Photovoltaic Module Monitoring System Based On DC Power Line Carrier Communication

Power line carrier communication technology uses power lines as the carrier to achieve data transmission.When it is used to build the communication network,It is not need that pave the communication lines.The traditional power line communication technology is used to the long-distance high-voltage transmission cable to complete data transmission.To achieve large-scale parallel communication,voltage modulation and demodulation technology is applied.In this paper,a set of cheap and feasible technical scheme for the monitoring of PV modules is proposed.The scheme adopts a power line communication which carries on the data transmission on the DC transmission cable and also can be applied to a certain scale series communication.In this paper,STM32M0 series 32-bit microcontroller is used as the master in the design of the monitoring module.To reduce the total cost of the monitoring module,2ASK modulation and demodulation circuit is built by operational amplifiers.It is found that the current loop unit to couple the signal to the transmission line in the the signal coupling unit.the coupling performance of the current loop is changed by the change of the current on the transmission line.When higher current is transmitted on the transmission line,signal intensity which is on the transmission line comes close to zero.In order to avoid phenomenon,It is that adding an air gap into the magnetic core can effectively solve the communication problems of magnetic saturation,thus realizing the high-current DC power line carrier communication.In this paper,the monitoring unit is divided into the coordinator host and the terminal slave.The former is installed into the confluence box,the latter is placed on the solar PV module.In the photovoltaic power station,the role of the confluence box is to collect the power generated by the multi-channel PV modules.In this paper,the signal flows into the confluence box with the current.The coordinator host send the data request command to each slave by polling.After the command from the slave is awakened,sent to host the voltage and current information that sample the corresponding photovoltaic.The host receive the information analysis and send to the computer software to display,to realize the PV module power generation system monitoring.