矿用级联多电平变换器输出谐波特性研究

Research on Output Harmonic Characteristics of Mining Cascade Multilevel Converter

级联多电平变换器能够提高电网稳定性、改善电能质量,并且具有功耗低的优点,因而广泛应用于煤矿电网的谐波抑制和无功补偿。然而,由于脉宽调制策略不同,级联多电平变换器输出电压谐波、电流纹波等不同,导致级联多电平有源电力滤波器谐波抑制能力降低。针对此问题,分别采用载波相移和交替反向载波层叠脉宽调制策略研究变换器输出电气特性。研究表明,基于载波相移的多电平变换器输出电气性能优于载波层叠。在MATLAB/Simulink平台上搭建级联多电平有源电力滤波器模型,仿真表明抑制后的3、5、7次等谐波的谐波含量远低于IEEE519谐波标准。

Cascaded multilevel converter improves grid stability,power quality,and has the advantage of low power consumption.As a result,they are widely used for harmonic suppression and reactive power compensation in coal mine networks.However,due to the different pulse width modulation strategies,the output voltage harmonics and current ripple of the cascaded multilevel converter differ,resulting in a reduced harmonic rejection capability of the cascaded multilevel active power filters.The output electrical characteristics of the converter were investigated using carrier phase shift and alternating inverse carrier cascade pulse width modulation strategies respectively to this problem.The research shown that the output electrical performance of carrier phase-shift based multilevel converters is superior to that of carrier cascading.The cascaded multilevel active power filter model is built on the MATLAB/Simulink platform and the simulation results show that the harmonic content of the suppressed 3rd,5th and 7th harmonics is well below the IEEE519 harmonic standard.