Research On Cross Regulation Characteristic Of Flyback Power With Multiple Output Port And Its Controlling Technique

As technology continues to progress and develop,high efficiency energy saving and high stability will be the future research subjects of the switch power supply.The switching power supplies,especially the small ones have very good prospect in future development.For the multiply output flyback power converter,owing to the effects of transformer leakage inductance,coil resistance and the parasitic parameters of diodes and capacitors,the actual output voltage will deviate from the nominal output voltage.In this paper we focused on improving the cross regulation of whole power system,took the multiply output auxiliary power supply in the servo motor driver system into consideration.We established the model of a 3-port flyback power converter,analyzed the changing of the loop current in one cycle,built up the mathematical relationship between the pulse voltage and the pre-load,and proposed a method to calculate the pre-load.With this proposed method,we can obtain the value of the pre-load to ensure the improved cross regulation and the requirements in power consumption and efficiency.In addition,we proposed the detailed analysis and calculation method for the relevant transformer parameters in the flyback power converter circuit.Considering that when the switch is turned off,the mutual effect of transformer will result in a high reflected voltage in the primary induction loop which in turn takes effect across the drain source of the switch tube and probably damage the switch tube,a parallel clamping circuit in the primary inductance loop is needed to protect the MOSFET.We analyzed the selection of the components of this clamping circuit and put forward the criteria for component selection and parameter calculation.Finally,we performed simulation analysis for the 3-port output flyback power converter and proved that the output voltage of each output voltage meets the requirements of the circuit design.