基于占空比动态分配控制的 并联交错CCM PFC变换器
A New Current-Sharing Controller for Parallel-Connected Interleaving CCM PFC Converter Based on a Duty-Cycle Dynamic Distribution Controller
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摘要: 为减小甚至消除均流过程对总输入电流及输出电压的扰动,以提高输入功率因数. 在平均电流控制策略的基础上,提出一种控制占空比在并联变换器内部动态分配的均流控制器,即只在并联变换器内部,根据其电流偏差程度进行占空比动态调节来实现均流. 同时,采用单DSP实现并联PFC变换器电感电流的均匀交错,以减小系统滤波器的体积和提高系统的效率. 以3个功率因数校正(PFC)变换器并联为例,利用提出的研究方案获得了良好的均流性能,并实现了并联PFC变换器电感电流的交错,减小了输入电流的高频纹波. 实验结果证明了该控制方案的正Abstract: A new current-sharing controller is proposed for parallel-connected PFC converters based on average-current control strategy, it can distribute the control duty-cycle automatically for each parallel-connected PFC converter to implement current balance by the difference from its reference current, and it should be emphasized that the proposed controller also can reduce and even eliminate the disturbance resulted by current-sharing process to total input current and output the voltage with higher input power factor. Moreover, the currents of parallel-connected converters are interleaved to diminish the size of system filter and increase conversion efficiency based on only a single DSP. Taking three parallel-connected PFC converters as an example, the controller addressed above is validated with experimental results in this paper, and it can achieve fine current-sharing performance and reduce the high-frequency ripple in total input current, so it can be a desirable digital solution for parallel-connected PFC converters in large power application.
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