中文摘要：

双级矩阵变换器（又称为间接矩阵变换器）是一种新的矩阵变换器拓扑，存在中间直流环节，但不包含储能的电容或者电感。因此，当输入侧电压不平衡时，输入输出电流波形将直接受到影响，降低了双级矩阵变换器的性能。针对这一问题，本文提出了一种基于瞬时无功理论的补偿方法。在输入电压不平衡情况下，该方法控制输入侧有功为恒定，构造输入电流矢量参考值，并对整流级电路和逆变级电路分别采用空间矢量脉宽调制，从而保证输出性能的稳定。实验结果表明，该方法有效地减小了输入输出电流中的谐波含量，改善了变换器的性能。

英文摘要：

Two-stage matrix converter （TSMC, also named indirect matrix converter） is a novel topology of matrix COnVerters, which is a direct three-phase AC to AC power conversion device. It has a real DC link, but without energystored capacitor or inductor. Input voltage unbalance in the source of TSMC can immediately reflect to the output side and lower its performance. In order to reduce the effect of input voltage unbalance, a compensation method based on instantaneous reactive power theory is proposed in this paper. Under unbalanced input voltages, the active power of input side is controlled as constant. The positive and negative sequence components of the unbalanced input voltages are calculated and the input current reference space vector is constructed. The rectifier and inverter can use space vector PWM-algorithms respectively. The output performance of TSMC can be stabilized. The experimental results show the proposed method can reduce the harmonics of input and output currents so as to improve the performance of TSMC.