基于MMC拓扑STATCOM综合控制策略研究

针对基于模块化多电平变换器(Modular Multilever Converter,简称MMC)的静止同步补偿器(Static Synchronous Compensator,简称STATCOM)提出了一种综合控制策略。根据MMC-STATCOM在不同工作状态下的性能要求以及最近电平逼近调制(Nearest Level Modulation,简称NLM)和载波移相SPWM(Carrier Phase Shifted SPWM,简称CPS-SPWM)两种控制策略的不同特点,在不同工作阶段分别选择合适的控制策略。基于瞬时无功功率理论,通过在d轴和q轴上分别叠加有功分量和无功分量的方法,在恒频启动阶段采用最近电平逼近调制并在电压外环采用斜坡控制,实现子模块电容电压快速稳定上升,在稳态阶段采用载波移相SPWM的分级控制,实现稳态时系统具有较好的输出性能。最后,综合控制策略进行了实验验证。

A Study on the Integrated Control Scheme for the STATCOM Based on MMC Topology

Perspective to the Static Synchronous Compensator (STATCOM) based on Modular Multilevel Converter (MMC), this paper presents an integrated control scheme. Based on performance requirements on MMC-STATCOM under different working conditions as well as different characteristics of two control strategies, namely the Nearest Level Modulation(NLM) and Carrier Phase Shifting SPWM(CPS-SPWM), this paper selects appropriate control strategies for different working stages respectively. Based on the theory of instantaneous reactive power, by superimposing active component and reactive component on the d-axis and q-axis respectively, we use NLM in the constant-frequency startup phase and slope control in the outer voltage loop to realize rapid and stable rise of capacitor voltage in the sub-module. Moreover, we adopt CPS SPWM hierarchical control in the steady-state phase to ensure good output performance of the system in the steady state. Finally, experimental verification is completed for the proposed integrated control scheme.