电子式互感器数据传输方法的分析与改进

Analysis and improvement of the methods of data transmission for electronic instrument transformers

分析了当前电子式电压/电流互感器的数据传输方案中存在的问题,在此基础上提出了改进的数据传输方案。方案包括数据传输的硬件结构设计以及串行通信协议。该方案采用CPLD作为通信控制器件,DSP作为接收数据的处理器件,简化了数据采集系统的硬件结构。通过全数字锁相环逻辑从曼彻斯特编码的基带信号中提取位同步信号,位同步精度显著提高,实现了可靠的串行通信。通信提供了可靠的误码检测手段,并对接收错误的数据采用Lagrange线性插值算法进行修复。分析与仿真表明该数据传输方案具有良好的性能。文中最后提供了一套设计实例作为电子式电压/电流互感器数据采集系统的设计参考。

Through analyzing the problems which exist in the data transmission schemes for the present electronic current/voltage transformers products, an improved scheme which includes both the design of hardware system and serial communication protocol is proposed. In the improved scheme, Complex Programmable Logic Device （CPLD） is used to control the serial communication and Digital Signal Processor （DSP） is used to process the received data, and the data acquisition system＇s hardware structure is simplified. By extracting bit-synchronous signal with digital phase locked loop from the base band signal, the accuracy of bit synchronization is improved remarkably, thus a reliable communication is achieved. A reliable error code check method is also provided in the serial communication protocol, And the error data extracted from the error code will be restored by Lagrange linear interpolation. The analysis and simulation prove that the data transmission based on this scheme can achieve a good performance. Finally, a design example is offered as a guide for the data acquisition system design of electronic current/voltage transformers.