电流品质优化的容错型三相四开关逆变器载波调制算法

摘要

The operational principle of three-phase four-switch inverter is analyzed and a simplified carrierbased modulation algorithm is proposed for it,which only performs simple arithmetic operations on reference voltage to achieve a unified modulation wave expression for four sections,without sector selection and trigonometric operations.It compensates the neutral-point voltage fluctuation of inverter to effectively suppress the distortion of its output current.With the effective ripple current as the assessment criterion,two approaches of zero-vector synthesis are compared,the time-domain analytical expression is deduced and the modulation approach with better output-current performance is determined.The correctness and feasibility of the proposed modulation algorithm are verified by the experimental results.%在深入分析四开关逆变器运行原理的基础上,提出一种基于载波调制的三相四开关逆变器简化算法,无需扇区选择、三角函数运算等复杂计算过程,只需对参考电压进行简单的四则运算,即可获得四扇区统一的调制波表达式.采用所提出的调制策略,可对逆变器中性点电压波动进行补偿,有效抑制了输出电流畸变.同时,对2种不同零矢量合成方案进行比较,以电流纹波有效值作为评估标准,推导出其在时域中的解析表达形式,最终确定输出电流性能更优良的调制方式.实验结果验证了所提出的调制算法的正确性和有效性.