二次谐波注入的光伏逆变器直流电压补偿研究  

Research on DC Voltage Compensation of Photovoltaic Inverter With Second Harmonic Injection

作　　者：张斌荣 王晶 马浩 张永凯 ZHANG Bin-rong;WANG Jing;MA Hao;ZHANG Yong-kai(State Grid Shandong Electric Power Company Jinan Power Supply Company,Jinan 250012,China)

机构地区：[1]国网山东省电力公司济南供电公司,山东济南250012

出　　处：《电力电子技术》2023年第1期83-87,共5页Power Electronics

基　　金：国家电网公司科技项目(5211HZ21012H);国家电网有限公司科技项目(5213A017000H)。

摘　　要：三电平中性点箝位(NPC)光伏逆变器的上下直流电容器之间存在的电压不平衡会损害系统的稳定性,并限制功率级的开关操作。因此这里提出了一种注入公共偏置电压的方法,将二次谐波分量和上下电容器电压差分量注入脉宽调制(PWM)控制器的控制环路中以补偿电容器之间的不平衡电压。先对NPC光伏逆变器的工作原理进行了分析,在此基础上推导了注入的公共偏置电压的计算方法和电路实现方法,并在仿真模型和实物样机中进行了验证。实验结果表明,所提的不平衡补偿方法可以有效实现直流电容器的不平衡电压补偿,且注入二次谐波半波信号拥有比注入二次谐波全波信号更快的响应速度和更好的补偿效果。The voltage unbalance between the upper and lower direct current capacitors of the three-level neutral point clamped(NPC) photovoltaic inverter will damage the stability of the system and limit the switching operation of the power stage.Therefore,a method of injecting common bias voltage is proposed,which injects the second harmonic component and the voltage difference component of upper and lower capacitors into the control loop of pulse width modulation(PWM) controller to compensate the unbalanced voltage between capacitors.Firstly,the working principle of NPC photovoltaic inverter is analyzed.On this basis,the calculation method and circuit implementation method of injected common bias voltage are deduced and verified in the simulation pmodel and physical prototype.The experimental results show that the proposed unbalance compensation method can effectively realize the unbalanced voltage compensation of direct current capacitor,and the injected second harmonic half wave signal has faster response speed and better compensation effect than the injected second harmonic signal.

关 键 词：光伏逆变器 直流电压补偿 中性点箝位 电压不平衡 

分 类 号：TM464[电气工程—电器]