A sensor for balancing flux in converters with a high frequency transformer link

A method for measuring a selected flux threshold below saturation by means of a pick-up winding is presented. The method is illustrated using a block wave oscillator and involves placing a pick-up winding in a square indentation in the center leg of an E-core. Incorporating an air gap, a high reluctance path is created at the area of the indentation. The remaining area saturates first and forces flux through the high reluctance path, which induces a voltage on the pick-up winding. The method was tested experimentally, and a proposed mathematical model was used to simulate the magnetic behavior of the sensor. Experimental and simulated results are presented and compared to verify the operation described. The significance of the sensor introduced here is that detection takes place before saturation occurs and the sensor is integrated in the core