具有快速负载动态响应的DC／DC开关变换器开环控制新策略

采用何种控制策略和如何实现控制方法是决定开关变换器的效率和性能的主要因素。单周控制方法是近年来提出的一种新型非线性控制策略。这对输入电源电压的变化具有快速的动态跟踪能力，但对负载变化的抑制能力差，基于等效受控源平均法，提出了一种新的非线性控制方法，使得PWM开关变换器的输出电压，在负载干扰和电源电压干扰下，具有优良的动态响应特性。以降压型变换器为例，首先建立开关变换器大信号低频平均电路模型。通过分析平均电路模型，可以推导出一种新型开环非线性控制策略。这种控制方法具有固有的稳定性，快速动态响应和无过冲等优点。为了实现新的控制方法，建立了电感电压低频分量的数学模型。计算机仿真和实验测试结果证明理论预期分析。

A NEW OPEN-LOOP CONTROL STRATEGY FOR A DC-DC SWITCHING CONVERTER WITH FAST LOAD TRANSIENT RESPONSE

Generally,the key determining the converter's performances is what control strategy is selected and how to implement the control law.The one cycle control method proposed in recently year is a kind of nonlinear control strategy which possesses fast response on line voltage vary and can eliminate the effect on the output voltage due to the disturbance of the line voltage.But the drawback of this control method is that it possesses slow response on load vary.A new open\|loop nonlinear control strategy based on equivalent controlled source average method is proposed in this paper.The new open loop contrl method can eliminate the effect on the output voltage of PWM dc/dc converters dur to the large and small signal disturbances of the line voltage and the load.The buck circuit was taken as a example to explain the new control method.First,the average large signal low frequency circuit model is set up.the new open loop nonlinear control strategy is constructed by analysis the average buck circuit model.It was found that the new open loop control method can eliminate the effect on the output voltage due to the large and small signal disturbance of the load.The control method can get the excellent performances,inherent stability,fast response and no overshoot.In order to realize the control method,the mathematical model of inductor voltage low frequency content is set up.Computer simulation and experimental verification of the described control strategy was performed.