A method of improving the stability of multiple-motor drive system fed by a 3-leg single inverter has been devised that employs the averages and differences of estimated parameters for field-oriented control. The para...A method of improving the stability of multiple-motor drive system fed by a 3-leg single inverter has been devised that employs the averages and differences of estimated parameters for field-oriented control. The parameters of each motor (stator current, rotor flux, and speed) are estimated using adaptive rotor flux observers to achieve sensorless control. The validity and effective of the proposed method have been demonstrated through simulations and experiments.展开更多
针对矢量推力双旋翼无人机姿态控制过程中存在强耦合、模型不精确的问题,提出了一种改进型的线性自抗扰姿态控制(linear active disturbance rejection controller,LADRC)方法。该方法利用改进线性扩张状态观测器(linear extended state...针对矢量推力双旋翼无人机姿态控制过程中存在强耦合、模型不精确的问题,提出了一种改进型的线性自抗扰姿态控制(linear active disturbance rejection controller,LADRC)方法。该方法利用改进线性扩张状态观测器(linear extended state observer,LESO)提高对总扰动的实时观测精度,根据姿态角的误差及其变化率引入模糊控制思想对线性状态误差反馈控制律进行在线参数整定,最后以矢量推力双旋翼飞行器为研究对象,对比PID和常规LADRC对外界扰动的抗扰效果,仿真试验验证了该方法能够较好估计补偿系统的总扰动,具有更好的抗扰性能和收敛速度。展开更多
Dual throat nozzle (DTN) is fast becoming a popular technique for thrust vectoring. The DTN is designed with two throats, an upstream minimum and a downstream minimum at the nozzle exit, with a cavity in between the u...Dual throat nozzle (DTN) is fast becoming a popular technique for thrust vectoring. The DTN is designed with two throats, an upstream minimum and a downstream minimum at the nozzle exit, with a cavity in between the upstream throat and exit. In the present study, a computational work has been carried out to analyze the performance of a dual throat nozzle at various mass flow rates of secondary flow and nozzle pressure ratios (NPR). Two-dimensional, steady, compressible Navier-Stokes equations were solved using a fully implicit finite volume scheme. The present computational results were validated with available experimental data. Based on the present results, the control effectiveness of thrust-vectoring is discussed in terms of the thrust coefficient and the coefficient of discharge.展开更多
以单相级联H桥整流器(cascaded H-bridge rectifier,CHBR)为研究对象,针对传统有限集模型预测功率控制(finite-control-set model predictive power control,FCSMPPC)算法计算量大、网侧谐波分布广泛等缺点,该文首先给出一种基于两矢量...以单相级联H桥整流器(cascaded H-bridge rectifier,CHBR)为研究对象,针对传统有限集模型预测功率控制(finite-control-set model predictive power control,FCSMPPC)算法计算量大、网侧谐波分布广泛等缺点,该文首先给出一种基于两矢量的MPPC(dual-vector-based MPPC,DVB-MPPC)算法,可以实现开关频率的固定并提高稳态性能。为进一步减小计算量,提出一种DVB简化MPPC算法,取消滚动计算过程,降低控制器运算负担。在此基础上,提出一种基于负载电流计算的调制信号补偿分量注入方法,实现电容电压平衡控制,该算法无需比例积分控制器,进一步简化控制系统结构。最后,对3种MPPC算法在单相三模块CHBR实验样机上进行实验对比研究,实验结果证明了所提算法的正确性与有效性。展开更多
文摘A method of improving the stability of multiple-motor drive system fed by a 3-leg single inverter has been devised that employs the averages and differences of estimated parameters for field-oriented control. The parameters of each motor (stator current, rotor flux, and speed) are estimated using adaptive rotor flux observers to achieve sensorless control. The validity and effective of the proposed method have been demonstrated through simulations and experiments.
文摘针对矢量推力双旋翼无人机姿态控制过程中存在强耦合、模型不精确的问题,提出了一种改进型的线性自抗扰姿态控制(linear active disturbance rejection controller,LADRC)方法。该方法利用改进线性扩张状态观测器(linear extended state observer,LESO)提高对总扰动的实时观测精度,根据姿态角的误差及其变化率引入模糊控制思想对线性状态误差反馈控制律进行在线参数整定,最后以矢量推力双旋翼飞行器为研究对象,对比PID和常规LADRC对外界扰动的抗扰效果,仿真试验验证了该方法能够较好估计补偿系统的总扰动,具有更好的抗扰性能和收敛速度。
文摘Dual throat nozzle (DTN) is fast becoming a popular technique for thrust vectoring. The DTN is designed with two throats, an upstream minimum and a downstream minimum at the nozzle exit, with a cavity in between the upstream throat and exit. In the present study, a computational work has been carried out to analyze the performance of a dual throat nozzle at various mass flow rates of secondary flow and nozzle pressure ratios (NPR). Two-dimensional, steady, compressible Navier-Stokes equations were solved using a fully implicit finite volume scheme. The present computational results were validated with available experimental data. Based on the present results, the control effectiveness of thrust-vectoring is discussed in terms of the thrust coefficient and the coefficient of discharge.
文摘以单相级联H桥整流器(cascaded H-bridge rectifier,CHBR)为研究对象,针对传统有限集模型预测功率控制(finite-control-set model predictive power control,FCSMPPC)算法计算量大、网侧谐波分布广泛等缺点,该文首先给出一种基于两矢量的MPPC(dual-vector-based MPPC,DVB-MPPC)算法,可以实现开关频率的固定并提高稳态性能。为进一步减小计算量,提出一种DVB简化MPPC算法,取消滚动计算过程,降低控制器运算负担。在此基础上,提出一种基于负载电流计算的调制信号补偿分量注入方法,实现电容电压平衡控制,该算法无需比例积分控制器,进一步简化控制系统结构。最后,对3种MPPC算法在单相三模块CHBR实验样机上进行实验对比研究,实验结果证明了所提算法的正确性与有效性。
