Research On A High-voltage DC Power Supply Based On DSP

High-voltage DC power supply is widely used in various fields.For example,withstanding voltage and insulation resistance test of high voltage electrical equipment;electrostatic precipitator and metal plating in industrial production;medical equipments such as CT machine,X-ray machine,all utilize high-voltage DC power supply.With the development of power electronic technology and control theory,high-voltage power supply with digital control has become a hot research topic.Based on the above background,this thesis mainly focuses on researching and developing high-voltage DC power supply.First of all,Buck chopper is introduced into the main circuit and used to modulate the voltage of high-voltage DC power supply by controlling the duty-cycle.To achieve zero voltage switching device,the transformer leakage inductance is used.Secondly,two-stage set-up system is adopted which aims to reduce the winding turn ratio of high frequency transformer.Bidirectional voltage–multiplying method is used to reduce stage of voltage doubling circuit and improve the stability of the power supply.Meanwhile,the equivalent circuit model of high-frequency transformer is proposed,the method of selecting core material is also mentioned,and the detailed design of high frequency transformer is put forward.Thirdly,the hardware and software design of high-voltage DC power control system is provided.Peripheral circuit of DSP28335,detection circuit,drive circuit and protection circuit are presented in details using DSP28335 as main-controller.Besides,this paper also describes the design about work flow of main program,fuzzy PID controller program,phase shift PWM pulse generation program and protection program.Besides,the fuzzy PID dual mode control is determined as the control strategy.In order to verify the reasonability and compare the advantages anddisadvantages of different controlling strategies,main circuit and controlling circuit of high-voltage DC power supply is simulated with Matlab/Simulink software.At last,experimental analysis is carried out on the experimental prototype of high-voltage DC power supply.The power supply works properly,the design requirements are satisfied basically which verifies the reasonability of these designs.The result shows that the design of the main circuit of high-voltage DC power supply is reasonable and the power transistor realizes zero voltage switching.In addition,the power supply has stable output voltage and small ripple.