同步发电机模型在MMC并网控制中的应用

摘要

为了实现模块化多电平换流器MMC (modular multilevel converter)快速、平滑并网,该文将同步发电机模型与同步发电机准同步并网原理应用于MMC并网控制.先对同步发电机进行建模,根据MMC的原理及其控制原则确定控制策略,并结合同步发电机模型设计控制器控制MMC输送到电网的功率,实现功率跟踪；引入同步发电机准同步并网原理,根据锁相环PLL (phase locked loop)检测到的电网电压与MMC输出电压的相位信息自动搜寻最佳合闸时间,控制MMC在最佳时刻平滑并入电网,实现友好并网.MATLAB/Simulink仿真结果验证了该控制策略的正确性和有效性.%In order to realize modular multilevel converter (MMC) grid-connected fast and smoothly, the model and quasi synchronous principle of synchronous generator is applied to control MMC in this paper. First, a model of synchronous generator is built, and a control strategy is determined according to the theory and control principle of MMC, and a controller is designed with the model of synchronous generator to control MMC conveying power to the grid and realize power tracking. The quasi synchronous principle of synchronous generator is introduced to search the optimal switching time according to the phase of grid voltage and MMC output voltage detected by PLL, and control MMC to connect with grid smoothly at the optimal time to realize grid-connected friendly. Simulation results of MATLAB/ simulink verify the correctness and effectiveness of this control strategy.