混合型模块化多电平换流器的模型预测控制方法

混合型模块化多电平拓扑是由传统模块化多电平拓扑在每个桥臂上增加一个H桥模块构成。对于混合型模块化多电平换流器(MMC),基于比例积分(PI)控制器的双闭环控制策略需要多个参数控制器且具有参数整定复杂、对控制参数敏感等问题。为此,结合子模块电容电压排序算法与H桥模块控制算法,提出一种基于模型预测控制的分层控制策略,该方法通过建立相对应的指标函数对交流侧电流、环流与子模块电容电压进行分层控制,从而确定各子模块与H桥模块的开关状态。与传统控制方法相比,该方法原理简单、无需考虑复杂的参数整定且可使系统具有良好的动静态性能。最后搭建了混合型模块化多电平换流器的仿真平台,仿真结果验证了所提控制策略的有效性与正确性。

Model Predictive Control of a Hybrid Modular Multilevel Converter

A hybrid topology of modular multilevel converter (MMC) is presented, which adds an H-bridge cell to each bridge of traditional topology.Two closed-loop control strategy based on proportion integration (PI) controller of hybrid MMC has many problems such as excessive parameter controllers, complex parameter tuning, and sensitive to parameters.Combining with sub-modules capacitor voltage sorting strategy and H-bridge module control algorithm, a hierarchical control method based on model predictive control (MPC) is proposed, which takes separate control on AC current, circulating current and submodular voltage on the basis of establishing of corresponding cost function, thus to determine the switching state of each module.Compared with traditional control method, the method is simple in principle and no PI parameters needed and has excellent static and dynamic performance.At last, a hybrid MMC simulation platform is constructed, and the simulation results verify that the proposed control strategy is of feasibility and correctness.