Design And Implementation Of Direct Current Power Carrier System

Compared with the traditional communication bus technology such as 485 bus,DC power carrier technology has the advantage of combining power supply line and signal line into one,which can reduce the hardware cost and construction complexity.The buses based on this technology,such as Powerbus and AS-I bus,are often based on FPGA or CPLD for protocol control,which is not flexible enough.This paper proposes a method to realize DC power carrier system with MCU as the core.Based on the hidden problem that AS-I bus technology is becoming mature in China but still relies on foreign AS-I4 U chips,the AS-I protocol is selected as the design object of this topic to realize the DC power carrier method,and the DC power carrier system based on the AS-I protocol is implemented independently,using ST’s microprocessor STM32H743 as the MCU,KEIL5 as the development environment,and Altium Designer software.Altium Designer software is used to design the receiver circuit and transmitter circuit to transmit and receive waveforms on the AS-I bus instead of the AS-I chip.The entire system can be divided into two categories: master and slave,both of which have basically the same hardware structure and for which MCU code is written separately.A master station is used to manage multiple slave stations,and the master station adopts a polling method to access each slave station separately and record the current information of each online slave station.In order to further demonstrate the flexibility of the MCU-based system and make up for the shortcomings of the AS-I protocol which is limited in many aspects while meeting industrial needs,this paper improves on the implementation of the AS-I system by changing the MCU program configuration to suit different applications according to specific scenarios.In view of the existing corridor equipment adopting multi-system management and mostly using three-wire system for signal transmission,taking the building corridor intelligent management system as an example,an improved scheme based on AS-I protocol is applied,which still adopts alternating pulse modulation for two-wire transmission in hardware and a custom transmission protocol in software part to centrally manage the communication and power supply of all equipment on the corridor.A heterogeneous data frame transmission method is designed to improve the transmission efficiency of transmission information to analog devices based on the AS-I protocol,enabling the system to meet real-time requirements while managing both analog and switching devices.The main research contents of this paper are as follows.(1)Hardware part,design the transmitting and receiving circuit of AS-I protocol bus transmission waveform,cooperate with MCU to control the working state of receiving and transmitting module,and realize the interconnection with AS-I chip;realize the communication protocol conversion by MCU and the voltage conversion of DC-DC module to the voltage on the bus can realize the interconnection with most of the weak power devices.(2)Software part,the master and slave stations are programmed separately according to the AS-I protocol to realize coding and decoding functions and adaptive control;the hardware part can be fed back to control;the master station adopts the addressing method to poll each slave station,which can automatically identify the slave station and interact with its information.(3)The application part of the system,the transmission voltage is dynamically adjustable and the message transmission protocol is customizable.The application is carried out with the intelligent corridor management system of the building as an example,which realizes the centralized management of equipment communication and power supply on the corridor of the building.This paper mainly introduces the hardware design and software design scheme of DC power carrier system,and extends this system scheme to realize a corridor intelligent management system.