基于FPGA的光伏逆变系统数据采集自动化

Automatic data acquisition design of PV inverter system based on FPGA

基于Altera的现场可编程门阵列(field-programmable gate array,FPGA)芯片Cyclone V,文章采用16位高精度、低成本的模数转换芯片AD7656,设计了单相光伏逆变系统的数据采集方案。该方案采集的电气参量包括光伏组件阵列输出的直流电压、直流电流,boost电路输出的直流电压,逆变输出的交流电压,逆变输出的交流电流和并网电流。利用高速硬件描述语言(very-high-speed integrated circuit hardware description language,VHDL)设计了新颖高效的串行外设接口(serial peripheral interface,SPI)控制器,通过FPGA与AD7656控制6路电气数据的同步采集。同时设计了独特的交互式JTAG-CTRL工具和集成电路IP软核模块。将采集顶层IP网表加载到FPGA控制板后,进行光伏逆变系统的自动化脚本配置和数据传输。该系统实现了单相光伏逆变器的数据采集、存储、控制和测试诊断自动化。实验结果表明,设计的采集系统具有较高的精度,电压电流的平均误差达到0.92%,而且在线测量系统工作稳定可靠。

A multi-channel data acquisition scheme for the single-phase photovoltaic（PV） inverter system is designed based on Altera field-programmable gate array（FPGA） chip Cyclone V and 16-bit high-precision and low-cost analog-to-digital conversion chip AD7656. It can be used in single-phase inverters of photovoltaic system where there are six electrical PV parameters including DC output voltage, DC output current, DC output voltage of boost circuit, AC output voltage of inverter, AC output current of inverter and grid-connected AC current. By using very-high-speed integrated circuit hardware description language（VHDL）, a novel serial peripheral interface（SPI） master is designed in FPGA chip to control the AD7656 interface of six-channel data acquisition. Moreover, the developed new and interactive JTAG-CTRL tool and integrated circuit IP soft core can configure the registers of automatic script and also transport these collected data after loading the top net list into FPGA board. The system has implemented the functions of data acquisition, storing, control, automatic test and debug etc. The test results indicate that the designed system has high accuracy with the average error of voltage and current of only 0. 92%, and the on-line measuring system works reliably.