基于混合调制技术H桥级联PCS的研究

Research on the Cascaded H-bridge PCS Based on Hybrid Modulation

针对应用于中压储能系统的H桥级联功率调节系统(PCS)提出了一种混合脉宽调制(PWM)方法。该调制方法综合高频PWM技术和最近电平逼近(NLM)技术的优点,在保证较高质量多电平输出波形的同时可降低功率器件开关频率,有利于降低开关损耗。此外,根据电压排序进行各功率单元工作模式的选择,可以调整各功率单元储能电池的充放电状态,控制简单,容易实现。在此详细分析了混合PWM技术的工作原理及实现方法,搭建了5级H桥级联PCS储能系统实验平台,实验结果表明所提调制方法及均衡控制能实现良好的交流多电平输出波形和储能电池的均衡控制,具有一定的工程应用价值。

A hybrid pulse width modulation （PWM） method is proposed,which is aimed at cascaded H-bridge power condition system（PCS） energy storage systems used in the medium voltage field.Advantages of the high frequency PWM and those of the nearest level modulation （NLM） are combined in this method and on the premise of guaranteeing the quality of multi-level output waveforms, this method can reduce frequency of switch devices, which is helpful to reduce switching loss.Experiment show that the modulation method and the balance control attain good quality of muhilevel alternating current voltage and realize energy storage hattery＇s balanced control, which has significant superiority.