载波调换调制技术在级联多电平SAPF中的应用

电容电压不平衡是影响级联H桥多电平并联有源电力滤波器(SAPF)安全可靠运行的关键问题。通过分析载波相移调制技术(CPS-SPWM)对直流侧电容电压的影响,提出了一种基于控制直流侧电容电压平衡的载波调换调制技术,确立了双电压环与电流环结合的三闭环SAPF控制策略。这种调制方式算法简单、易实现,能在较小开关频率下实现较好的补偿效果的同时,有效地解决级联H桥多电平SAPF直流侧电压平衡问题。仿真和实验证明,该载波调换调制技术是有效、实用的,能对直流侧电容电压平衡起到良好的控制效果。

Application of carrier exchange modulation technique in multi-level cascaded SAPF

Capacitor voltage imbalance is the key issue for the safe and reliable operation of cascaded H-bridge multi-level shunt active power filter (SAPF). This paper proposes a carrier exchange modulation technique based on DC capacitor voltage balance control by analyzing the impact of carrier phase shift modulation technique (CPS-SPWM) on DC side capacitor voltage, and establishes a combination of three closed-loop SAPF control strategy which includes a dual voltage loop and a current loop. This modulation algorithm is simple and easy to implement, and can achieve better compensation effect at lower switching frequency and effectively solve the DC side voltage balance problems for cascaded H-bridge multi-level SAPF at the same time. The simulation and experimental results show that the carrier exchange modulation technique is effective and practical, which could play a good control effect for DC capacitor voltage balance.