In light of demands for wireless monitoring and the characteristics of wireless channel,a complete deployment method containing channel survey,path loss estimation,and gradient grade of wireless relay nodes is propose...In light of demands for wireless monitoring and the characteristics of wireless channel,a complete deployment method containing channel survey,path loss estimation,and gradient grade of wireless relay nodes is proposed.It can be proved by experiments that under the premise of meeting the requirements of real-time and redundant-topology,the total number of relay nodes could be minimized by using the proposed method.展开更多
We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends ...We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.展开更多
Wireless sensing is an excellent approach for remotely operated solar power system.Not only being able to get the sensor data,such as voltage,current,and temperature,the system can also have a proper control for track...Wireless sensing is an excellent approach for remotely operated solar power system.Not only being able to get the sensor data,such as voltage,current,and temperature,the system can also have a proper control for tracking the Sun and sensing real-time data from a controller.In order to absorb the maximum energy by solar cells,it needs to track the Sun with proper angles.Arduino,H-bridge motor driver circuit,and Direct Current(DC)motor are used to alter the tilt angle of the solar PhotoVoltaic(PV)panel following the Sun while the azimuth and the elevation angles are fixed at noon.Unlike the traditional way,the tilt rotation is proposed to be stepped hourly.The solar PV panel is tilted 7:5∘in advance of current time to the west to produce more output voltage during an hour.As a result,the system is simple while providing good solar-tracking results and efficient power outputs.展开更多
A novel real-time monitoring system for photovoltaic(PV)generation is presented in this paper.Internet of Things(IoT)integrated with cloud servers and terminal applications allow the remote monitoring of centralized o...A novel real-time monitoring system for photovoltaic(PV)generation is presented in this paper.Internet of Things(IoT)integrated with cloud servers and terminal applications allow the remote monitoring of centralized or distributed pho-tovoltaic systems.The proposed system could realize the net-working communication of multiple nodes based on ZigBee,and upload the operational data to the cloud server via a 4G communications network.Then,the server selects three-phase current as the sample sets from the uploaded data to set up a composite current characteristic combining wavelet packet en-ergy with waveform parameter,and establishes a fault diagnosis model based on the probabilistic neural network to analyze the health status of the PV inverter online.This method requires little sampling frequency without an extra signal and saves the cost of local devices by placing online diagnostics on the server-side.In addition,the user could query and store the running information of the PV systems through the personal computer-side web or mobile phone with remote control.This article presents the hardware design of ZigBee and the 4G module,and composition of the diagnosis model for open circuit failure of the PV inverter through the cloud server,building the user software at the application layer.The final experimental results show that the proposed system has better communication performance and higher diagnostic accuracy in real-time monitoring.展开更多
基金provided by the Natinal Basic Research Program of China(No.2012CB026000)
文摘In light of demands for wireless monitoring and the characteristics of wireless channel,a complete deployment method containing channel survey,path loss estimation,and gradient grade of wireless relay nodes is proposed.It can be proved by experiments that under the premise of meeting the requirements of real-time and redundant-topology,the total number of relay nodes could be minimized by using the proposed method.
文摘We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.
文摘Wireless sensing is an excellent approach for remotely operated solar power system.Not only being able to get the sensor data,such as voltage,current,and temperature,the system can also have a proper control for tracking the Sun and sensing real-time data from a controller.In order to absorb the maximum energy by solar cells,it needs to track the Sun with proper angles.Arduino,H-bridge motor driver circuit,and Direct Current(DC)motor are used to alter the tilt angle of the solar PhotoVoltaic(PV)panel following the Sun while the azimuth and the elevation angles are fixed at noon.Unlike the traditional way,the tilt rotation is proposed to be stepped hourly.The solar PV panel is tilted 7:5∘in advance of current time to the west to produce more output voltage during an hour.As a result,the system is simple while providing good solar-tracking results and efficient power outputs.
基金This work was supported in part by the National Natural Science Foundation of China under grant no.51207091the Key Project of National Natural Science Foundation of China under grant no.51637001/E070701.
文摘A novel real-time monitoring system for photovoltaic(PV)generation is presented in this paper.Internet of Things(IoT)integrated with cloud servers and terminal applications allow the remote monitoring of centralized or distributed pho-tovoltaic systems.The proposed system could realize the net-working communication of multiple nodes based on ZigBee,and upload the operational data to the cloud server via a 4G communications network.Then,the server selects three-phase current as the sample sets from the uploaded data to set up a composite current characteristic combining wavelet packet en-ergy with waveform parameter,and establishes a fault diagnosis model based on the probabilistic neural network to analyze the health status of the PV inverter online.This method requires little sampling frequency without an extra signal and saves the cost of local devices by placing online diagnostics on the server-side.In addition,the user could query and store the running information of the PV systems through the personal computer-side web or mobile phone with remote control.This article presents the hardware design of ZigBee and the 4G module,and composition of the diagnosis model for open circuit failure of the PV inverter through the cloud server,building the user software at the application layer.The final experimental results show that the proposed system has better communication performance and higher diagnostic accuracy in real-time monitoring.
