Low cost concepts to reduce the voltage ripple of a DC power supply

If the gain of current feedback is low, the short term stability of a magnet power supply will be affected by a soft power line. Typically, the step-change and the imbalance of the three phase power line cause the most serious voltage ripple. Usually, voltage feedback with a coupling transformer is considered to reduce the voltage ripple. However, for the high current power supply, the space and cooling problem of the coupling transformer become inconvenient. In this paper, we suggest to use a toroidal core with a compensation winding, working like a DCCT, as the coupling transformer. Then, a high speed detector of the AC line level is developed. It restricts the voltage ripple passing to the coupling transformer. These methods have the advantage of small size, low power consumption and low cost