Hou Hongsheng

Research of speed-torque characteristics of brushless DC motor based on back electromotive force

Speed-torque characteristics of brushless DC motors with trapezoidal and sinusoidal back electromotive force (EMF) based on two devices conducted drive method are analyzed separately. A back EMF coefficient using the average value during conduction region is used to calculate the speed-torque characteristics with real back EMF. Simulation and experimental results show this method can precisely meet the real speed-torque characteristics.

Analysis and optimization on characteristics of brushless DC motors based on overlapping commutation

In this paper, overlapping commutation technology is used to eliminate the torque ripple, optimize the speed-torque characteristic, improve the output power, reduce the copper losses in brushless DC motors. Simulation and experimental results show its easy to realize and make brushless DC motor suitable for more precise applications.

Speed-torque characteristics of brushless DC motor based on average back EMF during conduction area

Speed-torque characteristics of brushless DC motor with ideal trapezoidal back electromotive force (EMF) is obtained under the analysis of the commutation and conduction region with two switches conducted and six states driven mode. The back EMF coefficient is calculated from the average value of back EMF during conduction area to speed. And torque coefficient is calculated from the ratio of average torque and average current. Then the speed-torque characteristics expression of brushless DC motor with unideal back EMF is gotten instead by the new back EMF coefficient and torque coefficient. Simulation and experimental results show this method can precisely meet the real speed-torque characteristics.

Auto-Disturbances Rejection Control Design of Brushless DC Motor Drive Based on Plunger Pump Hydraulic System

In the brushless direct current motor driving plunger pump hydraulic system, overload and load sudden change will happen in starting period and speed stable working time. An auto-disturbance rejection controller composed by TD, ESO and NLSEF is designed to solve those problems. At starting, the output speed will reach the setting value with no overshoot in a short time. A very small speed oscillation will occur when large load sudden change during work area. The experimental results show the controller ensure very good robustness and adaptability under starting and load disturbance.