Design Of Bipolar And High-stability DC Magnet Power Supply

With the continuous development of science and technology,electronic products are widely used in industrial production and life.The power supply as an important part has increasingly higher technical indicators and performance requirements.The corrector power supply applied to the accelerator can quickly correct the position of the light beam to improve the quality of the light source.The power of corrector power supply is not high,but it requires very high responding speed and long-term stability.This paper studies and designs a bipolar DC magnet power supply that meets the frequency response bandwidth exceeding 5k Hz and the long-term stability is less than 100 ppm.First,by analyzing the basic control method and performance index of the magnet power supply,and in combination with the technical requirements of the power supply in this paper,a design using a linear power supply was selected to avoid large ripples.The power MOSFET as the core components,its selection basis is analyzed in detail from the classification and characteristics.In terms of loop control,a double closed loop control method is proposed to take into account the requirements of stability and responding speed,while suppressing interference.Then,the power system design is divided into five categories,and the design ideas and methods of the circuits of each part in each category are explained in detail.In order to solve the bipolar output of the power supply,H-bridge are composed of two MOSFETs in switch mode and two MOSFETs in linear mode.At the same time,in order to achieve safe and stable output of the power supply,a filter circuit and a protection circuit are designed.In the control part,the working logic of MCU,sampling circuit,DAC circuit,H-bridge control circuit and communication circuit is analyzed,and a suitable design method is proposed.Through the explanation of the man-machine interface design,the operation method of the power supply is given in detail.Finally,the transfer function of the system loop is simulated in MATLAB,and a test platform is set up to test the performance of the prototype.Among them,the actual performance of the frequency response bandwidth,output ripple,and stability is much higher than the technical requirements,and other functions also meet the index,verifying the feasibility of the design in this paper.