Fixed Frequency Voltage Doubling Type Wide Gain LLC Resonant Converter With Common Resonant Branches
郭泓展 1潘健 1熊嘉鑫2
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作者信息
1. 湖北工业大学电气与电子工程学院,湖北省武汉市 430068
2. 东南大学电气工程学院,江苏省 南京市 210096
折叠
摘要
宽增益和高性能是LLC谐振变换器应用于电动汽车、可再生能源系统等领域的关键,而传统变频控制下存在开关频率范围宽、电压调节性能差的问题.为此,基于倍压整流结构提出一种共谐振支路的改进型拓扑,设计了定频变占空比的调制策略.首先给出了变换器的拓扑介绍及工作原理;其次根据增益特性分析了电感比和品质因数对增益的影响,根据零电压导通(zero voltage conduction,ZVS)条件对参数进行了约束;最后比较了变换器性能.仿真及实验表明,该变换器可实现宽输出电压调节,具有良好的软开关性能.相比于传统变频控制,始终工作在最佳谐振频率点,电路中循环电流小.
Abstract
Wide gain and high performance are the keys for the LLC resonant converter applications in electric vehicles,renewable energy systems,etc.,while there are problems of wide switching frequency ranges and poor voltage regulation performances under the conventional pulse frequency modulation.To this end,an improved topology of the Common resonant branches is proposed based on the voltage doubling rectifier structure,and the fixed frequency variable duty ratio modulation strategy is designed.Firstly,the topology introduction and operating principle of the converter are given;secondly,the effects of the inductance ratio and quality factor on the gain are analyzed with the gain characteristics,and the parameters are constrained according to the ZVS condition;finally,the converter performance is compared with the conventional ones.Simulations and experiments show that the converter is able to achieve the wide output voltage regulation,haing good soft switching performance.Compared with conventional pulse frequency modulation,the proposed control here always works at the optimal resonant frequency point with the small circulating current in the circuit.
维普
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