Buck电路在光伏供电的输电线路视频监控系统的应用

Application of a Buck Converter used in Photovoltaic Power Supply Transmission Line Video Monitoring system

针对高压输电线路远程视频监控系统的供电难等问题,设计了一种监控系统,其中使用光伏阵列和超级电容器,组成能够自给电能的独立系统。光伏用直流变换器(DC-DC)不仅将直流电压变换到匹配的直流电压,而且还要实现最大功率点跟踪(MPPT),使光伏电池的输出电压始终工作在最大功率点附近,变换电路需要对电流进行跟踪。因此提出了一种基于MPPT的降压斩波电路(Buck电路),并对采用PI控制的变换器动态过程进行仿真分析。仿真结果表明:采用MPPT控制的Buck电路可以有效的降低光伏电池的输出电压,且输出稳定,输出功率、电压、电流等参数波动很小,在外界环境变化时具有良好的跟踪效果,可以实现为超级电容器充电和视频监控系统供电的要求。

It is difficult to solve the problem of power supply for remote video monitoring system used in HV transmission line. So a monitoring system was designed,including the photovoltaic array and the super capacitor, the independent system can be self-sufficiency in electricity. The DC converter for photovoltaic is able to not only transform direct current voltage to DC voltage matching, but also to achieve maximum power point tracking（MPPT）. The DC converter is needed to track the current conversion circuit for the output voltage of the photovoltaic cells is always working in the vicinity of the maximum power point. So a Buck converter based on MPPT was presented, and through ongoing simulation analysis about the dynamic process of PI control converter. The analysis and simulation results indicate that the output voltage of the photovoltaic battery can be effectively reduced by using Buck converter based on MPPT technology. And the output parameters of buck chopper are stable, including the fluctuation of output power, voltage, current are very small. The good track effect is presented when the external environment changes. The Buck converter based on MPPT technology can be achieved for the super capacitor charging and the power supply requirements for the video monitoring system.