随着现代电力工业技术的不断发展，电能质量作为衡量电力系统是否正常运行和管理水平高低的重要指标，对于电网的安全稳定运行具有重要意义。静止无功补偿器（STATCOM）通过动态改变输出电压来实现和电力系统的无功功率交换，从而达到稳定系统电压、抑制电压波动和闪变、提高系统功率因数等目的。有效解决了日益严重的电能质量问题，是动态无功调节的前沿和未来的发展方向。 首先，课题通过对比分析基于二极管钳位、飞跨电容钳位和链式H桥逆变单元级联的多电平拓扑结构的各自优势，提出了采用H桥逆变单元级联多电平拓扑结构的STATCOM装置。从H桥逆变单元的调制策略出发，分析了应用于链式STATCOM的单极倍频载波移相SPWM调制策略；通过分析比较基于瞬时无功功率理论的无功电流检测算法，提出本文所采用的无功电流检测算法；阐述了链式STATCOM补偿无功功率和维持公共连接点电压的基本工作原理。从控制器设计与编程实现的难易和直流电压控制鲁棒性强弱的角度出发，设计了基于闭环和Boost变换控制相结合的链式STATCOM电流控制器，其中闭环控制的目的是为了消除补偿的静态误差和提高控制系统的鲁棒性。然后，通过Boost功率变换控制实现了链式STATCOM的直流电压的自动稳定控制，基于下垂特性设计了链式STATCOM的H桥逆变单元的直流电压均衡控制。该均衡控制方法赋予各个H桥逆变单元独立性，利用单元间的有功能量交换实现直流电压的均衡控制，因而该算法的控制参数容易整定，鲁棒性强。 通过仿真效果的验证，链式STATCOM采用的基于闭环Boost电流控制策略、基于Boost功率变换的直流电压自动稳定控制和基于下垂特性的直流电压均衡控制的动态响应快、稳态特性好、鲁棒性强、算法实现简单。

With the development of modern electric power industry technology, Power Quality is taken as an important index to judge the normal operation of power system and management level.Power Quality has important significance for stable operation of power grid. Through reactive power exchange by changing the output voltage dynamically, STATCOM achieve the purpose of system voltage stability, suppressing fluctuation and flicker of voltage, improving power factor, etc. The growing power quality issues are solved effectively.STATCOM is regarded as the frontier and developing direction for adjusting reactive power dynamically. Primarily, the paper proposed a multilevel topology STATCOM device cascaded by H bridge inverter unit through compared different cascaded multilevel topology structures based on Diode-clamped, Flying Capacitors-clamped or H bridge inverter unit. Monopole unipolar of double requency carrier phase-shifting SPWM modulation strategy applied to cascade STATCOM are analysed starting from modulation strategy of H bridge inverter unit. A detection algorithm of reactive current is presented by Analyzing and comparing detection algorithm of reactive current based on instantaneous reactive power theory.The paper explained basic operation principle how the cascade STATCOM compensated reactive power and maintain the voltage of public join point. Cascade STATCOM current controller based on closed loop Boost converter control is designed by consideration of controller design, programming realization and DC voltage control robustness. It is the purposes of closed-loop control that eliminating static error compensation and enhancing the robustness of control system. Then, DC voltage automatic stability control of cascade STATCOM are achieved by Boost power conversion control. The DC voltage balance control of cascade STATCOM based on H bridge inverter unit is designed by drooping characteristics. This balance control makes each H bridge inverter unit independently. DC voltage balance control strategy is achieved by active energy exchange among H bridge inverter unit. Therefore, this method has advtanges of good robustness and esay-adjusted controls parameter. Cascade STATCOM current controller based on closed loop Boost converter control strategy, DC voltage automatic stability control based on Boost power conversion control and The DC voltage balance control based on drooping characteristics strategy have these advatanges of fast dynamic response, good steady-state characteristic, Strong robustness and simple algorithm.