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电流滞环Buck DC-DC变换器控制策略具有良好的稳态控制和快响应的优点,并适合于进行智能并联均流控制[1]。但是,如果稳态过程和负载突变的动态过程用相同的控制策略,实验结果出现暂态恢复时间过长,输出电压不能恢复到期望值等问题[2-3],所以要对动态过程的控制加以改进。
目前,DC-DC变换器的动态过程控制取得了很大进展,主要有用电压控制和基于电容电荷平衡控制相结合的控制方式[4-5],基于最优负载特性控制[6],基于具有全局寻优的遗传算法的最优PID控制[7],基于数字预测控制方法的模糊PID控制[8],基于PWM/PSM相结字预测控制方法的模糊PID控制[8],基于PWM/PSM相结合模式控制[9],以及基于全局滑膜控制器实现全局切换函数的控制[10],都有效改善了电压模式控制在负载突变的暂态中响应时间长及超调大的问题。
上述控制方法主要通过电压误差或电压滞环控制来改善负载突变动态特性。本文为了保留电流滞环控制的优越性,针对动态响应过程中存在的不足,分析实际负载突变过程应有的情形,建立动态响应过程的数学模型,提出相应的与电流滞环控制相结合的动态过程控制策略。
Improvement to Digital Current Following Control Strategy in Buck DC-DC Converter
doi: 10.3969/j.issn.1001-0548.2017.06.003
- Received Date: 2016-09-24
- Rev Recd Date: 2017-06-07
- Publish Date: 2017-11-30
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Key words:
- Buck DC-DC converter /
- current following control /
- dynamic response /
- load changes
Abstract: Based on the existing control strategy and experimental result of the digital current following controlling Buck DC-DC converter, the reasons why load chances the dynamic response time is long and the output voltage can not recover expected value are analyzed, and an improved control strategy is proposed. Based on the existing control strategy, the improved control strategy adds the detection of the load changes process. If the load changes occur, the new control strategy is switched automatically. According to the shock loading and unloading, the mathematical models of the changes are established respectively, the corresponding control strategies are designed, and the hardware test results are given. The experimental results show that the proposed control strategy is correct and feasible in steady state control and dynamic process control. On the basis of ensuring the output voltage accuracy in steady state, the dynamic performance of the converter is improved.
Citation: | CHENG Hong-li, JIA Long-fei. Improvement to Digital Current Following Control Strategy in Buck DC-DC Converter[J]. Journal of University of Electronic Science and Technology of China, 2017, 46(6): 812-818. doi: 10.3969/j.issn.1001-0548.2017.06.003 |