基于Matlab的离网光伏单相全桥 逆变器控制策略

为了解决离网光伏发电系统为负载供电时逆变器输出电压存在谐波畸变率高的问题,提出一种改进的逆变器控制策略。首先,根据离网光伏发电系统的结构建立了单相全桥逆变器的数学模型;其次,基于数学模型分析,在接线性负载和投切线性负载时对逆变器采用电压电流双闭环控制策略,而在接非线性负载时引入输出电流反馈量,提出了由电感电流内环、输出电压外环、输出电流负反馈组成的逆变器多环稳压控制策略;最后,基于Matlab进行仿真,通过河北科技大学直流微电网系统进行试验验证,并将试验结果与仿真结果进行了对比分析。结果表明,上述3种工况下的逆变器电压谐波畸变率分别为1.8%,2.7%和2.3%,均满足小于5%的要求。研究结果对于改善逆变器的性能,提高离网光伏发电效率,以及发展新能源发电具有参考价值。

Control strategy of off-grid photovoltaic single-phase full-bridge inverter based on Matlab

In order to solve the problem that the output voltage of the inverter has high harmonic distortion rate when the off-grid photovoltaic system supplies power for the load, an improved inverter control strategy is proposed. Firstly, a mathematical model of a single-phase full-bridge inverter is established according to the structure of the off-grid photovoltaic power generation system. Secondly, based on the mathematical model analysis, the inverter uses a voltage-current double closed-loop control strategy for the wiring load; the output current feedback amount is introduced when the nonlinear load is connected, and the multi-loop voltage regulation control strategy of the inverter consisting of the inductor current inner loop, the output voltage outer loop and the output current negative feedback is proposed. Finally, simulation is conducted based on Matlab, experimental verification is conducted with the Hebei University of Science and Technology DC microgrid system, and the experimental results and simulation results are compared and analyzed. The results show that under the above three conditions, the inverter voltage and harmonic distortion rates are 1.8%, 2.7%, and 2.3%, respectively, meeting the requirement of less than 5%. This paper has research value for improving the performance of inverters and improving the efficiency of photovoltaic power generation and the development of new energy power generation.