In power electronics, the modular multilevel converter (MMC) is an easily scalable topology with an high output voltage quality. It is suitable for the transmission of large amounts of electrical power over long distances, which supports the realization of the ongoing energy transition. State-of-the-art methods require a comparatively large total cell capacitance in the system for energy pulsations during operation. In the present paper, in order to minimize this total capacitance, first a new method is developed to model the system, and second, by help of this model, optimal current trajectories are calculated. These currents are used for control to reduce the energy pulsation over the complete operating range, and thus, to better utilize the hardware. The new method independent on the Clarke transformations is implemented on a laboratory scale setup, and measurement results are presented which validate the new method. Furthermore, the new method is compared to the state-of-the-art method of the compensation of the 2nd harmonic and outperforms the latter significantly. This applies to the entire operating range for different power factors. A total reduction of up to 44% of the energy pulsations is achieved.

中文翻译：

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利用优化的电流轨迹减少模块化多电平转换器中的能量脉动

在电力电子领域，模块化多电平转换器（MMC）是一种易于扩展的拓扑，具有较高的输出电压质量。它适合长距离传输大量电能，从而支持正在进行的能量转换。最新的方法需要系统中较大的总电池电容，以便在运行期间产生能量脉冲。在本文中，为了使总电容最小，首先开发了一种对系统进行建模的新方法，其次，借助该模型，可以计算出最佳电流轨迹。这些电流用于控制，以减少整个工作范围内的能量脉动，从而更好地利用硬件。独立于Clarke变换的新方法是在实验室规模的设备上实施的，并给出了可验证新方法的测量结果。此外，将新方法与补偿二次谐波的最新方法进行了比较，并且明显优于后者。这适用于不同功率因数的整个工作范围。总共可减少多达44％的能量脉动。