Modeling of losses in a sandwiched-winding matrix transformer

This paper assesses the suitability of the sandwiched-winding matrix HF power transformer for low-profile applications from the loss standpoint. Finite-element simulations and experiments suggest that the core loss can be adequately characterized by approximating the matrix transformer as a collection of identical uncoupled elements. Thus, a matrix transformer with a large number of elements may have higher core loss than a conventional (tall) transformer, and more core loss than winding loss. Eddy-current analysis reveals that the interconnects which parallel the elements incur a significant fraction of the winding loss. Thus, load distribution is recommended to eliminate the paralleling interconnects in matrix transformers     

Modeling of nonreciprocal six-pole transformer based on helicon resonator

A model of a six-pole nonreciprocal transformer representing a helicon resonator with three inductance coils placed at 120° angles is discussed. Calculations of transformer’s inductive parameters and scattering matrix components are presented. It is shown that such a transformer appears to be a nonreciprocal Y-circulator.     

Modeling of the seven-terminal transformer implemented in the LTGC-QO

In this paper a seven-terminal transformer has been designed. We have suggested its equivalent-circuit model. This transformer has a primary coil with a center tap and two secondary coils. Based on this transformer, a low-cost transformer-based gate-coupled quadrature oscillator (LTGC-QO) using 0.18 µm CMOS technology has been developed. The LTGC-QO consumes 7 mW at 1 V power supply. The simulated phase noise at 1 MHz offset is–116.3 dBc/Hz. The chip area is 400×500 µm.     

三相电压型PWM整流器的建模方法

整流器模型建立直接影响控制策略,通常系统采用基尔霍夫定律和拉格朗日方程建立数学模型,其状态变量间存在耦合。文中针对开关函数描述的数学模型为非线性且控制器设计困难的特征,采用开关周期平均法建立系统平均模型,分离扰动得到稳态模型和线性时不变的小信号模型。结果表明,小信号模型较传统模型更有利系统控制器的设计。     

Small Signal Modeling of a High Bandwidth Voltage Regulator Using Coupled Inductors

Today's voltage regulator (VR) for the microprocessor requires a current loop to achieve adaptive voltage positioning and phase current sharing. A fundamental limitation, current loop sample hold effect, limits the control bandwidth to be pushed beyond 1/6 of the switching frequency. This paper reveals the limitation of the control bandwidth of a two-phase buck converter using peak current control scheme. The limitation can be overcome by coupling the two output inductors. A new small signal model is proposed to study the sample hold effect in coupled-inductor implementations. The relationship between the coupling coefficient and the sample hold effect is then discussed. Based on these understandings, a strongly coupled two-phase buck converter has double the bandwidth of the noncoupled VR; and this is experimentally verified     

Modeling of magnetizing inductance and leakage inductance in amatrix transformer

Winding and core geometries are described for a matrix transformer constructed from integrated core and z-folded flex circuits. The magnetizing inductance is derived using the reluctance method and exploiting structural periodicity and symmetry. The internal leakage inductance is computed from the magnetic field distribution, and the interconnect leakage inductance from inductance formulas and current distribution. The results show that the interconnects are responsible for most of the leakage inductance. The modeling predicts inductance values that agree well with experimental measurements     

三相电压型PWM整流器建模与仿真

建立了三相电压型PWM整流器的数学模型,并对其矢量控制策略进行了分析,采用输入电压空间矢量定向,根据参考指令电压矢量直接计算空间电压矢量位置和作用时间,结合直接电流控制的方法进行电流跟踪控制,仿真结果证明了该方案的有效性.     

Design of a pulse-current transformer

It is shown that the speed of response of a pulse-current transformer is mainly limited by the propagation delay along the secondary winding.     

高压集成电路中的HV MOS晶体管BSIM3 I-V模型改进

针对SPICE BSIM3模型在对大量应用于高压集成电路中的轻掺杂漏高压MOS(简称HV MOS)晶体管建模上的不足,提出了基于BSIM3的高压MOS晶体管I-V模型改进.研究中使用Agilent ICCAP测量系统对HVMOS晶体管进行数据采集,并分析其源漏电阻受栅源、源漏和衬底电压的影响及与标准工艺低压MOS晶体管的差异,针对BSIM3模型源代码中源漏电阻R ds的相关参数算法进行了改进,保留BSIM3v3原有参数的同时增加了R ds的二次栅压调制因子Prwg2和有效Vas参数δ的栅压调制因子δ1,δ2,在开放的SPICE和BSIM3v3源代码上对模型库文件进行修改并实现了优化.仿真结果表明采用改进后的模型,在ICCAP下的测量曲线与参数提取后的I-V仿真曲线十分吻合,该模型大大提高了BSIM3 I-V模型模拟HV MOS晶体管时的精确度,对于高压集成电路的设计与仿真有着极其重要的意义.     

高压集成电路中的HV MOS晶体管BSIM3 I-V模型改进

针对SPICE BSIM3模型在对大量应用于高压集成电路中的轻掺杂漏高压MOS(简称HV MOS)晶体管建模上的不足,提出了基于BSIM3的高压MOS晶体管I-V模型改进.研究中使用Agilent ICCAP测量系统对HVMOS晶体管进行数据采集,并分析其源漏电阻受栅源、源漏和衬底电压的影响及与标准工艺低压MOS晶体管的差异,针对BSIM3模型源代码中源漏电阻R ds的相关参数算法进行了改进,保留BSIM3v3原有参数的同时增加了R ds的二次栅压调制因子Prwg2和有效Vas参数δ的栅压调制因子δ1,δ2,在开放的SPICE和BSIM3v3源代码上对模型库文件进行修改并实现了优化.仿真结果表明采用改进后的模型,在ICCAP下的测量曲线与参数提取后的I-V仿真曲线十分吻合,该模型大大提高了BSIM3 I-V模型模拟HV MOS晶体管时的精确度,对于高压集成电路的设计与仿真有着极其重要的意义.     

高压线极化散射矩阵的理论建模

对高压线的极化散射矩阵进行理论建模 ,推导出其具体的解析式 ,并讨论了某种雷达入射波下理想高压线的散射矩阵及其在某一入射角下的最优化情形 ,给出了数值仿真结果 ,为直升机识别高压线提供新的途径 ,并改善识别效果 ,提高直升机的避障及生存能力     

Modeling of the transmission of power line communication signal through the power electric transformer

In this work, we investigate the transmission of outdoor power line communication (PLC) in the power electric network. For this purpose, we propose an efficient and accurate modeling of the propagation of PLC signal through a power transformer using bond graph theory. Electrical energy is a univocally measurable physical quantity which is not the case of the voltage and the current. The analysis by bond graph where theoretical concept is based on energy and its conservation appear to be the most appropriate for modeling the transmission of low level PLC signals. To demonstrate this advantage, we treat an application on a power transformer and we compare our results to the measure and those obtained by another method of calculation.     

Comparison of Modeling Approaches for the Capacitance–Voltage and Current–Voltage Characteristics of Advanced Gate Stacks

In this paper, we compare the capacitance-voltage and current-voltage characteristics of gate stacks calculated with different simulation models developed by seven different research groups, including open and closed boundaries approaches to solve the Schroumldinger equation inside the stack. The comparison has been carried out on template device structures, including pure SiO₂ dielectrics and high-kappa stacks, forcing the use of the same physical parameters in all models. Although the models are based on different modeling assumptions, the discrepancies among results in terms of capacitance and leakage current are small. These discrepancies have been carefully investigated by analyzing the individual modeling parameters and the internal quantities (e.g., tunneling probabilities and subband energies) contributing to current and capacitance     

Modeling and Control of a Novel Six-Leg Three-Phase High-Power Converter for Low Voltage Fuel Cell Applications

In this paper, an averaged model for a recently proposed novel three-phase transformer-isolated phase-shift dc–dc converter is derived. Fuel cell static and dynamic characteristics are used for the converter power stage design consideration. The controller is then designed based upon the power stage parameters and system dynamic requirements. The entire system has been designed, fabricated, and tested using a commercial 1.2-kW proton exchange membrane fuel cell. The experimental results match the simulation results fairly well on both fuel cell source dynamic and step load transient responses.     

A unified design criterion for ZVT DC-DC PWM converters with constant auxiliary Voltage source

This paper proposes a design criterion for calculating the resonant auxiliary elements of zero-voltage transition dc-dc pulsewidth-modulated (PWM) converters that use a dc auxiliary voltage source. The proposed criterion is based on stored energy in resonant auxiliary elements and takes into account the influence of the auxiliary voltage source value. Using this criterion, the reactive energy can be kept at a minimum level and a reduction of the auxiliary elements current ratings is achieved, which leads to lower conduction losses and improved converter efficiency. In addition, a reduction in size of auxiliary magnetic elements can be accomplished. To illustrate the usefulness of the proposed design criterion, the paper compares results obtained from the True-PWM Zero-Voltage Switching pole boost converter designed according to the proposed criterion, and from the original design guidelines. Experimental results show an efficiency gain of about 1% for a wide load range and 1.5% at full load. In addition, a reduction of about 52% in the auxiliary transformer volume for the implemented prototype was achieved, ensuring a reduction in overall converter size. Experimental results were obtained using a 1-kW 100-kHz laboratory prototype.     

Modeling and Design for a Novel Adaptive Voltage Positioning (AVP) Scheme for Multiphase VRMs

Adaptive voltage positioning (AVP) has been used in multiphase voltage regulator module (VRM) applications. A novel scheme, called AVP $+$, is analyzed in this paper. Small signal model is used to look into the control performance issues such as output impedance and stability. The model has been verified in the experiments and simulations. Compared to a conventional AVP schemes, the present scheme provides better stability margin and output-impedance performance. This is especially true for the prevailing trend of using ceramic output capacitors and high switching frequency. The focus of the present paper is the small-signal modeling for control loop design using the AVP$+$ scheme which was never analyzed before. And the comparisons were made between AVP$+$ and AVP$-$ on the stability and output impedance performance.      

三相交流调压电路在MATLAB中的建模与仿真

阐述了三相交流调压电路的工作原理,分析了触发角α不同时三相负载上的输出电压波形.然后在MATLAB/Simulink中给出了其详细的建模过程,最后对仿真结果进行了比较分析,其仿真波形与理论分析波形完全一致,验证了三相交流电压电路建模过程完全正确.     

Electronic error compensation of a current transformer

A scheme is presented employing two precision resistors and an electronic amplifier for reducing the ratio and phase-angle errors in a current transformer. The amplifier supplies only the error current. The proposed arrangement facilitates the adaptability of inexpensive low ampere-turn c.t.s for calibration work in the laboratory.     

OISD MOSFET阈值电压建模与结构设计

对一种新型半绝缘SOI MOS器件的阈值电压进行建模,该器件采用源漏注氧OISD技术,具有优良的自加热效应抑制能力和耐压特性.由于沟道中存在复杂的二维势场分布,OISD MOSFET阈值电压,亚阈值斜率及短沟道效应均受到硅窗口尺寸的调制.给出了一个基于数值仿真的OISD MOSFET阈值电压简单模型,该模型可指导器件结构设计,并通过MEDICI二维数值仿真进行验证.最后,对OISD MOSFET亚阈值斜率、短沟道阈值电压偏移以及DIBL因子等重要电学参量进行详细的研究.