Abstract：Operating on big signal condition, the work mode of DC-DC switching converter isn’t only one, so, a novel optimal control strategy based on the simplified unified discrete model is presented, which is easy to be realized adopting digital way for DC-DC converter operating in CCM and DCM. The power-exponent functions in model coefficient matrix are linearized to simplify the unified discrete model based on CCM and DCM. According to the voltage and current characteristics of simplified model, the objective function is designed. Optimal control strategy is deduced by substituting model states into objective function and minimizing the objective function. According to the recursion states and optimal control, the operation mode of simplified model is decided by itself and the output of model provides the optimization output track. For compensating the control error caused by parasitic parameters in actual converter system, the optimal control is modified according to the output error of actual system and model. In this paper, the simplified unified discrete model of Boost converter is founded, optimal control is obtained, and digital PI is adopted to adjust control error. Simulation and experimental results validate that the output voltage of converter can be controlled with fast response and without impulse voltage in starting period, and the output voltage of converter can be controlled accurately and quickly on various work conditions.
刘庆丰, 冷朝霞, 孙晋坤, 王华民. 基于简化统一模型的DC-DC开关变换器数字优化控制策略[J]. 电工技术学报, 2012, 27(6): 118-125.
Liu Qingfeng, Leng Zhaoxia, SunJinkun, Wang Huamin. A Novel Digital Optimal Control for DC-DC Converters Based on Simplified Unified Model. Transactions of China Electrotechnical Society, 2012, 27(6): 118-125.
[1] Guo L, Hung Y J, Nelms R M. Digital implementation of sliding mode fuzzy controllers for boost converters[C]. Proceedings of the IEEE Applied Power Electronics Conference and Exposition, 2006: 1424-1429. [2] Zhang W F, Feng G, Liu Y F. A direct duty cycle calculation algorithm for digital power factor correction(PFC) implementation[C]. Proceedings of the 35th Annual IEEE Power Electronics Specialists Conference, 2004: 2326-2332. [3] 马皓, 郎芸萍. 一种关于单相Boost功率因数校正器数字控制的改进算法[J]. 电工技术学报, 2006, 21(2): 83-87. Ma Hao, Lang Yunping. An Improved Algorithm for DSP Implementation of Boost PFC Converter[J]. Transactions of China Electrotechnical Society, 2006, 21(2): 83-87. [4] 彭力, 张凯, 康勇, 等. 数字控制PWM逆变器性能分析及改进[J]. 中国电机工程学报, 2006, 26(9): 65-70. Peng Li, Zhang Kai, Kang Yong, et al. Performance analysis and improvement of digital controlled PWM inverter[J]. Proceedings of the CSEE, 2006, 26(9): 65-70. [5] He D, Nelms R M. Fuzzy logic peak current-mode control for dc-dc converters using an inexpensive 8-bit microcontroller[C]. Proceedings of the Applied Power Electronics Conference and Exposition, 2005, 3: 2000 -2006. [6] Hsieh, Optimal C H Fuzzy-immune-PID controllers design of PWM DC-DC converters[C]. Proceedings of the Conference of the IEEE Fuzzy Information Processing Society, 2007: 123-128. [7] Lam H K, Lee T H, Leung F H F, et al. Fuzzy control of DC-DC switching converters: stability and robustness analysis[C]. Proceedings of the 27th Annual Conference of the IEEE Industrial Electronics Society, 2001, 2: 899-902. [8] S He Y, Luo F L Study of sliding mode control for DC-DC converters[C]. Proceedings of the International Conference on Power System Technology, 2004, 2: 1969-1974. [9] Guo L, Hung Y J, Nelms R M. Digital implementation of sliding mode fuzzy controllers for boost converters[C]. Proceedings of the IEEE Applied Power Electronics Conference and Exposition , 2006: 1424-1429. [10] Jaen C, Pou J, Pindado R, et al. Sliding mode controller applied to PWM DC-DC converters based on an averaged model[C]. Proceedings of the Compatibility in Power Electronics, 2007: 1-5. [11] 张波, 曲颖. Buck DC-DC 变换器分岔和混沌的精确离散模型及实验研究[J]. 中国电机工程学报, 2003, 23(12): 99-103. Zhang Bo, Qu Ying. Study on the Experiment and the precise discrete model of bifurcation and chaos for Buck DC-DC converter[J]. Proceedings of the CSEE, 2003, 23(12): 99-103. [12] 张波, 曲颖. 电压反馈型Boost变换器DCM的精确离散映射及其分岔和混沌现象[J]. 电工技术学报, 2002, 17(3): 43-47. Zhang Bo, Qu Ying. The precise discrete mapping of voltage-fed DCM boost converter and its bifurcation and chaos[J]. Transactions of China Electrotechnical Society, 2002, 17(3): 43-47. [13] 冷朝霞, 刘健, 刘庆丰, 等. 开关DC-DC变换器的统一离散模型[J]. 电工技术学报, 2009, 24(4): 114-120. Leng Zhaoxia, Liu Jian, Liu Qingfeng, et al. A unified discrete model of switching DC-DC converters[J]. Transactions of China Electrotechnical Society, 2009, 24(4): 114-120. [14] 郑大钟. 线性系统理论[M]. 北京: 清华大学出版社, 1990: 139. [15] 刘树林, 刘健, 杨银铃, 等. Boost变换器的能量传输模式及输出纹波电压分析[J]. 中国电机工程学报, 2006, 26(5): 119-124. Liu Shulin, Liu Jian, Yang Yinling, et al. Energy transmission modes and output ripple voltage of boost converters[J]. Proceedings of the CSEE, 2006, 26(5): 119-124. [16] 蔡宣三, 龚绍文. 高频功率电子学[M]. 北京: 科学出版社, 1993: 57.
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