Wave digital simulation of passive systems in linear state‐space form

This paper deals with wave digital modeling of passive state‐space models. The set of differential equations must be of linear state‐space form, but all parameters can be time‐variant and/or nonlinear. For such state‐space models, a canonical internally passive reference circuit is presented and used for deriving wave digital structures. In order to show the usability, special solutions for important basic linear time‐variant models are compared with wave digital simulation results. Moreover, the wave digital modeling of a nonlinear and time‐variant oscillator is discussed. Especially for a lossless oscillator an implementation is proposed, which preserves energy under finite‐arithmetic conditions. This is verified by comparing simulation results with the analytical solution of a gravity pendulum. Copyright © 2009 John Wiley & Sons, Ltd.     

A practical guide to multidimensional wave digital algorithms using an example of fluid dynamics

The wave digital concept for numerical integration of partial differential equations leads to algorithms with highly advantageous features as robustness, full localness and massive parallelism. However, the required synthesis of an internally multidimensionally passive reference circuit, from which the algorithm is derived, usually demands an in‐depth knowledge of circuit theory and a high level of intuition. In this practical guide, a step‐by‐step approach for the synthesis of such reference circuits is introduced to relax these requirements, using the nonlinear fluid dynamic equations as a nontrivial example. General implementation issues for the wave digital algorithm are discussed as well as applying arbitrary passive linear multistep methods in place of the commonly used trapezoidal rule. As an example, we take the well‐known numerically critical shock tube problem, the solution of which is problematic when the trapezoidal rule is used as unwanted oscillations occur. These oscillations are suppressed when using the second‐order accurate Gear method instead. Copyright © 2010 John Wiley & Sons, Ltd.     

Controller design for 2-DOF underactuated mechanical systems based on controlled Lagrangians and application to Acrobot control

On the basis of controlled Lagrangians, a controller design is proposed for underactuated mechanical systems with two degrees of freedom. A new kinetic energy equation (K-equation) independent of the gyroscopic forces is found due to the use of their property. As a result, the necessary and sufficient matching condition comprises the new K-equation and the potential energy equation (P-equation) cascaded, the regular condition, and the explicit gyroscopic forces. Further, for two classes of input decoupled systems that cover the main benchmark examples, the new K-equation, respectively, degenerates from a quasilinear partial differential equation (PDE) into an ordinary differential equation (ODE) under some choice and into a homogeneous linear PDE with two kinds of explicit general solutions. Benefiting from one of the general solutions, the obtained smooth state feedback controller for the Acrobots is of a more general form. Specifically, a constant fixed in a related paper by the system parameters is converted into a controller parameter ranging over an open interval along with some new nonlinear terms involved. Unlike what is mentioned in the related paper, some categories of the Acrobots cannot be stabilized with the existing interconnection and damping assignment passivity based control (IDA-PBC) method. As a contribution, the system can be locally asymptotically stabilized by the selection of the new controller parameter except for only one special case.     

组合波发生器的设计

为了对气体绝缘变电站站(GIS)二次电子设备进行冲击电压抗扰度试验。按照IEC610000-4-5/GB17626.5的要求,应用MULTISIM仿真组合波发生器回路中各元件的参数值。用拉普拉斯变换用MATLAB求解二阶电路微分方程验证了得到的各元件参数。研制了一台以三电极场畸变开关作为主控开关的组合波发生器。实验结果表明设计的组合波发生器输出的开路电压波和短路电流波符合IEC/GB的要求,可以作为冲击电压抗扰度试验的模拟信号发生器。     

SOC方式载波电能表的研制与特点

分析了传统电力载波抄表系统的通信难题，设计出一种符合我国低压电力线信道传输特性的数字载波抄表系统。载波电表采用SOC(System On Chip——单块集成电路上完成系统工作)方式，以最新的载波专用集成ASIC电路为核心，外围器件很少；该ASIC内嵌入的快速CPU与相应接口电路配合可完成载波信号调制解调、电能脉冲采集管理、通信协议处理等综合功能，通信模式采用载波频率可自适应跳变的窄带扩频方式，各项参数能够自适应调整以适应时变性大的电力信道，因此SOC载波电表具有通信性能优越、功耗小、成本低的特点。     

A pseudo‐differential current‐reuse structure for opamp‐sharing pipelined analog‐to‐digital converters

In this paper, a power efficient pseudo‐differential (PD) current‐reuse structure is presented to alleviate the memory effects of opamp‐sharing in pipelined analog‐to‐digital converters. To implement the PD current‐reuse structure, a switched‐capacitor circuit is introduced for multiplying digital‐to‐analog converter, which has a slight modification compared with the conventional switching scheme with no power penalty. In the proposed multiplying digital‐to‐analog converter circuit, the common‐mode offset amplification of the PD structures is eliminated. Moreover, a PD current‐reuse amplifier is developed from the telescopic structure with an inverter‐based gain‐boosting circuit. The effectiveness of the proposed structure is evaluated in comparison with existing current‐reuse techniques. Copyright © 2014 John Wiley & Sons, Ltd.     

用于防雷器带电试验组合波发生器电路参数的理论计算

组合波信号发生器(CWG)主要用于浪涌保护器或电子设备电磁兼容试验,要求在虚拟阻抗Z为2Ω的情况下,输出1.2/50μs开路电压波或8/20μs短路电流波。基于电路微分方程的方法对CWG等效电路进行数学计算,导出相应的数学关系,给出一套计算图表。对电路参数计算结果进行电路仿真,并将计算结果应用于实际CWG电路设计。同CWG标准参数要求比对,仿真结果最大偏差小于6%;实际设计的CWG参数最大偏差小于8%。结果表明,针对CWG电路参数的计算采用的方法是正确的,计算结果可以应用于CWG设计中电路参数的选取。     

基于微分进化算法的电路模型匹配技术

根据电路模型单元库实现装备数学模型和物理模型的映射匹配,是基于模型的装备快速测试中的一项关键技术.电路模型匹配技术是进行基于装备物理模型进行故障诊断的基础.对模拟电路中的基本数学模型单元和物理模型单元进行了总结,建立了相应的模型库,针对装备中最基本的单元——可观测的模拟电路系统,提出了利用微分进化算法进行模拟电路模型匹...     

Passivity‐based control for stabilization,regulation and tracking purposes of a class of nonlinear systems

In this paper, a new passivity‐based control (PBC) scheme based on state feedback is proposed in order to solve tracking, regulation and stabilization problems for a class of multi‐input multi‐output (MIMO) nonlinear systems expressed in the normal form, with time‐invariant parameters and locally bounded reference weakly minimum phase. For the proposed control scheme two new different state feedbacks, one non‐adaptive for the case when the system parameters are assumed to be known and the other adaptive for the case of unknown parameters, are developed. For the adaptive case it is assumed that the unknown parameters appear linearly in the equations. Analysis of the transient behaviour of the proposed control schemes is presented through the simulation of two examples. Copyright © 2006 John Wiley & Sons, Ltd.     

三相并网逆变器基准正弦电路研究

与电网电压同步的三相基准正弦电路是三相并网逆变器的重要组成部分.这里提出并研究了一种新颖的与电网电压同步的数字化三相基准正弦电路,它由电网电压取样电路、正弦波/方波转换电路、时钟信号形成电路等构成.对其各单元电路的原理进行论述,给出了关键电路参数设计准则.实验结果表明,该基准正弦电路与三相电网电压同步,输出电压谐波畸变...     

双声路声表面波传感器测量系统研究

环境温度对声表面波传感器影响较大,常采用双声路结构补偿环境温度的影响,本文结合声表面波器件结构,设计了一种新的测量系统。它由交替工作的延迟线振荡器、混频电路和数字信号处理电路组成。延迟线振荡器输出信号经滤波后与109MHz的本机晶体振荡器输出信号相混频,通过低通滤波取其差频,并经整形后由数字信号处理电路处理。应用标准信号源验证了测量系统的准确性,频率跟踪特性误差在50Hz以内。测量系统显示直观,精度高,是双声路声表面波传感器理想的测量系统。     

Multivariate theory‐based passivity criteria for linear fractional networks

In traditional linear network theory, the positive‐real (PR) criteria are widely used to judge the passivity of elements and networks in the light of the fact that there exists an equivalent relationship between the passivity and the PR property of their immittance functions (matrices). However, the equivalence will no longer hold when the fractional elements are introduced into the network, and the PR criteria are not suitable in complex frequency domain anymore. On the other hand, the rapid development of fractional‐order circuits and systems and the corresponding study in fractional circuit analysis and designs put forward an urgent requirement for the passivity criterion, which can tackle linear fractional networks. Hence, in this paper, we propose new passivity criteria for linear fractional networks by aid of generalized Tellegen's theorem and multivariable PR theory. By using the proposed criteria, the passivity of linear fractional networks can be judged, and the steps of the proposed criterion are illustrated by examples.     

Limit‐cycle stable control of current‐mode dc‐dc converter with zero‐perturbation dynamical compensation

Regarding the non‐limit‐cycle instabilities, which commonly exist in the feedback‐controlled switching power converters, a new zero‐perturbation dynamical compensation method is proposed based on a simplified self‐stable dynamical compensation condition in this paper. With a current‐mode Buck converter as the subject of investigation, the corresponding self‐stable perturbation control equation is given. At the same time, the system stability boundary is obtained based on the investigation of the system eigenvalues, and hence, the working range of control parameters is determined. Finally, the presented simulation and experiment results reveal that the new zero‐perturbation dynamical compensation controller is easily realized with an analog circuit and it will not sacrifice the working range of the original reference current compared with the traditional slope compensation. Copyright © 2013 John Wiley & Sons, Ltd.     

三相逆变器数字孪生系统的参数辨识研究

电力电子变换器的参数辨识能提升系统控制和运行效果,然而传统的参数辨识方法难以同时辨识多组参数且辨识结果精度较低。针对此问题,提出了基于数字孪生的三相逆变器参数辨识方法。首先,构造出数字孪生三相逆变器,包括利用Runge-kutta库塔方法建立三相逆变器主电路的数学模型和控制器离散模型。然后,利用自适应粒子群优化算法更新并优化数字孪生逆变器的电路参数,直至数字孪生逆变器和物理逆变器相应的电路参数相同。最后,通过仿真和实验验证了所提参数辨识方法的有效性。结果表明,该方法在稳态与动态条件下均能快速地辨识出物理逆变器的电感、寄生电阻和开关管内阻参数,辨识结果的相对误差在2%以内。     

Canonic realization of wave digital filters involving unit elements

Recently, a method has been developed by means of which canonic wave digital filters can be derived from originally noncanonic ladder wave digital filters. This method applies only to wave digital filters which are derived from pure LC-ladder reference filters. In the paper, it is shown how noncanonic wave digital filters corresponding to reference filters containing unit elements can be transformed such that a canonic realization of these filters can be obtained as well.     

基于SVPWM补偿优化的三电平NPC并网逆变器容错控制

为保证并网系统中三电平中点箝位（neutral point clamped,NPC）型并网逆变器单相桥臂短路或断路故障后持续运行,提出一种基于空间矢量脉宽调制（space vector pulse width modulation,SVPWM）的优化补偿型低共模电压容错控制策略。首先,通过分析故障后八开关三相逆变器（eight switch three phase inverters,ESTPI）拓扑开关状态对应的共模电压大小,确定参考电压矢量合成规则;然后通过一个基波周期内中点电流情况分析中点电位波动机理,进而对空间矢量合成进行调节补偿,并设计低通滤波器和滞环控制器进一步对补偿进行优化调整,保证并网电流质量的同时有效抑制了直流母线中点电位偏移。仿真结果表明,该容错控制策略能够实现三电平NPC并网逆变器单相桥臂故障后并网系统的稳定可靠运行,每个基波周期有三分之一时间的共模电压得到改善,优化补偿后的并网电流质量显著提高,且在并网电流突变时具备良好的控制特性。     

On stochastic modelling of linear circuits

In this paper, the deterministic modelling of linear circuits is replaced by stochastic modelling by including variance in the parameters (resistance, inductance and capacitance). Our method is based on results from the theory of stochastic differential equations. This method is general in the following sense. Any electrical circuit that consists of resistances, inductances and capacitances can be modelled by ordinary differential equations, in which the parameters of the differential operators are the functions of circuit elements. The deterministic ordinary differential equation can be converted into a stochastic differential equation by adding noise to the input potential source and to the circuit elements. The noise added in the potential source is assumed to be a white noise and that added in the parameters is assumed to be a correlated process because these parameters change very slowly with time and hence must be modelled as a correlated process. In this paper, we model a series RLC circuit by using the proposed method. The stochastic differential equation that describes the concentration of charge in the capacitor of a series RLC circuit is solved. Numerical simulations in MATLAB are obtained using the Euler–Maruyama method. Copyright © 2008 John Wiley & Sons, Ltd.     

Efficient output waveform evaluation of a CMOS inverter based on short‐circuit current prediction

A novel approach for obtaining the output waveform, the propagation delay and the short‐circuit power dissipation of a CMOS inverter is introduced. The output voltage is calculated by solving the circuit differential equation only for the conducting transistor while the effect of the short‐circuit current is considered as an additional charge, which has to be discharged through the conducting transistor causing a shift to the output waveform. The short‐circuit current as well as the corresponding discharging current are accurately predicted as functions of the required time shift of the output waveform. A program has been developed that implements the proposed method and the results prove that a significant speed improvement can be gained with a minor penalty in accuracy. Copyright © 2002 John Wiley & Sons, Ltd.     

Semistate models of electrical circuits including memristors

In this paper we present several semistate or differential‐algebraic models arising in nodal analysis of nonlinear circuits including memristors. The goal is to characterize the tractability index of these models under strict passivity assumptions, a key issue for the numerical simulation of circuit dynamics. We show that the main model, which combines memristors' fluxes and charges, is index two. From a technical point of view, this result is based on the use of a projector along the image of the leading matrix, in contrast to previous index analyses. For charge‐controlled memristors, the elimination of fluxes yields an index one system in topologically nondegenerate circuits, and an index two model otherwise. Analogous results are also proved to hold for flux‐controlled memristors. Our framework accommodates coupling effects among resistors, memristors, capacitors and inductors. Copyright © 2010 John Wiley & Sons, Ltd.     

基于PCHD模型的振荡浮子式波浪发电系统的无源控制

波浪能是最复杂的一种可再生能源,这一特性导致其功率控制算法的实现性差。针对这一问题,文章基于一种全封闭的振荡浮子式波浪发电系统的动力学模型,构建波浪发电系统的端口受控的耗散哈密顿模型(PCHD),并设计无源性控制器,为改善系统动态响应在无源性控制器中注入阻尼。仿真结果表明,在波浪变化条件下,该系统能实现最佳状态的快速跟踪,且有良好的动态特性。通过采用PCHD模型,使控制器设计过程具有结构性的特点,物理意义清晰,设计简单。