Research Of Large Current Measurement For High Magnetic Field Based On Lead-acid Batteries Power

Based on the requirements of High-stability Flat-Top long pulse magnetic,Wuhan National High Magnetic Field Center builds a set of battery type pulse power system to supply power for magnet, in order to realize Flat-top long pulse magnet field of40T above. The whole power system should do real-time monitoring to high DC current which reaches up to intim KA in more than one locations, and this has high demand for data acquisition. After full investigation, we found that the measuring device both at home and abroad which can meet the request has prevalent problems like high cost, complicated system and so on. Accordingly,this thesis designs long pulse high current measurement device with Rogowski coil and integrator as main measurment unit, after testing by thousands of times, the error of integrator itself always lower than1%within100s, it totally meets the test requests of batter type pulse power system and ensure stable and regular performance of the whole system. This thesis mainly involves the test of high DC current, design of integrator with low drift in a long time, implementation of data acquisition, and the application of the measurement device during every test line of the whole power system.On the point of test for high DC current, combined the principle and advantages of Rogowski coils, this thesis determines to use Rogowski coils as tools for current signal test.About the design of integrator, this thesis compares some kinds of integrator frequently used and chooses analog integrator as main integral unit; based on the expected aim of data acquisition system, this thesis fixes the design proposal of integrator; then works out the solution for integral error of integrator and gets the good level of zero drift; also the control system is designed for integral unit, and its function is performanced very well.On the point of data acquisition, this thesis chooses suitable acquisition board with high speed and high accuracy, by matching up with Rogowski coils and integrator, two signals is output from integrator, one channel is applied to data acquisition interface display, the other one channel is applied to real-time protection system for test bug. Finally, the measurement device is applied to the tests of the battery type power supply system, including the performance test of master switch, test of real-time protection system, overall debug test of power system under different magnet load and so on, these entire tests is finished. And a periodical purpose of32T long pulse is realized.