基于载波频率切换的SVG电容电压均衡研究  

Research on SVG Capacitor Voltage Equalization Based on Carrier Frequency Switching

作　　者：孙健 左广杰 许明阳 荆方杰 SUN Jian;ZUO Guang-jie;XU Ming-yang;JING Fang-jie(XJ Electric Co.,Ltd.,Xuchang 461000,China)

机构地区：[1]许继电气股份有限公司,河南许昌461000

出　　处：《电力电子技术》2023年第6期86-89,共4页Power Electronics

摘　　要：电容电压均衡是链式静止无功发生器(SVG)稳定运行的基本条件,然而广泛应用的单极性倍频载波移相正弦脉宽调制(CPS-SPWM)策略却是导致电容电压不均衡的重要因素之一,需研究有效抑制电容电压的不均衡策略。首先,分析了电容电压的稳态数学模型和调制策略导致电容电压不均衡的机理。其次,基于减小链节输出低次边带谐波电压幅值的思路,提出了载波频率同步切换策略,仅在换流链电流较小时采用高载波频率。最后,仿真和实验结果表明,载波频率同步切换策略解决了调制策略导致的电容电压不均衡问题,提高了电容电压均衡控制能力,最小运行电流也进一步降低。Capacitor voltage equalization is the basic condition for the stable operation of the chain-type static var generator(SVG).However,the widely used unipolar frequency-multiplying carrier phase-shifted sinusoidal pulse width modulation(CPS-SPWM)strategy is an important cause of the capacitor voltage imbalance.It is necessary to study effective strategies to suppress capacitor voltage imbalance.Firstly,the steady-state mathematical model of the capacitor voltage and the mechanism of the modulation strategy leading to the capacitor voltage imbalance are analyzed.Secondly,based on the idea of reducing the amplitude of the low-order sideband harmonic voltage of the link output,a carrier frequency synchronous switching strategy is proposed,which uses a high carrier frequency when the commutating chain current is small.Finally,the simulation and experimental results show that the carrier frequency synchronous switching strategy solves the capacitor voltage imbalance caused by the modulation strategy,improves the equalization control capability of the capacitor voltage,and further reduces the minimum operating current.

关 键 词：静止无功发生器 电容电压均衡 载波频率 

分 类 号：TM714.3[电气工程—电力系统及自动化]