Reliability Improvement of DC-DC Power Converters by Means of Feedback Signals Reserve

The paper deals with the problem of reliability in switching mode DC-DC power converters. The object of the study is voltage feedback circuits. Unexpected failures of these circuits most often occur due to electronic components degradation under harsh operating conditions and mechanical overloads. Such failures cause uncontrolled increase of output voltage and current of power converter. To avoid this, a new method of reserving voltage feedback signals is presented and demonstrated on the basis of flyback topology. Two independent feedback signals are formed both from an optocoupler located on the load side of DC-DC converter and from a power transformer auxiliary winding, together forming two independent output voltage control loops. The validity of the proposed method is confirmed by the results of computer simulation with the use of MatLab/Simulink environment. The obtained results can be used in design of fault-tolerant secondary power supplies that operate in harsh operating conditions.