基于直接移相角控制的移相全桥LLC变换器混合控制策略

Hybrid Control Strategy of Phase-Shifted Full-Bridge LLC Converter Based on Digital Direct Phase-Shift Control

基于移相全桥LLC(PSFB-LLC)变换器,提出一种数字式直接相移控制(DDPSC)方法,并将该方法与传统线性控制相结合,提出一种混合控制策略。该控制策略结合了线性控制和DDPSC控制的优点,易于实现,动态响应快。PSFB-LLC电路结构简单并且工作在定频模式下,在全负载范围内能够实现开关管的零电压开关(ZVS)和整流二极管的零电流开关(ZCS)。该文对PSFB-LLC变换器谐振腔进行了详细分析,基于相平面分析和时域模型求解给出了混合控制策略的具体实现方案,并研制了一台3 kW的原理样机,通过实验结果验证了DDPSC控制器及混合策略的可行性和有效性。

A digital direct phase shift control(DDPSC)method is presented based on phase-shifted full-bridge LLC(PSFB-LLC)converter.This paper combines the presented method with the conventional linear control to obtain a hybrid control strategy.The strategy has both the advantages of linear control and DDPSC control.It is not only easy to realize but also has quick dynamic responses.The PSFB-LLC circuit structure is simple and it works in fixed frequency mode;it can realize the ZVS of the switch tube and the ZCS of the rectifier diode in wide load range.In this paper,the PSFB-LLC converter resonator is analyzed in detail;the concrete realization scheme of the hybrid control strategy is given by analyzing the phase plane and the time domain model;a 3kW principle prototype is finally developed;the feasibility and effectiveness of DDPSC controller and hybrid strategy are verified by experimental results.