Two TFs （transfer functions） are needed to analyze switching DC-DC converters in control-voltage mode： the duty-cycle to output-voltage （control to output） and the input-voltage to output-voltage （line to output...Two TFs （transfer functions） are needed to analyze switching DC-DC converters in control-voltage mode： the duty-cycle to output-voltage （control to output） and the input-voltage to output-voltage （line to output）. To obtain these TFs a small-signal analysis is required. The CCM （continuous conduction mode） and the DCM （discontinuous conduction mode） analysis are different. When a circuit includes the loss resistances of the components, the number of parameters increases considerably, making manual nodal-loop circuit analysis techniques impractical to obtain the TFs. Moreover, these circuits are bilinear （non-linear） and it is necessary to linearize the equations at a DC operating-point （approximate linearization）. Vorp6rian describes a PWM （pulse-width-modulated） switch model that includes all non-linear parts of the DC-DC switching converters. This model can be linearized and replaced on the switching converter schematic leading to a linear circuit. At this point it is possible to use symbolic analysis programs to obtain these TFs or to simply apply numerical values for either the Bode diagrams or the calculation of poles and zeros. Here we describe an application of Ekrem Cangeici＇s method on X DC-DC converter to obtain control to output and line to output TFs in CCM and DCM including loss resistances. The method presented in this paper is optimized to use in the online publishing platform OctaveRS. Also the control to output TF for PCC （peak current controlled） in CCM is obtained.展开更多
以单相PWM整流器为研究对象,以提高其DQ电流解耦控制的电流内环动态响应速度,增加算法控制精度,实现单位功率因数为目标,首先,建立整流器DQ电流解耦控制的数学模型。其次,针对单相系统坐标变换需要构造虚拟正交分量问题,分析了传统的四...以单相PWM整流器为研究对象,以提高其DQ电流解耦控制的电流内环动态响应速度,增加算法控制精度,实现单位功率因数为目标,首先,建立整流器DQ电流解耦控制的数学模型。其次,针对单相系统坐标变换需要构造虚拟正交分量问题,分析了传统的四分之一周期延时算法与2阶广义积分（second-order generalized integrator,SOGI）算法,研究了一种基于虚拟信号反馈（virtual signal feedback,VSF）的DQ电流解耦控制算法,并给出了电感参数灵敏度分析。然后,为消除电感不匹配对功率因数的不良影响,提出了一种基于稳态q轴电流偏移的电感误差在线补偿算法。最后,对所提出算法进行了仿真和实验验证,同时与传统的延时算法和SOGI算法作对比分析,结果验证了所提算法的正确性以及有效性。展开更多
为了克服传统单相电流型PWM逆变器存在的储能电感及其电流大、输出电压波形畸变严重的固有缺陷,提出了一种具有储能电感电流限定的单周期非线性控制单相电流型PWM逆变器,储能电感电流在高于和低于限定值两种情况时逆变器分别工作在续流...为了克服传统单相电流型PWM逆变器存在的储能电感及其电流大、输出电压波形畸变严重的固有缺陷,提出了一种具有储能电感电流限定的单周期非线性控制单相电流型PWM逆变器,储能电感电流在高于和低于限定值两种情况时逆变器分别工作在续流方式和Boost方式。深入分析研究了这种逆变器一个低频输出周期内的八种电路模式、开关状态方程和高频开关工作过程等稳态原理特性,推导出了电压传输比、储能电感电流限定值、储能电感、输入和输出滤波器、功率开关电压和电流应力等主要参数的设计准则。设计并研制成功的1k VA 110VDC/220V50Hz逆变器样机具有单级升压变换、变换效率高、输出波形质量高、储能电感小等优点,证实了所提出研究方案和理论分析的正确性,有效地克服了传统单相电流型PWM逆变器的固有缺陷。展开更多
Single photon detection is one of the key technologies for quantum key distribution in quantum communication. As a novel single photon detection technology, superconducting nanowire single photon detector (SNSPD) surp...Single photon detection is one of the key technologies for quantum key distribution in quantum communication. As a novel single photon detection technology, superconducting nanowire single photon detector (SNSPD) surpasses conventional semiconducting single photon detectors with high count rate and low dark count rate. In this article, we introduce SNSPD fabricated from NbN ultrathin superconducting film and lab-based SNSPD system. The characteristics of single photon response pulse of SNSPD are analyzed in detail. Also discussed is the relationship between waveform of single photon response and system bandwidth. Circuit model is made to analyze the performance of SNSPD. The simulation result agrees well with the experimental data. Those results are valuable for understanding the mechanism of SNSPD and building future SNSPD system for quantum communication.展开更多
文摘Two TFs （transfer functions） are needed to analyze switching DC-DC converters in control-voltage mode： the duty-cycle to output-voltage （control to output） and the input-voltage to output-voltage （line to output）. To obtain these TFs a small-signal analysis is required. The CCM （continuous conduction mode） and the DCM （discontinuous conduction mode） analysis are different. When a circuit includes the loss resistances of the components, the number of parameters increases considerably, making manual nodal-loop circuit analysis techniques impractical to obtain the TFs. Moreover, these circuits are bilinear （non-linear） and it is necessary to linearize the equations at a DC operating-point （approximate linearization）. Vorp6rian describes a PWM （pulse-width-modulated） switch model that includes all non-linear parts of the DC-DC switching converters. This model can be linearized and replaced on the switching converter schematic leading to a linear circuit. At this point it is possible to use symbolic analysis programs to obtain these TFs or to simply apply numerical values for either the Bode diagrams or the calculation of poles and zeros. Here we describe an application of Ekrem Cangeici＇s method on X DC-DC converter to obtain control to output and line to output TFs in CCM and DCM including loss resistances. The method presented in this paper is optimized to use in the online publishing platform OctaveRS. Also the control to output TF for PCC （peak current controlled） in CCM is obtained.
文摘以单相PWM整流器为研究对象,以提高其DQ电流解耦控制的电流内环动态响应速度,增加算法控制精度,实现单位功率因数为目标,首先,建立整流器DQ电流解耦控制的数学模型。其次,针对单相系统坐标变换需要构造虚拟正交分量问题,分析了传统的四分之一周期延时算法与2阶广义积分（second-order generalized integrator,SOGI）算法,研究了一种基于虚拟信号反馈（virtual signal feedback,VSF）的DQ电流解耦控制算法,并给出了电感参数灵敏度分析。然后,为消除电感不匹配对功率因数的不良影响,提出了一种基于稳态q轴电流偏移的电感误差在线补偿算法。最后,对所提出算法进行了仿真和实验验证,同时与传统的延时算法和SOGI算法作对比分析,结果验证了所提算法的正确性以及有效性。
文摘为了克服传统单相电流型PWM逆变器存在的储能电感及其电流大、输出电压波形畸变严重的固有缺陷,提出了一种具有储能电感电流限定的单周期非线性控制单相电流型PWM逆变器,储能电感电流在高于和低于限定值两种情况时逆变器分别工作在续流方式和Boost方式。深入分析研究了这种逆变器一个低频输出周期内的八种电路模式、开关状态方程和高频开关工作过程等稳态原理特性,推导出了电压传输比、储能电感电流限定值、储能电感、输入和输出滤波器、功率开关电压和电流应力等主要参数的设计准则。设计并研制成功的1k VA 110VDC/220V50Hz逆变器样机具有单级升压变换、变换效率高、输出波形质量高、储能电感小等优点,证实了所提出研究方案和理论分析的正确性,有效地克服了传统单相电流型PWM逆变器的固有缺陷。
基金supported by the National Natural Science Foundation of China (Grant No. 60801046)National Basic re-search Pogram of China(Grant No.2009CB929602)Science and Technology Commission of Shanghai Municipality (Grant Nos. 08dz1400702 & 08PJ1411200)
文摘Single photon detection is one of the key technologies for quantum key distribution in quantum communication. As a novel single photon detection technology, superconducting nanowire single photon detector (SNSPD) surpasses conventional semiconducting single photon detectors with high count rate and low dark count rate. In this article, we introduce SNSPD fabricated from NbN ultrathin superconducting film and lab-based SNSPD system. The characteristics of single photon response pulse of SNSPD are analyzed in detail. Also discussed is the relationship between waveform of single photon response and system bandwidth. Circuit model is made to analyze the performance of SNSPD. The simulation result agrees well with the experimental data. Those results are valuable for understanding the mechanism of SNSPD and building future SNSPD system for quantum communication.
