Proportional Difference Operator (PDO) method is proposed for the first time to determine the key parameters of a MOSFET, including the threshold voltage and ca rrier mobility.This method is applied to the transfer ch...Proportional Difference Operator (PDO) method is proposed for the first time to determine the key parameters of a MOSFET, including the threshold voltage and ca rrier mobility.This method is applied to the transfer characteristic of a MOSFET first, and then the effect of gate voltage on carrier mobility is considered. The dependence of carrier mobility on the gate voltage is obtained.展开更多
The problem of chatter vibration is associated with adverse consequences that often lead to tool impairment and poor surface finished in a workpiece, and thus, controlling or suppressing chatter vibrations is of great...The problem of chatter vibration is associated with adverse consequences that often lead to tool impairment and poor surface finished in a workpiece, and thus, controlling or suppressing chatter vibrations is of great significance to improve machining quality. In this paper, a workpiece and an actuator dynamics are considered in modeling and controller design. A proportional-integral controller(PI) is presented to control and actively damp the chatter vibration of a workpiece in the milling process. The controller is chosen on the basis of its highly stable output and a smaller amount of steady-state error. The controller is realized using analog operational amplifier circuit. The work has contributed to planning a novel approach that addresses the problem of chatter vibration in spite of technical hitches in modeling and controller design. The method can also lead to considerable reduction in vibrations and can be beneficial in industries in term of cost reduction and energy saving. The application of this method is verified using active damping device actuator(ADD) in the milling of steel.展开更多
并网运行的交直流混合微网中,交流侧接入非线性负载会导致公共并网点(point of common coupling,PCC)处电流出现明显畸变。为避免引入额外有源滤波器装置,在基于综合惯量的互联变换器控制基础上,叠加准比例谐振控制器用于谐波补偿控制,...并网运行的交直流混合微网中,交流侧接入非线性负载会导致公共并网点(point of common coupling,PCC)处电流出现明显畸变。为避免引入额外有源滤波器装置,在基于综合惯量的互联变换器控制基础上,叠加准比例谐振控制器用于谐波补偿控制,通过公共并网点处电流反馈信号,实现电流正弦性和交直流侧功率平衡。同时,在谐波补偿环节引入多采率控制,解决了互联变换器低开关频率控制过程中的延时而导致的谐波重构误差问题,改善谐波补偿效果,并给出准比例谐振控制器参数的设计过程。基于Matlab/Sinmulink仿真实验结果表明所提方案稳态特性好,动态响应快,对负荷突变适应性好,控制算法简单可靠。展开更多
文摘Proportional Difference Operator (PDO) method is proposed for the first time to determine the key parameters of a MOSFET, including the threshold voltage and ca rrier mobility.This method is applied to the transfer characteristic of a MOSFET first, and then the effect of gate voltage on carrier mobility is considered. The dependence of carrier mobility on the gate voltage is obtained.
基金supported by National Natural Science Foundation of China(Grant No.51675440)Fundamental Research Funds for the Central Universities of China(Grant no.3102018gxc025)
文摘The problem of chatter vibration is associated with adverse consequences that often lead to tool impairment and poor surface finished in a workpiece, and thus, controlling or suppressing chatter vibrations is of great significance to improve machining quality. In this paper, a workpiece and an actuator dynamics are considered in modeling and controller design. A proportional-integral controller(PI) is presented to control and actively damp the chatter vibration of a workpiece in the milling process. The controller is chosen on the basis of its highly stable output and a smaller amount of steady-state error. The controller is realized using analog operational amplifier circuit. The work has contributed to planning a novel approach that addresses the problem of chatter vibration in spite of technical hitches in modeling and controller design. The method can also lead to considerable reduction in vibrations and can be beneficial in industries in term of cost reduction and energy saving. The application of this method is verified using active damping device actuator(ADD) in the milling of steel.
文摘并网运行的交直流混合微网中,交流侧接入非线性负载会导致公共并网点(point of common coupling,PCC)处电流出现明显畸变。为避免引入额外有源滤波器装置,在基于综合惯量的互联变换器控制基础上,叠加准比例谐振控制器用于谐波补偿控制,通过公共并网点处电流反馈信号,实现电流正弦性和交直流侧功率平衡。同时,在谐波补偿环节引入多采率控制,解决了互联变换器低开关频率控制过程中的延时而导致的谐波重构误差问题,改善谐波补偿效果,并给出准比例谐振控制器参数的设计过程。基于Matlab/Sinmulink仿真实验结果表明所提方案稳态特性好,动态响应快,对负荷突变适应性好,控制算法简单可靠。
