The Design And Research On Monitoring System Of Three-Phase Inverter Based On CAN Bus

Inverter is widely used in industrial applications. With the development of the times, the requirements of inverter power supply are continuously increasing. Currently, the high- performance inverter with comprehensive network functions is required, and be real intelligent devices by network monitor. Based on the 300kw and combined three-phase inverter, this paper researches and designs configuration and implementation of its monitoring system based on CAN bus.This paper analyzes the circuit topologies of three-phase inverter and their respective advantages and disadvantages, and selects the combined three-phase inverter as the target studied . It establishes three mathematical models in ABC,αβand d,q coordinate system, and expounds waveform control technique of instantaneous value PID closed-loop control and repetitive control in synchronous coordinate system.As the design of monitoring system is based on the CAN bus, this paper elaborates the CAN bus technique which is used latter, including CAN bus values, CAN hierarchical structure, communication protocol-coding, CAN bus arbitration technique, principles and methods of error handling. CAN bus arbitration technique and error handling function is prominent advantages of CAN bus, therefore this paper offers a detailed presentation about them.The main tasks of monitoring system designed are collecting field data, transferring timely data collected to monitoring place by CAN bus communication and there making real-time update show of the data and transferring corresponding control signals to inverter according to the data received. This paper analyzes the main functions and requirements of the monitoring system, elaborates ideas and methods of hardware and software in the design of monitoring system. It expounds the realization of CAN Interface Adapter Card between CAN bus and computer in monitoring place, and CAN communication modules in respective inverter; during software design, it expounds the communication protocol of the monitoring system, program flow chart and the key issues within software design : error handling during CAN communication and data packet filtering. Along with the development of science and technology, the real-time demand of monitoring system of three-phase inverter will be increasingly high, CAN bus communication with high baud rate will be trend of the monitoring system design. This paper analyzes the difficulty to achieve CAN bus communication with baud rate maximum value 1Mbps and provides a solution based on CAN bus bit timing and synchronization mechanisms.In order to verify the feasibility of the CAN communication system designed, experiments are made in the laboratory: CAN communication experiment of monitoring system designed, transferring error-data rate experiment and high baud rate experiment, and the experimental results are analyzed. The results show that the communication system can make stable, reliable communications.