Digital Resonant Converter Technology And Its Application In Magnetic Field Power Supply

With more and more application in different fields, the modern switching power supply tends to miniaturization and high frequency development. High frequency can greatly improve the power density of the switching power supply.However,at the same time, high frequency also means high switching losses, which greatly affected the performance of switching power supply, becoming the main obstacle to further improve the power density.Nowadays, with the development of electronic information technology, in many areas (such as communication, liquid crystal display, etc), the demand for power supply performance becomes more and more high, pulse width modulation (PWM) power supply has been unable to meet its requirements.And in order to overcome this shortcoming, people have put forward a variety of resonant power supply.In the accelerator, there are many kinds of power supply.The power supply is mainly controlled by pulse width modulation (PWM) control mode.Pulse frequency modulation (PFM) digital resonant power supply has many advantages such as good stability, high efficiency, high precision and so on.PFM digital resonant power supply is used to replace the traditional small and medium power PWM analog power supply in many fields.In the present case, due to the limitation of the output power of the PFM digital resonant power supply, the main power supply of the accelerator power supply is still the PWM power supply. In this paper, a low voltage and high current digital resonant power supply is designed based on the requirements of the klystron focusing magnet in Linac.In this paper, the voltage and current characteristics of series, parallel, LCC and LLC resonant converter are introduced and compared in detail. Combined with the power supply design requirements, the power converter circuit structure employ the LLC topology with synchronous rectification.The controller part of the DSP control chip use TMS320F28027.Chapter 3 of the paper introduces a unique analysis tool called first harmonic approximation (FHA) for controlling frequency modulation. And the half bridge LLC resonant converter use this analysis tool to establish its model. Then a design process is given about 25A/13V half bridge LLC resonant power supply, including power circuit and digital control circuit design.The functions of control chip,the functions of peripheral modules,and the DSP control software are briefly introduced.Finally, the test data of 25A/13V half bridge LLC resonant power supply is given.