光伏直流升压汇集系统的模型降阶启动控制策略

光伏直流升压汇集系统正常运行的前提是系统完成预充电，平稳建立直流母线电压。为了快速且更加稳定地完成该过程，该文研究了光伏直流升压汇集系统的拓扑结构和充电特点，在此基础上提出可控充电阶段电压外环采用比例（P）控制器可实现等效模型降阶，同时利用电容器对电流的积分作用来消除稳态误差。将其与多端模块化多电平换流器（modular multilevel converter， MMC）软启动中常用的电压外环比例积分（PI）控制进行了对比分析，结果表明，其降低了系统等效模型的阶次，且无需直流参考电压斜率控制器，有利于充电过程中系统的稳定及控制参数的选取。最后，通过MATLAB/Simulink仿真验证了所提控制策略的正确性和有效性。

Order-reduced Startup Strategy for Boosting and Collecting of Photovoltaic System

The precondition for the normal operation of the PV system is to complete the pre-charge and establish DC bus voltage. To complete the process fast and more stably， the topological structure and charging characteristics of DC boost system for photovoltaic system are studied in this paper. On this basis， the paper proposes that the proportional controller can be used to reduce the order of the equivalent model in the controlled charging stage. At the same time， the steady-state error is eliminated by the integral action of the capacitor on the current. Compared to the proportion and integral control of the voltage outer loop used in the soft start of multi-terminal MMC， it reduces the order of the equivalent system model and does not need slope controller for DC reference voltage. It is beneficial to the system stability and the selection of control parameters during the charging process. Finally， the correctness and effectiveness of the proposed control strategy is verified by MATLAB/Simulink simulation.