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1.
This paper presents a novel average current mode control (ACC) strategy for the control of pulse width modulated (PWM) DC-DC converters, which represents a drastic improvement over conventional ACC. This new method consists of the addition of an auxiliary controller into the control loop, besides the current and voltage regulators. The model-based auxiliary controller can increase the closed loop small-signal bandwidth of Buck derived converters, preserving loop gain crossover frequency and stability margins over significant changes of the power stage passive elements values, the load and the line voltage. Moreover, this control scheme shows much better disturbance rejection properties, i.e., closed loop impedance and audiosusceptibility, than conventional ACC. From a control theory point of view, robust performance is achieved preserving stability. A Buck prototype has been experimentally tested with different LC output filters, line and load conditions, including discontinuous conduction mode. Measurements of the small signal frequency response of the converter have been carried out, showing the improvement achieved by the proposed control scheme. The empirical large signal response of the converter under load steps is also shown in order to validate the concept 相似文献
2.
Based on a generalized state-space sampled data modeling, an iterative and efficient algorithm for deriving the small signal transfer functions of any DC-DC power converter is proposed. This algorithm is suitable to be implemented in a software program as an analytical tool for automated control analysis of general DC-DC power converters. Such a tool would reduce considerably the time needed by research engineers in modeling existing and new topologies and control methods. The algorithm proposed is applicable to different kinds of linear and nonlinear control methods. It has been verified on different power converters and control methods 相似文献
3.
An H-bridge transistorized converter intended for front-end power conversion at a high power-factor and a constant desired output voltage has been analyzed. The state-space model of the H-bridge converter controlled by the bipolar pulse width modulated (PWM) technique is described and the expressions for the equilibrium points of operation of the state variables corresponding to the circuit parameters have been derived. The converter is intended for use as a voltage source feeding an inverter. Hence the requirement of maintaining a desired DC voltage at its output becomes necessary. Transient behavior of two control strategies have been tested to examine their performance in stabilising the converter at the desired operating state. Comparison of the two feedback strategies has been done by simulation studies and the one that was found superior has been experimentally implemented. The experimental implementation of the controller for the converter operation in the rectifier mode is also described. The experimental results obtained are presented and compared with simulation results to validate the controller's performance under transient conditions. 相似文献
4.
In this paper, a high switching frequency buck converter using insulated gate bipolar transistors (IGBTs) is presented. This was done by using an auxiliary branch made of an IGBT of the same type as the one used for the main switch and saturable inductors. The proposed topology allows both switches to be fully soft switched to keep the efficiency high over a wide load range. Because of its topology the open loop behavior of the converter can be unstable. A detailed small signal analysis is presented to explain this behavior and as a basis for the synthesis of a closed loop controller. Experimental measurements on a laboratory prototype demonstrated the accuracy of the small signal analysis and validated the operation of the auxiliary network. The resulting efficiency is around 92% over a 200 to 800W output power range and at a 80-kHz switching frequency 相似文献
5.
State-space models are derived for pulse-width-modulated (PWM) converters operating at constant switching frequency under current programmed control. One model neglects the sample-and-hold effect of the current loop and is therefore representative of the traditional approach to modeling current programmed converters. The order of the model is the same as that of the power stage. A second state-space model is derived which incorporates the sample-and-hold effect. The order of this model is two higher than that of the power stage. A comparison of the two models is made which clearly demonstrates the superiority of the second modeling approach. As the models are in state-space form they may be quite readily used in a CAD package for general converter analysis and design, to determine all transfer functions and associated pole/zero locations of interest 相似文献
6.
Several methods have been developed until today for the analysis of PWM converters operating in discontinuous conduction mode (DCM) and many endeavours have been done in order to solve two well known problems: the nontrivial calculation of the internally controlled instant at which the current flowing into the diode falls to zero and the subsequent order reduction of the state-space model of the circuit due to the disappearance of one state variable. In this work a new approach to the modeling of PWM converters for the large signal analysis in DCM operation is presented. It is based on a closed-form discrete-time state-space model obtained by introducing a time-adaptive function for the calculation of the instant at which the diode current falls to zero, and an equivalent fictitious configuration of the circuit during the idle phase, in order to prevent the unconditioned order reduction of the state-space model. A four-terminal device is also introduced which allows a unified representation of the PWM buck, boost, buck-boost, and Cuk converters in DCM operation using the fictitious configuration. The model proposed can be used for circuit oriented simulations both in open and closed loop operation and for an accurate ripple inspection, automatically accounting for DCM to CCM (continuous conduction mode) transitions and vice versa 相似文献
7.
带光耦双闭环反激式开关电源小信号模型分析 总被引:1,自引:0,他引:1
双闭环控制在开关电源中的应用非常普遍,是因为它使系统具有较好的动态性和稳定性。文章就是在双闭环控制的反激电路中,分析了反激变换器的功率级电路的平均模型和控制电路中TL431和光耦器件的非理想模型;运用控制理论写出整个变换器系统闭环的环增益,并且用网络分析仪测出系统环增益,结果表明系统具有良好的稳定性和动态性。 相似文献
8.
混合动力船舶双向DC-DC变换器的研究与设计 总被引:1,自引:0,他引:1
针对全桥双向DC-DC变换器Buck和Boost两种模式参数设计要求不同的问题,提出了一种"占空比-变压器-电感"匹配设计法。对全桥双向DC-DC变换器的两种工作模式分别进行建模,设计了闭环控制系统,Buck模式的闭环控制系统保证了动力电池恒压充电;Boost模式的闭环控制系统保证了母线电压恒定。根据混合动力船舶的特点设计了双向DCDC变换器,仿真实验验证了所设计的双向DC-DC变换器控制系统和控制策略的正确性,保证了分别处于两种工作模式时输出端电压稳定。 相似文献
9.
In this paper, a detailed modelling and analysis of a switched inductor (SI)-based improved single-ended primary inductor converter (SEPIC) has been presented. To increase the gain of conventional SEPIC converter, input and output side inductors are replaced with SI structures. Design and stability analysis for continuous conduction mode operation of the proposed SI-SEPIC converter has also been presented in this paper. State space averaging technique is used to model the converter and carry out the stability analysis. Performance and stability analysis of closed loop configuration is predicted by observing the open loop behaviour using Nyquist diagram and Nichols chart. System was found to stable and critically damped. 相似文献
10.
11.
提出了一种基于电网电压补偿的多电平变频器控制方法,从主回路拓扑结构出发,以低压变频器规则采样法为基本理论,详细介绍了适合于多电平变频器控制的理论分析和算法推导过程。并给出了适合数字信号处理的采样原理和采样时序。直接根据电网电压的变化,实时调节输出电压,能获得与闭环系统相媲美的理想机械特性和运行效果。该方法不仅具有计算步骤简单、输出SPWM对称性好、精度高和控制方便的特点,而且适用于任何电平数目及拓扑结构。试验结果表明,和其他多电平控制方法相比,使用效果好,有很高的利用价值。 相似文献
12.
《Power Electronics, IEEE Transactions on》2009,24(8):2000-2012
13.
Comprehensive analyses for the buck-boost, pulse width modulation DC/DC converters applying peak current current-mode control are given. The analysis provides closed-form solutions for steady-state output, small-signal loop gain, and conducted susceptibility. It also proves that the state-space averaged model developed for converter using a single-loop voltage-mode control is valid for a current-mode-controlled converter. 相似文献
14.
This paper presents the analysis and design of a multiple feedback loop control scheme for single-phase voltage-source uninterruptible power supply (UPS) inverters with an L-C filter. The control scheme is based on sensing the current in the capacitor of the load filter and using it in an inner feedback loop. An outer voltage feedback loop is also incorporated to ensure that the load voltage is sinusoidal and well regulated. A general state-space averaged model of the UPS system is first derived and used to establish the steady-steady quiescent point. A linearized small signal dynamic model is then developed from the system general model using perturbation and small-signal approximation. The linearized system model is employed to examine the incremental dynamics of the power circuit and select appropriate feedback variables for stable operation of the closed-loop UPS system. Experimental verification of a laboratory model of the UPS system under the proposed closed-loop operation is provided for both linear and nonlinear loads. It is shown that the control scheme offers improved performance measures over existing schemes, It is simple to implement and capable of producing nearly perfect sinusoidal load voltage waveform at moderate switching frequency and reasonable size of filter parameters. Furthermore, the scheme has excellent dynamic response and high voltage utilization of the DC source 相似文献
15.
Byeong-Rim Jo Hee-Wook Ahn Gun-Woo Moon Hyun-Chil Choi Myung-Joong Youn 《Power Electronics, IEEE Transactions on》1996,11(1):147-161
A new output voltage control technique is proposed to obtain the improved buck-boost operation of the quantum series resonant power converter (QSRC). The new nonlinear dynamic model of QSRC is first derived and the cross-coupled nonlinear term existing in the output voltage dynamics is decoupled by using control methods such as the periodic control of the boosting switch (PCBS) and the resonant current control (RCC). By applying the state-space averaging concept to the decoupled dynamics, two linear large signal averaged models are obtained for PCBS and RCC schemes. Using the proposed technique, the flux imbalance problem of the isolation transformer and the robustness of the output voltage response can be easily considered. This technique can also be widely applicable to the cascade buck-boost power converter, which can be implemented by inserting a boosting switch between the output filter inductor and the ripple capacitor of the forward power converter. The validity of the proposed scheme is confirmed by the computer simulations and the experiments 相似文献
16.
为满足大型激光陀螺仪(ring laser gyroscope, RLG)中激光器激励源输出高精度、高稳定度的要求,针对单端反激变换器输出性能较差的问题,本文在传统反激变换器的输出端增加电感、电容元件,构成了输出带电容-电感-电容(capacitor inductor capacitor, CLC)滤波的单端反激变换器。在此基础上,采用开关元件平均模型法确定该变换器的静态工作点,建立电流连续模式(continuous conduction mode, CCM)下的四阶小信号模型;推导出相关传递函数,并引入相位超前校正环节以提高系统的稳定性;借助MATLAB软件构建比例-积分-微分(proportion-integral-differential, PID)控制的系统模型,完成了对带CLC滤波的反激变换器的分析与验证。结果表明,利用小信号建模理论建立的变换器模型是合理的,对激光器激励源的优化设计有参考意义。 相似文献
17.
A current-mode control power convertor model that is accurate at frequencies from DC to half the switching frequency is described for constant-frequency operation. Using a simple pole-zero transfer function, the model is able to predict subharmonic oscillation without the need for discrete-time z -transform models. The accuracy of sampled-data modeling is incorporated into the model by a second-order representation of the sampled-data transfer function which is valid up to half the switching frequency. Predictions of current loop gain; control-to-output; output impedance; and audio susceptibility transfer functions were confirmed with measurements on a buck converter. The audio susceptibility of the buck converter can be nulled with the appropriate value of external ramp. The modeling concentrates on constant-frequency pulse-width modulation (PWM) converters, but the methods can be applied to variable-frequency control and discontinuous conduction mode 相似文献
18.
分析了Sepic和Flyback拓扑结构,根据DC/DC模块电源对辅助电源的需求,提出了Sepic和Flyback混合拓扑的辅助电源,能够输出多路不同幅值电压,并且可以实现各路输出电压之间的隔离。利用状态空间平均法建立了Sepic拓扑的小信号模型,设计了电压和电流双环控制的补偿器,并用Matlab仿真软件进行了分析。该辅助电源应用于一款非隔离的宽范围输入且输出可调的DC/DC模块电源,实现了三路互相隔离的12 V输出电压,一路非隔离的6 V输出电压,输出电压波形稳定,能够满足隔离悬浮供电,也能满足不同芯片对电压范围的要求。 相似文献
19.
This paper presents a high-performance DC-DC switching mode power supply designed to deliver a regulated 0-50 V/0-10 A output. The proposed power supply is based on a modified version of the zero-voltage switching (ZVS) full-bridge (FB) phase-shift DC-DC converter, which incorporates commutation auxiliary inductors to provide ZVS for the entire load range as well as a commutation aid circuit to clamp the output diode voltage. The control strategy is based on two control loops operating in cascade mode. The inner loop maintains a regulated output current, whereas the external voltage loop regulates the output voltage, independently of load and input-voltage changes. In order to obtain a high-reliability converter, the control circuit has been implemented using just two integrated circuits (ICs). The phase-shift regulator UC3875 IC generates the gate drive signal to the MOSFET's. The control loop regulators are implemented using the TL074 IC. A theoretical analysis was conducted, and experimental results were obtained for a 0-50 V/0-10 A power supply operating at 100 kHz 相似文献
20.
《Power Electronics, IEEE Transactions on》2008,23(5):2310-2318