A Current-Mode DC-DC Buck Converter with High Stability and Fast Dynamic Response

A current-mode DC-DC buck converter with high stability is presented. The loop gain＇s expression of the current-mode converter is derived by employing an advanced model of a current-mode control converter. After analyzing the loop gain＇s expression, which illustrates the method of selecting suitable frequency compensation for the control loop,a novel pole-zero tracking frequency compensation is proposed. Based on theoretical analysis, a DC-DC buck converter with high stability is designed with 0.5μm-CMOS technology. The simulated results reveal that the stability of the converter is independent of the load current and the input voltage. Moreover,the converter provides a full load transient response setting time of less than 5μs and overshoots and undershoots of less than 30mV.

考虑PWM波形特征的纳米晶磁心损耗模型的研究及验证

磁心损耗精确预测对于电力电子变压器的优化设计至关重要。然而,传统的磁心损耗模型在复杂激励下适用性较差,尤其对于占空比可调、高次谐波含量丰富的PWM波磁心损耗预测,计算精度显著下降。基于Jordan损耗分离模型,建立了一种考虑PWM波形特征的磁心损耗计算方法。首先,该方法根据激励波形特征,推导出相应的波形系数及等效频率来计算PWM波激励下的动态涡流损耗,将Jordan模型的适用范围从正弦拓展到PWM波激励下的磁心损耗计算;然后,分析了不同占空比激励下激励波形有效频率及高次谐波含量变化对损耗系数的影响,并对其进行数学表征,实现了整个占空比范围内磁心损耗的精确预测;最后,搭建了高频非正弦激励下软磁材料磁特性测量平台,针对1K107B纳米晶材料,测量了两种典型PWM波激励下的损耗数据。实验结果表明,所建立的磁心损耗模型具有较高的计算精度,相比于传统的Steinmetz改进公式,整体精度提高了25%。

一种低延时低功耗PWM比较器电路设计

设计了一种基于HHGrace 0.35μm BCD工艺的低延时低功耗电压型静态脉冲宽度调制(Pulse Width Modulation,PWM)比较器,主要应用于高频低功耗的开关电源系统。设计中包含动态尾电流源和改进型正反馈放大器,以改进传统跨导放大器(Operational Transconductance Amplifier,OTA)型比较器高延迟和高功耗等问题。仿真结果表明:在1.2~5.0 V供电电压范围内稳定工作,最大上升沿延时35 ns,最大下降沿延时41 ns,支持6 MHz开关频率的系统,比较精度8 mV,失调电压439μV,静态功耗仅为2.5μA(1.2 V供电)和4.4μA(5.0 V供电)。

不平衡电网下电流源型PWM整流器改进型无差拍控制

三相电流源型PWM整流器运行在电网电压不平衡情况下,引起直流侧及网侧电流存在大量低次谐波,势必对后级变换器供电稳定性、安全性等存在不利影响。针对该问题,首先建立整流器数学模型,推导出不平衡电网下直流侧电压和网侧电流表达式,揭示出系统直流侧和网侧电流产生低次谐波的机理。其次,根据瞬时功率理论设计内环电流参考指令,并利用无差拍控制实现网侧电流对参考电流的跟踪。然而传统无差拍控制存在延时问题,将影响网侧电流的跟随性能,造成电能质量下降。为解决该问题,提出了网侧电流内环改进型无差拍控制,利用两步预测法补偿系统延时。最后,基于Matlab/Simulink平台搭建仿真模型,验证所提控制策略的正确性与有效性。结果表明,所提方法能有效抑制直流侧和网侧电流低次谐波,实现网侧电流正弦化和直流侧电压稳定输出。

定频PWM控制混合桥双LLC谐振变换器研究

针对宽输出电压应用中传统频率控制LLC谐振变换器工作频率范围宽且存在较大循环电流的问题,提出1种定频PWM控制混合桥双LLC谐振变换器。根据原边侧结构的不同,所提变换器有3种拓扑结构形式,分别为半桥-半桥双LLC谐振变换器、半桥-全桥双LLC谐振变换器、全桥-全桥双LLC谐振变换器。其中,原边侧结构并联输入,2个变压器二次侧串联输出。相较于传统频率控制LLC变换器,3种拓扑形态始终在谐振频率点工作,缩小了开关频率范围;在PWM控制策略下,可以分别实现2倍电压增益、3倍电压增益和4倍电压增益以适应宽电压场合;电路中循环电流损耗低,软开关性能良好。Simulink仿真和实验结果验证了所提方案的可行性。

基于非线性扰动观测器的三相PWM整流器滑模控制

针对交流微电网中三相PWM整流器的运行状态易受负载扰动、滤波电容参数摄动影响的问题,本文提出一种基于非线性扰动观测器的三相PWM整流器滑模控制方法。首先,将负载扰动、滤波电容参数摄动等视为集总扰动,构建电压环非线性模型。其次,设计非线性扰动观测器,实现集总扰动的在线估计。为实现主动抗干扰控制和滑模抖振抑制,将估计的集总扰动引入到滑模面中,得到了一种含有扰动估计的新型滑模面。最后,基于滑模控制理论设计电压外环滑模控制器,并采用Lyapunov稳定性理论对其进行了稳定性证明。动态性能测试结果表明,非线性扰动观测器能够快速、准确地对集总扰动进行估计;与双环PI控制相比,所提控制的过渡过程时间减少了60%,电压跌落量减少了54%;滤波电容参数变化时,所提控制的动态性能保持良好。稳态性能测试结果表明,与传统滑模控制和双环PI控制相比,所提控制的电流总谐波畸变率分别减少了70%和44%,同时滑模抖振得到了有效地抑制。测试结果证明了所提控制方法的强抗负载扰动能力和良好的滤波电容参数鲁棒性。

基于PWM软开关技术的智能充电机的设计与实现

针对由工频变压器和整流电路组成的传统充电机存在体积大、不便运输、可靠性差等缺陷,采用无工频变压器开关电源技术,按照蓄电池充电特性曲线特点,采用恒流-恒压(CC-CV)充电法,进行系统方案及主电路设计,并使用整流—Buck降压斩波模式和PWM软开关技术控制充电机电路。实验表明,与工频型充电机相比,该方法能显著延长蓄电池使用寿命。

基于三矢量的PWM整流器改进模型预测直接功率控制方法

为解决传统模型预测直接功率控制存在的开关频率不恒定、计算量大、共模电压大问题,设计了一种三矢量模型预测直接功率控制方法。该方法通过在单个控制周期内输出三个不同电压矢量,克服了传统方法因连续多个周期输出相同电压矢量造成的开关频率不恒定问题;同时,在两相静止坐标系中,通过优化空间电压矢量图划分方法,采用两个代价函数确定电网电压矢量所在扇区,将算法的遍历次数从27次降至10次,克服了传统方法计算量大的问题;此外,通过去除两个冗余零矢量PPP与NNN,将共模电压抑制在Udc/3以内。最后搭建了5kW实验样机进行实验验证,仿真与实验结果表明,该方法可以有效降低计算量,输出谐波和共模电压抑制效果优于传统方法。

DESIGN OF TERNARY CURRENT-MODE CMOS CIRCUITS BASED ON SWITCH-SIGNAL THEORY

By applying switch-signal theory, the interaction between MOS transmission switch-ing transistor and current signal in current-mode CMOS circuits is analyzed, and the theory oftransmission current-switches which is suitable to current-mode CMOS circuits is proposed. Thecircuits, such as ternary full-adder etc., designed by using this theory have simpler circuit struc-tures and correct logic functions. It is confirmed that this theory is efficient in guiding the logicdesign of current-mode CMOS circuits at switch level.

一种基于离散时域模型的单相PWM整流器控制参数多目标优化设计方法

单相PWM整流器一般采用电压外环比例积分、电流内环比例谐振的双闭环控制方法,在实现交流侧高功率因数的同时稳定直流侧输出电压,因此受到国内外学者的广泛研究。然而,在内外环控制参数设计阶段,传统设计方法一般根据经验选取控制参数,参数选取范围较大,且无法量化评估控制参数的时域控制效果,导致参数优化整定困难。为此,该文提出一种基于离散时域模型的内外环控制参数多目标优化设计方法。首先,采用传统设计方法确定电压外环比例、积分控制参数以及电流内环比例、谐振控制参数的安全设计空间;然后,基于离散时域模型将安全设计空间正映射至控制参数的时域性能空间,实现电流内环控制参数对交流侧功率因数以及电压外环控制参数对直流侧电压超调量的量化评估。在此基础上,通过进一步约束性能目标得到性能优化设计空间,考虑内外环控制参数的耦合效应,对内外环性能优化设计空间进行重新组合,再将其映射至性能空间,得到内外环控制目标帕累托最优前沿下的最优设计空间,从中选取内外环控制参数的优化设计点,在典型工况下实验测得的交流侧功率因数为0.981 26,直流输出电压超调量绝对值为1.37%,证明了所提优化设计方法的正确性。

三相PWM整流器离散空间矢量无模型预测电流控制策略

针对PWM整流器模型预测控制对系数参数准确性高度依赖的问题,提出一种基于离散空间矢量的无模型预测电流控制(MFPCC)策略。该策略通过矢量合成,在每个控制周期应用两个基本矢量,提高了预测电流的准确性;通过峰谷采样,分别测量并存储上一控制周期两个基本矢量作用下的电流梯度;并建立电流梯度方程,从而根据应用矢量的电流梯度进一步更新剩余6个未应用矢量的电流梯度,结合当前时刻的电流采样值,实现未来时刻的电流预测,得到下一时刻最优的虚拟矢量。该方法不依赖于任何系统参数,且消除了传统MFPCC策略中电流梯度更新停滞现象,降低了输出电流谐波。最后,通过实验和仿真验证了所提方法的有效性和优越性。

A Synthesis of Electronically Controllable Current-Mode PI, PD and PID Controllers Employing CCCDBAs

This paper presents a synthesis of current-mode PI, PD and PID controllers employing current controlled current differential buffer amplifiers (CCCDBAs). The features of these controllers are that: the output parameters can be electronically/independently controlled by adjusting corresponding bias currents in the proportional, integral, and deviation controllers;circuit description of the PID controller is simply formulated, it consists of four CCCDBAs cooperating with two grounded capacitors, and PI and PD controllers are composed of three CCCCDBAs and a grounded capacitor. Without any external resistor, the proposed circuits are very suitable to develop into integrated circuit architecture. The given results from the PSpice simulation agree well with the theoretical anticipation. The approximate power consumption in a closed loop control system consisting of the PI, PD and PID controller with low-pass filter passive plant are 4.03 mW, 4.85 mW and 5.71 mW, respectively, at ±1.5 V power supply voltages.

Electronically Controllable Fully-Uncoupled Explicit Current-Mode Quadrature Oscillator Using VDTAs and Grounded Capacitors

An electronically controllable fully uncoupled explicit current-mode quadrature oscillator employing Voltage Differencing Transconductance Amplifiers (VDTAs) as active elements has been presented. The proposed configuration employs two VDTAs along with grounded capacitors and offers the following advantageous features 1) fully and electronically independent control of condition of oscillation (CO) and frequency of oscillation (FO);2) explicit current-mode quadrature oscillations;and 3) low active and passive sensitivities. The workability of proposed configuration has been demonstrated by PSPICE simulations with TSMC CMOS 0.18 μm process parameters.

双闭环控制的三相电压型PWM整流器的研究

针对传统的不控整流电路中网侧电流谐波很大、晶闸管相控整流电路中深控时网侧功率因数低和闭环控制时动态响应慢等问题,设计出一种引入脉冲宽度调制技术的三相电压型整流器。在完成三相电压型整流器的电压外环电流内环的双闭环控制系统设计的基础上,对其进行了仿真实验。仿真结果表明,与不控或相控整流电路相比,该三相电压型PWM整流电路中,不仅输入电流的谐波大大减小,电能可双向流动,能够实现整流和逆变状态下的单位功率因数运行,还可较好地抑制负载突变时直流侧电压的波动,从而显著提高系统的抗扰能力,真正实现绿色环保和高效节能的高度结合。

An Active-Only Temperature-Insensitive Current-Mode Biquad Filter Based on Differentiator Structures Employing CCCCTAs

This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.

Universal Current-Controlled Current-Mode Biquad Filter Employing MO-CCCCTAs and Grounded Capacitors

This paper presents a universal current-controlled current-mode biquad filter employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs). The proposed filter employs only three MO- CCCCTAs and two grounded capacitors. The proposed filter can simultaneously realize low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) responses in current form by choosing appropriate current output branches. In addition, the pole frequency and quality factor of the proposed filter circuit can be tuned independently and electronically over the wide range by adjusting the external bias currents. The circuit possesses low active and passive sensitivity performance. The validity of proposed filter is verified through PSPICE simulations.

Voltage/Current-Mode Multifunction Filters Using One Current Feedback Amplifier and Grounded Capacitors

One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.

多相直线感应电机PWM谐波电流计算及分析

PWM谐波电流是引起电机高频振动的主要原因,准确且快速的PWM谐波电流计算是分析电机高频振动的关键。为此,针对直线感应电机电磁场特性,提出了多相直线感应电机PWM谐波电流解析计算方法。首先,根据直线感应电机在高频激励下的电磁场特性建立高频等效电路拓扑;其次,建立直线感应电机的二维电磁场模型,并基于能量法计算高频等效电路参数;再次,分析了PWM谐波电流与绕组电流相位、谐波电流阶次以及谐波电流频率之间的关系;最后,基于静态堵驻实验,验证了计算方法及结论的正确性。相比于有限元方法,该方法极大地减小了时间成本,适用于电机优化设计阶段,且同样适用于旋转电机。

三相电压型PWM整流器的虚拟转矩冲量平衡控制策略

模型预测控制具有结构简单、鲁棒性强和动静态性能良好等优点,因此其在三相电压型PWM整流器系统中得到了广泛应用。然而,模型预测控制的电压外环采用PI线性调节器进行调节,影响了直流侧电压的动态性能。为此提出了虚拟转矩冲量平衡控制策略,从而使直流侧电压仅经过1次调节即可实现快速收敛。为了实现此策略,首先,根据数学模型推导得到了虚拟转矩的表达式;其次,根据负载突变前、后直流侧输出电压保持不变,同时结合功率守恒原则,分析建立了负载突变时的虚拟转矩冲量平衡控制方程,求得零矢量与前进矢量的作用时间;最后,通过仿真和实验实现了三相电压型PWM整流器系统负载突变时的虚拟转矩冲量平衡控制,验证了所提算法的正确性与有效性。

Inductor Current Sampled Feedback Control of Chaos in Current-Mode Boost Converter

A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique.The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system.The stability criterion,feedback gain,and corresponding critical duty ratio are obtained from the eigenvalue of the map.The simulation results verify the t heoretical analysis results of the control strategy.