Research On High-precision Capacitor Charging Power Supply Based On MOSFET

Non-steady state NMR measuring scheme has the ability to measure the pulsed magnetic field with high precision in a broad span.Hence,the high quality measuring results of field intensity makes it possible for demanding pulsed magnetic field environment scientific research and befits design requirements for pulsed magnet.To optimize the Non-steady state NMR Method,the repeat accuracy of the pulsed external magnetic field is needed to minimize its impacts to the accuracy of NMR Method designing.The high precision charger becomes the necessity to achieve the high repeat accuracy pulsed magnetic field.In this essay,the designed and the developed of a high precision capacitor charging power supply(CCPS)using MOSFET is specified to meet the high repeat-accuracy demands of the pulsed magnetic field.For the requirements of capacitor charging power with high input power factor and fast repeat charging speed.The main circuit structure combined with the previous stage Buck-Boost PFC circuit and the post-stage LCC resonant circuit is proposed,and the corresponding hybrid control strategy is taken as the charging scheme of the capacitor charging power.The working principle of the previous stage Buck-Boost PFC circuit and the working characteristics of the post-stage LCC resonant circuit are analyzed.The four working stages and the realization way of the hybrid control strategy and the closed-loop control of the charging power are described.And verified by MATLAB simulation.In order to improve the anti-jamming performance of the charging power supply and to ensure the charging accuracy,by analyzing the operating characteristics of the MOSFET to optimize the design of the drive circuit and the main circuit layout and the corresponding buffer circuit to reduce the interference of the circuit.For accurate acquisition capacitor voltage signal,use the principle of differential amplification.A high precision and good stability of the acquisition circuit is designed.Finally,according to the above research results,the power supply realization scheme is given,the prototype system of charging power is built and the experiment is tested.The experimental results show that the charging accuracy of the designed and developed capacitor charging power is better than 0.1%,which satisfies the requirement of the Non-steady state NMR test scheme.