CAJ | 학술논문

在模块化多电平换流器(modular multilevel converter， MMC)中，针对阀控层的直流电压控制，在载波移相调制方式的基础上，提出了改进型子模块电容电压均衡控制方法，以降低开关器件的开关频率。针对极控层的直流电压控制，推导了稳态时MMC电流离散数学模型，设计了电流内环离散控制器，实现了系统直流电压控制和功率解耦控制。为抑制由交流系统故障引起的直流电压波动，提出了含直流电压控制环节的外环有功功率控制器，以提高系统的持续运行能力。算例仿真结果验证了所提方法的有效性。
재모괴화다전평환류기(modular multilevel converter， MMC)중，침대벌공층적직류전압공제，재재파이상조제방식적기출상，제출료개진형자모괴전용전압균형공제방법，이강저개관기건적개관빈솔。침대겁공층적직류전압공제，추도료은태시MMC전류리산수학모형，설계료전류내배리산공제기，실현료계통직류전압공제화공솔해우공제。위억제유교류계통고장인기적직류전압파동，제출료함직류전압공제배절적외배유공공솔공제기，이제고계통적지속운행능력。산례방진결과험증료소제방법적유효성。
In allusion to DC voltage control in valve control layer of modular multilevel converter (MMC), based on carrier phase shifted pulse-width modulation (PWM) an improved capacitor voltage balancing control method for submodules is proposed to decrease the switching frequency of switching devices. In allusion to DC voltage control of polar control layer, a discrete mathematical model of MMC current under steady state is derived and an inner-loop current discrete controller for MMC is designed to implement the DC voltage control and decoupled power control of MMC based HVDC (MMC-HVDC) power transmission system. To suppress the DC voltage fluctuation caused by the fault occurred in AC system, an outer-loop active power controller containing DC voltage controller is put forward to enhance the continuous operation ability of MMC-HVDC power transmission system. The validity of the proposed method is verified by results of example simulation.