三维磁场模拟六通道高精度恒流源设计与实现

Design and implementation of six-channel high-precision current source for 3Dmagnetic field simulation

针对舰船磁场测试设计了一种用于模拟三维磁场的六通道高精度恒流源,该恒流源采用微控制器STM32F103和FPGA的双核控制架构,通过USB总线通信实现对恒流源的设置与控制。恒流源包括三路直流通道和三路交流通道。直流恒流源由高精度D/A输出激励电压,控制压控恒流源模块输出;交流恒流源在FPGA内构建DDS核心,生成数字波形序列控制并行D/A输出交流电压信号,驱动压控恒流源模块输出。针对影响恒流源精度的关键因素,采用硬件和软件相结合的校准方法,实现高精度恒流输出。实际测试表明,设计的恒流源6个通道可同时输出,恒流源输出范围1~1 000 mA,绝对误差小于0.14 mA,而且设备体积小,稳定可靠。

A six-channel high-precision constant-current source for simulating 3Dmagnetic field was designed for ship magnetic field testing.This constant-current source adopts the dual-core control architecture of microcontroller STM32F103and FPGA,and realizes the setting and control of constant current source through USB bus communication.The constant-current source was consisted of three DC channels and three AC channels.DC constantcurrent source was driven by high-precision D/A to control voltage-controlled constant-current source output;AC constant-current source built DDS core in FPGA,and generated digital waveform sequence to control parallel D/A output AC voltage signal,and drove voltage-controlled constant-current source output.Aiming at the key factors that affected the accuracy of constant-current source,the calibration method combining hardware and software was adopted to realize high-precision constant-current output.The actual test results showed that the designed constant-current source can output in six channels at the same time,and the output range kept between 1mA^1000mA,the absolute error was less than 0.14mA,and the device was small in size,stable and reliable.