根据半桥LLC谐振变换器的拓扑结构, 采用了一种混合控制方式, 整合了电荷控制和传统频率控制两种控制方式。与目前的电荷型控制、双频率控制等常用控制方式相比, 该控制方式增加的频率补偿斜坡, 使得补偿器的设计十分简单, 改进的线路瞬态性能可降低输出电容器值。根据基波分析法得到半桥LLC谐振变换器等效电路, 确定了直流增益与品质因数、归一化频率和谐振电感与励磁电感的比值之间的关系式, 并由该关系式设计出合适的谐振器件参数。通过混合控制方式与设计的LLC谐振参数搭建了一台5 kW/±85 V半桥LLC谐振变换器进行实验验证, 实验结果显示, 该样机动态特性良好, 能够得到稳定的输出电压和具有较高的传输效率, 验证了所采用的控制方法和基波分析法设计的LLC谐振参数的可行性。

A hybrid control method which integrates charge and frequency control methods is adopted based on half-bridge LLC resonant converter. Compared with the current control methods such as charge-type control, dual-frequency control, average current-mode control, PWM-PFM hybrid control and PLL control, this control method can improve the energy transmission efficiency, increase the frequency compensation slope, make the compensator design very simple, improve the transient performance of the line and reduce output capacitor value. According to the equivalent circuit of half-bridge LLC resonant converter obtained by fundamental wave analysis method, the relationship between DC gain and quality factor, normalized frequency resonance and the ratio of inductance to excitation inductance is determined, and appropriate resonant device parameters are designed. A 5 kW/±85 V half-bridge LLC resonant converter is built according to the hybrid control method and the designed LC resonant parameters. The experimental results show that the prototype has good dynamic characteristics and can obtain stable output voltage and high transmission efficiency. The feasibility of the control method and the design of LLC resonant parameters is verified.