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Lianchao Sheng,Wei Li,Guo Ye,Song Jiang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8
To reveal the system vibration mechanism, comprehensive consideration of the motor rotor vibration form and the electromechanical coupling effect, a torsional vibration coupling model of the rotor system under electromagnetic effects and terminal load disturbance is established based on the motor theory and Maxwell equations. According to the Melnikov method, the balance point and stability region of the undisturbed Hamilton system are analyzed, and the influence of the system damping and terminal load on the torsional characteristics of the PMSM rotor system is clarified. The specific path and mechanism of the PMSM rotor system instability of the shearer cutting section are revealed. The load excitation f and the system damping u are selected as single control variables, respectively, to analyze the movement state of the system when different variables change. This research can provide a reference for system parameter optimization and selection of common working conditions.
Sheng Lianchao,Li Min,Li Yueqi,Li Wei 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3
The wind turbine blades have complex stress states, and the load has the characteristics of time-varying and uncertainty. Aiming at the interference problem caused by complex and variable load characteristics to the individual pitch control system, combined with the variable-pitch load characteristics, based on the permanent magnet synchronous motor (PMSM) vector control strategy and LADRC (Auto Disturbance Rejection Speed Controller), an individual pitch speed controller is designed. Linear expansion state observer is built. The control algorithm is deduced and the relationship between each control parameter is analyzed to improve the anti-interference ability of the system to the abrupt load of the pitch. On this basis, the system position tracking controller is built. Finally, a vector control simulation model was built based on MATLB/Simulink, and a speed control simulation was carried out. The simulation results show that LADRC has a strong anti-load disturbance capability, and has better anti-disturbance resistance than PID speed control, and the position controller based on this has a better position tracking eff ect. At the same time, the eff ectiveness of the designed independent pitch speed controller has also been verifi ed through experiments. It is of great signifi cance for improving the conversion effi ciency of wind energy
Du Wenlong,Li Wei,Lu En,Sheng Lianchao,Chen Yuming,Jiang Song 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5
In order to improve the stability of low-speed and high-torque permanent magnet synchronous motor control in the shearer semi-direct cutting system under large load fl uctuation and strong impact conditions, an improved model predictive torque control strategy based on duty cycle is proposed which can eff ectively reduce the fl ux and torque ripples and improve steadystate control performance. This method combines the separate process of the voltage vector selection and the duty cycle calculation through the predictive model combined with duty cycle. Then, the optimal voltage vector and its duration is selected simultaneously based on minimizing the cost function. In addition, in order to mitigates the computational burden of the proposed method, the voltage vectors in the fi nite control set is pre-selected using hysteresis comparator according to the motor operating status. Furthermore, the duty cycle pulse width modulation is introduced to obtain a fi xed switching frequency of the inverter. The results of simulation experiments confi rm that the proposed strategy can signifi cantly reduce the fl ux and torque ripples and improve the steady state performance while maintaining fast dynamic response.