基于ARM的程控直流恒流源设计

发布时间：2018-08-20 18:44

【摘要】：恒流源是现代电子工业和科学实验不可或缺的仪器设备，广泛应用于电子测量、仪表调试、医疗器械和航空航天等领域。随着电子技术的发展，数据采集与处理能力的不断提高，，许多领域对恒流源的稳定度和精密度要求越来越高。只有具备高精度、高稳定度、低纹波、大量程及强可靠性等特点的恒流源，才有更多的实用价值。本毕业论文对可编程直流恒流源的工作原理进行了详细的研究，并设计了一款基于ARM的LPC1114程控恒流源系统。文中给出了具体的软、硬件设计方案和系统调试结果，测试数据表明该恒流源系统实现了高精度、高稳定度和低纹波的恒流输出。整个系统主要包括LPC1114主控电路、线性稳压电源电路、D/A转换电路、恒流输出电路和电压采样电路。在实现过程中，使用NXP公司ARM Cortex-M0核心芯片LPC1114作为主控制器。通过LPC1114内嵌的A/D控制器完成对电压采样值的模数转换，进而将设定的电流值I D与实际输出电流值I L进行比较，并采用PI控制算法对电流偏差值进行调整。如果电流偏差太大，主控制器就将其馈送回恒流电路，恒流电路对电流偏差值作出相应的精度调整后输出、再次采样比较，直至输出电流值逼近设定电流值满足精度，并将结果显示值LCD上。在完成了系统硬件设计和实现、软件设计和程序编写后，对系统性能进行了测试。实验测试结果表明：输出电流范围为200mA到2000mA，系统实现了±2mA的微步进调整，电流测量绝对误差小于0.1％+3mA。系统运行稳定可靠，纹波特性良好，在高精度小功率领域具有较高的实用价值。
[Abstract]:Constant-current source is an indispensable instrument in modern electronic industry and scientific experiment. It is widely used in electronic measurement, instrument debugging, medical device, aerospace and other fields. With the development of electronic technology and the improvement of data acquisition and processing ability, the stability and precision of constant current sources are required more and more in many fields. Only the constant current source with high precision, high stability, low ripple, large number of program and strong reliability can have more practical value. In this thesis, the working principle of programmable DC constant current source is studied in detail, and a LPC1114 program controlled constant current source system based on ARM is designed. The hardware and software design scheme and system debugging results are given in this paper. The test data show that the constant current output with high precision, high stability and low ripple can be achieved by the constant current source system. The whole system mainly includes LPC1114 main control circuit, linear voltage stabilized power supply circuit and D / A conversion circuit, constant current output circuit and voltage sampling circuit. In the process of implementation, NXP ARM Cortex-M0 core chip LPC1114 is used as the main controller. Through the A / D controller embedded in LPC1114, the voltage sampling value A / D conversion is completed, and then the current value I D is compared with the actual output current value I L, and the Pi control algorithm is used to adjust the current deviation value. If the current deviation is too large, the main controller feeds it back to the constant current circuit, and the constant current circuit adjusts the current deviation value to the output, and samples and compares it again, until the output current value approaches the set current value to meet the accuracy. The result is displayed on the value LCD. After the system hardware design and implementation, software design and programming, the system performance was tested. The experimental results show that the output current ranges from 200mA to 2000mA.The system realizes the micro-step adjustment of 卤2mA, and the absolute error of current measurement is less than 0.1% 3mA. The system is stable and reliable, and has good ripple characteristics. It has high practical value in the field of high precision and low power.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN86

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