In recent years, significant research and adoption of periodic variable switching frequency PWM (P-VSFPWM) have been observed in AC/DC voltage source converters (VSCs). This technique aims to reduce ripple in AC inductor current and DC capacitor voltage, suppress injected current harmonic amplitudes for EMC compliance, and minimize switching losses. However, the presence of overlapped harmonic spectra from different switching harmonic bands can lead to heightened harmonic magnitudes due to the wide frequency variation, necessitating additional filtering measures. Surprisingly, there is notable absence of harmonic spectra analysis under P-VSFPWM, despite the growing concern over supra-harmonics (2-150 kHz) emission injected to the grid from the electric vehicle (EV) chargers. To address this gap, this paper proposes the interleaved P-VSFPWM to mitigate harmonics overlap without deviating from the intended purpose of P-VSFPWM. A fast-acquisition supra-harmonics model under arbitrary P-VSFPWM has been proposed based on vectorization, facilitating the subsequent filter design process. Furthermore, this study identifies the optimal P-VSFPWM profile with minimal required filtering inductance based on the spectra analysis. These findings are verified by PLECS simulations and experimental results.

中文翻译：

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电动汽车充电器中带简化滤波器的三相有源前端变换器的频率设计


近年来，在 AC/DC 电压源转换器 (VSC) 中，周期性可变开关频率 PWM (P-VSFPWM) 的研究和采用得到了广泛关注。该技术旨在减少交流电感器电流和直流电容器电压中的纹波，抑制注入电流谐波幅度以实现 EMC 合规性，并最大限度地减少开关损耗。然而，由于频率变化较大，来自不同开关谐波频带的重叠谐波频谱的存在可能导致谐波幅度增大，从而需要额外的滤波措施。令人惊讶的是，尽管人们越来越关注从电动汽车 (EV) 充电器注入电网的超谐波 (2-150 kHz) 发射，但 P-VSFPWM 下明显缺乏谐波频谱分析。为了解决这一问题，本文提出了交错式 P-VSFPWM 来减轻谐波重叠，同时又不偏离 P-VSFPWM 的预期目的。提出了一种基于矢量化的快速采集任意P-VSFPWM下的超谐波模型，方便了后续的滤波器设计过程。此外，本研究根据频谱分析确定了具有最小所需滤波电感的最佳 P-VSFPWM 曲线。这些发现得到了 PLECS 模拟和实验结果的验证。