级联式双向DC-DC变换器的模型预测控制

Model Predictive Control Method for Cascaded Bi-Directional DC-DC Converter

级联式双向DC-DC变换器具有结构简单、功率密度高且适用于大变比变换场合等优点,但其传统的双闭环控制方法中,控制结构复杂,PI参数设置困难。据此引入模型预测控制(MPC)思想对级联式双向DC-DC变换器进行控制。模型预测控制具有控制思想简单、易于包含系统的约束条件及控制器易于实现等优点,该控制策略包括建立变换器模型和其可能的开关状态、定义代价函数两个步骤。本文对级联式双向DC-DC变换器的模型预测控制进行仿真分析和实验验证。同时,将其与传统双闭环控制方法进行实验对比,实验结果显示,模型预测控制方法能够使母线电压准确追踪给定值,与传统双闭环控制相比,动态过程中母线电压的超调减小6.25%左右,变换器的动态响应时间减少0.3s。由此证明所提出模型预测控制方法的可行性及有效性。

The cascaded bidirectional DC-DC converter has the advantages of simple structure, high power density, suitable for the higher ratio conversion applications, et al. However, conventional double closed-loop control method has the shortcomings of complicated control structure, difficult PI parameter selection. Accordingly, the model predictive control （MPC） is introduced in this paper. Model predictive control has many advantages, such as simple control concept, easy to contain constraints, easy to imply its controller and so on. Establishing converter models and its possible switching states and defining the cost function are included into this control strategy. In this paper, simulation and experimental verification of model predictive control are carried out and MPC method is compared with conventional double closed-loop method. The experimental results show that MPC can make the voltage of DC bus track the given value accurately. Compared to conventional double closed-loop control method, the overshoot of DC bus voltage in dynamic process can reduce 62.5% and the dynamic response time of converter can reduce 0.3s. Therefore, the feasibility and effectiveness of MPC method are proved.