At light load, the efficiency of LCC resonant converters decreases dramatically. The burst mode is a good choice to improve it. However, the burst frequency is changing at different loads, and the audible noise is unavoidable when the burst frequency enters into the audible range (20 Hz–20 kHz). In this article, according to the state trajectories of two steady-state modes, four different burst modes for LCC resonant converters based on trajectory control are proposed, which cover different power ranges. Then, the proposed state trajectories of four burst modes are described, and the width of burst on pulses is derived accordingly. By switching to different burst modes under different loads, the proposed adaptive burst mode can cover a much wider load range free of audible noise. Finally, to verify the proposed adaptive burst mode, an LCC converter prototype is constructed, which shows that the burst frequency keeps above audible range from 0.2% to 20% full load with efficiency improved.

中文翻译：

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降低可听噪声的 LCC 谐振转换器的自适应突发模式


在轻负载时，LCC 谐振转换器的效率急剧下降。突发模式是改进它的一个不错的选择。然而，突发频率在不同负载下是变化的，当突发频率进入可听范围（20 Hz-20 kHz）时，可听噪声是不可避免的。本文根据两种稳态模式的状态轨迹，提出了基于轨迹控制的LCC谐振变换器的四种不同的突发模式，覆盖了不同的功率范围。然后，描述了四种突发模式的所提出的状态轨迹，并相应地推导了脉冲上的突发宽度。通过在不同负载下切换到不同的突发模式，所提出的自适应突发模式可以覆盖更宽的负载范围，而不会产生可闻噪声。最后，为了验证所提出的自适应突发模式，构建了 LCC 转换器原型，结果表明突发频率在 0.2% 至 20% 满载的情况下保持在可听范围以上，并且效率有所提高。