Multi carrier PWM of the modular multilevel VSC for medium voltage applications
Multi carrier PWM of the modular multilevel VSC for medium voltage applications
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DOI：
10.1109/apec.2012.6166159
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
Emmanuel Amankwah;J. Clare;Patrick Wheeler;A. Watson
中科院分区：
文献类型：
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作者：
Emmanuel Amankwah;J. Clare;Patrick Wheeler;A. Watson
本文提出了集成的电平移动和相移多载波调制方案，以确保PWM和本地电容电压平衡的模块化多电平变换器（M2LC）的中压应用。调制方案中的任一个与单元电压平衡算法的集成确保了浮置电容器电压在M2LC电压源转换器的整个操作中被平衡。基于合成输出波形的谐波含量和本地电容器电压的峰峰值涟漪，提出了两种方案的比较。转换器的半导体损耗也进行了评估和比较，这些调制方案在一个典型的中压电网应用。结果表明，这两种方案在合成输出波形质量方面具有竞争力。然而，相移方案提供更少的电容器电压涟漪，而电平移位方案提供低转换器损耗。PLECS仿真软件包和一个10kVA的9级实验样机证实了这一概念。
This paper presents integrated level-shifted and phase-shifted multi carrier modulation schemes that ensures PWM and local capacitor voltage balancing of the Modular Multilevel Converter (M2LC) for medium voltage applications. The integration of either of the modulation schemes with the cell voltage balancing algorithm ensures the floating capacitor voltages are balanced throughout the operation of the M2LC voltage source converter. A comparison of the two schemes is presented based on the harmonic content of the synthesized output waveforms and peak-to-peak ripple of the local capacitor voltages. The converter semiconductor losses are also evaluated and compared for these modulation schemes in a typical medium voltage grid application. It is shown that both schemes are competitive in terms of the synthesized output waveform quality. However the phase shifted scheme offers less capacitor voltage ripple while the level shifted scheme offers low converter loss. The concepts are confirmed with both PLECS simulation package and a 10kVA 9-level experimental prototype.