混合级联逆变器的混合频率载波调制技术
发布时间：2018-11-28 15:10
【摘要】：混合频率载波调制法可以解决混合级联7电平逆变器的功率环流问题,但其输出电压的谐波特性较差。为此,提出了一种改进的混合频率载波调制策略,该策略使得高压单元运行在单极倍频正弦脉宽调制(sinusoidal pulse width modulation,SPWM)下,从而提高了高压单元的等效开关频率。此外,对高、低压单元的开关策略进行了优化改进,减少了开关次数。相比于改进前的方法,在高压单元开关频率相同时,其等效开关频率可提高1倍,逆变器输出电压的谐波将分布在更高的频段,从而改善了逆变器输出的电能质量,同时消除了功率环流。由仿真结果可知,在相同开关频率下,改进后的方法使得输出电压的较低次谐波由约1 k Hz提高到了约2 k Hz,并且不会出现功率环流现象。研究结果对所提出的改进的混合频率或波调制策略的实用化有一定意义。
[Abstract]:The hybrid frequency carrier modulation method can solve the power circulation problem of hybrid cascaded 7-level inverter, but the harmonic characteristics of the output voltage are poor. In this paper, an improved hybrid frequency carrier modulation strategy is proposed, which makes the high voltage unit run under the unipole frequency doubling sinusoidal pulse width modulation (sinusoidal pulse width modulation,SPWM), thus increasing the equivalent switching frequency of the high voltage unit. In addition, the switching strategies of high and low voltage units are optimized and improved to reduce the number of switches. Compared with the previous method, the equivalent switching frequency of the high voltage unit can be doubled when the switching frequency is the same, and the harmonic of the output voltage of the inverter will be distributed in a higher frequency band, thus improving the power quality of the inverter output. At the same time, the power circulation is eliminated. The simulation results show that, at the same switching frequency, the improved method increases the output voltage from about 1 k Hz to about 2 k Hz, and there is no power circulation phenomenon. The results are significant for the practical application of the improved hybrid frequency or wave modulation strategy.
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本文编号：2363234
[Abstract]:The hybrid frequency carrier modulation method can solve the power circulation problem of hybrid cascaded 7-level inverter, but the harmonic characteristics of the output voltage are poor. In this paper, an improved hybrid frequency carrier modulation strategy is proposed, which makes the high voltage unit run under the unipole frequency doubling sinusoidal pulse width modulation (sinusoidal pulse width modulation,SPWM), thus increasing the equivalent switching frequency of the high voltage unit. In addition, the switching strategies of high and low voltage units are optimized and improved to reduce the number of switches. Compared with the previous method, the equivalent switching frequency of the high voltage unit can be doubled when the switching frequency is the same, and the harmonic of the output voltage of the inverter will be distributed in a higher frequency band, thus improving the power quality of the inverter output. At the same time, the power circulation is eliminated. The simulation results show that, at the same switching frequency, the improved method increases the output voltage from about 1 k Hz to about 2 k Hz, and there is no power circulation phenomenon. The results are significant for the practical application of the improved hybrid frequency or wave modulation strategy.
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本文编号：2363234
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