中文摘要：

分析双级矩阵变换器输出电压非线性根源与特征。鉴于它和双PWM变频器、传统矩阵变换器在结构和功能方面的相似性，对其非线性特征进行对比分析，发现双级矩阵变换器的非线性有其明显的独特性，如窄脉冲、器件电压降、滤波电容电压纹波等，这些问题与调制策略、工作机理、拓扑结构和运行状态等有关。为保证系统可靠运行，补偿非线性所带来的负面影响，提出一种修正调制算法，并给出基于变载波调制的非线性补偿策略，克服了己有算法在实现上的固有缺陷，提高了系统波形质量。在高调制系数区域内，性能改善尤为明显，运行可靠性也相应提高。实验结果证明了所提方案的正确性及可行性。

英文摘要：

The nonlinearity sources and features of two-stage matrix converter （TSMC） output voltage were analyzed. Due to the similarity of two-stage, traditional matrix converter and active-front-end converter in terms of structure and function, comparisons were carried out. It was found that the nonlinearity of TSMC had many special features, such as narrow pulse, device voltage drops and ripples of filter capacitor which was concerned with modulation strategy, operating mechanism and topologies. To meet the end of reliable operation and compensate the negative affects of nonlinearity, revised modulation strategy and nonlinearity compensation a/gorithrns were proposed. The key to the improved modulation strategy was one time varying distribution factor which was introduced to overcome the constraints from real practice, and the minimum narrow pulse restriction could be met without special handling. As a result, the waveform quality of TSMC both in output and input was improved greatly, especially in the region where the modulation index is close to limitation. The experimental results verify the feasibility of the proposed method.