Symmetry is not only used to simplify the analysis of three-phase electrical systems, but it is also used to define its voltages, currents and loads. When the loads are symmetrical, the currents of a three-phase AC system are expected to be symmetrical as well. Given the proper conditions, in converters such as the matrix converter (MC), the output voltages and currents are expected to be sinusoidal with periodic symmetry. However, in some cases this symmetry is broken so that, there appears nonlinear behaviors such as quasiperiodicity and so on. Based on simulations and experiments, this paper focuses on an analysis of a quasiperiodic behavior and the presence of a DC component in the output currents of a Venturini modulated MC. The presence of such behaviors in the output currents indicates that the symmetry in a period is broken. The broken symmetries appear when the input and output frequencies are mismatched. In addition, this paper shows the possibility to recover the symmetry of the output currents of the MC. The method for symmetry recovery is based on a time-delayed feedback control. The simulation and experimental results indicate the possibility of attenuating the quasiperiodic behavior and DC component.

中文翻译：

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矩阵变换器中输出电流的破坏对称性及其恢复控制

对称性不仅用于简化三相电气系统的分析，还用于定义其电压、电流和负载。当负载对称时，三相交流系统的电流也应该是对称的。在适当的条件下，在矩阵转换器 (MC) 等转换器中，输出电压和电流预计为具有周期性对称性的正弦曲线。然而，在某些情况下，这种对称性被打破，从而出现准周期性等非线性行为。基于模拟和实验，本文重点分析准周期行为和文丘里尼调制 MC 输出电流中直流分量的存在。输出电流中这种行为的存在表明一个周期内的对称性被打破。当输入和输出频率不匹配时，就会出现破坏的对称性。此外，本文还展示了恢复 MC 输出电流对称性的可能性。对称恢复的方法是基于延时反馈控制。模拟和实验结果表明衰减准周期行为和直流分量的可能性。