MMC的无锁相环直接功率控制仿真

目前新型模块化多电平换流器（modular multilevel converter,MMC）多采用电压外环电流内环的双闭环直接电流控制策略,研究MMC的直接功率控制（direct power control,DPC）策略以减少系统控制参数,改善动态响应慢等问题。在αβ坐标系下推导关于MMC的DPC数学模型,并设计了一种无锁相环的DPC控制系统,为消除系统频率和电感参数的变化对控制系统的干扰,设计了一种无系统角频率和电感参数的功率解耦控制器,将双闭环简化为功率单环。考虑电网强度对换流站运行特性的影响,计算出直接功率控制策略适用于交流系统强度范围。最后在MATLAB/Simulink中仿真验证,结果表明上述设计控制策略的有效性。

Simulation Research on Direct Power Control of Modular Multilevel Converter without Phase Lock Loop

The strategy of outer voltage and inner current loop direct current double-loop control is commonly usedfor currently new modular multilevel converter（MMC）.This paper studies direct power control（DPC） strategy ofMMC to reduce system control parameters and improve the dynamic response.In αβ coordinates it derives mathe-matical model of DPC on the MMC and designs a control system without the Phase Lock Loop（PLL）.Then it de-signs a power decoupling controller with non-system angular frequency and inductor parameters to eliminate theinterference to the control system,and simplifies double closed loop to power single ring.It discusses the impact ofthe strength of the grid on converter station operating characteristics and calculates direct power control strategyfor AC systems intensity range.Finally,through the simulation research of the designed system with Matlab/Simu-link,the results show that the proposed methods are correct and effective.