Control art of switching converters
Control art of switching converters
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DOI：
10.7907/tqg2-gk48
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发表时间：
1991
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影响因子：
--
通讯作者：
K. Smedley
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文献类型：
--
作者：
K. Smedley
切换流图模型：开关流图是一个统一的图形模型的大信号，小信号和稳态行为的脉宽调制（PWM）开关变换器。在流图中引入开关支路来表示PWM开关变换器的开关。开关流图模型很容易推导，它提供了一个直观的物理理解开关转换器系统。小信号开关流图生成解析传递函数，大信号开关流图与TUTSIM仿真程序兼容。PWM开关变换器的开关流图揭示了一种规律性的模式，它们预测了右半平面（RHP）零点，这是由占空比控制信号对开关变换器输出的不平衡影响引起的。标准的阻尼电路，能够消除RHP零的设计。推导了电流模式控制开关变换器的一般模型。此外，还对大信号模型和小信号模型进行了实验验证。单周期控制技术：单周期控制技术被设想为在真实的时间中控制开关的占空比d，使得在每个周期中，开关输出处的斩波波形的平均值精确地等于控制参考。实现电路中发现任何类型的开关，恒定频率，恒定的ON时间，恒定的OFF时间，和变量。单周期控制完全抑制输入信号，并线性地全部通过控制信号。该技术将非线性开关转换为线性开关。实验进行了使用单周期控制技术的降压转换器和Cuk转换器。单周期控制被发现拒绝输入扰动和输入滤波器动态。单周期控制转换器的二极管电压在一个周期内瞬时跟随控制参考。单周期控制利用开关转换器的脉冲和非线性特性来实现二极管电压平均值的瞬时控制。该技术适用于PWM开关变换器和准谐振变换器的大信号控制。
Switching Flow-Graph Model: The Switching Flow-Graph is a unified graphical model of large-signal, small-signal and steady-state behavior of pulse-width-modulated (PWM) switching converters. Switching branches are introduced into the flow-graph to represent the switches of the PWM switching converters. The Switching Flow-Graph model is easy to derive, and it provides a visual physical understanding of switching converter systems. The small-signal Switching Flow-Graph generates analytical transfer functions and the large-signal Switching Flow-Graph is compatible with the TUTSIM simulation program. The Switching Flow-Graphs of PWM switching converters reveal a regular pattern, and they predict right-half-plane (RHP) zeros, caused by the imbalanced effects of the duty-ratio control signal on the output of the switching converters. Criteria are found for the design of damping circuits that are capable of eliminating RHP zeros. General models are derived for current-mode controlled switching converters. In addition, the large-signal model and the small-signal model are verified by experiments. One-Cycle Control Technique: The One-Cycle Control technique is conceived to control the duty-ratio d of the switch in real time such that in each cycle the average of the chopped waveform at the switch output is exactly equal to the control reference. Implementation circuits are found for any type of switch, constant frequency, constant ON-time, constant OFF-time, and variable. One-Cycle Control fully rejects the input signal, and linearly all passes the control signal. This technique turns a nonlinear switch into a linear one. Experiments were conducted using the One-Cycle Control technique on the buck converter and the Cuk converter. One-Cycle Control was found to reject input perturbations and input filter dynamics. The diode voltage of One-Cycle Controlled converters follows the control reference instantaneously in one cycle. One-Cycle Control takes advantage of the pulsed and nonlinear nature of switching converters to achieve instantaneous control of the average value of the diode voltage. This technique is suitable for large-signal control of PWM switching converters and quasi-resonant converters.