Optimized Simulation Design And Implementation Of The Primary Side Regulated Flyback Converter

Flyback converters are extremely common circuit topologies in switching power supplies and perform well in AC/DC and DC/DC applications.It has a simple structure and low cost,and can achieve the electrical isolation of the primary and secondary sides effectively.It is very suitable for small and medium power appliances.The conventional flyback converters sample the secondary voltage and implement secondary side regulated control with the opticalcoupler equipment and the TL431.This kind of feedback controller has the problems of low lifetime and high cost of opticalcoupler equipment.Moreover,the opticalcoupler equipment and TL431 have complicated structures and large volume,making it difficult to reduce the size of such converters.Therefore,people began to study a new type of primary side regulated technology(PSR).The primary side regulated technology(PSR)is a new type of control technology in recent years.This paper first introduces several existing control methods for primary side regulated,analyzes their working principles,compares and summarizes the advantages and disadvantages of these control methods.Then,this paper introduces the different working modes and control methods of the primary-side regulated flyback converter in detail,and gives the error analysis of its main parameters.This paper uses the state-space averaging method to make a detailed derivation of the small-signal modeling of the primary-side regulated flyback converter.The modeling and simulation are in MATLAB software in this paper.In the process of modeling and simulating the primary-side regulated flyback converter,this paper uses an oscillating filter circuit to filter the oscillation waveform of the inductor discharge.As a result,a better sampling effect is obtained in the sampling period of the inductor discharge time.Finally,the circuit design and parameter calculation of the hardware are carried out.Based on the traditional auxiliary circuit,this paper designs a new type of protection circuit,which is around the protection mechanism of the control chip.The circuit can solve the problem of "hiccup" protection after the chip exits the protection state effectively.In order to verify its practicality,the author implements hardware of the designed circuit and the experimental measurement and analysis of the prototype are carried out.Experimental results show that the primary-side regulated flyback converter has the smaller size,costs less and can still maintain good stability.It has a certain application value.