基于諧波等值電路的兩級式DC/DC變換器建模方法研究
王建宇1，徐修華2，李晗3
（1 江蘇句容抽水蓄能有限公司, 江蘇 句容 212416；2 國網浙江寧波市奉化區供電有限公司，浙江 寧波 315500；
3 國網江蘇省電力有限公司徐州供電分公司，江蘇 徐州 221006）
摘 要：采用諧波狀態空間法對兩級式DC/DC變換器建模時，狀態變量的增加使系統變得復雜，斬波子模塊間開關頻率的不同導致模型基頻不確定，系統諧波狀態描述難以獲得。基于時變周期系統理論和狄利克雷條件，建立了各子模塊的諧波狀態空間模型，繪制了各子模塊的諧波等值電路圖；根據基爾霍夫定律，得到了整個系統的諧波；用諧波阻抗代替周期性開關行為簡化了電路；提出了多開關頻率背景下諧波狀態方程基頻的確定方法，在簡化等值電路的基礎上推導了兩級DC/DC變換器的諧波狀態空間模型。仿真結果表明，等值電路引入的諧波狀態空間模型具有較高的精度，在以直流配電網為背景的多級DC/DC變換器頻率耦合研究中具有較高的應用價值。
關鍵詞：諧波狀態空間；時變周期系統；諧波等值電路；多開關頻率
中圖分類號：TM46 文獻標識碼：A 文章編號：1007-3175(2021)03-0013-07
Two-Stage DC/DC Converter Modeling Method Based on Harmonic Equivalent Circuit
WANG Jian-yu1, XU Xiu-hua2, LI Han3
（1 Jiangsu Jurong Pumped Storage Co., Ltd, Jurong 212416, China;
2 Fenghua Power Supply Company, State Grid Zhejiang Electric Power Company, Ningbo 315500, China;
3 State Grid Jiangsu Electric Power Co., Ltd Xuzhou Power Supply Company, Xuzhou 221006, China）
Abstract: When the two-stage DC/DC converter is modeled by the harmonic state space method, the harmonic state equation cannot be written due to the complicated system operation and the increase of state variables. The different switching frequencies between the chopping sub-modules lead to the model fundamental frequency unconfirmed. Based on the time-varying periodic system theory and the Dirichlet condition, the harmonic state space model of the sub-module is established, and the harmonic equivalent circuit of each sub-module is drawn. According to Kirchhoff 's law, the harmonics of the whole system are obtained. The circuit is simplified by using harmonic impedance instead of periodic switching behavior. Finally, the fundamental frequency determination method of harmonic state equation in multi-switching frequency background is proposed. The harmonic state space model of two-stage DC/DC converter is derived based on the simplified circuit. The simulation results show that the harmonic state space model introduced by the simplified equivalent circuit has higher accuracy and has higher value in the study of the frequency coupling of multi-stage DC/DC converters with DC distribution network as background.
Key words: harmonic state space; time-varying periodic system; harmonic equivalent circuit; multi-switching frequency
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