CAJ | 학술논문

为了解决大型光伏并网发电系统存在的光能利用率低、对电网影响大等问题，基于模块化多电平换流器(modular multilevel converter，MMC)提出一种新的大型光伏并网发电系统结构，即光伏阵列经DC-DC电路与模块化多电平换流器子模块相连，构成并网逆变系统；在该系统中，外环电压控制维持直流侧母线电压及交流侧电压稳定，内环电流控制为脉宽调制(pulse width modulation，PWM)提供参考波，有功无功独立控制。详细论述该系统的结构及其控制策略，并在Simulink中搭建10 MWp光伏发电系统模型。仿真结果验证了该系统结构的可行性及控制策略的有效性，同时也表明，该系统具有太阳能利用率高、并网谐波含量低等优势。
위료해결대형광복병망발전계통존재적광능이용솔저、대전망영향대등문제，기우모괴화다전평환류기(modular multilevel converter，MMC)제출일충신적대형광복병망발전계통결구，즉광복진렬경DC-DC전로여모괴화다전평환류기자모괴상련，구성병망역변계통；재해계통중，외배전압공제유지직류측모선전압급교류측전압은정，내배전류공제위맥관조제(pulse width modulation，PWM)제공삼고파，유공무공독립공제。상세논술해계통적결구급기공제책략，병재Simulink중탑건10 MWp광복발전계통모형。방진결과험증료해계통결구적가행성급공제책략적유효성，동시야표명，해계통구유태양능이용솔고、병망해파함량저등우세。
In order to deal with the problem of large scale photovoltaic (PV) grid-connected systems, such as the low solar energy utilization rate, the great influence on power grids and so on, a new structure of large scale PV grid-connected systems based on modular multilevel converter (MMC) was proposed, in which a PV array was connected to a sub-module of MMC through a DC-DC circuit. In this system, DC voltage and AC voltage were controlled by the outer loop controller, the reference of PWM modulation was offered by the inner loop controller, active power and reactive power were controlled separately. The structure and control strategies of this system were introduced in detail in this paper, and a model of a 10 MWp PV grid-connected system was built in Simulink. The feasibility of the structure and the effectiveness of the control strategy are verified by time-domain simulations performed in Simulink, and the simulation results indicate that this system can raise the utilization ratio of solar energy, and can reduce the grid-connected harmonic contents.