A current sharing state detection method for parallel redundant power system based on the spectrum of ripple

Abstract

The current sharing state of the parallel redundant SMPS(Switching Mode Power Supply) in any electronic system is an essential factor that affects the system’s stability. For the diode-based parallel redundant power supply structure, this paper proposes a new power supply current sharing state detection method. This method calculates each branch current out from the frequency spectrum of the ripple wave at the load side, based on the switching frequency characteristics of SMPS and the principle of frequency synthesis. Two sets of experiments are designed to verify the proposed method’s principle and effectiveness. The result shows that the maximum relative error of the branch’s current measurement is less than 7%. In addition, this method has a wide range of application value because it has single-measurement-point and non-intrusive characteristics and dramatically reduces the cost and complexity of the detection system.