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| 摘要: |
| 载波移相正弦脉冲宽度调制(SPWM)应用于高压大容量链式多电平逆变器场合时,若载波频率太低,各载波初相位对输出电压相位影响较大,可能造成链式逆变器各单相桥榆出电压基波初相位存在明显差异,引起电容电压不平衡.推导了载波移相SPWM输出电压的数学表达式,分析了低开关频率下输出电压的谐波特性及其对逆变器运行的影响,提出应选择较高的载波频率.数字仿真和物理实验结果表明.在一相串联桥数大于4时,选择高于300 Hz的载波频率.可保证各桥输出电压初相位差异小于0.5°对电容电压的影响可忽略. |
| 关键词: 载波移相 链式多电平逆变器 静止同步补偿器 开关频率 |
| DOI： |
| 分类号:TM464 |
| 基金项目:国家重点基础研究发展规划(973计划)? |
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| Selection of phase-shift SPWM switching frequency |
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YUAN Zhichang SONG Qiang LIU Wenhua
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| Abstract: |
| PS-SPWM(Phase-Shift Sinusoidal Pulse-Width Modulation) is frequently applied in cascaded multi-level inverter such as STATCOM or DSTATCOM.If its switching frequency is too low,the base voltage of single H-bridge will be highly sensitive to the carrier wave phase-shift,which might cause unbalanced voltage on its DC links.The mathematical expressions of PS-SPWM output voltage are deduced,and special phenomena of PS-SPWM with low switching frequency is introduced,especially the influence of base voltage phase ... |
| Key words: SPWM |
