Power carrier communication is a unique and basic communication method for power systems. It refers to a technology that uses an existing power line to transmit analog or digital signals at high speed through a carrier. Since the widely used power line is used as the communication channel, no special maintenance channel is required, and the engineering cost is greatly reduced. This technology is widely used in street lighting control, power line security, harsh environment communication, etc., which require long distance and multi-node. However, due to the complexity and diversity of the domestic power grid, for example, when the residential power consumption peaks, a large number of loads are continuously connected and disconnected, which will cause different degrees of attenuation and interference to the carrier signal; when the carrier signal is modulated on the power line At the peak point of each AC cycle, the generated fixed pulse is very easy to lose the signal; and the existing power carrier module is expensive, and requires high-performance MCU support. Therefore, the power carrier needs a lot of research to achieve a wider application [1~2].
The purpose of this paper is to use the FSK modulation technology to realize power carrier communication, optimize the algorithm, provide a function interface, make the power carrier communication easier to use, and ensure the accuracy of communication data transmission is above 96%.
2 system overall design structure
The main function of the system is to realize that the upper computer sends data to the single-chip microcomputer through the serial port, and the single-chip microcomputer modulates the signal by FSK frequency modulation mode, and the carrier signal is coupled to the power line for signal transmission through the push-pull output circuit. At the other node of the power line, the carrier signal is restored to the original signal through the detection input circuit, the power amplifier circuit and the software algorithm, and after verification, it is sent to another host computer through the serial port. Both the signal output and the input provide a functional interface for subsequent development of user engineering [3].
3 system overall software design
　 3.1 System overall software flow chart
When the MCU starts running, after each timer, IO port and system clock are initialized, it will wait for 5s, then detect the corresponding baud rate selection IO port and power carrier mode select IO port to complete all initialization. After the program starts normal operation, the MCU will continuously receive the serial port signal and the power carrier signal, and will forward the signal after receiving the signal check.
â—High-efficiency, energy-saving design, full display of green concept from inside to outside
The system adopts a high-efficiency rectifier, the peak efficiency of the rectifier is greater than 96.2%, and the power consumption of the rectifier sleep is as low as 4W or less.
â—The rectifier module is small in size and high in power density, improving the utilization of cabinet space
â—Fully digital design, more stable performance
The rectifier adopts DSP+MCU dual digital circuit control mode, the system adopts CAN+RS485 dual bus control, the system power supply reliability is higher, and the transmission rate is faster.
High efficiency rectifier
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