A pulse frequency modulation（PFM） circuit for retinal prosthesis,which generates electrical pulses with frequency proportional to the intensity of incident light, is presented. The fundamental characteristic of the ...A pulse frequency modulation（PFM） circuit for retinal prosthesis,which generates electrical pulses with frequency proportional to the intensity of incident light, is presented. The fundamental characteristic of the circuit is described and analyzed. The circuit is realized in 0.6μm CMOS process,and the simulation results testify to the possibility of sub-retinal implantation.展开更多
Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency cont...Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid.However,there are some control difficulties in the primary frequency modulation control of gas turbines,such as the coupling effect of the fuel control loop and speed control loop,slow tracking speed,and so on.To relieve the abovementioned difficulties,a control strategy based on the desired dynamic equation proportional integral(DDE-PI)is proposed in this paper.Based on the parameter stability region,a parameter tuning procedure is summarized.Simulation is carried out to address the ease of use and simplicity of the proposed tuning method.Finally,DDE-PI is applied to the primary frequency modulation system of an MS6001B heavy-duty gas turbine.The simulation results indicate that the gas turbine with the proposed strategy can obtain the best control performance with a strong ability to deal with system uncertainties.The proposed method shows good engineering application potential.展开更多
This paper gives a spectrum expression which is simple and has a clear physical conception for pulse frequency modulation signal, and has been confirmed by an experiment simultaneously.
By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinu- soidal pulse width modulation （BSPWM） and unipolar double-frequency sinusoidal pulse width modulati...By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinu- soidal pulse width modulation （BSPWM） and unipolar double-frequency sinusoidal pulse width modulation （UDFSPWM） respectively, the performances of the two modulation strategies are analyzed in detail. The circuit parameters, used in this paper, are fixed. When the systems, modulated by BSPWM and UDFSPWM, have the same switching frequency, the stabil- ity boundaries of the two systems are the same. However, when the equivalent switching frequencies of the two systems are the same, the BSPWM modulated system is more stable than the UDFSPWM modulated system. In addition, a convenient method of establishing the discrete-time model of piecewise smooth system is presented. Finally, the analytical results are confirmed by circuit simulations and experimental measurements.展开更多
A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft swi...A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft switching of two stage cascade converters. It lays technical foundation for high power density, high efficiency and low cost aeronautical static inverter. The operation and design approach of this topology are carefully analyzed and studied. The validity of this topology is verified by simulation and test.展开更多
A new type of window called combined window is designed to get higher Ratio of Mainlobe to Sidelobes (RMS) and lower Mainlobe Widening Factor (MWF). Simulation results prove that the new window can solve the contradic...A new type of window called combined window is designed to get higher Ratio of Mainlobe to Sidelobes (RMS) and lower Mainlobe Widening Factor (MWF). Simulation results prove that the new window can solve the contradiction between RMS and MWF better than classic windows.展开更多
针对原边反馈反激变换器具有辅助绕组而成本偏高的问题,基于原边反馈与峰值电流控制方案,提出了一种基于开关管漏极反馈的反激变换器模型。与原边反馈反激变换器相比,漏极反馈反激变换器能够减少变压器辅助绕组,降低了成本,且具有较高...针对原边反馈反激变换器具有辅助绕组而成本偏高的问题,基于原边反馈与峰值电流控制方案,提出了一种基于开关管漏极反馈的反激变换器模型。与原边反馈反激变换器相比,漏极反馈反激变换器能够减少变压器辅助绕组,降低了成本,且具有较高的稳定性。首先,对此漏极反馈反激变换器模型进行了理论分析,并提出了一种高精度漏极采样方法。其次,基于开关网络模型法对工作在断续导通模式(Discontinuous conduction mode,DCM)下脉冲频率调制(Pulse frequency modulation,PFM)的漏极反馈反激变换器进行了小信号建模并进行补偿设计。通过Matlab/Simulink搭建模型验证其正确性;最后搭建试验平台来进行验证。结果表明,所提出的漏极反馈反激变换器模型是可行的。展开更多
Using a one-dimensional fluid model, the pulse-modulated radio-frequency dielectric barrier discharge in atmospheric helium is described. The influences of the pulse duty cycle on the discharge characteristics are stu...Using a one-dimensional fluid model, the pulse-modulated radio-frequency dielectric barrier discharge in atmospheric helium is described. The influences of the pulse duty cycle on the discharge characteristics are studied. The numerical results show that the dependence of discharge characteristics on the duty cycle is sensitive in the region of around 40% duty cycle under the given simulation parameters. In the case of a larger duty cycle, the plasma density is higher, the discharge becomes more intense, but the power consumption is higher. When the duty cycle is lower, one can get a weaker discharge, lower plasma density and higher electron temperature in the bulk plasma. In practical applications, in order to get a higher plasma density and a lower power consumption, it is more important to choose a suitable duty cycle to modulate the RF power supply.展开更多
提出一种可根据负载变化在脉冲宽度调制(pulse width modulation,PWM)和脉冲频率调制(pulse frequency modulation,PFM)两种工作模式间自动切换的降压DC-DC芯片的设计法,推导出临界切换状态下的负载电流值表达式,在此基础上设计了一种PW...提出一种可根据负载变化在脉冲宽度调制(pulse width modulation,PWM)和脉冲频率调制(pulse frequency modulation,PFM)两种工作模式间自动切换的降压DC-DC芯片的设计法,推导出临界切换状态下的负载电流值表达式,在此基础上设计了一种PWM/PFM自动切换的DC-DC芯片.该系统在较大的负载变化范围内均具有较高效率.展开更多
设计了基于SG1525宽温度工作范围的340 W LLC谐振DC/DC变换器。介绍了一种利用集成控制芯片SG1525来实现脉冲频率调制(PFM)-脉宽调制(PWM)控制的方法。为解决轻载或空载时LLC谐振变换器工作频率太高、损耗大的问题,提出了在轻载或空载...设计了基于SG1525宽温度工作范围的340 W LLC谐振DC/DC变换器。介绍了一种利用集成控制芯片SG1525来实现脉冲频率调制(PFM)-脉宽调制(PWM)控制的方法。为解决轻载或空载时LLC谐振变换器工作频率太高、损耗大的问题,提出了在轻载或空载时采用PWM控制的策略,并提出了实现电路。最后在340 W样机上进行了实验验证,证明了利用SG1525可以实现PFM控制和轻载时的PWM控制。该电路结构简单,参数设计灵活,且可以实现变频控制和PWM控制的无缝切换,很好地满足了宽温度要求。展开更多
脉冲频率调制(PFM)及脉宽调制(PWM)方式是串联谐振电容器充电电源(Capacitor Charging Power Supply,简称CCPS)电路的两种工作模式。前者具有较强的抗负载短路能力,可开环控制,是较常使用的充电方式;后者是近年来研究的一大热点。为研究...脉冲频率调制(PFM)及脉宽调制(PWM)方式是串联谐振电容器充电电源(Capacitor Charging Power Supply,简称CCPS)电路的两种工作模式。前者具有较强的抗负载短路能力,可开环控制,是较常使用的充电方式;后者是近年来研究的一大热点。为研究PFM及PWM方式串联谐振CCPS电路的工作过程,给出了其电路原理图及各阶段的等效电路,建立了该电路的数学模型。通过ORCAD仿真和数学仿真的方法,给出了输出电压变化情况下谐振电路的工作状态,并给出了该电路主要波形。实验结果验证了所采用控制方案的正确性和充电系统的有效性。展开更多
针对红外光通信存在的调制解调复杂、传输距离短等问题,提于一种新颖的脉冲频率（pulse frequency modulation,PFM）调制方式,并设计了4阶带通滤波器滤除带通噪声,构建接收转发电路延长了传输距离。研制了一套宽角度的红外光音频传输系...针对红外光通信存在的调制解调复杂、传输距离短等问题,提于一种新颖的脉冲频率（pulse frequency modulation,PFM）调制方式,并设计了4阶带通滤波器滤除带通噪声,构建接收转发电路延长了传输距离。研制了一套宽角度的红外光音频传输系统。音频传输实验结果表明：该系统实现了较好的音频传输效果,降低了红外光通信系统在传输过程中的功率损耗,延长了传输距离,同时实现了0°~360°传输方向的自主调节,表明本系统具有良好的工程应用价值。展开更多
文摘A pulse frequency modulation（PFM） circuit for retinal prosthesis,which generates electrical pulses with frequency proportional to the intensity of incident light, is presented. The fundamental characteristic of the circuit is described and analyzed. The circuit is realized in 0.6μm CMOS process,and the simulation results testify to the possibility of sub-retinal implantation.
基金supported by Science and Technology Project of Jiangsu Frontier Electric Technology Co.,Ltd. (Grant Number KJ202004),Gao A.M. (author who received the grant).
文摘Gas turbines play core roles in clean energy supply and the construction of comprehensive energy systems.The control performance of primary frequency modulation of gas turbines has a great impact on the frequency control of the power grid.However,there are some control difficulties in the primary frequency modulation control of gas turbines,such as the coupling effect of the fuel control loop and speed control loop,slow tracking speed,and so on.To relieve the abovementioned difficulties,a control strategy based on the desired dynamic equation proportional integral(DDE-PI)is proposed in this paper.Based on the parameter stability region,a parameter tuning procedure is summarized.Simulation is carried out to address the ease of use and simplicity of the proposed tuning method.Finally,DDE-PI is applied to the primary frequency modulation system of an MS6001B heavy-duty gas turbine.The simulation results indicate that the gas turbine with the proposed strategy can obtain the best control performance with a strong ability to deal with system uncertainties.The proposed method shows good engineering application potential.
文摘This paper gives a spectrum expression which is simple and has a clear physical conception for pulse frequency modulation signal, and has been confirmed by an experiment simultaneously.
基金supported by the National Natural Science Foundation of China (Grant No. 51277146)the Foundation of Delta Science,Technologythe Education Development Program for Power Electronics (Grant No. DREG2011003)
文摘By deriving the discrete-time models of a digitally controlled H-bridge inverter system modulated by bipolar sinu- soidal pulse width modulation （BSPWM） and unipolar double-frequency sinusoidal pulse width modulation （UDFSPWM） respectively, the performances of the two modulation strategies are analyzed in detail. The circuit parameters, used in this paper, are fixed. When the systems, modulated by BSPWM and UDFSPWM, have the same switching frequency, the stabil- ity boundaries of the two systems are the same. However, when the equivalent switching frequencies of the two systems are the same, the BSPWM modulated system is more stable than the UDFSPWM modulated system. In addition, a convenient method of establishing the discrete-time model of piecewise smooth system is presented. Finally, the analytical results are confirmed by circuit simulations and experimental measurements.
文摘A new combined soft switching technique and a novel topology of aeronautical static inverter with high frequency pulse dc link are proposed in this paper, namely an electrical isolated converter can realize soft switching of two stage cascade converters. It lays technical foundation for high power density, high efficiency and low cost aeronautical static inverter. The operation and design approach of this topology are carefully analyzed and studied. The validity of this topology is verified by simulation and test.
文摘A new type of window called combined window is designed to get higher Ratio of Mainlobe to Sidelobes (RMS) and lower Mainlobe Widening Factor (MWF). Simulation results prove that the new window can solve the contradiction between RMS and MWF better than classic windows.
文摘针对原边反馈反激变换器具有辅助绕组而成本偏高的问题,基于原边反馈与峰值电流控制方案,提出了一种基于开关管漏极反馈的反激变换器模型。与原边反馈反激变换器相比,漏极反馈反激变换器能够减少变压器辅助绕组,降低了成本,且具有较高的稳定性。首先,对此漏极反馈反激变换器模型进行了理论分析,并提出了一种高精度漏极采样方法。其次,基于开关网络模型法对工作在断续导通模式(Discontinuous conduction mode,DCM)下脉冲频率调制(Pulse frequency modulation,PFM)的漏极反馈反激变换器进行了小信号建模并进行补偿设计。通过Matlab/Simulink搭建模型验证其正确性;最后搭建试验平台来进行验证。结果表明,所提出的漏极反馈反激变换器模型是可行的。
基金supported jointly by National Natural Science Foundation of China （No. 10835004） and National Basic Research Program of China （No. 2010CB832901）
文摘Using a one-dimensional fluid model, the pulse-modulated radio-frequency dielectric barrier discharge in atmospheric helium is described. The influences of the pulse duty cycle on the discharge characteristics are studied. The numerical results show that the dependence of discharge characteristics on the duty cycle is sensitive in the region of around 40% duty cycle under the given simulation parameters. In the case of a larger duty cycle, the plasma density is higher, the discharge becomes more intense, but the power consumption is higher. When the duty cycle is lower, one can get a weaker discharge, lower plasma density and higher electron temperature in the bulk plasma. In practical applications, in order to get a higher plasma density and a lower power consumption, it is more important to choose a suitable duty cycle to modulate the RF power supply.
文摘提出一种可根据负载变化在脉冲宽度调制(pulse width modulation,PWM)和脉冲频率调制(pulse frequency modulation,PFM)两种工作模式间自动切换的降压DC-DC芯片的设计法,推导出临界切换状态下的负载电流值表达式,在此基础上设计了一种PWM/PFM自动切换的DC-DC芯片.该系统在较大的负载变化范围内均具有较高效率.
文摘设计了基于SG1525宽温度工作范围的340 W LLC谐振DC/DC变换器。介绍了一种利用集成控制芯片SG1525来实现脉冲频率调制(PFM)-脉宽调制(PWM)控制的方法。为解决轻载或空载时LLC谐振变换器工作频率太高、损耗大的问题,提出了在轻载或空载时采用PWM控制的策略,并提出了实现电路。最后在340 W样机上进行了实验验证,证明了利用SG1525可以实现PFM控制和轻载时的PWM控制。该电路结构简单,参数设计灵活,且可以实现变频控制和PWM控制的无缝切换,很好地满足了宽温度要求。
文摘脉冲频率调制(PFM)及脉宽调制(PWM)方式是串联谐振电容器充电电源(Capacitor Charging Power Supply,简称CCPS)电路的两种工作模式。前者具有较强的抗负载短路能力,可开环控制,是较常使用的充电方式;后者是近年来研究的一大热点。为研究PFM及PWM方式串联谐振CCPS电路的工作过程,给出了其电路原理图及各阶段的等效电路,建立了该电路的数学模型。通过ORCAD仿真和数学仿真的方法,给出了输出电压变化情况下谐振电路的工作状态,并给出了该电路主要波形。实验结果验证了所采用控制方案的正确性和充电系统的有效性。
文摘针对红外光通信存在的调制解调复杂、传输距离短等问题,提于一种新颖的脉冲频率（pulse frequency modulation,PFM）调制方式,并设计了4阶带通滤波器滤除带通噪声,构建接收转发电路延长了传输距离。研制了一套宽角度的红外光音频传输系统。音频传输实验结果表明：该系统实现了较好的音频传输效果,降低了红外光通信系统在传输过程中的功率损耗,延长了传输距离,同时实现了0°~360°传输方向的自主调节,表明本系统具有良好的工程应用价值。
