Research And Design Of Multi-output Flyback Switching Power

Switching power supply is a kind of power supply that is widely used.The continuous improvement of semiconductor technology has promoted the progress of switching power supply.The power equipment is continuously refined and modularized,the required power quality requirements are continuously improved,and the application environment is gradually diversified.It is very important to design a switching power supply module with good dynamic response and multiple outputs.The main purpose of this article is to design a multi-output flyback switching power supply for inverters that provides 5V,± 12 V DC power.A double closed-loop feedback loop is used to adjust the output voltage so that it can ensure that the output voltage remains unchanged when the input voltage is unstable.A zero-pole compensation network is used to improve dynamic response efficiency and anti-interference ability.The thesis introduces the topology of several commonly used switching power supplies.Through comparison,the appropriate topology is selected based on the application and the required functions,and the detailed parameter analysis of the selected flyback topology is performed.The selection and analysis were performed in the feedback control mode of the power supply.A DSP control chip is used as the main control chip,and the structure of the control chip TMS320F28069 is briefly described.The peripheral circuits of the control chip and the design of the sub-circuits of each system in this design are introduced in detail.The principle block diagram of the system was drawn and analyzed,and the working process was described in detail.Various parameters of the high-frequency transformer,such as the selection of the magnetic core,the radius of the coil wire and the number of turns of the coil winding,were calculated and determined.The design of the compensation network is described in detail.The flyback switch power supply based on the current PWM control mode is poor transient response to this problem,the introduction of a leading phase of loop compensation to optimize the system.The zero-pole compensation amplifier is selected according to the transfer function.The parameters of the amplifier are calculated.Use MATLAB to draw a bode diagram,compare the changes in the graphics before and after adding the compensation network,and analyze the impact on the system after adding the compensation network.Use Simulink in MATLAB to simulate the overall circuit of the system,and check whether its important output voltage can meet expectations.In the end,it is measured that the important output end can meet the output requirement standard,and the system has a certain anti-interference ability.Use Altium Designer software for schematic and PCB drawing.The experimental results of the produced prototype are compared with the simulation values,and test whether the test data meets the requirements..In the end,it was determined through experiments that the produced prototype has basically met the design specifications in terms of output ripple and voltage accuracy,and can be used inside the inverter as its auxiliary power source.