstrated the validity of the theoretical research.

Adaptive fuzzy PID controllers, combining fuzzy controllers which are highly adaptable with conventional PID controllers which have no control error, have been used in vector control systems of permanent synchronous machines(PMSM). In this paper, an adaptive fuzzy PID controller of which membership functions are dramatically improved is designed and applied to a PMSM. Then, simulation in Simulink and practical experiment verify that the controller is well-suited for the system. Finally, a novel stability analysis method for those systems based on adaptive fuzzy PID is proposed and it proves that the PMSM control system in this paper is stable.

Interior permanent magnet synchronous motors often work under flux weakening state in electrical vehicles for higher speed but faults, such as overcurrent and overvoltage, might occur during that process, after which the power transistors are closed immediately and the battery packs are charged through three-phase uncontrolled rectifier composed of six fly-wheel diodes. It is called uncontrolled generation. The characteristics of uncontrolled generation, especially the output DC voltage and current quality of three-phase uncontrolled rectifier, need to be analyzed because they are relevant to the life and health of battery packs. At first, the model of uncontrolled generation is established. Then, analysis on the output properties of three-phase uncontrolled rectifier is carried out by means of mathematical calculation and simulation. Finally, a simple way to protect battery packs is described.