级联型SVG单载波调制策略研究

A Single-carrier Modulation Strategy for Cascade SVG

多电平脉宽调制策略是级联型静止无功发生器(staticvar generator,SVG)的核心技术。提出一种改进的载波同相层叠调制策略,即单载波调制策略,采用单路三角形载波实现多电平调制,兼有载波同相层叠调制良好的消谐特性和载波移相调制开关分配均衡的优点;针对级联型SVG直流侧电压不平衡现象,提出一种参考直流侧电压排序的开关分配策略;将单载波调制策略与电压电流双闭环控制结合,应用于级联型SVG。最后,利用PSIM仿真软件搭建级联型SVG仿真模型,对比基于单载波调制的控制方案和传统控制方案的电压平衡控制效果,验证单载波调制及控制方案的有效性;在低压环境搭建七电平SVG实验样机,验证所提方法的可行性。

The multi-level pulse width modulation strategy is the core technology of the Cascade SVG. This paper presents an improved carrier phase disposition modulation strategy, namely single-carrier modulation strategy. This improved modulation strategy, which uses a single triangular carrier to achieve multi-level modulation, has advantages of both good harmonic characteristics of carrier phase disposition modulation and switch balanced distribution by carrier phase shifted modulation. Aim at the DC side voltage imbalance of the Cascade SVG, this paper presents a switching allocation strategy refer to DC voltage; The combination of single-carrier modulation strategy and the voltage and current double loop control is applied to the Cascade SVG. Finally, the proposed modulation strategy and control method was verified by the PSIM simulation and the SVG prototype.