Applied Mechanics and Materials Vols. 143-144

Abstract: A novel sensorless control method of permanent magnet synchronous motor (PMSM) based on low frequency (LF) current signal injection is proposed in this paper. A LF sinusoidal current signal is superimposed into the estimated d-axis, and the corresponding voltage response and current response are detected to estimate the rotor speed and the rotor position. This method doesn't rely on the non-ideal features but just the fundamental model of PMSM. As a result, the introduced method can be applied to not only IPMSM, but also to SPMSM. Theoretical analysis and simulation results are carried out. The simulation results indicate that the rotor position and speed can be obtained exactly at low and zero speed. The approach ensures good dynamic and static performances, and can realize accurate position servo control.

Abstract: In this paper, a new ESO sliding mode controller that can improve the system stability was designed ,as to the strong nonlinear of generator excitation system and the characteristics of vulnerable to external disturbance, which application of feedback linearization, ESO and sliding model variable structure control theory. Firstly, it realized to linearization for nonlinear mould based on the feedback linearization theory, then it provide dynamic compensation for generator excitation system through constructing extended state observation device (ESO). The methods of factorial is used to design sliding mode switch function, theoretically, it guarantee generator rotor equation with expectations of poles. In order to reduce chattering ,through index near rate and quasi sliding mode control dynamic method to get the sliding control rate, it make the form conciseness, The results of simulation show that the speed , accuracy and stability of system are significantly improved by controller in dynamic and static . Introduction

Abstract: To determine the control method using overlapping commutation overlap time, this article on the four-phase permanent magnet brushless DC motor torque ripple based on the analysis of the use of overlapping commutation torque ripple suppression in the overlap time were derived by Ansoft software calculated four-phase permanent magnet brushless DC motor parameters, using MATLAB/Simulink software and simulate the model, simulation results were derived.

Abstract: Field-oriented control of permanent magnet synchronous motor fed by matrix converter is designed. By introducing space vector modulation for inverter, AC-AC matrix converter is equivalent to AC-DC-AC substitution. Then, perfect PWM technology is adopted for virtual rectifier and virtual inverter of substitution whose modulating schedule and model are analyzed and deduced. of field-oriented control for matrix converter fed permanent magnet synchronous motor is built up. Finally, simulations are carried out, and simulating results show that the proposed system is feasible and valid, which provides theoretical foundations for experimentation.

Abstract: This paper analyzes the calculation method of unbalanced electromagnetic force by rotor winding inter-turn short-circuit fault, analytical calculating method neglects saturation, cogging and other factors, so the calculation accuracy is not high, in order to accurately calculate the magnetic field and the unbalanced electromagnetic force, this paper propose to analyze generator magnetic field by a finite element software Ansys, the obtained magnetic field data are further used to analyze the distributed electromagnetic force and the total force that generator rotor suffered, electromagnetic force distribution law of different slots, different levels of inter-turn short-circuit are got, which provide a basis for further studying the full force on generator rotor.

Abstract: Aiming at safe commutation and improving quality of output waveform, the paper presents a new varying-step safe commutation strategy of matrix converter by analyzing the character of traditional four-step commutation and improved four-step commutation strategy. On the basis of input-voltage-based commutation this new strategy synthetically considers the magnitude of input voltage and output current direction and accordingly distinguishes the safe partition and the unsafe partition. Then different commutation strategies are adopted in different partition which improving the reliability of commutation and decreasing the commutation time to improve the quality of output waveform. Finally, the( ) experiment results demonstrate the availability and reliability of the presented commutation strategy. Thereby, the open-circuit or short-circuit faulty caused by abnormal commutation can be eliminated. The output waveform can be improved because the commutation time can be decreased by 2/3 compared to the traditional four-step commutation strategy.

Abstract: In order to overcome the disadvantages which existed in traditional control system of electro-excavator,such as backward technology,large noise,inconvenient operation,low dynamic efficiency,high cost and so on,the structure and the working principle of DC speed control system were firstly analyzed.Then core board UTU2440-F-V4.5 was adopted to design a digital controller, which can produce 12 triggering pulses to trigger 12 GTOs and monitor the work condition of electro-excavator.Furthermore,synchronous signal detection circuit,work parameter detection circuit and triggering pulse circuit were discussed in detail.Finally,good performance of speed,convenient maintenance and significant energy saving of DC speed control system were proved by experiments.

Abstract: The mathematical model of three-level PWM rectifier is a multi-input multi-output system of strongly coupled system. In industrial applications, PI controller is adopted as the main regulator of the rectifier, but parameter setting of the PI controller is of great impact on the system. In this paper, we put forward a method of applying LQR algorithm to the controller of the power inner loop, combined with the power mathematical mode of the three-level PWM rectifier. The feasibility and accuracy of the method is verified through the simulation.

Abstract: This paper investigates the detent force modeling of a slotted iron core type vertical permanent magnet linear synchronous motor (PMLSM) for ropeless elevator applications. Variable network non-linear magnetic equivalent circuit model is established to predict the detent force of PMLSM. The topology structure of equivalent magnetic circuit is developed and the permeances are derived and calculated. The end effect of two end teeth is essential for analysis of detent force and it is focused in the modeling. Magnetic saturation of primary iron-core also be taken into account. In final some 3-D finite-element numerical calculation results are used to validate the feasibility of the proposed method.

Abstract: For each characteristic of surface-mounted permanent magnet motor and built-in permanent magnet motor, this paper presents a new rotor hybrid topologies structure of both the permanent magnet motors. Surface Mounted, built-in and hybrid permanent magnet motor topology model were established using the finite element method for to calculate the static magnetic field three structures of the motor. Comparative analysis of their contour distribution of the pole from the amplitude distribution within the air gap flux density and the flux density of the cloud were done. Air-gap magnetic field distribution in permanent magnet motor proposed new structure is more close to the sine, which is basis on the motor design, operation and so on.