Development Of Control System Of Low Voltage And High Current＿Switching Power Supply Based On FPGA

With the rise of new energy industry,switching power supply,as a common power supply,is widely used.High current and high voltage are the two difficult directions for switching power supply.In this paper,focusing on the realization of low voltage and high current,the digital control and power output of the switching power supply are studied in depth.The switching power supply with output voltage 15 V and output current up to 40 amperes is designed.The specific work is as follows:(1)The paper first introduces the design principle of the switching power supply,compares the advantages and disadvantages of various digital control methods,and ultimately selects FPGA as the control core of the switching power supply with moderate difficulty,and introduces the relevant technologies required for the design.According to the design requirements,combined with the advantages and disadvantages of various types of topology of switching power supply,BUCK + half-bridge topology is used to complete the design.(2)In the design of FPGA control systems,DDS and PWM are combined to generate corresponding PWM control signals.At the same time,the output ripple is sampled,and according to its signal characteristics,the PWM waveform is corrected accordingly to ensure the accuracy of the switch power control.A digital control method of staggered phase control is presented by taking advantage of the advantages of the phase control of the digital signal in the field programmable gate array.The simulation and experimental results show that the control method can meet the design requirements.(3)Based on the staggered phase control method,four signals with different phases are generated to control the four-way half-bridge circuit in turn,which avoids the drawbacks of the traditional current-sharing circuit,improves the output current of the switching power supply,and reduces the design difficulty of the switching power supply.Various circuit modules needed in the circuit,such as filter circuit,transformer,voltage collection,current detection,are introduced in detail.The experimental data show that the prototype of switching power supply can output 15V/40 A steadily,with output ripple less than or equal to 150 m V and efficiency > 80%,which meets the design requirements.