【作者】 王立杰；

【导师】 孙玉坤；

【作者基本信息】 江苏大学 ， 电力电子与电力传动， 2007， 硕士

【摘要】 基于链式多电平逆变器结构的静止同步补偿器(STATCOM)是一种新型无功补偿装置，它具有发出容性无功功率和吸收感性无功功率的双向补偿功能。本文研究了在平衡负荷和不平衡负荷条件下静止同步补偿器的控制方法，及适用于链式多电平逆变器结构的PWM新方法。首先，本文分析了STATCOM的工作原理，建立了链式STATCOM的有功-无功电流暂态模型，通过引进多变量非线性控制逆系统方法，设计了基于逆系统方法和有功-无功电流解耦的非线性动态无功电流控制策略，设计了DSP为核心的控制系统。研究了注入零序矢量对PWM控制的影响，由此得出了适用于链式多电平逆变器结构的三角载波移相-开关频率最优PWM法(PS-SFO-PWM)。仿真结果表明，基于逆系统方法和有功-无功电流解耦的非线性动态无功电流控制具有良好的动态性能。PS-SFO-PWM法在不提高开关频率的情况下，实现了等效高频载波的效果，并提高了直流电压的利用率。本文探讨了在负荷不对称条件下的控制策略，提出了根据正序、负序电压开关值合成PWM控制的负序电流补偿方法。该方法有效地补偿了负荷的负序电流。更多还原

【Abstract】 STATCOM based on cascade multilevel inverters is a new type of reactive power compensator, which can generate or draw reactive power from the power network. The main object of this paper is to deal with the control strategy of STATCOM used in distribution system under balanced loads and unbalanced loads, and new PWM strategy for Cascade STATCOM.First, the principle of STATCOM is analyzed in detail. By theoretical analysis, the mathematic model based on the i_p-i_q (real and reactive current) is modeled, which reflectsthe characteristics of STATCOM. Then, on the basis of this model, the multivariable nonlinear control method based on inverse-system is introduced. Consequently a pseudo linear i_p - i_q decoupled system is obtained and the fast and decoupled closed-loop control for reactivecurrent is achieved, and the control system based on DSP is designed. Triangular carrier phase shifting-switch frequency optional PWM (PS-SFO-PWM) for Cascade STATCOM is presented. The new PWM strategy brings about the effect of high frequency carrier without the increase of switch frequency, and at the same time improves the use of DC side voltage. Last, the control strategy of STATCOM under the unbalance loads is investigated. The compensation way with the instantaneous value of negative-sequence voltage to adjust the pulse width of balance compensation gains good characteristics, which can compensate negative-sequence current caused by loads effectively and quickly.更多还原