大功率电流源型SVG的拓扑与控制

Topology and Control of High Power Current Source Converter SVG

传统电流源型变换器交流侧需设置交流电容器来实现交流电流的连续和能量的缓冲,但交流电容器既昂贵,又存在与交流侧电感发生谐振的风险,严重制约其大功率化。基于此,从工程实现角度出发,运用直流电流复注变换式AC/DC变换思想构造一种采用分流电感实现恒稳直流？近似正弦交流变换的大功率电流源型静止无功发生器（SVG）拓扑。分析SVG电路拓扑的原理,给出开关的触发时序;建立SVG的非线性数学模型,给出一种全局线性化的有功无功控制策略;通过仿真和实验对拓扑电路的可行性以及控制策略的正确性进行验证。结果表明,所提出的拓扑输入输出性能优良,无需滤波即可获得近似正弦波形的交流电流;全局线性化方法不依赖SVG的运行状态,控制器在全状态域控制有效,系统能在全局范围内获得良好的线性控制性能。

The traditional current source converter needs to set an AC capacitor to achieve continuous current and energy buffering in its AC side. However, the AC capacitor is expensive and there is the risk of resonance with the inductor in AC side, seriously restricting the development of high-power. Thereby, from the point of view of engineering realization, using the idea of AC/DC conversion of DC current reinjection conversion to construct a high power SVG topology based on distributed-current-inductance can achieve the conversion of constant DC current ？ approximate sinusoidal AC current. Moreover, the working principle of the topology circuit is analyzed and the trigger timing of the switch is given. The nonlinear mathematical model of the system is established, and an active and reactive power control strategy based on global linearization method is proposed. The feasibility of the topology circuit and the correctness of the control strategy are verified by simulations and experiments. The results show that the proposed topological input and output performance is excellent, and can output three-phase AC approximate sinusoidal current without filtering. The global linearization method does not depend on the SVG system operating state, and the validity of the controller is guaranteed in the global scope,thus the SVG system obtains excellent linear controlling performance in the global scope.