A Single-Cycle Forward-Flybaсk Stabilized DC-DC Voltage Converter Part. 2. Power Stage Control Device

Abstract

The article addresses the development of a single-cycle single-transistor forward-flyback DC voltage converter. The article’s second part shows the features of constructing a secondary power supply source based on a single-cycle single-transistor forward-flyback power converter stage considered in the article’s first part [1]. The power supply is constructed as a closed-loop automatic control system responding to mismatch of the output voltage from its setpoint value based on the principle of subordinate current control. The PWM controller initial starting scheme with its subsequent auxiliary feeding from the power transformer additional windings is proposed. The results of studying the scheme carried out using computer simulation in the OrCAD software are presented. The proposed scheme allows the device to remain operational even with a relatively poor coupling coefficient between the transformer’s power and auxiliary feed windings. In the OrCAD software, a simulation computer model was developed for a secondary power supply source based on the new structure of a single-cycle single-transistor forward-flyback power converter stage with the proposed method for starting the PWM controller. Based on the results obtained from studying the processes running in the secondary power supply source, time diagrams confirming the circuit operability are presented. The simulation has shown that a sufficiently large output power can be obtained on a single-cycle single-transistor forward-flyback power converter stage.